rfc9711.original   rfc9711.txt 
RATS L. Lundblade Internet Engineering Task Force (IETF) L. Lundblade
Internet-Draft Security Theory LLC Request for Comments: 9711 Security Theory LLC
Intended status: Standards Track G. Mandyam Category: Standards Track G. Mandyam
Expires: 10 March 2025 Mediatek USA ISSN: 2070-1721 Mediatek USA
J. O'Donoghue J. O'Donoghue
Qualcomm Technologies Inc. Qualcomm Technologies Inc.
C. Wallace C. Wallace
Red Hound Software, Inc. Red Hound Software, Inc.
6 September 2024 January 2025
The Entity Attestation Token (EAT) The Entity Attestation Token (EAT)
draft-ietf-rats-eat-31
Abstract Abstract
An Entity Attestation Token (EAT) provides an attested claims set An Entity Attestation Token (EAT) provides an attested claims set
that describes state and characteristics of an entity, a device like that describes the state and characteristics of an entity, a device
a smartphone, IoT device, network equipment or such. This claims set such as a smartphone, an Internet of Things (IoT) device, network
is used by a relying party, server or service to determine the type equipment, or such. This claims set is used by a relying party,
and degree of trust placed in the entity. server, or service to determine the type and degree of trust placed
in the entity.
An EAT is either a CBOR Web Token (CWT) or JSON Web Token (JWT) with An EAT is either a CBOR Web Token (CWT) or a JSON Web Token (JWT)
attestation-oriented claims. with attestation-oriented claims.
Status of This Memo Status of This Memo
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction
1.1. Entity Overview . . . . . . . . . . . . . . . . . . . . . 7 1.1. Entity Overview
1.2. EAT as a Framework . . . . . . . . . . . . . . . . . . . 8 1.2. EAT as a Framework
1.3. Operating Model and RATS Architecture . . . . . . . . . . 9 1.3. Operating Model and RATS Architecture
1.3.1. Relationship between Evidence and Attestation 1.3.1. Relationship between Evidence and Attestation Results
Results . . . . . . . . . . . . . . . . . . . . . . . 9 2. Terminology
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 10 3. Top-Level Token Definition
3. Top-Level Token Definition . . . . . . . . . . . . . . . . . 12 4. The Claims
4. The Claims . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.1. eat_nonce (EAT Nonce) Claim
4.1. eat_nonce (EAT Nonce) Claim . . . . . . . . . . . . . . . 14 4.2. Claims Describing the Entity
4.2. Claims Describing the Entity . . . . . . . . . . . . . . 14 4.2.1. ueid (Universal Entity ID) Claim
4.2.1. ueid (Universal Entity ID) Claim . . . . . . . . . . 15 4.2.1.1. Rules for Creating UEIDs
4.2.1.1. Rules for Creating UEIDs . . . . . . . . . . . . 15 4.2.1.2. Rules for Consuming UEIDs
4.2.1.2. Rules for Consuming UEIDs . . . . . . . . . . . . 18 4.2.2. sueids (Semi-permanent UEIDs) Claim (SUEIDs)
4.2.2. sueids (Semi-permanent UEIDs) Claim (SUEIDs) . . . . 18 4.2.3. oemid (Hardware OEM ID) Claim
4.2.3. oemid (Hardware OEM Identification) Claim . . . . . . 19 4.2.3.1. Random Number-Based OEM ID
4.2.3.1. Random Number Based OEM ID . . . . . . . . . . . 19 4.2.3.2. IEEE-Based OEM ID
4.2.3.2. IEEE Based OEM ID . . . . . . . . . . . . . . . . 20 4.2.3.3. IANA Private Enterprise Number-Based OEM ID
4.2.3.3. IANA Private Enterprise Number Based OEM ID . . . 20 4.2.4. hwmodel (Hardware Model) Claim
4.2.4. hwmodel (Hardware Model) Claim . . . . . . . . . . . 21 4.2.5. hwversion (Hardware Version) Claim
4.2.5. hwversion (Hardware Version) Claim . . . . . . . . . 22 4.2.6. swname (Software Name) Claim
4.2.6. swname (Software Name) Claim . . . . . . . . . . . . 22 4.2.7. swversion (Software Version) Claim
4.2.7. swversion (Software Version) Claim . . . . . . . . . 22 4.2.8. oemboot (OEM Authorized Boot) Claim
4.2.8. oemboot (OEM Authorized Boot) Claim . . . . . . . . . 23 4.2.9. dbgstat (Debug Status) Claim
4.2.9. dbgstat (Debug Status) Claim . . . . . . . . . . . . 23 4.2.9.1. Enabled
4.2.9.1. Enabled . . . . . . . . . . . . . . . . . . . . . 24 4.2.9.2. Disabled
4.2.9.2. Disabled . . . . . . . . . . . . . . . . . . . . 24 4.2.9.3. Disabled Since Boot
4.2.9.3. Disabled Since Boot . . . . . . . . . . . . . . . 24 4.2.9.4. Disabled Permanently
4.2.9.4. Disabled Permanently . . . . . . . . . . . . . . 24 4.2.9.5. Disabled Fully and Permanently
4.2.9.5. Disabled Fully and Permanently . . . . . . . . . 25 4.2.10. location (Location) Claim
4.2.10. location (Location) Claim . . . . . . . . . . . . . . 25 4.2.11. uptime (Uptime) Claim
4.2.11. uptime (Uptime) Claim . . . . . . . . . . . . . . . . 26 4.2.12. bootcount (Boot Count) Claim
4.2.12. bootcount (Boot Count) Claim . . . . . . . . . . . . 26 4.2.13. bootseed (Boot Seed) Claim
4.2.13. bootseed (Boot Seed) Claim . . . . . . . . . . . . . 26 4.2.14. dloas (Digital Letters of Approval) Claim
4.2.14. dloas (Digital Letters of Approval) Claim . . . . . . 27 4.2.15. manifests (Software Manifests) Claim
4.2.15. manifests (Software Manifests) Claim . . . . . . . . 28 4.2.16. measurements (Measurements) Claim
4.2.16. measurements (Measurements) Claim . . . . . . . . . . 29 4.2.17. measres (Software Measurement Results) Claim
4.2.17. measres (Software Measurement Results) Claim . . . . 30 4.2.18. submods (Submodules)
4.2.18. submods (Submodules) . . . . . . . . . . . . . . . . 32 4.2.18.1. Submodule Claims-Set
4.2.18.1. Submodule Claims-Set . . . . . . . . . . . . . . 35 4.2.18.2. Detached Submodule Digest
4.2.18.2. Detached Submodule Digest . . . . . . . . . . . 36 4.2.18.3. Nested Tokens
4.2.18.3. Nested Tokens . . . . . . . . . . . . . . . . . 36 4.3. Claims Describing the Token
4.3. Claims Describing the Token . . . . . . . . . . . . . . . 36 4.3.1. iat (Timestamp) Claim
4.3.1. iat (Timestamp) Claim . . . . . . . . . . . . . . . . 37 4.3.2. eat_profile (EAT Profile) Claim
4.3.2. eat_profile (EAT Profile) Claim . . . . . . . . . . . 37 4.3.3. intuse (Intended Use) Claim
4.3.3. intuse (Intended Use) Claim . . . . . . . . . . . . . 38 5. Detached EAT Bundles
5. Detached EAT Bundles . . . . . . . . . . . . . . . . . . . . 38 6. Profiles
6. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . 39 6.1. Format of a Profile Document
6.1. Format of a Profile Document . . . . . . . . . . . . . . 40 6.2. Full and Partial Profiles
6.2. Full and Partial Profiles . . . . . . . . . . . . . . . . 40 6.3. List of Profile Issues
6.3. List of Profile Issues . . . . . . . . . . . . . . . . . 41 6.3.1. Use of JSON, CBOR, or Both
6.3.1. Use of JSON, CBOR or both . . . . . . . . . . . . . . 41 6.3.2. CBOR Map and Array Encoding
6.3.2. CBOR Map and Array Encoding . . . . . . . . . . . . . 41 6.3.3. CBOR String Encoding
6.3.3. CBOR String Encoding . . . . . . . . . . . . . . . . 41 6.3.4. CBOR Preferred Serialization
6.3.4. CBOR Preferred Serialization . . . . . . . . . . . . 42 6.3.5. CBOR Tags
6.3.5. CBOR Tags . . . . . . . . . . . . . . . . . . . . . . 42 6.3.6. COSE/JOSE Protection
6.3.6. COSE/JOSE Protection . . . . . . . . . . . . . . . . 42 6.3.7. COSE/JOSE Algorithms
6.3.7. COSE/JOSE Algorithms . . . . . . . . . . . . . . . . 42 6.3.8. Detached EAT Bundle Support
6.3.8. Detached EAT Bundle Support . . . . . . . . . . . . . 43 6.3.9. Key Identification
6.3.9. Key Identification . . . . . . . . . . . . . . . . . 43 6.3.10. Endorsement Identification
6.3.10. Endorsement Identification . . . . . . . . . . . . . 43 6.3.11. Freshness
6.3.11. Freshness . . . . . . . . . . . . . . . . . . . . . . 44 6.3.12. Claims Requirements
6.3.12. Claims Requirements . . . . . . . . . . . . . . . . . 44 6.4. The Constrained Device Standard Profile
6.4. The Constrained Device Standard Profile . . . . . . . . . 45 7. Encoding and Collected CDDL
7. Encoding and Collected CDDL . . . . . . . . . . . . . . . . . 47 7.1. Claims-Set and CDDL for CWT and JWT
7.1. Claims-Set and CDDL for CWT and JWT . . . . . . . . . . . 47 7.2. Encoding Data Types
7.2. Encoding Data Types . . . . . . . . . . . . . . . . . . . 48 7.2.1. Common Data Types
7.2.1. Common Data Types . . . . . . . . . . . . . . . . . . 48 7.2.2. JSON Interoperability
7.2.2. JSON Interoperability . . . . . . . . . . . . . . . . 48 7.2.3. Labels
7.2.3. Labels . . . . . . . . . . . . . . . . . . . . . . . 49 7.2.4. CBOR Interoperability
7.2.4. CBOR Interoperability . . . . . . . . . . . . . . . . 49 7.3. Collected CDDL
7.3. Collected CDDL . . . . . . . . . . . . . . . . . . . . . 49 7.3.1. Payload CDDL
7.3.1. Payload CDDL . . . . . . . . . . . . . . . . . . . . 49 7.3.2. CBOR-Specific CDDL
7.3.2. CBOR-Specific CDDL . . . . . . . . . . . . . . . . . 54 7.3.3. JSON-Specific CDDL
7.3.3. JSON-Specific CDDL . . . . . . . . . . . . . . . . . 55 8. Privacy Considerations
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 56 8.1. UEID and SUEID Privacy Considerations
8.1. UEID and SUEID Privacy Considerations . . . . . . . . . . 56 8.2. Location Privacy Considerations
8.2. Location Privacy Considerations . . . . . . . . . . . . . 57 8.3. Boot Seed Privacy Considerations
8.3. Boot Seed Privacy Considerations . . . . . . . . . . . . 57 8.4. Replay Protection and Privacy
8.4. Replay Protection and Privacy . . . . . . . . . . . . . . 57 9. Security Considerations
9. Security Considerations . . . . . . . . . . . . . . . . . . . 57 9.1. Claim Trustworthiness
9.1. Claim Trustworthiness . . . . . . . . . . . . . . . . . . 57 9.2. Key Provisioning
9.2. Key Provisioning . . . . . . . . . . . . . . . . . . . . 58 9.2.1. Transmission of Key Material
9.2.1. Transmission of Key Material . . . . . . . . . . . . 58 9.3. Freshness
9.3. Freshness . . . . . . . . . . . . . . . . . . . . . . . . 59 9.4. Multiple EAT Consumers
9.4. Multiple EAT Consumers . . . . . . . . . . . . . . . . . 59 9.5. Detached EAT Bundle Digest Security Considerations
9.5. Detached EAT Bundle Digest Security Considerations . . . 59 9.6. Verification Keys
9.6. Verification Keys . . . . . . . . . . . . . . . . . . . . 60 10. IANA Considerations
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 60
10.1. Reuse of CBOR and JSON Web Token (CWT and JWT) Claims 10.1. Reuse of CBOR and JSON Web Token (CWT and JWT) Claims
Registries . . . . . . . . . . . . . . . . . . . . . . . 60 Registries
10.2. CWT and JWT Claims Registered by This Document . . . . . 60 10.2. CWT and JWT Claims Registered by This Document
10.3. UEID URN Registered by this Document . . . . . . . . . . 67 10.3. UEID URNs Registered by This Document
10.4. CBOR Tag for Detached EAT Bundle Registered by this 10.4. CBOR Tag for Detached EAT Bundle Registered by This
Document . . . . . . . . . . . . . . . . . . . . . . . . 68 Document
10.5. Intended Use Registry . . . . . . . . . . . . . . . . . 68 10.5. Intended Use Registry
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 69 11. References
11.1. Normative References . . . . . . . . . . . . . . . . . . 69 11.1. Normative References
11.2. Informative References . . . . . . . . . . . . . . . . . 72 11.2. Informative References
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 74 Appendix A. Examples
A.1. Claims Set Examples . . . . . . . . . . . . . . . . . . . 75 A.1. Claims Set Examples
A.1.1. Simple TEE Attestation . . . . . . . . . . . . . . . 75 A.1.1. Simple TEE Attestation
A.1.2. Submodules for Board and Device . . . . . . . . . . . 76 A.1.2. Submodules for Board and Device
A.1.3. EAT Produced by Attestation Hardware Block . . . . . 77 A.1.3. EAT Produced by an Attestation Hardware Block
A.1.4. Key / Key Store Attestation . . . . . . . . . . . . . 78 A.1.4. Key / Key Store Attestation
A.1.5. Software Measurements of an IoT Device . . . . . . . 80 A.1.5. Software Measurements of an IoT Device
A.1.6. Attestation Results in JSON . . . . . . . . . . . . . 83 A.1.6. Attestation Results in JSON
A.1.7. JSON-encoded Token with Submodules . . . . . . . . . 83 A.1.7. JSON-Encoded Token with Submodules
A.2. Signed Token Examples . . . . . . . . . . . . . . . . . . 84 A.2. Signed Token Examples
A.2.1. Basic CWT Example . . . . . . . . . . . . . . . . . . 84 A.2.1. Basic CWT Example
A.2.2. CBOR-encoded Detached EAT Bundle . . . . . . . . . . 85 A.2.2. CBOR-Encoded Detached EAT Bundle
A.2.3. JSON-encoded Detached EAT Bundle . . . . . . . . . . 87 A.2.3. JSON-Encoded Detached EAT Bundle
Appendix B. UEID Design Rationale . . . . . . . . . . . . . . . 88 Appendix B. UEID Design Rationale
B.1. Collision Probability . . . . . . . . . . . . . . . . . . 88 B.1. Collision Probability
B.2. No Use of UUID . . . . . . . . . . . . . . . . . . . . . 91 B.2. No Use of UUID
Appendix C. EAT Relation to IEEE.802.1AR Secure Device Identity Appendix C. EAT Relation to IEEE.802.1AR Secure Device Identity
(DevID) . . . . . . . . . . . . . . . . . . . . . . . . . 91 (DevID)
C.1. DevID Used With EAT . . . . . . . . . . . . . . . . . . . 92 C.1. DevID Used with EAT
C.2. How EAT Provides an Equivalent Secure Device Identity . . 92 C.2. How EAT Provides an Equivalent Secure Device Identity
C.3. An X.509 Format EAT . . . . . . . . . . . . . . . . . . . 93 C.3. An X.509 Format EAT
C.4. Device Identifier Permanence . . . . . . . . . . . . . . 93 C.4. Device Identifier Permanence
Appendix D. CDDL for CWT and JWT . . . . . . . . . . . . . . . . 94 Appendix D. CDDL for CWT and JWT
Appendix E. New Claim Design Considerations . . . . . . . . . . 96 Appendix E. New Claim Design Considerations
E.1. Interoperability and Relying Party Orientation . . . . . 96 E.1. Interoperability and Relying Party Orientation
E.2. Operating System and Technology Neutral . . . . . . . . . 96 E.2. Operating System and Technology Neutral
E.3. Security Level Neutral . . . . . . . . . . . . . . . . . 97 E.3. Security Level Neutral
E.4. Reuse of Extant Data Formats . . . . . . . . . . . . . . 97 E.4. Reuse of Extant Data Formats
E.5. Proprietary Claims . . . . . . . . . . . . . . . . . . . 97 E.5. Proprietary Claims
Appendix F. Endorsements and Verification Keys . . . . . . . . . 98 Appendix F. Endorsements and Verification Keys
F.1. Identification Methods . . . . . . . . . . . . . . . . . 99 F.1. Identification Methods
F.1.1. COSE/JWS Key ID . . . . . . . . . . . . . . . . . . . 99 F.1.1. COSE/JWS Key ID
F.1.2. JWS and COSE X.509 Header Parameters . . . . . . . . 99 F.1.2. JWS and COSE X.509 Header Parameters
F.1.3. CBOR Certificate COSE Header Parameters . . . . . . . 99 F.1.3. CBOR Certificate COSE Header Parameters
F.1.4. Claim-Based Key Identification . . . . . . . . . . . 100 F.1.4. Claim-Based Key Identification
Appendix G. Changes from Previous Drafts . . . . . . . . . . . . 100 Contributors
G.1. From draft-ietf-rats-eat-30 . . . . . . . . . . . . . . . 100 Authors' Addresses
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 101
1. Introduction 1. Introduction
An Entity Attestation Token (EAT) is a message made up of claims An Entity Attestation Token (EAT) is a message made up of claims
about an entity. An entity may be a device, some hardware or some about an entity. An entity may be a device, some hardware, or some
software. The claims are ultimately used by a relying party who software. The claims are ultimately used by a relying party who
decides if and how it will interact with the entity. The relying decides if and how it will interact with the entity. The relying
party may choose to trust, not trust or partially trust the entity. party may choose to trust, not trust, or partially trust the entity.
For example, partial trust may be allowing a monetary transaction For example, partial trust may be allowing a monetary transaction
only up to a limit. only up to a limit.
The security model and goal for attestation are unique and are not The security model and goal for attestation are unique and are not
the same as for other security standards like those for server the same as those for other security standards such as server
authentication, user authentication and secured messaging. To give authentication, user authentication, and secured messaging. To give
an example of one aspect of the difference, consider the association an example of one aspect of the difference, consider the association
and life-cycle of key material. For authentication, keys are and life cycle of key material. For authentication, keys are
associated with a user or service and set up by actions performed by associated with a user or service and are set up by actions performed
a user or an operator of a service. For attestation, the keys are by a user or an operator of a service. For attestation, the keys are
associated with specific devices and are configured by device associated with specific devices and are configured by device
manufacturers. The reader is assumed to be familiar with the goals manufacturers. Since the reader is assumed to be familiar with the
and security model for attestation as described in RATS Architecture goals and security model for attestation as described in "Remote
[RFC9334] and are not repeated here. ATtestation procedureS (RATS) Architecture" [RFC9334], they are not
repeated here.
This document defines some common claims that are potentially of This document defines some common claims that are potentially of
broad use. EAT additionally allows proprietary claims and for broad use. EAT additionally allows proprietary claims and for
further claims to be standardized. Here are some examples: further claims to be standardized. Here are some examples:
* Make and model of manufactured consumer device * Make and model of manufactured consumer device
* Make and model of a chip or processor, particularly for a * Make and model of a chip or processor, particularly for a
security-oriented chip security-oriented chip
* Identification and measurement of the software running on a device * Identification and measurement of the software running on a device
* Configuration and state of a device * Configuration and state of a device
* Environmental characteristics of a device like its Global * Environmental characteristics of a device such as its Global
Positioning Sytem (GPS) location Positioning System (GPS) location
* Formal certifications received * Formal certifications received
EAT is constructed to support a wide range of use cases. EAT is constructed to support a wide range of use cases.
No single set of claims can accommodate all use cases so EAT is No single set of claims can accommodate all use cases, so EAT is
constructed as a framework for defining specific attestation tokens constructed as a framework for defining specific attestation tokens
for specific use cases. In particular, EAT provides a profile for specific use cases. In particular, EAT provides a profile
mechanism to be able to clearly specify the claims needed, the mechanism to be able to clearly specify the claims needed, the
cryptographic algorithms that should be used, and other cryptographic algorithms that should be used, and other
characteristics for a particular token and use case. Section 6 characteristics for a particular token and use case. Section 6
describes profile contents and provides a profile that is suitable describes profile contents and provides a profile that is suitable
for constrained device use cases. for constrained device use cases.
The entity's EAT implementation generates the claims and typically The entity's EAT implementation generates the claims and typically
signs them with an attestation key. It is responsible for protecting signs them with an attestation key. It is responsible for protecting
the attestation key. Some EAT implementations will use components the attestation key. Some EAT implementations will use components
with very high resistance to attack like Trusted Platform Modules or with very high resistance to attack such as Trusted Platform Modules
Secure Elements. Others may rely solely on simple software defenses. or Secure Elements. Others may rely solely on simple software
defenses.
Nesting of tokens and claims sets is accommodated for composite Nesting of tokens and claims sets is accommodated for composite
devices that have multiple subsystems. devices that have multiple subsystems.
An EAT may be encoded in either JavaScript Object Notation (JSON) An EAT may be encoded in either JavaScript Object Notation (JSON)
[RFC8259] or Concise Binary Object Representation (CBOR) [RFC8949] as [RFC8259] or Concise Binary Object Representation (CBOR) [RFC8949] as
needed for each use case. EAT is built on CBOR Web Token (CWT) needed for each use case. EAT is built on the CBOR Web Token (CWT)
[RFC8392] and JSON Web Token (JWT) [RFC7519] and inherits all their [RFC8392] and JSON Web Token (JWT) [RFC7519] and inherits all their
characteristics and their security mechanisms. Like CWT and JWT, EAT characteristics and their security mechanisms. Like CWT and JWT, EAT
does not imply any message flow. does not imply any message flow.
Following is a very simple example. It is JSON format for easy The following is a very simple example. It is presented in JSON
reading, but could also be CBOR. Only the Claims-Set, the payload format for easy reading, but it could also be CBOR. Only the Claims-
for the JWT, is shown. Set, the payload for the JWT, is shown.
{ {
"eat_nonce": "MIDBNH28iioisjPy", "eat_nonce": "MIDBNH28iioisjPy",
"ueid": "AgAEizrK3Q", "ueid": "AgAEizrK3Q",
"oemid": 76543, "oemid": 76543,
"swname": "Acme IoT OS", "swname": "Acme IoT OS",
"swversion": "3.1.4" "swversion": "3.1.4"
} }
This example has a nonce for freshness. This nonce is the base64url This example has a nonce for freshness. This nonce is the base64url
encoding of a 12 byte random binary byte string. The ueid is encoding of a 12-byte random binary byte string. The ueid (Universal
effectively a serial number uniquely identifying the device. This Entity ID) is effectively a serial number uniquely identifying the
ueid is the base64url encoding of a 48-bit MAC address preceded by device. This ueid is the base64url encoding of a 48-bit Media Access
the type byte 0x02. The oemid identifies the manufacturer using a Control (MAC) address preceded by the type byte 0x02. The oemid
Private Enterprise Number [PEN]. The software is identified by a (Hardware OEM ID) identifies the manufacturer using a Private
Enterprise Number (PEN) [PEN]. The software is identified by a
simple string name and version. It could be identified by a full simple string name and version. It could be identified by a full
manifest, but this is a minimal example. manifest, but this is a minimal example.
1.1. Entity Overview 1.1. Entity Overview
This document uses the term "entity" to refer to the target of an This document uses the term "entity" to refer to the target of an
EAT. Most of the claims defined in this document are claims about an EAT. Most of the claims defined in this document are claims about an
entity. An entity is equivalent to a target environment in an entity. An entity is equivalent to a target environment in an
attester as defined in [RFC9334]. attester as defined in [RFC9334].
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Submodules allow nesting of EATs and of claims-sets so that such Submodules allow nesting of EATs and of claims-sets so that such
hierarchies can be modeled. hierarchies can be modeled.
An entity is the same as a "system component", as defined in the An entity is the same as a "system component", as defined in the
Internet Security Glossary [RFC4949]. Internet Security Glossary [RFC4949].
Note that [RFC4949] defines "entity" and "system entity" as synonyms, Note that [RFC4949] defines "entity" and "system entity" as synonyms,
and that they may be a person or organization in addition to being a and that they may be a person or organization in addition to being a
system component. In the EAT context, "entity" never refers to a system component. In the EAT context, "entity" never refers to a
person or organization. The hardware and software that implement a person or organization. The hardware and software that implement a
web site server or service may be an entity in the EAT sense, but the website server or service may be an entity in the EAT sense, but the
organization that operates, maintains or hosts the web site is not an organization that operates, maintains, or hosts the website is not an
entity. entity.
Some examples of entities: Some examples of entities:
* A Secure Element * A Secure Element
* A Trusted Execution Environment (TEE) * A Trusted Execution Environment (TEE)
* A network card in a router * A network card in a router
* A router, perhaps with each network card in the router a submodule * A router, perhaps with each network card in the router being a
submodule
* An Internet of Things (IoT) device * An IoT device
* An individual process * An individual process
* An app on a smartphone * An app on a smartphone
* A smartphone with many submodules for its many subsystems * A smartphone with many submodules for its many subsystems
* A subsystem in a smartphone like the modem or the camera * A subsystem in a smartphone such as the modem or the camera
An entity may have strong security defenses against hardware invasive An entity may have strong security defenses against hardware-invasive
attacks. It may also have low security, having no special security attacks. It may also have low security, i.e., having no special
defenses. There is no minimum security requirement to be an entity. security defenses. There is no minimum security requirement to be an
entity.
1.2. EAT as a Framework 1.2. EAT as a Framework
EAT is a framework for defining attestation tokens for specific use EAT is a framework for defining attestation tokens for specific use
cases, not a specific token definition. While EAT is based on and cases, not a specific token definition. While EAT is based on and
compatible with CWT and JWT, it can also be described as: compatible with CWT and JWT, it can also be described as:
* An identification and type system for claims in claims-sets * An identification and type system for claims in claims-sets
* Definitions of common attestation-oriented claims * Definitions of common attestation-oriented claims
* Claims defined in CDDL and serialized using CBOR or JSON * Claims defined in Concise Data Definition Language (CDDL) and
serialized using CBOR or JSON
* Security envelopes based on CBOR Object Signing and Encryption * Security envelopes based on CBOR Object Signing and Encryption
(COSE) and Javascript Object Signing and Encryption (JOSE) (COSE) and JSON Object Signing and Encryption (JOSE)
* Nesting of claims sets and tokens to represent complex and * The nesting of claims sets and tokens to represent complex and
compound devices compound devices
* A profile mechanism for specifying and identifying specific tokens * A profile mechanism for specifying and identifying specific tokens
for specific use cases for specific use cases
EAT uses the name/value pairs the same as CWT and JWT to identify EAT uses name/value pairs to identify individual claims the same way
individual claims. Section 4 defines common attestation-oriented as CWT and JWT. Section 4 defines common attestation-oriented claims
claims that are added to the CWT and JWT IANA registries. As with that have been added to the "CBOR Web Token (CWT) Claims" and "JSON
CWT and JWT, no claims are mandatory and claims not recognized should Web Token Claims" IANA registries. As with CWT and JWT, no claims
be ignored. are mandatory and claims not recognized should be ignored.
Unlike, but compatible with CWT and JWT, EAT defines claims using Unlike (but compatible with) CWT and JWT, EAT defines claims using
Concise Data Definition Language (CDDL) [RFC8610]. In most cases the CDDL [RFC8610]. In most cases, the same CDDL definition is used for
same CDDL definition is used for both the CBOR/CWT serialization and both the CBOR/CWT serialization and the JSON/JWT serialization.
the JSON/JWT serialization.
Like CWT and JWT, EAT uses COSE and JOSE to provide authenticity, Like CWT and JWT, EAT uses COSE and JOSE to provide authenticity,
integrity and optionally confidentiality. EAT places no new integrity, and optionally confidentiality. EAT places no new
restrictions on cryptographic algorithms, retaining all the restrictions on cryptographic algorithms, retaining all the
cryptographic flexibility of CWT, COSE, JWT and JOSE. cryptographic flexibility of CWT, COSE, JWT, and JOSE.
EAT defines a means for nesting tokens and claims sets to accommodate EAT defines a means for nesting tokens and claims sets to accommodate
composite devices that have multiple subsystems and multiple composite devices that have multiple subsystems and multiple
attesters. Tokens with security envelopes or bare claims sets may be attesters. Tokens with security envelopes or bare claims sets may be
embedded in an enclosing token. The nested token and the enclosing embedded in an enclosing token. The nested token and the enclosing
token do not have to use the same encoding (e.g., a CWT may be token do not have to use the same encoding (e.g., a CWT may be
enclosed in a JWT). enclosed in a JWT).
EAT adds the ability to detach claims sets and send them separately EAT adds the ability to detach claims sets and send them separately
from a security-enveloped EAT that contains a digest of the detached from a security-enveloped EAT that contains a digest of the detached
claims set. claims set.
This document registers no media or content types for the This document registers no media or content types for the
identification of the type of EAT, its serialization encoding or identification of the EAT type, serialization encoding, or security
security envelope. The definition and registration of EAT media envelope. The definition and registration of EAT media types are
types is addressed in [EAT.media-types]. addressed in [EAT.media-types].
Finally, the notion of an EAT profile is introduced that facilitates Finally, the notion of an EAT profile that facilitates the creation
the creation of narrowed definitions of EATs for specific use cases of narrowed definitions of EATs for specific use cases in follow-on
in follow-on documents. One basic profile for constrained devices is documents is introduced. One basic profile for constrained devices
normatively defined. is normatively defined.
1.3. Operating Model and RATS Architecture 1.3. Operating Model and RATS Architecture
EAT follows the operational model described in Figure 1 in RATS EAT follows the operational model described in Figure 1 of RATS
Architecture [RFC9334]. To summarize, an attester generates evidence Architecture (Section 3 of [RFC9334]). To summarize, an attester
in the form of a claims set describing various characteristics of an generates evidence in the form of a claims set describing various
entity. Evidence is usually signed by a key that proves the attester characteristics of an entity. Evidence is usually signed by a key
and the evidence it produces are authentic. The claims set either that proves the attester and the evidence it produces are authentic.
includes a received nonce or uses some other means to assure The claims set either includes a received nonce or uses some other
freshness. means to assure freshness.
A verifier confirms an EAT is valid by verifying the signature and A verifier confirms an EAT is valid by verifying the signature and
may vet some claims using reference values. The verifier then may vet some claims using reference values. The verifier then
produces attestation results, which may also be represented as an produces attestation results, which may also be represented as an
EAT. The attestation results are provided to the relying party, EAT. The attestation results are provided to the relying party,
which is the ultimate consumer of the Remote Attestation Procedure. which is the ultimate consumer of the RAT. The relying party uses
The relying party uses the attestation results as needed for its use the attestation results as needed for its use case, perhaps allowing
case, perhaps allowing an entity to access a network, allowing a an entity to access a network, a financial transaction, or such. In
financial transaction or such. In some cases, the verifier and some cases, the verifier and relying party are not distinct entities.
relying party are not distinct entities.
1.3.1. Relationship between Evidence and Attestation Results 1.3.1. Relationship between Evidence and Attestation Results
Any claim defined in this document or in the IANA CWT or JWT registry Any claim defined in this document or in the IANA "CBOR Web Token
may be used in evidence or attestation results. The relationship of (CWT) Claims" or "JSON Web Token Claims" registries may be used in
claims in attestation results to evidence is fundamentally governed evidence or attestation results. The relationship of claims in
by the verifier and the verifier's policy. attestation results to evidence is fundamentally governed by the
verifier and the verifier's policy.
A common use case is for the verifier and its policy to perform A common use case is for the verifier and its policy to perform
checks, calculations and processing with evidence as the input to checks, calculations, and processing with evidence as the input to
produce a summary result in attestation results that indicates the produce a summary result in attestation results that indicates the
overall health and status of the entity. For example, measurements overall health and status of the entity. For example, measurements
in evidence may be compared to reference values the results of which in evidence may be compared to reference values, the results of which
are represented as a simple pass/fail in attestation results. are represented as a simple pass/fail in attestation results.
It is also possible that some claims in the Evidence will be It is also possible that some claims in the evidence will be
forwarded unmodified to the relying party in attestation results. forwarded unmodified to the relying party in attestation results.
This forwarding is subject to the verifier's implementation and This forwarding is subject to the verifier's implementation and
policy. The relying party should be aware of the verifier's policy policy. The relying party should be aware of the verifier's policy
to know what checks it has performed on claims it forwards. to know what checks it has performed on claims it forwards.
The verifier may modify claims it forwards, for example, to implement The verifier may modify claims it forwards, for example, to implement
a privacy preservation functionality. It is also possible the a privacy preservation functionality. It is also possible the
verifier will put claims in the attestation results that give details verifier will put claims in the attestation results that give details
about the entity that it has computed or looked up in a database. about the entity that it has computed or looked up in a database.
For example, the verifier may be able to put an "oemid" claim in the For example, the verifier may be able to put an "oemid" claim in the
attestation results by performing a look up based on a "ueid" claim attestation results by performing a lookup based on a "ueid" claim
(e.g., serial number) it received in evidence. (e.g., serial number) it received in evidence.
This specification does not establish any normative rules for the This specification does not establish any normative rules for the
verifier to follow, as these are a matter of local policy. It is up verifier to follow, as these are a matter of local policy. It is up
to each relying party to understand the processing rules of each to each relying party to understand the processing rules of each
verifier to know how to interpret claims in attestation results. verifier to know how to interpret claims in attestation results.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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In this document, the structure of data is specified in CDDL In this document, the structure of data is specified in CDDL
[RFC8610] [RFC9165]. [RFC8610] [RFC9165].
The examples in Appendix A use CBOR diagnostic notation defined in The examples in Appendix A use CBOR diagnostic notation defined in
Section 8 of [RFC8949] and Appendix G of [RFC8610]. Section 8 of [RFC8949] and Appendix G of [RFC8610].
This document reuses terminology from JWT [RFC7519] and CWT This document reuses terminology from JWT [RFC7519] and CWT
[RFC8392]: [RFC8392]:
base64url-encoded: base64url-encoded is as described in [RFC7515], base64url encoded: As described in [RFC7515], i.e., using a URL- and
i.e., using URL- and filename-safe character set [RFC4648] with filename-safe character set [RFC4648] with all trailing '='
all trailing '=' characters omitted and without the inclusion of characters omitted and without the inclusion of any line breaks,
any line breaks, whitespace, or other additional characters. whitespace, or other additional characters.
Claim: A piece of information asserted about a subject. A claim is Claim: A piece of information asserted about a subject. A claim is
represented as a value and either a name or key to identify it. represented as a value and either a name or a key to identify it.
Claim Name: A unique text string that identifies the claim. It is Claim Name: A unique text string that identifies the claim. It is
used as the claim name for JSON encoding. used as the claim name for JSON encoding.
Claim Key: The CBOR map key used to identify a claim. (The term Claim Key: The CBOR map key used to identify a claim. (The term
"Claim Key" comes from CWT. This document, like COSE, uses the "Claim Key" comes from CWT. This document, like COSE [RFC9052],
term "label" to refer to CBOR map keys to avoid confusion with uses the term "label" to refer to CBOR map keys to avoid confusion
cryptographic keys.) with cryptographic keys.)
Claim Value: The value portion of the claim. A claim value can be Claim Value: The value portion of the claim. A claim value can be
any CBOR data item or JSON value. any CBOR data item or JSON value.
Claims Set: The CBOR map or JSON object that contains the claims Claims Set: The CBOR map or JSON object that contains the claims
conveyed by the CWT or JWT. conveyed by the CWT or JWT.
This document reuses terminology from RATS Architecure [RFC9334]: This document reuses terminology from RATS Architecture [RFC9334]:
Attester: A role performed by an entity (typically a device) whose Attester: A role performed by an entity (typically a device) whose
evidence must be appraised in order to infer the extent to which evidence must be appraised in order to infer the extent to which
the attester is considered trustworthy, such as when deciding the attester is considered trustworthy, such as when deciding
whether it is authorized to perform some operation. whether it is authorized to perform some operation.
Verifier: A role that appraises the validity of evidence about an Verifier: A role that appraises the validity of evidence about an
attester and produces attestation results to be used by a relying attester and produces attestation results to be used by a relying
party. party.
Relying Party: A role that depends on the validity of information Relying Party: A role that depends on the validity of information
about an attester, for purposes of reliably applying application about an attester for purposes of reliably applying application-
specific actions. Compare /relying party/ in [RFC4949]. specific actions. For comparison, see "relying party" in
[RFC4949].
Evidence: A set of claims generated by an attester to be appraised Evidence: A set of claims generated by an attester to be appraised
by a verifier. Evidence may include configuration data, by a verifier. Evidence may include configuration data,
measurements, telemetry, or inferences. measurements, telemetry, or inferences.
Attestation Results: The output generated by a verifier, typically Attestation Results: The output generated by a verifier, typically
including information about an attester, where the verifier including information about an attester, where the verifier
vouches for the validity of the results vouches for the validity of the results.
Reference Values: A set of values against which values of claims can Reference Values: A set of values against which values of claims can
be compared as part of applying an appraisal policy for evidence. be compared as part of applying an appraisal policy for evidence.
Reference Values are sometimes referred to in other documents as Reference values are sometimes referred to in other documents as
known-good values, golden measurements, or nominal values, "known-good values", "golden measurements", or "nominal values",
although those terms typically assume comparison for equality, although those terms typically assume comparison for equality
whereas here reference values might be more general and be used in whereas reference values in this document might be more general
any sort of comparison. and used in any sort of comparison.
Endorsement: A secure statement that an Endorser vouches for the Endorsement: A secure statement that an endorser vouches for the
integrity of an attester's various capabilities such as claims integrity of an attester's various capabilities such as claims
collection and evidence signing. collection and evidence signing.
This document reuses terminology from CDDL [RFC8610]: This document reuses terminology from CDDL [RFC8610]:
Group Socket: refers to the mechanism by which a CDDL definition is Group Socket: The mechanism by which a CDDL definition is extended,
extended, as described in [RFC8610] and [RFC9165] as described in [RFC8610] and [RFC9165].
3. Top-Level Token Definition 3. Top-Level Token Definition
An "EAT" is an encoded (serialized) message the purpose of which is An "EAT" is an encoded (serialized) message, the purpose of which is
to transfer a Claims-Set between two parties. An EAT MUST contain a to transfer a Claims-Set between two parties. An EAT MUST contain a
Claims-Set. In this document an EAT is always a CWT or JWT. Claims-Set. In this document, an EAT is always a CWT or JWT.
An EAT MUST have authenticity and integrity protection. CWT and JWT An EAT MUST have authenticity and integrity protection. CWT and JWT
provide that in this document. provide that in this document.
Further documents may define other encodings and security mechanims Further documents may define other encodings and security mechanisms
for EAT. for EAT.
The identification of a protocol element as an EAT follows the The identification of a protocol element as an EAT follows the
general conventions used for CWTs and JWTs. Identification depends general conventions used for CWTs and JWTs. Identification depends
on the protocol carrying the EAT. In some cases it may be by media on the protocol carrying the EAT. In some cases, it may be by media
type (e.g., in a HTTP Content-Type field). In other cases it may be type (e.g., in an HTTP Content-Type field). In other cases, it may
through use of CBOR tags. There is no fixed mechanism across all use be through use of CBOR tags. There is no fixed mechanism across all
cases. use cases.
This document also defines another message, the detached EAT bundle This document also defines another message, the detached EAT bundle
(see Section 5), which holds a collection of detached claims sets and (see Section 5), which holds a collection of detached claims sets and
an EAT that provides integrity and authenticity protection for them. an EAT that provides integrity and authenticity protection for them.
Detached EAT bundles can be either CBOR or JSON encoded. Detached EAT bundles can be either CBOR or JSON encoded.
The following CDDL defines the top-level $EAT-CBOR-Tagged-Token, The following CDDL defines the top-level $EAT-CBOR-Tagged-Token,
$EAT-CBOR-Untagged-Token and $EAT-JSON-Token-Formats sockets (see $EAT-CBOR-Untagged-Token, and $EAT-JSON-Token-Formats sockets (see
Section 3.9 of [RFC8610]), enabling future token formats to be Section 3.9 of [RFC8610]), enabling future token formats to be
defined. Any new format that plugs into one or more of these sockets defined. Any new format that plugs into one or more of these sockets
MUST be defined by an IETF standards action. Of particular use may MUST be defined by an IETF Standards Action [RFC8126]. Of particular
be a token type that provides no direct authenticity or integrity use may be a token type that provides no direct authenticity or
protection for use with transports mechanisms that do provide the integrity protection for use with transport mechanisms that do
necessary security services [UCCS]. provide the necessary security services [UCCS].
Nesting of EATs is allowed and defined in Section 4.2.18.3. This Nesting of EATs is allowed and defined in Section 4.2.18.3. This
includes the nesting of an EAT that is a different format than the includes the nesting of an EAT that is in a different format than the
enclosing EAT, i.e., the nested EAT may be encoded using CBOR and the enclosing EAT, i.e., the nested EAT may be encoded using CBOR and the
enclosing EAT encoded using JSON or vice versa. The definition of enclosing EAT encoded using JSON or vice versa. The definition of
Nested-Token references the CDDL defined in this section. When new Nested-Token references the CDDL defined in this section. When new
token formats are defined, the means for identification in a nested token formats are defined, the means for identification in a nested
token MUST also be defined. token MUST also be defined.
The top-level CDDL type for CBOR-encoded EATs is EAT-CBOR-Token and The top-level CDDL type for CBOR-encoded EATs is EAT-CBOR-Token and
for JSON is EAT-JSON-Token (while CDDL and CDDL tools provide enough for JSON-encoded EATs is EAT-JSON-Token (while CDDL and CDDL tools
support for shared definitions of most items in this document, they provide enough support for shared definitions of most items in this
do not provide enough support for this sharing at the top level). document, they do not provide enough support for this sharing at the
top level).
EAT-CBOR-Token = $EAT-CBOR-Tagged-Token / $EAT-CBOR-Untagged-Token EAT-CBOR-Token = $EAT-CBOR-Tagged-Token / $EAT-CBOR-Untagged-Token
$EAT-CBOR-Tagged-Token /= CWT-Tagged-Message $EAT-CBOR-Tagged-Token /= CWT-Tagged-Message
$EAT-CBOR-Tagged-Token /= BUNDLE-Tagged-Message $EAT-CBOR-Tagged-Token /= BUNDLE-Tagged-Message
$EAT-CBOR-Untagged-Token /= CWT-Untagged-Message $EAT-CBOR-Untagged-Token /= CWT-Untagged-Message
$EAT-CBOR-Untagged-Token /= BUNDLE-Untagged-Message $EAT-CBOR-Untagged-Token /= BUNDLE-Untagged-Message
EAT-JSON-Token = $EAT-JSON-Token-Formats EAT-JSON-Token = $EAT-JSON-Token-Formats
$EAT-JSON-Token-Formats /= JWT-Message $EAT-JSON-Token-Formats /= JWT-Message
$EAT-JSON-Token-Formats /= BUNDLE-Untagged-Message $EAT-JSON-Token-Formats /= BUNDLE-Untagged-Message
4. The Claims 4. The Claims
This section describes new claims defined for attestation that are to This section describes new claims defined for attestation that have
be added to the CWT [IANA.CWT.Claims] and JWT [IANA.JWT.Claims] IANA been added to the IANA "CBOR Web Token (CWT) Claims"
[IANA.CWT.Claims] and "JSON Web Token Claims" [IANA.JWT.Claims]
registries. registries.
All definitions, requirements, creation and validation procedures, All definitions, requirements, creation and validation procedures,
security considerations, IANA registrations and so on from CWT and security considerations, IANA registrations, and so on from CWT and
JWT carry over to EAT. JWT carry over to EAT.
This section also describes how several extant CWT and JWT claims This section also describes how several extant CWT and JWT claims
apply in EAT. apply in EAT.
The set of claims that an EAT must contain to be considered valid is The set of claims that an EAT must contain to be considered valid is
context dependent and is outside the scope of this specification. context dependent and is outside the scope of this specification.
Specific applications of EATs will require implementations to Specific applications of EATs will require implementations to
understand and process some claims in particular ways. However, in understand and process some claims in particular ways. However, in
the absence of such requirements, all claims that are not understood the absence of such requirements, all claims that are not understood
by implementations MUST be ignored. by implementations MUST be ignored.
CDDL, along with a text description, is used to define each claim CDDL, along with a text description, is used to define each claim
independent of encoding. Each claim is defined as a CDDL group. In independent of encoding. Each claim is defined as a CDDL group. In
Section 7 on encoding, the CDDL groups turn into CBOR map entries and "Encoding and Collected CDDL" (Section 7), the CDDL groups turn into
JSON name/value pairs. CBOR map entries and JSON name/value pairs.
Each claim defined in this document is added to the $$Claims-Set- Each claim defined in this document is added to the $$Claims-Set-
Claims group socket. Claims defined by other specifications MUST Claims group socket. Claims defined by other specifications MUST
also be added to the $$Claims-Set-Claims group socket. also be added to the $$Claims-Set-Claims group socket.
All claims in an EAT MUST use the same encoding except where All claims in an EAT MUST use the same encoding except where
otherwise explicitly stated (e.g., in a CBOR-encoded token, all otherwise explicitly stated (e.g., in a CBOR-encoded token, all
claims must be CBOR-encoded). claims must be encoded with CBOR).
This specification includes a CDDL definition of most of what is This specification includes a CDDL definition of most of what is
defined in [RFC8392]. Similarly, this specification includes CDDL defined in [RFC8392]. Similarly, this specification includes CDDL
for most of what is defined in [RFC7519]. These definitions are in for most of what is defined in [RFC7519]. These definitions are in
Appendix D and are not normative. Appendix D and are not normative.
Each claim described has a unique text string and integer that Each claim described has a unique text string and integer that
identifies it. CBOR-encoded tokens MUST use only the integer for identifies it. CBOR-encoded tokens MUST only use the integer for
claim keys. JSON-encoded tokens MUST use only the text string for claim keys. JSON-encoded tokens MUST only use the text string for
claim names. claim names.
4.1. eat_nonce (EAT Nonce) Claim 4.1. eat_nonce (EAT Nonce) Claim
An EAT nonce is either a byte or text string or an array of byte or An EAT nonce is either a byte, a text string, or an array of bytes or
text strings. The array option supports multistage EAT verification text strings. The array option supports multistage EAT verification
and consumption. and consumption.
A claim named "nonce" was defined and registered with IANA for JWT, A claim named "nonce" was defined for JWT and registered with IANA in
but MUST NOT be used because it does not support multiple nonces. No the "JSON Web Token Claims" registry, but it MUST NOT be used because
previous "nonce" claim was defined for CWT. To distinguish from the it does not support multiple nonces. No previous "nonce" claim was
previously defined JWT "nonce" claim, this claim is named "eat_nonce" defined for CWT. To distinguish from the previously defined JWT
in JSON-encoded EATs. The CWT nonce defined here is intended for "nonce" claim, this claim is named "eat_nonce" in JSON-encoded EATs.
general purpose use and retains the "Nonce" claim name instead of an The CWT nonce defined here is intended for general purpose use and
EAT-specific name. retains the "Nonce" claim name instead of an EAT-specific name.
An EAT nonce MUST have at least 64 bits of entropy. A maximum EAT An EAT nonce MUST have at least 64 bits of entropy. A maximum EAT
nonce size is set to limit the memory required for an implementation. nonce size is set to limit the memory required for an implementation.
All receivers MUST be able to accommodate the maximum size. All receivers MUST be able to accommodate the maximum size.
In CBOR, an EAT nonce is a byte string between 8 and 64 bytes in In CBOR, an EAT nonce is a byte string between 8 and 64 bytes in
length. In JSON, an EAT nonce is a text string between 8 and 88 length. In JSON, an EAT nonce is a text string between 8 and 88
bytes in length. bytes in length.
$$Claims-Set-Claims //= $$Claims-Set-Claims //=
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4.2. Claims Describing the Entity 4.2. Claims Describing the Entity
The claims in this section describe the entity itself. They describe The claims in this section describe the entity itself. They describe
the entity whether they occur in evidence or occur in attestation the entity whether they occur in evidence or occur in attestation
results. See Section 1.3.1 for discussion on how attestation results results. See Section 1.3.1 for discussion on how attestation results
relate to evidence. relate to evidence.
4.2.1. ueid (Universal Entity ID) Claim 4.2.1. ueid (Universal Entity ID) Claim
The "ueid" claim conveys a UEID, which identifies an individual The "ueid" claim conveys a UEID, which identifies an individual
manufactured entity like a mobile phone, a water meter, a Bluetooth manufactured entity such as a mobile phone, water meter, Bluetooth
speaker or a networked security camera. It may identify the entire speaker, or networked security camera. It may identify the entire
entity or a submodule. It does not identify types, models or classes entity or a submodule. It does not identify types, models, or
of entities. It is akin to a serial number, though it does not have classes of entities. It is akin to a serial number, though it does
to be sequential. not have to be sequential.
UEIDs MUST be universally and globally unique across manufacturers UEIDs MUST be universally and globally unique across manufacturers
and countries, as described in Section 4.2.1.1. UEIDs MUST also be and countries, as described in Section 4.2.1.1. UEIDs MUST also be
unique across protocols and systems, as tokens are intended to be unique across protocols and systems, as tokens are intended to be
embedded in many different protocols and systems. No two products embedded in many different protocols and systems. No two products
anywhere, even in completely different industries made by two anywhere, even in completely different industries made by two
different manufacturers in two different countries should have the different manufacturers in two different countries, should have the
same UEID (if they are not global and universal in this way, then same UEID (if they are not global and universal in this way, then
relying parties receiving them will have to track other relying parties receiving them will have to track other
characteristics of the entity to keep entities distinct between characteristics of the entity to keep entities distinct between
manufacturers). manufacturers).
UEIDs are not designed for direct use by humans (e.g., printing on UEIDs are not designed for direct use by humans (e.g., printing on
the case of a device), so no such representation is defined. the case of a device), so no such representation is defined.
There are privacy considerations for UEIDs. See Section 8.1. There are privacy considerations for UEIDs. See Section 8.1.
A Device Identifier URN is registered for UEIDs. See Section 10.3. A Device Identifier (DevID) URN is registered for UEIDs. See
Section 10.3.
$$Claims-Set-Claims //= (ueid-label => ueid-type) $$Claims-Set-Claims //= (ueid-label => ueid-type)
ueid-type = JC<base64-url-text .size (10..44) , bstr .size (7..33)> ueid-type = JC<base64-url-text .size (10..44) , bstr .size (7..33)>
4.2.1.1. Rules for Creating UEIDs 4.2.1.1. Rules for Creating UEIDs
These rules are solely for the creation of UEIDs. The EAT consumer These rules are solely for the creation of UEIDs. The EAT consumer
need not have any awareness of them. need not have any awareness of them.
A UEID is constructed of a single type byte followed by the unique A UEID is constructed of a single type byte followed by the unique
bytes for that type. The type byte assures global uniqueness of a bytes for that type. The type byte assures global uniqueness of a
UEID even if the unique bytes for different types are accidentally UEID even if the unique bytes for different types are accidentally
the same. the same.
UEIDS are variable length to accommodate the types defined here and UEIDS are of variable length to accommodate the types defined here as
future-defined types. well as future-defined types.
UEIDs SHOULD NOT be longer than 33 bytes. If they are longer, there UEIDs SHOULD NOT be longer than 33 bytes. If they are longer, there
is no guarantee that a receiver will be able to accept them. See is no guarantee that a receiver will be able to accept them. See
Appendix B. Appendix B.
A UEID is permanent. It MUST NOT change for a given entity. A UEID is permanent. It MUST NOT change for a given entity.
The different types of UEIDs 1) accommodate different manufacturing The different types of UEIDs 1) accommodate different manufacturing
processes, 2) accommodate small UEIDs, 3) provide an option that does processes, 2) accommodate small UEIDs, and 3) provide an option that
not require registration fees and central administration. does not require registration fees and central administration.
In the unlikely event that a new UEID type is needed, it MUST be In the unlikely event that a new UEID type is needed, it MUST be
defined in a standards-track update to this document. defined in an update to this document on the Standards Track.
A manufacturer of entities MAY use different types for different A manufacturer of entities MAY use different types for different
products. They MAY also change from one type to another for a given products. They MAY also change from one type to another for a given
product or use one type for some items of a given product and another product or use one type for some items of a given product and another
type for other. type for others.
+======+======+=====================================================+ +======+======+=====================================================+
| Type | Type | Specification | | Type | Type | Specification |
| Byte | Name | | | Byte | Name | |
+======+======+=====================================================+ +======+======+=====================================================+
| 0x01 | RAND | This is a 128, 192 or 256-bit random number | | 0x01 | RAND | This is a 128-, 192-, or 256-bit random number |
| | | generated once and stored in the entity. This | | | | generated once and stored in the entity. This |
| | | may be constructed by concatenating enough | | | | may be constructed by concatenating enough |
| | | identifiers to make up an equivalent number of | | | | identifiers to make up an equivalent number of |
| | | random bits and then feeding the concatenation | | | | random bits and then feeding the concatenation |
| | | through a cryptographic hash function. It may | | | | through a cryptographic hash function. It may |
| | | also be a cryptographic quality random number | | | | also be a cryptographic quality random number |
| | | generated once at the beginning of the life of | | | | generated once at the beginning of the life of |
| | | the entity and stored. It MUST NOT be smaller | | | | the entity and stored. It MUST NOT be smaller |
| | | than 128 bits. See the length analysis in | | | | than 128 bits. See the length analysis in |
| | | Appendix B. | | | | Appendix B. |
+------+------+-----------------------------------------------------+ +------+------+-----------------------------------------------------+
| 0x02 | IEEE | This makes use of the device identification | | 0x02 | IEEE | This makes use of the device identification |
| | EUI | scheme operated by the IEEE. An EUI is either | | | EUI | scheme operated by the IEEE. An Extended Unique |
| | | an EUI-48, EUI-60 or EUI-64 and made up of an | | | | Identifier (EUI) is either an EUI-48, EUI-60, or |
| | | OUI, OUI-36 or a CID, different registered | | | | EUI-64 that is made up of an Organizationally |
| | | company identifiers, and some unique per-entity | | | | Unique Identifier (OUI), an OUI-36, or a Company |
| | | identifier. EUIs are often the same as or | | | | ID (CID), which are different registered company |
| | | identifiers and some unique per-entity |
| | | identifiers. EUIs are often the same as or |
| | | similar to MAC addresses. This type includes | | | | similar to MAC addresses. This type includes |
| | | MAC-48, an obsolete name for EUI-48. (Note that | | | | MAC-48, an obsolete name for EUI-48. (Note that |
| | | while entities with multiple network interfaces | | | | while entities with multiple network interfaces |
| | | may have multiple MAC addresses, there is only | | | | may have multiple MAC addresses, there is only |
| | | one UEID for an entity; changeable MAC addresses | | | | one UEID for an entity; changeable MAC addresses |
| | | that do not meet the permanence requirements in | | | | that do not meet the permanence requirements in |
| | | this document MUST NOT be used for the UEID or | | | | this document MUST NOT be used for the UEID or |
| | | SUEID) [IEEE.802-2001], [OUI.Guide]. | | | | Semi-permanent UEID (SUEID).) See |
| | | [IEEE.802-2001] and [OUI.Guide]. |
+------+------+-----------------------------------------------------+ +------+------+-----------------------------------------------------+
| 0x03 | IMEI | This makes use of the International Mobile | | 0x03 | IMEI | This makes use of the International Mobile |
| | | Equipment Identity (IMEI) scheme operated by the | | | | Equipment Identity (IMEI) scheme operated by the |
| | | GSMA. This is a 14-digit identifier consisting | | | | Global System for Mobile Communications |
| | | of an 8-digit Type Allocation Code (TAC) and a | | | | Association (GSMA). This is a 14-digit |
| | | 6-digit serial number allocated by the | | | | identifier consisting of an 8-digit Type |
| | | manufacturer, which SHALL be encoded as byte | | | | Allocation Code (TAC) and a 6-digit serial |
| | | string of length 14 with each byte as the | | | | number allocated by the manufacturer, which |
| | | digit's value (not the ASCII encoding of the | | | | SHALL be encoded as a byte string of length 14 |
| | | digit; the digit 3 encodes as 0x03, not 0x33). | | | | with each byte as the digit's value (not the |
| | | The IMEI value encoded SHALL NOT include Luhn | | | | ASCII encoding of the digit; the digit 3 encodes |
| | | checksum or SVN information. See | | | | as 0x03, not 0x33). The IMEI encoded value |
| | | SHALL NOT include the Luhn checksum or Software |
| | | Version Number (SVN) information. See |
| | | [ThreeGPP.IMEI]. | | | | [ThreeGPP.IMEI]. |
+------+------+-----------------------------------------------------+ +------+------+-----------------------------------------------------+
Table 1: UEID Composition Types Table 1: UEID Composition Types
4.2.1.2. Rules for Consuming UEIDs 4.2.1.2. Rules for Consuming UEIDs
For the consumer, a UEID is solely a globally unique opaque For the consumer, a UEID is solely a globally unique opaque
identifier. The consumer does not and should not have any awareness identifier. The consumer does not and should not have any awareness
of the rules and structure used to achieve global uniqueness. of the rules and structure used to achieve global uniqueness.
All implementations MUST be able to receive UEIDs up to 33 bytes All implementations MUST be able to receive UEIDs up to 33 bytes
long. 33 bytes is the longest defined in this document and gives long. 33 bytes is the longest defined in this document and gives
necessary entropy for probabilistic uniqueness. necessary entropy for probabilistic uniqueness.
The consumer of a UEID MUST treat it as a completely opaque string of The consumer of a UEID MUST treat it as a completely opaque string of
bytes and MUST NOT make any use of its internal structure. The bytes and MUST NOT make any use of its internal structure. The
reasons for this are: reasons for this are:
* UEIDs types vary freely from one manufacturer to the next. * UEID types vary freely from one manufacturer to the next.
* New types of UEIDs may be defined. * New types of UEIDs may be defined.
* The manufacturer of an entity is allowed to change from one type * The manufacturer of an entity is allowed to change from one type
of UEID to another anytime they want. of UEID to another anytime they want.
For example, when the consumer receives a type 0x02 UEID, they should For example, when the consumer receives a type 0x02 UEID, they should
not use the OUI part to identify the manufacturer of the device not use the OUI part to identify the manufacturer of the device
because there is no guarantee all UEIDs will be type 0x02. Different because there is no guarantee all UEIDs will be type 0x02. Different
manufacturers may use different types. A manufacturer may make some manufacturers may use different types. A manufacturer may make some
of their product with one type and others with a different type or of their product with one type and others with a different type or
even change to a different type for newer versions of their product. even change to a different type for newer versions of their product.
Instead, the consumer should use the "oemid" claim. Instead, the consumer should use the "oemid" claim.
4.2.2. sueids (Semi-permanent UEIDs) Claim (SUEIDs) 4.2.2. sueids (Semi-permanent UEIDs) Claim (SUEIDs)
The "sueids" claim conveys one or more semi-permanent UEIDs (SUEIDs). The "sueids" claim conveys one or more semi-permanent UEIDs (SUEIDs).
An SUEID has the same format, characteristics and requirements as a An SUEID has the same format, characteristics, and requirements as a
UEID, but MAY change to a different value on entity life-cycle UEID but MAY change to a different value on entity life-cycle events.
events. An entity MAY have both a UEID and SUEIDs, neither, one or An entity MAY have both a UEID and SUEIDs, neither, or one or the
the other. other.
Examples of life-cycle events are change of ownership, factory reset Examples of life-cycle events are change of ownership, factory reset,
and on-boarding into an IoT device management system. It is beyond and onboarding into an IoT device management system. It is beyond
the scope of this document to specify particular types of SUEIDs and the scope of this document to specify particular types of SUEIDs and
the life-cycle events that trigger their change. An EAT profile MAY the life-cycle events that trigger their change. An EAT profile MAY
provide this specification. provide this specification.
There MAY be multiple SUEIDs. Each has a text string label the There MAY be multiple SUEIDs. Each has a text string label, the
purpose of which is to distinguish it from others. The label MAY purpose of which is to distinguish it from others. The label MAY
name the purpose, application or type of the SUEID. For example, the name the purpose, application, or type of the SUEID. For example,
label for the SUEID used by XYZ Onboarding Protocol could thus be the label for the SUEID used by the XYZ Onboarding Protocol could
"XYZ". It is beyond the scope of this document to specify any SUEID thus be "XYZ". It is beyond the scope of this document to specify
labeling schemes. They are use case specific and MAY be specified in any SUEID labeling schemes. They are use case specific and MAY be
an EAT profile. specified in an EAT profile.
If there is only one SUEID, the claim remains a map and there still If there is only one SUEID, the claim remains a map and there still
MUST be a label. MUST be a label.
An SUEID provides functionality similar to an IEEE LDevID An SUEID provides functionality similar to an IEEE Local Device
[IEEE.802.1AR]. Identifier (LDevID) [IEEE.802.1AR].
There are privacy considerations for SUEIDs. See Section 8.1. There are privacy considerations for SUEIDs; see Section 8.1.
A Device Identifier URN is registered for SUEIDs. See Section 10.3. A DevID URN is registered for SUEIDs; see Section 10.3.
$$Claims-Set-Claims //= (sueids-label => sueids-type) $$Claims-Set-Claims //= (sueids-label => sueids-type)
sueids-type = { sueids-type = {
+ tstr => ueid-type + tstr => ueid-type
} }
4.2.3. oemid (Hardware OEM Identification) Claim 4.2.3. oemid (Hardware OEM ID) Claim
The "oemid" claim identifies the Original Equipment Manufacturer The "oemid" claim identifies the Original Equipment Manufacturer
(OEM) of the hardware. Any of the three forms described below MAY be (OEM) of the hardware. Any of the three forms described below MAY be
used at the convenience of the claim sender. The receiver of this used at the convenience of the claim sender. The receiver of this
claim MUST be able to handle all three forms. claim MUST be able to handle all three forms.
Note that the "hwmodel" claim in Section 4.2.4, the "oemboot" claim Note that the "hwmodel" claim in Section 4.2.4, the "oemboot" claim
in Section 4.2.8 and "dbgstat" claim in Section 4.2.9 depend on this in Section 4.2.8, and the "dbgstat" claim in Section 4.2.9 depend on
claim. this claim.
Sometimes one manufacturer will acquire or merge with another. Sometimes one manufacturer will acquire or merge with another.
Depending on the situation and use case newly manfactured devices may Depending on the situation and use case, newly manufactured devices
continue to use the old OEM ID or switch to a new one. This is left may continue to use the old OEM ID or switch to a new one. This is
to the discretion of the manufacturers, but they should consider how left to the discretion of the manufacturers, but they should consider
it affects the above-mentioned claims and the attestation eco-system how it affects the above-mentioned claims and the attestation
for their devices. The considerations are the same for all three ecosystem for their devices. The considerations are the same for all
forms of this claim. three forms of this claim.
4.2.3.1. Random Number Based OEM ID 4.2.3.1. Random Number-Based OEM ID
The random number based OEM ID MUST be 16 bytes (128 bits) long. The random number-based OEM ID MUST be 16 bytes (128 bits) long.
The OEM may create their own ID by using a cryptographic-quality The OEM may create their own ID by using a cryptographic-quality
random number generator. They would perform this only once in the random number generator. They would perform this only once in the
life of the company to generate the single ID for said company. They life of the company to generate the single ID for said company. They
would use that same ID in every entity they make. This uniquely would use that same ID in every entity they make. This uniquely
identifies the OEM on a statistical basis and is large enough should identifies the OEM on a statistical basis and is large enough should
there be ten billion companies. there be ten billion companies.
In JSON-encoded tokens this MUST be base64url-encoded. In JSON-encoded tokens, this MUST be base64url encoded.
4.2.3.2. IEEE Based OEM ID 4.2.3.2. IEEE-Based OEM ID
The IEEE operates a global registry for MAC addresses and company The IEEE operates a global registry for MAC addresses and company
IDs. This claim uses that database to identify OEMs. The contents IDs. This claim uses that database to identify OEMs. The contents
of the claim may be either an IEEE MA-L, MA-M, MA-S or an IEEE CID of the claim may be either an IEEE MA-L, MA-M, MA-S, or CID
[IEEE-RA]. An MA-L, formerly known as an OUI, is a 24-bit value used [IEEE-RA]. An MA-L (formerly known as an OUI) is a 24-bit value used
as the first half of a MAC address. MA-M similarly is a 28-bit value as the first half of a MAC address. Similarly, MA-M is a 28-bit
uses as the first part of a MAC address, and MA-S, formerly known as value used as the first part of a MAC address, and MA-S (formerly
OUI-36, a 36-bit value. Many companies already have purchased one of known as OUI-36) is a 36-bit value. Many companies already have
these. A CID is also a 24-bit value from the same space as an MA-L, purchased one of these. A CID is also a 24-bit value from the same
but not for use as a MAC address. IEEE has published Guidelines for space as an MA-L but is not for use as a MAC address. IEEE has
Use of EUI, OUI, and CID [OUI.Guide] and provides a lookup service published Guidelines for Use of EUI, OUI, and CID [OUI.Guide] and
[OUI.Lookup]. provides a lookup service [OUI.Lookup].
Companies that have more than one of these IDs or MAC address blocks Companies that have more than one of these IDs or MAC address blocks
SHOULD select one and prefer that for all their entities. SHOULD select one as preferred and use that for all their entities.
Commonly, these are expressed in Hexadecimal Representation as Commonly, these are expressed in hexadecimal representation as
described in [IEEE.802-2001]. It is also called the Canonical described in [IEEE.802-2001]. It is also called the canonical
format. When this claim is encoded the order of bytes in the bstr format. When this claim is encoded, the order of bytes in the bstr
are the same as the order in the Hexadecimal Representation. For is the same as the order in the hexadecimal representation. For
example, an MA-L like "AC-DE-48" would be encoded in 3 bytes with example, an MA-L like "AC-DE-48" would be encoded in 3 bytes with
values 0xAC, 0xDE, 0x48. values 0xAC, 0xDE, and 0x48.
This format is always 3 bytes in size in CBOR. This format is always 3 bytes in size in CBOR.
In JSON-encoded tokens, this MUST be base64url-encoded and always 4 In JSON-encoded tokens, this MUST be base64url encoded and always 4
bytes. bytes.
4.2.3.3. IANA Private Enterprise Number Based OEM ID 4.2.3.3. IANA Private Enterprise Number-Based OEM ID
IANA maintains a registry for Private Enterprise Numbers (PEN) [PEN]. IANA maintains a registry for Private Enterprise Numbers [PEN]. A
A PEN is an integer that identifies an enterprise and may be used to PEN is an integer that identifies an enterprise, and it may be used
construct an object identifier (OID) relative to the following OID to construct an object identifier (OID) relative to the following OID
arc that is managed by IANA: iso(1) identified-organization(3) dod(6) arc that is managed by IANA: iso(1) identified-organization(3) dod(6)
internet(1) private(4) enterprise(1). internet(1) private(4) enterprise(1).
For EAT purposes, only the integer value assigned by IANA as the PEN For EAT purposes, only the integer value assigned by IANA as the PEN
is relevant, not the full OID value. is relevant, not the full OID value.
In CBOR this value MUST be encoded as a major type 0 integer and is In CBOR, this value MUST be encoded as a major type 0 integer and is
typically 3 bytes. In JSON, this value MUST be encoded as a number. typically 3 bytes. In JSON, this value MUST be encoded as a number.
$$Claims-Set-Claims //= ( $$Claims-Set-Claims //= (
oemid-label => oemid-pen / oemid-ieee / oemid-random oemid-label => oemid-pen / oemid-ieee / oemid-random
) )
oemid-pen = int oemid-pen = int
oemid-ieee = JC<oemid-ieee-json, oemid-ieee-cbor> oemid-ieee = JC<oemid-ieee-json, oemid-ieee-cbor>
oemid-ieee-cbor = bstr .size 3 oemid-ieee-cbor = bstr .size 3
oemid-ieee-json = base64-url-text .size 4 oemid-ieee-json = base64-url-text .size 4
oemid-random = JC<oemid-random-json, oemid-random-cbor> oemid-random = JC<oemid-random-json, oemid-random-cbor>
oemid-random-cbor = bstr .size 16 oemid-random-cbor = bstr .size 16
oemid-random-json = base64-url-text .size 24 oemid-random-json = base64-url-text .size 24
4.2.4. hwmodel (Hardware Model) Claim 4.2.4. hwmodel (Hardware Model) Claim
The "hwmodel" claim differentiates hardware models, products and The "hwmodel" claim differentiates hardware models, products, and
variants manufactured by a particular OEM, the one identified by OEM variants manufactured by a particular OEM, namely the one identified
ID in Section 4.2.3. It MUST be unique within a given OEM ID. The by the OEM ID in Section 4.2.3. It MUST be unique within a given OEM
concatenation of the OEM ID and "hwmodel" give a global identifier of ID. The concatenation of the OEM ID and "hwmodel" gives a global
a particular product. The "hwmodel" claim MUST only be present if an identifier of a particular product. The "hwmodel" claim MUST only be
"oemid" claim described in Section 4.2.3 is present. present if an "oemid" claim described in Section 4.2.3 is present.
The granularity of the model identification is for each OEM to The granularity of the model identification is for each OEM to
decide. It may be very granular, perhaps including some version decide. It may be very granular, perhaps including some version
information. It may be very general, perhaps only indicating top- information. It may be very general, perhaps only indicating top-
level products. level products.
The "hwmodel" claim is for use in protocols and not for human The "hwmodel" claim is for use in protocols and not for human
consumption. The format and encoding of this claim should not be consumption. The format and encoding of this claim should not be
human-readable to discourage use other than in protocols. If this human readable to discourage use other than in protocols. If this
claim is to be derived from an already-in-use human-readable claim is to be derived from an already-in-use human-readable
identifier, it can be run through a hash function. identifier, it can be run through a hash function.
There is no minimum length so that an OEM with a very small number of There is no minimum length so that an OEM with a very small number of
models can use a one-byte encoding. The maximum length is 32 bytes. models can use a one-byte encoding. The maximum length is 32 bytes.
All receivers of this claim MUST be able to receive this maximum All receivers of this claim MUST be able to receive this maximum
size. size.
The receiver of this claim MUST treat it as a completely opaque The receiver of this claim MUST treat it as a completely opaque
string of bytes, even if there is some apparent naming or structure. string of bytes, even if there is some apparent naming or structure.
skipping to change at page 22, line 14 skipping to change at line 972
$$Claims-Set-Claims //= ( $$Claims-Set-Claims //= (
hardware-model-label => hardware-model-type hardware-model-label => hardware-model-type
) )
hardware-model-type = JC<base64-url-text .size (4..44), hardware-model-type = JC<base64-url-text .size (4..44),
bytes .size (1..32)> bytes .size (1..32)>
4.2.5. hwversion (Hardware Version) Claim 4.2.5. hwversion (Hardware Version) Claim
The "hwversion" claim is a text string the format of which is set by The "hwversion" claim is a text string, of which the format is set by
each manufacturer. The structure and sorting order of this text each manufacturer. The structure and sorting order of this text
string can be specified using the version-scheme item from CoSWID string can be specified using the version-scheme item from Concise
[RFC9393]. It is useful to know how to sort versions so the newer Software Identification (CoSWID) [RFC9393]. It is useful to know how
can be distinguished from the older. A "hwversion" claim MUST only to sort versions so the newer ones can be distinguished from the
be present if a "hwmodel" claim described in Section 4.2.4 is older ones. A "hwversion" claim MUST only be present if a "hwmodel"
present. claim, as described in Section 4.2.4, is present.
$$Claims-Set-Claims //= ( $$Claims-Set-Claims //= (
hardware-version-label => hardware-version-type hardware-version-label => hardware-version-type
) )
hardware-version-type = [ hardware-version-type = [
version: tstr, version: tstr,
? scheme: $version-scheme ? scheme: $version-scheme
] ]
4.2.6. swname (Software Name) Claim 4.2.6. swname (Software Name) Claim
The "swname" claim contains a very simple free-form text value for The "swname" claim contains a very simple free-form text value for
naming the software used by the entity. Intentionally, no general naming the software used by the entity. Intentionally, no general
rules or structure are set. This will make it unsuitable for use rules or structure are set. This will make it unsuitable for use
cases that wish precise naming. cases that wish precise naming.
If precise and rigourous naming of the software for the entity is If precise and rigorous naming of the software for the entity is
needed, the "manifests" claim described in Section 4.2.15 may be used needed, the "manifests" claim, as described in Section 4.2.15, may be
instead. used instead.
$$Claims-Set-Claims //= ( sw-name-label => tstr ) $$Claims-Set-Claims //= ( sw-name-label => tstr )
4.2.7. swversion (Software Version) Claim 4.2.7. swversion (Software Version) Claim
The "swversion" claim makes use of the CoSWID version-scheme defined The "swversion" claim makes use of the CoSWID version-scheme defined
in [RFC9393] to give a simple version for the software. A in [RFC9393] to give a simple version for the software. A
"swversion" claim MUST only be present if a "swname" claim described "swversion" claim MUST only be present if a "swname" claim, as
in Section 4.2.6 is present. described in Section 4.2.6, is present.
The "manifests" claim Section 4.2.15 may be instead if this is too The "manifests" claim (Section 4.2.15) may be used instead if this is
simple. too simple.
$$Claims-Set-Claims //= (sw-version-label => sw-version-type) $$Claims-Set-Claims //= (sw-version-label => sw-version-type)
sw-version-type = [ sw-version-type = [
version: tstr version: tstr
? scheme: $version-scheme ? scheme: $version-scheme
] ]
4.2.8. oemboot (OEM Authorized Boot) Claim 4.2.8. oemboot (OEM Authorized Boot) Claim
An "oemboot" claim with value of true indicates the entity booted An "oemboot" claim with a value of "true" indicates that the entity
with software authorized by the manufacturer of the entity as booted with software authorized by the manufacturer of the entity as
indicated by the "oemid" claim described in Section 4.2.3. It indicated by the "oemid" claim described in Section 4.2.3. It
indicates the firmware and operating system are fully under control indicates that the firmware and operating system are fully under
of the OEM and may not be replaced by the end user or even the control of the OEM and may not be replaced by the end user or even
enterprise that owns the device. The means of control may be by the enterprise that owns the device. The means of control may be by
cryptographic authentication of the software, by the software being cryptographic authentication of the software, the software being in
in Read-Only Memory (ROM), a combination of the two or other. If Read-Only Memory (ROM), a combination of the two, or other. If this
this claim is present the "oemid" claim MUST be present. claim is present, the "oemid" claim MUST be present.
$$Claims-Set-Claims //= (oem-boot-label => bool) $$Claims-Set-Claims //= (oem-boot-label => bool)
4.2.9. dbgstat (Debug Status) Claim 4.2.9. dbgstat (Debug Status) Claim
The "dbgstat" claim applies to entity-wide or submodule-wide debug The "dbgstat" claim applies to entity-wide or submodule-wide debug
facilities of the entity like [JTAG] and diagnostic hardware built facilities of the entity like [JTAG] and diagnostic hardware built
into chips. It applies to any software debug facilities related to into chips. It applies to any software debug facilities related to
privileged software that allows system-wide memory inspection, privileged software that allows system-wide memory inspection,
tracing or modification of non-system software like user mode tracing, or modification of non-system software like user-mode
applications. applications.
This characterization assumes that debug facilities can be enabled This characterization assumes that debug facilities can be enabled
and disabled in a dynamic way or be disabled in some permanent way, and disabled in a dynamic way or be disabled in some permanent way,
such that no enabling is possible. An example of dynamic enabling is such that no enabling is possible. An example of dynamic enabling is
one where some authentication is required to enable debugging. An one where some authentication is required to enable debugging. An
example of permanent disabling is blowing a hardware fuse in a chip. example of permanent disabling is blowing a hardware fuse in a chip.
The specific type of the mechanism is not taken into account. For The specific type of the mechanism is not taken into account. For
example, it does not matter if authentication is by a global password example, it does not matter if authentication is by a global password
or by per-entity public keys. or by per-entity public keys.
skipping to change at page 24, line 5 skipping to change at line 1061
As with all claims, the absence of the "dbgstat" claim means it is As with all claims, the absence of the "dbgstat" claim means it is
not reported. not reported.
This claim is not extensible so as to provide a common interoperable This claim is not extensible so as to provide a common interoperable
description of debug status. If a particular implementation description of debug status. If a particular implementation
considers this claim to be inadequate, it can define its own considers this claim to be inadequate, it can define its own
proprietary claim. It may consider including both this claim as a proprietary claim. It may consider including both this claim as a
coarse indication of debug status and its own proprietary claim as a coarse indication of debug status and its own proprietary claim as a
refined indication. refined indication.
The higher levels of debug disabling requires that all debug The higher levels of debug disabling require that all debug disabling
disabling of the levels below it be in effect. Since the lowest of the levels below it be in effect. Since the lowest level requires
level requires that all of the target's debug be currently disabled, that all of the target's debug be currently disabled, all other
all other levels require that too. levels require that too.
There is no inheritance of claims from a submodule to a superior There is no inheritance of claims from a submodule to a superior
module or vice versa. There is no assumption, requirement or module or vice versa. There is no assumption, requirement, or
guarantee that the target of a superior module encompasses the guarantee that the target of a superior module encompasses the
targets of submodules. Thus, every submodule must explicitly targets of submodules. Thus, every submodule must explicitly
describe its own debug state. The receiver of an EAT MUST NOT assume describe its own debug state. The receiver of an EAT MUST NOT assume
that debug is turned off in a submodule because there is a claim that debug is turned off in a submodule because there is a claim
indicating it is turned off in a superior module. indicating it is turned off in a superior module.
An entity may have multiple debug facilities. The use of plural in An entity may have multiple debug facilities. The use of plural in
the description of the states refers to that, not to any aggregation the description of the states refers to that, not to any aggregation
or inheritance. or inheritance.
skipping to change at page 24, line 38 skipping to change at line 1094
4.2.9.1. Enabled 4.2.9.1. Enabled
If any debug facility, even manufacturer hardware diagnostics, is If any debug facility, even manufacturer hardware diagnostics, is
currently enabled, then this level must be indicated. currently enabled, then this level must be indicated.
4.2.9.2. Disabled 4.2.9.2. Disabled
This level indicates all debug facilities are currently disabled. It This level indicates all debug facilities are currently disabled. It
may be possible to enable them in the future. It may also be that may be possible to enable them in the future. It may also be that
they were enabled in the past, but they are currently disabled. they were enabled in the past but are currently disabled.
4.2.9.3. Disabled Since Boot 4.2.9.3. Disabled Since Boot
This level indicates all debug facilities are currently disabled and This level indicates all debug facilities are currently disabled and
have been so since the entity booted/started. have been so since the entity booted/started.
4.2.9.4. Disabled Permanently 4.2.9.4. Disabled Permanently
This level indicates all non-manufacturer facilities are permanently This level indicates all non-manufacturer facilities are permanently
disabled such that no end user or developer can enable them. Only disabled such that no end user or developer can enable them. Only
skipping to change at page 25, line 29 skipping to change at line 1134
disabled = JC< "disabled", 1 > disabled = JC< "disabled", 1 >
disabled-since-boot = JC< "disabled-since-boot", 2 > disabled-since-boot = JC< "disabled-since-boot", 2 >
disabled-permanently = JC< "disabled-permanently", 3 > disabled-permanently = JC< "disabled-permanently", 3 >
disabled-fully-and-permanently = disabled-fully-and-permanently =
JC< "disabled-fully-and-permanently", 4 > JC< "disabled-fully-and-permanently", 4 >
4.2.10. location (Location) Claim 4.2.10. location (Location) Claim
The "location" claim gives the geographic position of the entity from The "location" claim gives the geographic position of the entity from
which the attestation originates. Latitude, longitude, altitude, which the attestation originates. Latitude, longitude, altitude,
accuracy, altitude-accuracy, heading and speed MUST be as defined in accuracy, altitude-accuracy, heading, and speed MUST be as defined in
the W3C Geolocation API [W3C.GeoLoc] (which, in turn, is based on the W3C Geolocation API [W3C.GeoLoc] (which, in turn, is based on
[WGS84]). If the entity is stationary, the heading is NaN (floating- [WGS84]). If the entity is stationary, the heading is Not a Number
point not-a-number). Latitude and longitude MUST be provided. If (NaN) (i.e., a floating-point NaN). Latitude and longitude MUST be
any other of these values are unknown, they are omitted. provided. If any other of these values are unknown, they are
omitted.
The location may have been cached for a period of time before token The location may have been cached for a period of time before token
creation. For example, it might have been minutes or hours or more creation. For example, it might have been minutes, hours, or more
since the last contact with a GNSS satellite. Either the timestamp since the last contact with a Global Navigation Satellite System
or age data item can be used to quantify the cached period. The (GNSS) satellite. Either the timestamp or the age data item can be
timestamp data item is preferred as it a non-relative time. If the used to quantify the cached period. The timestamp data item is
entity has no clock or the clock is unset but has a means to measure preferred as it is a non-relative time. If the entity has no clock
the time interval between the acquisition of the location and the or the clock is unset but has a means to measure the time interval
token creation the age may be reported instead. The age is in between the acquisition of the location and the token creation, the
seconds. age may be reported instead. The age is in seconds.
See location-related privacy considerations in Section 8.2. See location-related privacy considerations in Section 8.2.
$$Claims-Set-Claims //= (location-label => location-type) $$Claims-Set-Claims //= (location-label => location-type)
location-type = { location-type = {
latitude => number, latitude => number,
longitude => number, longitude => number,
? altitude => number, ? altitude => number,
? accuracy => number, ? accuracy => number,
skipping to change at page 26, line 38 skipping to change at line 1186
4.2.11. uptime (Uptime) Claim 4.2.11. uptime (Uptime) Claim
The "uptime" claim contains the number of seconds that have elapsed The "uptime" claim contains the number of seconds that have elapsed
since the entity or submodule was last booted. since the entity or submodule was last booted.
$$Claims-Set-Claims //= (uptime-label => uint) $$Claims-Set-Claims //= (uptime-label => uint)
4.2.12. bootcount (Boot Count) Claim 4.2.12. bootcount (Boot Count) Claim
The "bootcount" claim contains a count of the number times the entity The "bootcount" claim contains a count of the number of times the
or submodule has been booted. Support for this claim requires a entity or submodule has been booted. Support for this claim requires
persistent storage on the device. a persistent storage on the device.
$$Claims-Set-Claims //= (boot-count-label => uint) $$Claims-Set-Claims //= (boot-count-label => uint)
4.2.13. bootseed (Boot Seed) Claim 4.2.13. bootseed (Boot Seed) Claim
The "bootseed" claim contains a value created at system boot time The "bootseed" claim contains a value created at system boot time
that allows differentiation of attestation reports from different that allows differentiation of attestation reports from different
boot sessions of a particular entity (e.g., a certain UEID). boot sessions of a particular entity (e.g., a certain UEID).
This value is usually public. It is not a secret and MUST NOT be This value is usually public. It is not a secret and MUST NOT be
used for any purpose that a secret seed is needed, such as seeding a used for any purpose where a secret seed is needed, such as seeding a
random number generator. random number generator.
There are privacy considerations for this claim. See Section 8.3. There are privacy considerations for this claim; see Section 8.3.
$$Claims-Set-Claims //= (boot-seed-label => binary-data) $$Claims-Set-Claims //= (boot-seed-label => binary-data)
4.2.14. dloas (Digital Letters of Approval) Claim 4.2.14. dloas (Digital Letters of Approval) Claim
The "dloas" claim conveys one or more Digital Letters of Approval The "dloas" claim conveys one or more Digital Letters of Approval
(DLOAs). A DLOA [DLOA] is a document that describes a certification (DLOAs). A DLOA [DLOA] is a document that describes a certification
that an entity has received. Examples of certifications represented that an entity has received. Examples of certifications represented
by a DLOA include those issued by Global Platform [GP-Example] and by a DLOA include those issued by GlobalPlatform [GP-Example] and
those based on Common Criteria [CC-Example]. The DLOA is unspecific those based on Common Criteria [CC-Example]. The DLOA is unspecific
to any particular certification type or those issued by any to any particular certification type or those issued by any
particular organization. particular organization.
This claim is typically issued by a verifier, not an attester. This claim is typically issued by a verifier, not an attester.
Verifiers MUST NOT issue this claim unless the entity has received Verifiers MUST NOT issue this claim unless the entity has received
the certification indicated by the DLOA. the certification indicated by the DLOA.
This claim MAY contain more than one DLOA. If multiple DLOAs are This claim MAY contain more than one DLOA. If multiple DLOAs are
present, verifiers MUST NOT issue this claim unless the entity has present, verifiers MUST NOT issue this claim unless the entity has
skipping to change at page 27, line 36 skipping to change at line 1233
DLOA documents are always fetched from a registrar that stores them. DLOA documents are always fetched from a registrar that stores them.
This claim contains several data items used to construct a Uniform This claim contains several data items used to construct a Uniform
Resource Locator (URL) for fetching the DLOA from the particular Resource Locator (URL) for fetching the DLOA from the particular
registrar. registrar.
This claim MUST be encoded as an array with either two or three This claim MUST be encoded as an array with either two or three
elements. The first element MUST be the URL for the registrar. The elements. The first element MUST be the URL for the registrar. The
second element MUST be a platform label indicating which platform was second element MUST be a platform label indicating which platform was
certified. If the DLOA applies to an application, then the third certified. If the DLOA applies to an application, then the third
element is added which MUST be an application label. The method of element is added, which MUST be an application label. The method of
constructing the registrar URL, platform label and possibly constructing the registrar URL, platform label, and possibly
application label is specified in [DLOA]. application label is specified in [DLOA].
The retriever of a DLOA MUST follow the recommendation in [DLOA] and The retriever of a DLOA MUST follow the recommendation in [DLOA] and
use TLS or some other means to be sure the DLOA registrar they are use Transport Layer Security (TLS) or some other means to be sure the
accessing is authentic. The platform and application labels in the DLOA registrar they are accessing is authentic. The platform and
claim indicate the correct DLOA for the entity. application labels in the claim indicate the correct DLOA for the
entity.
$$Claims-Set-Claims //= ( $$Claims-Set-Claims //= (
dloas-label => [ + dloa-type ] dloas-label => [ + dloa-type ]
) )
dloa-type = [ dloa-type = [
dloa_registrar: general-uri dloa_registrar: general-uri
dloa_platform_label: text dloa_platform_label: text
? dloa_application_label: text ? dloa_application_label: text
] ]
4.2.15. manifests (Software Manifests) Claim 4.2.15. manifests (Software Manifests) Claim
The "manifests" claim contains descriptions of software present on The "manifests" claim contains descriptions of software present on
the entity. These manifests are installed on the entity when the the entity. These manifests are installed on the entity when the
software is installed or are created as part of the installation software is installed or are created as part of the installation
process. Installation is anything that adds software to the entity, process. Installation is anything that adds software to the entity,
possibly factory installation, the user installing elective possibly factory installation, the user installing elective
applications and so on. The defining characteristic of a manifest is applications, and so on. The defining characteristic of a manifest
that it is created by the software manufacturer. The purpose of this is that it is created by the software manufacturer. The purpose of
claim is to relay unmodified manifests to the verifier and possibly this claim is to relay unmodified manifests to the verifier and
to the relying party. possibly to the relying party.
Some manifests are signed by their software manufacturer Some manifests are signed by their software manufacturer
independently, and some are not either because they do not support independently, and some are not because either they do not support
signing or the manufacturer chose not to sign them. For example, a signing or the manufacturer chose not to sign them. For example, a
CoSWID might be signed independently before it is included in an EAT. CoSWID might be signed independently before it is included in an EAT.
When signed manifests are put into an EAT, the manufacturer's When signed manifests are put into an EAT, the manufacturer's
signature SHOULD be included even though an EAT's signature will also signature SHOULD be included even though an EAT's signature will also
cover the manifest. This allows the receiver to directly verify the cover the manifest. This allows the receiver to directly verify the
manufacturer-originated manifest. manufacturer-originated manifest.
This claim allows multiple manifest formats. For example, the This claim allows multiple manifest formats. For example, the
manifest may be a CBOR-encoded CoSWID, an XML-encoded SWID or other. manifest may be a CBOR-encoded CoSWID, an XML-encoded Software
Identification of the type of manifest is always by a Constrained Identification (SWID), or other. Identification of the type of
Application Protocol (CoAP) Content-Format integer [RFC7252]. If manifest is always by a Constrained Application Protocol (CoAP)
there is no CoAP identifier registered for a manifest format, one Content-Format integer [RFC7252]. If there is no CoAP identifier
MUST be registered. registered for a manifest format, one MUST be registered.
This claim MUST be an array of one or more manifests. Each manifest This claim MUST be an array of one or more manifests. Each manifest
in the claim MUST be an array of two. The first item in the array of in the claim MUST be an array of two. The first item in the array of
two MUST be an integer CoAP Content-Format identifier. The second two MUST be an integer CoAP Content-Format identifier. The second
item is MUST be the actual manifest. item is MUST be the actual manifest.
In JSON-encoded tokens the manifest, whatever encoding it is, MUST be In JSON-encoded tokens, the manifest, whatever encoding it is, MUST
placed in a text string. When a non-text encoded manifest like a be placed in a text string. When a non-text encoded manifest such as
CBOR-encoded CoSWID is put in a JSON-encoded token, the manifest MUST a CBOR-encoded CoSWID is put in a JSON-encoded token, the manifest
be base-64 encoded. MUST be base64 encoded.
This claim allows for multiple manifests in one token since multiple This claim allows for multiple manifests in one token since multiple
software packages are likely to be present. The multiple manifests software packages are likely to be present. The multiple manifests
MAY be of different encodings. In some cases EAT submodules may be MAY be of different encodings. In some cases, EAT submodules may be
used instead of the array structure in this claim for multiple used instead of the array structure in this claim for multiple
manifests. manifests.
A CoSWID manifest MUST be a payload CoSWID, not an evidence CoSWID. A CoSWID manifest MUST be a payload CoSWID, not an evidence CoSWID.
These are defined in [RFC9393]. These are defined in [RFC9393].
This claim is extensible for use of manifest formats beyond those This claim is extensible for use of manifest formats beyond those
mentioned in this document. No particular manifest format is mentioned in this document. No particular manifest format is
preferred. For manifest interoperability, an EAT profile as defined preferred. For manifest interoperability, an EAT profile, as defined
in Section 6, should be used to specify which manifest format(s) are in Section 6, should be used to specify which manifest format(s) is
allowed. allowed.
$$Claims-Set-Claims //= ( $$Claims-Set-Claims //= (
manifests-label => manifests-type manifests-label => manifests-type
) )
manifests-type = [+ manifest-format] manifests-type = [+ manifest-format]
manifest-format = [ manifest-format = [
content-type: coap-content-format, content-type: coap-content-format,
content-format: JC< $manifest-body-json, content-format: JC< $manifest-body-json,
$manifest-body-cbor > $manifest-body-cbor >
] ]
$manifest-body-cbor /= bytes .cbor untagged-coswid $manifest-body-cbor /= bytes .cbor untagged-coswid
$manifest-body-json /= base64-url-text $manifest-body-json /= base64-url-text
4.2.16. measurements (Measurements) Claim 4.2.16. measurements (Measurements) Claim
The "measurements" claim contains descriptions, lists, evidence or The "measurements" claim contains descriptions, lists, evidence, or
measurements of the software that exists on the entity or any other measurements of the software that exists on the entity or on any
measurable subsystem of the entity (e.g. hash of sections of a file other measurable subsystem of the entity (e.g., hash of sections of a
system or non-volatile memory). The defining characteristic of this file system or non-volatile memory). The defining characteristic of
claim is that its contents are created by processes on the entity this claim is that its contents are created by processes on the
that inventory, measure or otherwise characterize the software on the entity that inventory, measure, or otherwise characterize the
entity. The contents of this claim do not originate from the software on the entity. The contents of this claim do not originate
manufacturer of the measurable subsystem (e.g. developer of a from the manufacturer of the measurable subsystem (e.g., developer of
software library). a software library).
This claim can be a [RFC9393]. When the CoSWID format is used, it This claim can be a [RFC9393]. When the CoSWID format is used, it
MUST be an evidence CoSWID, not a payload CoSWID. MUST be an evidence CoSWID, not a payload CoSWID.
Formats other than CoSWID MAY be used. The identification of format Formats other than CoSWID MAY be used. The identification of format
is by CoAP Content Format, the same as the "manifests" claim in is by CoAP Content-Format, the same as the "manifests" claim in
Section 4.2.15. Section 4.2.15.
$$Claims-Set-Claims //= ( $$Claims-Set-Claims //= (
measurements-label => measurements-type measurements-label => measurements-type
) )
measurements-type = [+ measurements-format] measurements-type = [+ measurements-format]
measurements-format = [ measurements-format = [
content-type: coap-content-format, content-type: coap-content-format,
content-format: JC< $measurements-body-json, content-format: JC< $measurements-body-json,
$measurements-body-cbor > $measurements-body-cbor >
] ]
$measurements-body-cbor /= bytes .cbor untagged-coswid $measurements-body-cbor /= bytes .cbor untagged-coswid
$measurements-body-json /= base64-url-text $measurements-body-json /= base64-url-text
4.2.17. measres (Software Measurement Results) Claim 4.2.17. measres (Software Measurement Results) Claim
The "measres" claim is a general-purpose structure for reporting The "measres" claim is a general-purpose structure for reporting the
comparison of measurements to expected reference values. This claim comparison of measurements to expected reference values. This claim
provides a simple standard way to report the result of a comparison provides a simple standard way to report the result of a comparison
as success, failure, fail to run, and absence. as success, failure, fail to run, and absence.
It is the nature of measurement systems that they are specific to the It is the nature of measurement systems to be specific to the
operating system, software and hardware of the entity that is being operating system, software, and hardware of the entity that is being
measured. It is not possible to standardize what is measured and how measured. It is not possible to standardize what is measured and how
it is measured across platforms, OS's, software and hardware. The it is measured across platforms, OSes, software, and hardware. The
recipient must obtain the information about what was measured and recipient must obtain the information about what was measured and
what it indicates for the characterization of the security of the what it indicates for the characterization of the security of the
entity from the provider of the measurement system. What this claim entity from the provider of the measurement system. What this claim
provides is a standard way to report basic success or failure of the provides is a standard way to report basic success or failure of the
measurement. In some use cases it is valuable to know if measurement. In some use cases, it is valuable to know if
measurements succeeded or failed in a general way even if the details measurements succeeded or failed in a general way even if the details
of what was measured is not characterized. of what was measured are not characterized.
This claim MAY be generated by the verifier and sent to the relying This claim MAY be generated by the verifier and sent to the relying
party. For example, it could be the results of the verifier party. For example, it could be the results of the verifier
comparing the contents of the "measurements" claim, Section 4.2.16, comparing the contents of the "measurements" claim (Section 4.2.16)
to reference values. to reference values.
This claim MAY also be generated on the entity if the entity has the This claim MAY also be generated on the entity if the entity has the
ability for one subsystem to measure and evaluate another subsystem. ability for one subsystem to measure and evaluate another subsystem.
For example, a TEE might have the ability to measure the software of For example, a TEE might have the ability to measure the software of
the rich OS and may have the reference values for the rich OS. the rich OS and may have the reference values for the rich OS.
Within an entity, attestation target or submodule, multiple results Within an entity, attestation target, or submodule, multiple results
can be reported. For example, it may be desirable to report the can be reported. For example, it may be desirable to report the
results for measurements of the file system, chip configuration, results for measurements of the file system, chip configuration,
installed software, running software and so on. installed software, running software, and so on.
Note that this claim is not for reporting the overall result of a Note that this claim is not for reporting the overall result of a
verifier. It is solely for reporting the result of comparison to verifier. It is solely for reporting the result of comparison to
reference values. reference values.
An individual measurement result (individual-result) is an array An individual measurement result (individual-result) is an array
consisting of two elements, an identifier of the measurement (result- consisting of two elements, an identifier of the measurement (result-
id) and an enumerated type of the result (result). Different id), and an enumerated type of the result (result). Different
measurement systems will measure different things and perhaps measure measurement systems will measure different things and perhaps measure
the same thing in different ways. It is up to each measurement the same thing in different ways. It is up to each measurement
system to define identifiers (result-id) for the measurements it system to define identifiers (result-id) for the measurements it
reports. reports.
Each individual measurement result is part of a group that may Each individual measurement result is part of a group that may
contain many individual results. Each group has a text string that contain many individual results. Each group has a text string that
names it, typically the name of the measurement scheme or system. names it, typically the name of the measurement scheme or system.
The claim itself consists of one or more groups. The claim itself consists of one or more groups.
The values for the results enumerated type are as follows: The values for the results enumerated type are as follows:
1 -- comparison successful: Indicates successful comparison to 1 -- comparison successful: The comparison to reference values was
reference values. successful.
2 -- comparison fail: The comparison was completed and did not 2 -- comparison fail: The comparison was completed but did not
compare correctly to the reference values. compare correctly to the reference values.
3 -- comparison not run: The comparison was not run. This includes 3 -- comparison not run: The comparison was not run. This includes
error conditions such as running out of memory. error conditions such as running out of memory.
4 -- measurement absent: The particular measurement was not 4 -- measurement absent: The particular measurement was not
available for comparison. available for comparison.
$$Claims-Set-Claims //= ( $$Claims-Set-Claims //= (
measurement-results-label => measurement-results-label =>
skipping to change at page 32, line 34 skipping to change at line 1450
comparison-successful = JC< "success", 1 > comparison-successful = JC< "success", 1 >
comparison-fail = JC< "fail", 2 > comparison-fail = JC< "fail", 2 >
comparison-not-run = JC< "not-run", 3 > comparison-not-run = JC< "not-run", 3 >
measurement-absent = JC< "absent", 4 > measurement-absent = JC< "absent", 4 >
4.2.18. submods (Submodules) 4.2.18. submods (Submodules)
Some devices are complex and have many subsystems. A mobile phone is Some devices are complex and have many subsystems. A mobile phone is
a good example. It may have subsystems for communications (e.g., Wi- a good example. It may have subsystems for communications (e.g., Wi-
Fi and cellular), low-power audio and video playback, and multiple Fi and cellular), low-power audio and video playback, and multiple
security-oriented subsystems like a TEE and a Secure Element. The security-oriented subsystems such as a TEE and a Secure Element. The
claims for a subsystem can be grouped together in a submodule. claims for a subsystem can be grouped together in a submodule.
Submodules may be used in either evidence or attestation results. Submodules may be used in either evidence or attestation results.
Because system architecture will vary greatly from use case to use Because system architecture will vary greatly from use case to use
case, there are no set requirements for what a submodule represents case, there are no set requirements for what a submodule represents
either in evidence or in attestation results. Profiles, Section 6, either in evidence or in attestation results. Profiles (Section 6)
may wish to impose requirements. An attester that outputs evidence may wish to impose requirements. An attester that outputs evidence
with submodules should document the semantics it associates with with submodules should document the semantics it associates with
particular submodules for the verifier. Likewise, a verifier that particular submodules for the verifier. Likewise, a verifier that
outputs attestation results with submodules should document the outputs attestation results with submodules should document the
semantics it associates with the submodules for the relying party. semantics it associates with the submodules for the relying party.
A submodule claim is a map that holds some number of submodules. A submodule claim is a map that holds some number of submodules.
Each submodule is named by its label in the submodule claim map. The Each submodule is named by its label in the submodule claim map. The
value of each entry in a submodule may be a Claims-Set, nested token value of each entry in a submodule may be a Claims-Set, nested token,
or Detached-Submodule-Digest. This allows for the submodule to serve or Detached-Submodule-Digest. This allows for the submodule to serve
as its own attester or not and allows for claims for each submodule as its own attester or not and allows for claims for each submodule
to be represented directly or indirectly, i.e., detached. to be represented directly or indirectly, i.e., detached.
A submodule may include a submodule, allowing for arbitrary levels of A submodule may include a submodule, allowing for arbitrary levels of
nesting. However, submodules do not inherit anything from the nesting. However, submodules do not inherit anything from the
containing token and must explicitly include all claims. Submodules containing token and must explicitly include all claims. Submodules
may contain claims that are present in any surrounding token or may contain claims that are present in any surrounding token or
submodule. For example, the top-level of the token may have a UEID, submodule. For example, the top level of the token may have a UEID,
a submodule may have a different UEID and a further subordinate a submodule may have a different UEID, and a further subordinate
submodule may also have a UEID. submodule may also have a UEID.
The following sub-sections define the three types for representing The following subsections define the three types for representing
submodules: submodules:
* A submodule Claims-Set * A submodule Claims-Set
* The digest of a detached Claims-Set * The digest of a detached Claims-Set
* A nested token, which can be any EAT * A nested token, which can be any EAT
The Submodule type definition and Nested-Token type definition vary The Submodule type and Nested-Token type definitions vary with the
with the type of encoding. The definitions for CBOR-encoded EATs are type of encoding. The definitions for CBOR-encoded EATs are as
as follows: follows:
Nested-Token = CBOR-Nested-Token Nested-Token = CBOR-Nested-Token
CBOR-Nested-Token = CBOR-Nested-Token =
JSON-Token-Inside-CBOR-Token / JSON-Token-Inside-CBOR-Token /
CBOR-Token-Inside-CBOR-Token CBOR-Token-Inside-CBOR-Token
CBOR-Token-Inside-CBOR-Token = bstr .cbor $EAT-CBOR-Tagged-Token CBOR-Token-Inside-CBOR-Token = bstr .cbor $EAT-CBOR-Tagged-Token
JSON-Token-Inside-CBOR-Token = tstr JSON-Token-Inside-CBOR-Token = tstr
$$Claims-Set-Claims //= (submods-label => { + text => Submodule }) $$Claims-Set-Claims //= (submods-label => { + text => Submodule })
Submodule = Claims-Set / CBOR-Nested-Token / Submodule = Claims-Set / CBOR-Nested-Token /
Detached-Submodule-Digest Detached-Submodule-Digest
The Submodule and Nested-Token definitions for JSON-encoded EATs is The Submodule and Nested-Token definitions for JSON-encoded EATs are
as below. This difference in definitions versus CBOR is necessary as below. The definitions are necessarily different than CBOR
because JSON has no tag mechanism and no byte string type to help because JSON has no tag mechanism and no byte-string type to help
indicate the nested token is CBOR. indicate that the nested token is CBOR.
Nested-Token = JSON-Selector Nested-Token = JSON-Selector
JSON-Selector = $JSON-Selector JSON-Selector = $JSON-Selector
$JSON-Selector /= [type: "JWT", nested-token: JWT-Message] $JSON-Selector /= [type: "JWT", nested-token: JWT-Message]
$JSON-Selector /= [type: "CBOR", nested-token: $JSON-Selector /= [type: "CBOR", nested-token:
CBOR-Token-Inside-JSON-Token] CBOR-Token-Inside-JSON-Token]
$JSON-Selector /= [type: "BUNDLE", nested-token: Detached-EAT-Bundle] $JSON-Selector /= [type: "BUNDLE", nested-token: Detached-EAT-Bundle]
$JSON-Selector /= [type: "DIGEST", nested-token: $JSON-Selector /= [type: "DIGEST", nested-token:
skipping to change at page 34, line 38 skipping to change at line 1545
Nested tokens can be one of three types as defined in this document Nested tokens can be one of three types as defined in this document
or types standardized in follow-on documents (e.g., [UCCS]). Nested or types standardized in follow-on documents (e.g., [UCCS]). Nested
tokens are the only mechanism by which JSON can be embedded in CBOR tokens are the only mechanism by which JSON can be embedded in CBOR
and vice versa. and vice versa.
The addition of further types is accomplished by augmenting the $EAT- The addition of further types is accomplished by augmenting the $EAT-
CBOR-Tagged-Token socket or the $JSON-Selector socket. CBOR-Tagged-Token socket or the $JSON-Selector socket.
When decoding a JSON-encoded EAT, the type of submodule is determined When decoding a JSON-encoded EAT, the type of submodule is determined
as follows. A JSON object indicates the submodule is a Claims-Set. as follows. A JSON object indicates that the submodule is a Claims-
In all other cases, it is a JSON-Selector, which is an array of two Set. In all other cases, it is a JSON-Selector, which is an array of
elements that indicates whether the submodule is a nested token or a two elements that indicates whether the submodule is a nested token
Detached-Submodule-Digest.The first element in the array indicates or a Detached-Submodule-Digest. The first element in the array
the type present in the second element. If the value is "JWT", indicates the type present in the second element. If the value is
"CBOR", "BUNDLE" or a future-standardized token types, e.g., [UCCS], "JWT", "CBOR", "BUNDLE", or future-standardized token types, e.g.,
the submodule is a nested token of the indicated type, i.e., JWT- see [UCCS], the submodule is a nested token of the indicated type,
Message, CBOR-Token-Inside-JSON-Token, Detached-EAT-Bundle, or a i.e., JWT-Message, CBOR-Token-Inside-JSON-Token, Detached-EAT-Bundle,
future type. If the value is "DIGEST", the submodule is a Detached- or a future type. If the value is "DIGEST", the submodule is a
Submodule-Digest. Any other value indicates a standardized extension Detached-Submodule-Digest. Any other value indicates a standardized
to this specification. extension to this specification.
When decoding a CBOR-encoded EAT, the CBOR item type indicates the When decoding a CBOR-encoded EAT, the CBOR item type indicates the
type of the submodule as follows. A map indicates a CBOR-encoded type of the submodule as follows. A map indicates a CBOR-encoded
submodule Claims-Set. An array indicates a CBOR-encoded Detached- submodule Claims-Set. An array indicates a CBOR-encoded Detached-
Submodule-Digest. A byte string indicates a CBOR-encoded CBOR- Submodule-Digest. A byte string indicates a CBOR-encoded CBOR-
Nested-Token. A text string indicates a JSON-encoded JSON-Selector. Nested-Token. A text string indicates a JSON-encoded JSON-Selector.
Where JSON-Selector is used in a CBOR-encoded EAT, the "DIGEST" type Where JSON-Selector is used in a CBOR-encoded EAT, the "DIGEST" type
and corresponding Detached-Submodule-Digest type MUST NOT be used. and corresponding Detached-Submodule-Digest type MUST NOT be used.
The type of a CBOR-encoded nested token is always determined by the The type of a CBOR-encoded nested token is always determined by the
CBOR tag encountered after the byte string wrapping is removed in a CBOR tag encountered after the byte string wrapping is removed in a
CBOR-encoded enclosing token or after the base64 wrapping is removed CBOR-encoded enclosing token or after the base64 wrapping is removed
in JSON-encoded enclosing token. in a JSON-encoded enclosing token.
The type of a JSON-encoded nested token is always determined by the The type of JSON-encoded nested token is always determined by the
string name in JSON-Selector and is always "JWT", "BUNDLE" or a new string name in JSON-Selector and is always "JWT", "BUNDLE", or a new
name standardized outside this document for a further type (e.g., name standardized outside this document for a further type (e.g.,
"UCCS"). This string name may also be "CBOR" to indicate the nested "UCCS"). This string name may also be "CBOR" to indicate the nested
token is CBOR-encoded. token is CBOR encoded.
"JWT": The second array item MUST be a JWT formatted according to "JWT": The second array item MUST be a JWT formatted according to
[RFC7519] [RFC7519].
"CBOR": The second array item MUST be some base64url-encoded CBOR "CBOR": The second array item MUST be some base64url-encoded CBOR
that is a tag, typically a CWT or CBOR-encoded detached EAT bundle that is a tag, typically a CWT or CBOR-encoded detached EAT
bundle.
"BUNDLE": The second array item MUST be a JSON-encoded Detached EAT "BUNDLE": The second array item MUST be a JSON-encoded Detached EAT
Bundle as defined in this document. Bundle as defined in this document.
"DIGEST": The second array item MUST be a JSON-encoded Detached- "DIGEST": The second array item MUST be a JSON-encoded Detached-
Submodule-Digest as defined in this document. Submodule-Digest as defined in this document.
As noted elsewhere, additional EAT types may be defined by a As noted elsewhere, additional EAT types may be defined by a
standards action. New type specifications MUST address the Standards Action. New type specifications MUST address the
integration of the new type into the Submodule claim type for integration of the new type into the Submodule claim type for
submodules. submodules.
4.2.18.1. Submodule Claims-Set 4.2.18.1. Submodule Claims-Set
The Claims-Set type provides a means of representing claims from a The Claims-Set type provides a means of representing claims from a
submodule that does not have its own attesting environment, i.e., it submodule that does not have its own attesting environment, i.e., it
has no keys distinct from the attester producing the surrounding has no keys distinct from the attester producing the surrounding
token. Claims are represented as a Claims-Set. Submodule claims token. Claims are represented as a Claims-Set. Submodule claims
represented in this way are secured by the same mechanism as the represented in this way are secured by the same mechanism as the
enclosing token (e.g., it is signed by the same attestation key). enclosing token (e.g., it is signed by the same attestation key).
The encoding of a submodule Claims-Set MUST be the same as the The encoding of a submodule Claims-Set MUST be the same as the
encoding as the surrounding EAT, e.g., all submodule Claims-Sets in a encoding of the surrounding EAT, e.g., all submodule Claims-Sets in a
CBOR-encoded token must be CBOR-encoded. CBOR-encoded token must be CBOR encoded.
4.2.18.2. Detached Submodule Digest 4.2.18.2. Detached Submodule Digest
The Detached-Submodule-Digest type is similar to a submodule Claims- The Detached-Submodule-Digest type is similar to a submodule Claims-
Set, except a digest of the Claims-Set is included in the claim with Set, except a digest of the Claims-Set is included in the claim with
the Claims-Set contents conveyed separately. The separately-conveyed the Claims-Set contents conveyed separately. The separately conveyed
Claims-Set is called a detached claims set. The input to the digest Claims-Set is called a "detached claims set". The direct input to
algorithm is directly the CBOR or JSON-encoded Claims-Set for the the digest algorithm is either the CBOR-encoded or the JSON-encoded
submodule. There is no byte-string wrapping or base 64 encoding. Claims-Set for the submodule. There is no byte string wrapping or
base64 encoding.
The data type for this type of submodule is an array consisting of The data type for this type of submodule is an array consisting of
two data items: an algorithm identifier and a byte string containing two data items: an algorithm identifier and a byte string containing
the digest. The hash algorithm identifier is always from the COSE the digest. The hash algorithm identifier is always from the "COSE
Algorithm registry, [IANA.COSE.Algorithms]. Either the integer or Algorithms" registry [IANA.COSE.Algorithms]. Either the integer or
string identifier may be used. The hash algorithm identifier is the string identifier may be used. The hash algorithm identifier is
never from the JOSE Algorithm registry. never from the JOSE Algorithm registry.
A detached EAT bundle, described in Section 5, may be used to convey A detached EAT bundle, as described in Section 5, may be used to
convey detached claims sets and the EAT containing the corresponding
detached digests. However, EAT does not require the use of a
detached EAT bundle. Any other protocols may be used to convey
detached claims sets and the EAT containing the corresponding detached claims sets and the EAT containing the corresponding
detached digests. EAT, however, does not require use of a detached detached digests. If detached Claims-Sets are modified in transit,
EAT bundle. Any other protocols may be used to convey detached then validation can fail.
claims sets and the EAT containing the corresponding detached
digests. If detached Claims-Sets are modified in transit then
validation can fail.
4.2.18.3. Nested Tokens 4.2.18.3. Nested Tokens
The CBOR-Nested-Token and JSON-Selector types provide a means of The CBOR-Nested-Token and JSON-Selector types provide a means of
representing claims from a submodule that has its own attesting representing claims from a submodule that has its own attesting
environment, i.e., it has keys distinct from the attester producing environment, i.e., it has keys distinct from the attester producing
the surrounding token. Claims are represented in a signed EAT token. the surrounding token. Claims are represented in a signed EAT token.
Inclusion of a signed EAT as a claim cryptographically binds the EAT Inclusion of a signed EAT as a claim cryptographically binds the EAT
to the surrounding token. If it was conveyed in parallel with the to the surrounding token. If it was conveyed in parallel with the
skipping to change at page 37, line 18 skipping to change at line 1669
of-creation of the token, the time at which the claims are collected of-creation of the token, the time at which the claims are collected
and the token is composed and signed. and the token is composed and signed.
The data for some claims may be held or cached for some period of The data for some claims may be held or cached for some period of
time before the token is created. This period may be long, even time before the token is created. This period may be long, even
days. Examples are measurements taken at boot or a geographic days. Examples are measurements taken at boot or a geographic
position fix taken the last time a satellite signal was received. position fix taken the last time a satellite signal was received.
There are individual timestamps associated with these claims to There are individual timestamps associated with these claims to
indicate their age is older than the "iat" timestamp. indicate their age is older than the "iat" timestamp.
CWT allows the use of floating-point for this claim. EAT disallows CWT allows the use of floating-point for this claim, whereas EAT
the use of floating-point. An EAT token MUST NOT contain an "iat" disallows the use of floating-point. An EAT token MUST NOT contain
claim in floating-point format. Any recipient of a token with a an "iat" claim in floating-point format. Any recipient of a token
floating-point format "iat" claim MUST consider it an error. with a floating-point format "iat" claim MUST consider it an error.
A 64-bit integer representation of the CBOR epoch-based time A 64-bit integer representation of the CBOR epoch-based time
[RFC8949] used by this claim can represent a range of +/- 500 billion [RFC8949] used by this claim can represent a range of +/- 500 billion
years, so the only point of a floating-point timestamp is to have years, so the only point of a floating-point timestamp is to have
precession greater than one second. This is not needed for EAT. precession greater than one second. This is not needed for EAT.
4.3.2. eat_profile (EAT Profile) Claim 4.3.2. eat_profile (EAT Profile) Claim
See Section 6 for the detailed description of an EAT profile. See Section 6 for the detailed description of an EAT profile.
The "eat_profile" claim identifies an EAT profile by either a Uniform The "eat_profile" claim identifies an EAT profile by either a Uniform
Resource Identifier (URI) or an Object Identifier (OID). Typically, Resource Identifier (URI) or an OID. Typically, the URI will
the URI will reference a document describing the profile. An OID is reference a document describing the profile. An OID is just a unique
just a unique identifier for the profile. It may exist anywhere in identifier for the profile. It may exist anywhere in the OID tree.
the OID tree. There is no requirement that the named document be There is no requirement that the named document be publicly
publicly accessible. The primary purpose of the "eat_profile" claim accessible. The primary purpose of the "eat_profile" claim is to
is to uniquely identify the profile even if it is a private profile. uniquely identify the profile even if it is a private profile.
The OID is always absolute and never relative. The OID is always absolute and never relative.
See Section 7.2.1 for OID and URI encoding. See Section 7.2.1 for OID and URI encoding.
$$Claims-Set-Claims //= (profile-label => general-uri / general-oid) $$Claims-Set-Claims //= (profile-label => general-uri / general-oid)
4.3.3. intuse (Intended Use) Claim 4.3.3. intuse (Intended Use) Claim
EATs may be employed in the context of several different EATs may be employed in the context of several different
applications. The "intuse" claim provides an indication to an EAT applications. The "intuse" claim provides an indication to an EAT
consumer about the intended usage of the token. This claim can be consumer about the intended usage of the token. This claim can be
used as a way for an application using EAT to internally distinguish used as a way for an application using EAT to internally distinguish
between different ways it utilizes EAT. The possible values are in between different ways it utilizes EAT. The possible values are in
the EAT Intended Use Registry defined in Section 10.5. the "Entity Attestation Token (EAT) Intended Uses" registry defined
in Section 10.5.
$$Claims-Set-Claims //= ( intended-use-label => intended-use-type ) $$Claims-Set-Claims //= ( intended-use-label => intended-use-type )
intended-use-type = JC< text, int> intended-use-type = JC< text, int>
5. Detached EAT Bundles 5. Detached EAT Bundles
A detached EAT bundle is a message to convey an EAT plus detached A detached EAT bundle is a message to convey an EAT plus detached
claims sets secured by that EAT. It is a top-level message like a claims sets secured by that EAT. It is a top-level message like a
CWT or JWT. It can occur in any place that a CWT or JWT occurs, for CWT or JWT. It can occur in any place that a CWT or JWT occurs, for
example as a submodule nested token as defined in Section 4.2.18.3. example, as a submodule nested token as defined in Section 4.2.18.3.
A detached EAT bundle may be either CBOR or JSON-encoded. A detached EAT bundle may be either CBOR or JSON encoded.
A detached EAT bundle consists of two parts. A detached EAT bundle consists of two parts.
The first part is an encoded EAT as follows: The first part is an encoded EAT that:
* MUST have at least one submodule that is a detached submodule * MUST have at least one submodule that is a detached submodule
digest as defined in Section 4.2.18.2 digest as defined in Section 4.2.18.2
* MAY be either CBOR or JSON-encoded and does not have to the the * MAY be either CBOR or JSON encoded and does not have to be the
same as the encoding of the bundle same as the encoding of the bundle
* MAY be a CWT, or JWT or some future-defined token type, but MUST * MAY be a CWT, JWT, or some future-defined token type, but it MUST
NOT be a detached EAT bundle NOT be a detached EAT bundle
* MUST be authenticity and integrity protected * MUST be authenticity and integrity protected
The same mechanism for distinguishing the type for nested token The same mechanism for distinguishing the type for nested token
submodules is employed here. submodules is employed here.
The second part is a map/object as follows: The second part is a map/object that:
* MUST be a Claims-Set * MUST be a Claims-Set
* MUST use the same encoding as the bundle * MUST use the same encoding as the bundle
* MUST be wrapped in a byte string when the encoding is CBOR and be * MUST be wrapped in a byte string when the encoding is CBOR and be
base64url-encoded when the encoding is JSON base64url encoded when the encoding is JSON
For CBOR-encoded detached EAT bundles, tag 602 can be used to For a CBOR-encoded detached EAT bundle, tag 602 can be used to
identify it. The standard rules apply for use or non-use of a tag. identify it. The standard rules apply for use or non-use of a tag.
When it is sent as a submodule, it is always sent as a tag to When it is sent as a submodule, it is always sent as a tag to
distinguish it from the other types of nested tokens. distinguish it from the other types of nested tokens.
The digests of the detached claims sets are associated with detached The digests of the detached claims sets are associated with detached
Claims-Sets by label/name. It is up to the constructor of the Claims-Sets by label/name. It is up to the constructor of the
detached EAT bundle to ensure the names uniquely identify the detached EAT bundle to ensure that the names uniquely identify the
detached claims sets. Since the names are used only in the detached detached claims sets. Since the names are used only in the detached
EAT bundle, they can be very short, perhaps one byte. EAT bundle, they can be very short, perhaps one byte.
BUNDLE-Messages = BUNDLE-Tagged-Message / BUNDLE-Untagged-Message BUNDLE-Messages = BUNDLE-Tagged-Message / BUNDLE-Untagged-Message
BUNDLE-Tagged-Message = #6.602(BUNDLE-Untagged-Message) BUNDLE-Tagged-Message = #6.602(BUNDLE-Untagged-Message)
BUNDLE-Untagged-Message = Detached-EAT-Bundle BUNDLE-Untagged-Message = Detached-EAT-Bundle
Detached-EAT-Bundle = [ Detached-EAT-Bundle = [
main-token : Nested-Token, main-token : Nested-Token,
skipping to change at page 39, line 35 skipping to change at line 1777
cbor-wrapped-claims-set> cbor-wrapped-claims-set>
} }
] ]
json-wrapped-claims-set = base64-url-text json-wrapped-claims-set = base64-url-text
cbor-wrapped-claims-set = bstr .cbor Claims-Set cbor-wrapped-claims-set = bstr .cbor Claims-Set
6. Profiles 6. Profiles
EAT makes normative use of CBOR, JSON, COSE, JOSE, CWT and JWT. Most EAT makes normative use of CBOR, JSON, COSE, JOSE, CWT, and JWT.
of these have implementation options to accommodate a range of use Most of these have implementation options to accommodate a range of
cases. use cases.
For example, COSE does not require a particular set of cryptographic For example, COSE does not require a particular set of cryptographic
algorithms so as to accommodate different usage scenarios and algorithms so as to accommodate different usage scenarios and
evolution of algorithms over time. Section 10 of [RFC9052] describes evolution of algorithms over time. Section 10 of [RFC9052] describes
the profiling considerations for COSE. the profiling considerations for COSE.
The use of encryption is optional for both CWT and JWT. Section 8 of The use of encryption is optional for both CWT and JWT. Section 8 of
[RFC7519] describes implementation requirement and recommendations [RFC7519] describes implementation requirements and recommendations
for JWT. for JWT.
Similarly, CBOR provides indefinite length encoding, which is not Similarly, CBOR provides indefinite-length encoding, which is not
commonly used, but valuable for very constrained devices. For EAT commonly used but is valuable for very constrained devices. For EAT
itself, in a particular use case some claims will be used and others itself, in a particular use case some claims will be used and others
will not. Section 4 of [RFC8949] describes serialization will not. Section 4 of [RFC8949] describes serialization
considerations for CBOR. considerations for CBOR.
For example a mobile phone use case may require the device make and For example, a mobile phone use case may require the device make and
model, and prohibit UEID and location for privacy reasons. The model and may prohibit UEID and location for privacy reasons. The
general EAT standard retains all this flexibility because it too is general EAT standard retains all this flexibility because it too is
aimed to accommodate a broad range of use cases. aimed to accommodate a broad range of use cases.
It is necessary to explicitly narrow these implementation options to It is necessary to explicitly narrow these implementation options to
guarantee interoperability. EAT chooses one general and explicit guarantee interoperability. EAT chooses one general and explicit
mechanism, the profile, to indicate the choices made for these mechanism, the profile, to indicate the choices made for these
implementation options for all aspects of the token. implementation options for all aspects of the token.
Below is a list of the various issues that should be addressed by a Below is a list of the various issues that should be addressed by a
profile. profile.
The "eat_profile" claim in Section 4.3.2 provides a unique identifier The "eat_profile" claim in Section 4.3.2 provides a unique identifier
for the profile a particular token uses. for the profile a particular token uses.
A profile can apply to evidence or to attestation results or both. A profile can apply to evidence results, attestation results, or
both.
6.1. Format of a Profile Document 6.1. Format of a Profile Document
A profile document does not have to be in any particular format. It A profile document does not have to be in any particular format. It
may be simple text, something more formal or a combination. may be simple text, something more formal, or a combination of both.
A profile may define, and possibly register, one or more new claims A profile may define, and possibly register, one or more new claims
if needed. A profile may also reuse one or more already defined if needed. A profile may also reuse one or more already defined
claims, either as-is or with values constrained to a subset or claims either as is or with values constrained to a subset or
subrange. subrange.
6.2. Full and Partial Profiles 6.2. Full and Partial Profiles
For a "full" profile, the receiver will be able to decode and verify For a "full" profile, the receiver will be able to decode and verify
every possible EAT sent when a sender and receiver both adhere to it. every possible EAT sent when a sender and receiver both adhere to it.
For a "partial" profile, there are still some protocol options left For a "partial" profile, there are still some protocol options left
undecided. undecided.
For example, a profile that allows the use of signing algorithms by For example, a profile that allows the use of signing algorithms by
the sender that the receiver is not required to support is a partial the sender that the receiver is not required to support is a partial
profile. The sender might choose a signing algorithm that some profile. The sender might choose a signing algorithm that some
receivers do not support. receivers do not support.
Full profiles MUST be complete such that a complying receiver can Full profiles MUST be complete such that a complying receiver can
decode, verify and check for freshness every EAT created by a decode, verify, and check for freshness for every EAT created by a
complying sender. Full profiles do not need to require the receiver complying sender. Full profiles do not need to require the receiver
fully handle every claim in an EAT from a complying sender. Profile to fully handle every claim in an EAT from a complying sender.
specifications may assume the receiver has access to the necessary Profile specifications may assume the receiver has access to the
verification keys or may go into specific detail on the means to necessary verification keys or may go into specific detail on the
access verification keys. means to access verification keys.
The "eat_profile" claim MUST NOT be used to identify partial The "eat_profile" claim MUST NOT be used to identify partial
profiles. profiles.
While fewer profiles are preferrable, sometimes several may be needed While fewer profiles are preferable, sometimes several may be needed
for a use case. One approach to handling variation in devices might for a use case. One approach to handling variation in devices might
be to define several full profiles that are variants of each other. be to define several full profiles that are variants of each other.
It is relatively easy and inexpensive to define profiles as they do It is relatively easy and inexpensive to define profiles as they do
not have to be standards track and do not have to be registered not have to be published on the Standards Track and do not have to be
anywhere. For example, flexibility for post-quantum algorithms can registered anywhere. For example, flexibility for post-quantum
be handled as follows. First, define a full profile for a set of algorithms can be handled as follows. First, define a full profile
non-post-quantum algorithms for current use. Then, when post-quantum for a set of non-post-quantum algorithms for current use. Then, when
algorithms are settled, define another full profile derived from the post-quantum algorithms are settled, define another full profile
first. derived from the first.
6.3. List of Profile Issues 6.3. List of Profile Issues
The following is a list of EAT, CWT, JWT, COSE, JOSE and CBOR options The following is a list of EAT, CWT, JWT, COSE, JOSE, and CBOR
that a profile should address. options that a profile should address.
6.3.1. Use of JSON, CBOR or both 6.3.1. Use of JSON, CBOR, or Both
A profile should specify whether CBOR, JSON or both may be sent. A A profile should specify whether CBOR, JSON, or both may be sent. A
profile should specify that the receiver can accept all encodings profile should specify that the receiver can accept all encodings
that the sender is allowed to send. that the sender is allowed to send.
This should be specified for the top-level and all nested tokens. This should be specified for the top level and all nested tokens.
For example, a profile might require all nested tokens to be of the For example, a profile might require all nested tokens to be of the
same encoding of the top level token. same encoding of the top-level token.
6.3.2. CBOR Map and Array Encoding 6.3.2. CBOR Map and Array Encoding
A profile should specify whether definite-length arrays/maps, A profile should specify whether definite-length arrays/maps,
indefinite-length arrays/maps or both may be sent. A profile should indefinite-length arrays/maps, or both may be sent. A profile should
specify that the receiver be able to accept all length encodings that specify that the receiver accepts all length encodings that the
the sender is allowed to send. sender is allowed to send.
This applies to individual EAT claims, CWT and COSE parts of the This applies to individual EAT claims, CWT, and COSE parts of the
implementation. implementation.
For most use cases, specifying that only definite-length arrays/maps For most use cases, specifying that only definite-length arrays/maps
may be sent is suitable. may be sent is suitable.
6.3.3. CBOR String Encoding 6.3.3. CBOR String Encoding
A profile should specify whether definite-length strings, indefinite- A profile should specify whether definite-length strings, indefinite-
length strings or both may be sent. A profile should specify that length strings, or both may be sent. A profile should specify that
the receiver be able to accept all types of string encodings that the the receiver accepts all types of string encodings that the sender is
sender is allowed to send. allowed to send.
For most use cases, specifying that only definite-length strings may For most use cases, specifying that only definite-length strings may
be sent is suitable. be sent is suitable.
6.3.4. CBOR Preferred Serialization 6.3.4. CBOR Preferred Serialization
A profile should specify whether or not CBOR preferred serialization A profile should specify whether or not CBOR preferred serialization
must be sent or not. A profile should specify the receiver be able must be sent or not. A profile should specify that the receiver
to accept preferred and/or non-preferred serialization so it will be accepts preferred and/or non-preferred serialization, so it will be
able to accept anything sent by the sender. able to accept anything sent by the sender.
6.3.5. CBOR Tags 6.3.5. CBOR Tags
The profile should specify whether the token should be a CWT Tag or The profile should specify whether the token should be a CWT tag or
not. not.
When COSE protection is used, the profile should specify whether COSE When COSE protection is used, the profile should specify whether COSE
tags are used or not. Note that RFC 8392 requires COSE tags be used tags are used or not. Note that RFC 8392 requires COSE tags be used
in a CWT tag. in a CWT tag.
Often a tag is unnecessary because the surrounding or carrying Often, a tag is unnecessary because the surrounding or carrying
protocol identifies the object as an EAT. protocol identifies the object as an EAT.
6.3.6. COSE/JOSE Protection 6.3.6. COSE/JOSE Protection
COSE and JOSE have several options for signed, MACed and encrypted COSE and JOSE have several options for signed, MACed, and encrypted
messages. JWT may use the JOSE NULL protection option. It is messages. JWT may use the JOSE NULL protection option. It is
possible to implement no protection, sign only, MAC only, sign then possible to implement no protection, sign only, MAC only, sign then
encrypt and so on. All combinations allowed by COSE, JOSE, JWT, and encrypt, and so on. All combinations allowed by COSE, JOSE, JWT, and
CWT are allowed by EAT. CWT are allowed by EAT.
A profile should specify all signing, encryption and MAC message A profile should specify all signing, encryption, and MAC message
formats that may be sent. For example, a profile might allow only formats that may be sent. For example, a profile might allow only
COSE_Sign1 to be sent. For another example, a profile might allow COSE_Sign1 to be sent. As another example, a profile might allow
COSE_Sign and COSE_Encrypt to be sent to carry multiple signatures COSE_Sign and COSE_Encrypt to be sent to carry multiple signatures
for post quantum cryptography and to use encryption to provide for post quantum cryptography and to use encryption to provide
confidentiality. confidentiality.
A profile should specify the receiver accepts all message formats A profile should specify that the receiver accepts all message
that are allowed to be sent. formats that are allowed to be sent.
When both signing and encryption are allowed, a profile should When both signing and encryption are allowed, a profile should
specify which is applied first. specify which is applied first.
6.3.7. COSE/JOSE Algorithms 6.3.7. COSE/JOSE Algorithms
See the section on "Application Profiling Considerations" in See "Application Profiling Considerations" (Section 10 of [RFC9052])
[RFC9052] for a discussion on selection of cryptographic algorithms for a discussion on the selection of cryptographic algorithms and
and related issues. related issues.
The profile MAY require the protocol or system using EAT to provide The profile MAY require the protocol or system using EAT to provide
an algorithm negotiation mechanism. an algorithm negotiation mechanism.
If not, the profile document should list a set of algorithms for each If not, the profile document should list a set of algorithms for each
COSE and JOSE message type allowed by the profile per Section 6.3.6. COSE and JOSE message type allowed by the profile per Section 6.3.6.
The verifier should implement all of them. The attester may The verifier should implement all of them. The attester may
implement any of them it wishes, possibly just one for each message implement any of them it wishes, possibly just one for each message
type. type.
If detached submodule digests are used the profile should address the If detached submodule digests are used, the profile should address
determination of the hash algorithm(s) for the digests. the determination of the hash algorithm(s) for the digests.
6.3.8. Detached EAT Bundle Support 6.3.8. Detached EAT Bundle Support
A profile should specify whether or not a detached EAT bundle A profile should specify whether or not a detached EAT bundle
(Section 5) can be sent. A profile should specify that a receiver be (Section 5) can be sent. A profile should specify that a receiver
able to accept a detached EAT bundle if the sender is allowed to send accepts a detached EAT bundle if the sender is allowed to send it.
it.
6.3.9. Key Identification 6.3.9. Key Identification
A profile should specify what must be sent to identify the A profile should specify what must be sent to identify the
verification, decryption or MAC key or keys. If multiple methods of verification, decryption, or MAC key(s). If multiple methods of key
key identification may be sent, a profile should require the receiver identification may be sent, a profile should require the receiver to
support them all. support them all.
Appendix F describes a number of methods for identifying verification Appendix F describes a number of methods for identifying verification
keys. When encryption is used, there are further considerations. In keys. When encryption is used, there are further considerations. In
some cases key identification may be very simple and in others some cases, key identification may be very simple, and in other
involve multiple components. For example, it may be simple through cases, multiple components may be involved. For example, it may be
use of COSE key ID or it may be complex through use of an X.509 simple through the use of a COSE key ID, or it may be complex through
certificate hierarchy. the use of an X.509 certificate hierarchy.
While not always possible, a profile should specify or make reference While not always possible, a profile should specify, or make
to, a full end-end specification for key identification. For reference to, a full end-to-end specification for key identification.
example, a profile should specify in full detail how COSE key IDs are For example, a profile should specify in full detail how COSE key IDs
to be created, their lifecycle and such rather than just specifying are to be created, their life cycle, and such rather than just
that a COSE key ID be used. For example, a profile should specify specifying that a COSE key ID be used. For example, a profile should
the full details of an X.509 hierarchy including extension specify the full details of an X.509 hierarchy including extension
processing, algorithms allowed and so on rather than just saying processing, algorithms allowed, and so on rather than just saying
X.509 certificates are used. X.509 certificates are used.
6.3.10. Endorsement Identification 6.3.10. Endorsement Identification
Similar to, or perhaps the same as verification key identification, Similar to, or perhaps the same as, verification key identification,
the profile may wish to specify how endorsements are to be the profile may wish to specify how endorsements are to be
identified. However note that endorsement identification is identified. However, note that endorsement identification is
optional, whereas key identification is not. optional, whereas key identification is not.
6.3.11. Freshness 6.3.11. Freshness
Security considerations, see Section 9.3, require a mechanism to Security considerations (see Section 9.3) require a mechanism to
provide freshness. This may be the EAT nonce claim in Section 4.1, provide freshness. This may be the EAT nonce claim in Section 4.1 or
or some claim or mechanism defined outside this document. The some claim or mechanism defined outside this document. Several
section on freshness in [RFC9334] describes several options. A options are described in "Freshness" (Section 10 of [RFC9334]). A
profile should specify which freshness mechanism or mechanisms can be profile should specify which freshness mechanism or mechanisms can be
used. used.
If the EAT nonce claim is used, a profile should specify whether If the EAT nonce claim is used, a profile should specify whether
multiple nonces may be sent. If a profile allows multiple nonces to multiple nonces may be sent. If a profile allows multiple nonces to
be sent, it should require the receiver to process multiple nonces. be sent, it should require the receiver to process multiple nonces.
6.3.12. Claims Requirements 6.3.12. Claims Requirements
A profile may define new claims that are not defined in this A profile may define new claims that are not defined in this
document. document.
This document requires an EAT receiver must accept tokens with claims This document requires that an EAT receiver must accept tokens with
it does not understand. A profile for a specific use case may claims it does not understand. A profile for a specific use case may
reverse this and allow a receiver to reject tokens with claims it reverse this and allow a receiver to reject tokens with claims it
does not understand. A profile for a specific use case may specify does not understand. A profile for a specific use case may specify
that specific claims are prohibited. that specific claims are prohibited.
A profile for a specific use case may modify this and specify that A profile for a specific use case may modify this and specify that
some claims are required. some claims are required.
A profile may constrain the definition of claims that are defined in A profile may constrain the definition of claims that are defined in
this document or elsewhere. For example, a profile may require the this document or elsewhere. For example, a profile may require the
EAT nonce be a certain length or the "location" claim always include EAT nonce to be a certain length or the "location" claim to always
the altitude. include the altitude.
Some claims are "pluggable" in that they allow different formats for Some claims are "pluggable" in that they allow different formats for
their content. The "manifests" claim (Section 4.2.15) along with the their content. The "manifests" claim (Section 4.2.15) along with the
measurement and "measurements" (Section 4.2.16) claims are examples measurement and "measurements" (Section 4.2.16) claims are examples
of this, allowing the use of CoSWID and other formats. A profile of this, allowing the use of CoSWID and other formats. A profile
should specify which formats are allowed to be sent, with the should specify which formats are allowed to be sent, with the
assumption that the corresponding CoAP content types have been assumption that the corresponding CoAP content types have been
registered. A profile should require the receiver to accept all registered. A profile should require the receiver to accept all
formats that are allowed to be sent. formats that are allowed to be sent.
Further, if there is variation within a format that is allowed, the Further, if there is variation within a format that is allowed, the
profile should specify which variations can be sent. For example, profile should specify which variations can be sent. For example,
there are variations in the CoSWID format. A profile that require there are variations in the CoSWID format, such as a profile that
the receiver to accept all variations that are allowed to be sent. requires the receiver to accept all variations that are allowed to be
sent.
6.4. The Constrained Device Standard Profile 6.4. The Constrained Device Standard Profile
It is anticipated that there will be many profiles defined for EAT It is anticipated that there will be many profiles defined for EAT
for many different use cases. This section gives a normative for many different use cases. This section gives a normative
definition of one profile that is good for many constrained device definition of one profile that is good for many constrained device
use cases. use cases.
The identifier for this profile is "urn:ietf:rfc:rfcTBD". The identifier for this profile is "urn:ietf:rfc:rfc9711".
// RFC Editor: please replace rfcTBD with this RFC number and remove
// this note.
+================+=============================================+ +================+==================================================+
| Issue | Profile Definition | | Issue | Profile Definition |
+================+=============================================+ +================+==================================================+
| CBOR/JSON | CBOR MUST be used | | CBOR/JSON | CBOR MUST be used. |
+----------------+---------------------------------------------+ +----------------+--------------------------------------------------+
| CBOR Encoding | Definite length maps and arrays MUST be | | CBOR Encoding | Definite-length maps and arrays MUST be |
| | used | | | used. |
+----------------+---------------------------------------------+ +----------------+--------------------------------------------------+
| CBOR Encoding | Definite length strings MUST be used | | CBOR Encoding | Definite-length strings MUST be used. |
+----------------+---------------------------------------------+ +----------------+--------------------------------------------------+
| CBOR | Preferred serialization MUST be used | | CBOR | Preferred serialization MUST be used. |
| Serialization | | | Serialization | |
+----------------+---------------------------------------------+ +----------------+--------------------------------------------------+
| COSE | COSE_Sign1 MUST be used | | COSE | COSE_Sign1 MUST be used. |
| Protection | | | Protection | |
+----------------+---------------------------------------------+ +----------------+--------------------------------------------------+
| Algorithms | The receiver MUST accept ES256, ES384 and | | Algorithms | The receiver MUST accept ES256, ES384, |
| | ES512; the sender MUST send one of these | | | and ES512; the sender MUST send one of |
+----------------+---------------------------------------------+ | | these. |
| Detached EAT | Detached EAT bundles MUST NOT be sent with | +----------------+--------------------------------------------------+
| Bundle Usage | this profile | | Detached EAT | Detached EAT bundles MUST NOT be sent |
+----------------+---------------------------------------------+ | Bundle Usage | with this profile. |
| Verification | Either the COSE kid or the UEID MUST be | +----------------+--------------------------------------------------+
| Key | used to identify the verification key. If | | Verification | Either the COSE key identifier (kid) or |
| Identification | both are present, the kid takes precedence. | | Key | the UEID MUST be used to identify the |
| | (It is assumed the receiver has access to a | | Identification | verification key. If both are present, |
| | database of trusted verification keys which | | | the kid takes precedence. (It is assumed |
| | allows lookup of the verification key ID; | | | the receiver has access to a database of |
| | the key format and means of distribution | | | trusted verification keys, which allows a |
| | are beyond the scope of this profile) | | | lookup of the verification key ID; the |
+----------------+---------------------------------------------+ | | key format and means of distribution are |
| Endorsements | This profile contains no endorsement | | | beyond the scope of this profile.) |
| | identifier | +----------------+--------------------------------------------------+
+----------------+---------------------------------------------+ | Endorsements | This profile contains no endorsement |
| Freshness | A new single unique nonce MUST be used for | | | identifier. |
| | every token request | +----------------+--------------------------------------------------+
+----------------+---------------------------------------------+ | Freshness | A new single unique nonce MUST be used |
| Claims | No requirement is made on the presence or | | | for every token request. |
| | absence of claims other than requiring an | +----------------+--------------------------------------------------+
| | EAT nonce. As per general EAT rules, the | | Claims | No requirement is made for the presence |
| | receiver MUST NOT error out on claims it | | | or absence of claims other than requiring |
| | does not understand. | | | an EAT nonce. As per general EAT rules, |
+----------------+---------------------------------------------+ | | the receiver MUST NOT error out on claims |
| | it does not understand. |
+----------------+--------------------------------------------------+
Table 2: Constrained Device Profile Definition Table 2: Constrained Device Profile Definition
Any profile with different requirements than those above MUST have a Any profile with different requirements than those above MUST have a
different profile identifier. different profile identifier.
Note that many claims can be present for tokens conforming to this Note that many claims can be present for tokens conforming to this
profile, even claims not defined in this document. Note also that profile, even claims not defined in this document. Note also that
even slight deviation from the above requirements is considered a even slight deviation from the above requirements is considered a
different profile that MUST have a different identifier. For different profile that MUST have a different identifier. For
example, if a kid (key identifier) or UEID is not used for key example, if a kid (key identifier) or UEID is not used for key
identification, it is not in conformance with this profile. For identification, it is not in conformance with this profile. As
another example, requiring the presence of some claim is also not in another example, requiring the presence of some claim is also not in
conformance and requires another profile. conformance and requires another profile.
Derivations of this profile are encouraged. For example another Derivations of this profile are encouraged. For example, another
profile may be simply defined as The Constrained Device Standard profile may be simply defined as "The Constrained Device Standard
Profile plus the requirement for the presence of claim xxxx and claim Profile" plus the requirement for the presence of claim xxxx and
yyyy. claim yyyy.
7. Encoding and Collected CDDL 7. Encoding and Collected CDDL
An EAT is fundamentally defined using CDDL. This document specifies An EAT is fundamentally defined using CDDL. This document specifies
how to encode the CDDL in CBOR or JSON. Since CBOR can express some how to encode the CDDL in CBOR or JSON. Since CBOR can express some
things that JSON cannot (e.g., tags) or that are expressed things that JSON cannot (e.g., tags) or that are expressed
differently (e.g., labels) there is some CDDL that is specific to the differently (e.g., labels), there is some CDDL that is specific to
encoding. the encoding.
7.1. Claims-Set and CDDL for CWT and JWT 7.1. Claims-Set and CDDL for CWT and JWT
CDDL was not used to define CWT or JWT. It was not available at the CDDL was not used to define CWT or JWT. It was not available at the
time. time.
This document defines CDDL for both CWT and JWT. This document does This document defines CDDL for both CWT and JWT. This document does
not change the encoding or semantics of anything in a CWT or JWT. not change the encoding or semantics of anything in a CWT or JWT.
A Claims-Set is the central data structure for EAT, CWT and JWT. It A Claims-Set is the central data structure for EAT, CWT, and JWT. It
holds all the claims and is the structure that is secured by signing holds all the claims and is the structure that is secured by signing
or other means. It is not possible to define EAT, CWT, or JWT in or other means. It is not possible to define EAT, CWT, or JWT in
CDDL without it. The CDDL definition of Claims-Set here is CDDL without it. The CDDL definition of Claims-Set here is
applicable to EAT, CWT and JWT. applicable to EAT, CWT, and JWT.
This document specifies how to encode a Claims-Set in CBOR or JSON. This document specifies how to encode a Claims-Set in CBOR or JSON.
With the exception of nested tokens and some other externally defined With the exception of nested tokens and some other externally defined
structures (e.g., SWIDs) an entire Claims-Set must be encoded in structures (e.g., SWIDs), an entire Claims-Set must be encoded in
either CBOR or JSON, never a mixture. either CBOR or JSON, never a mixture.
CDDL for the seven claims defined by [RFC8392] and [RFC7519] is CDDL for the seven claims defined by [RFC8392] and [RFC7519] is
included here. included here.
7.2. Encoding Data Types 7.2. Encoding Data Types
This makes use of the types defined in [RFC8610] Appendix D, Standard This makes use of the types defined in "Standard Prelude" (Appendix D
Prelude. of [RFC8610]).
7.2.1. Common Data Types 7.2.1. Common Data Types
time-int is identical to the epoch-based time, but disallows time-int is identical to the epoch-based time but disallows floating-
floating-point representation. point representation.
For CBOR-encoded tokens, OIDs are specified using the CDDL type name For CBOR-encoded tokens, OIDs are specified using the CDDL type name
"oid" from [RFC9090]. They are encoded without the tag number. For "oid" from [RFC9090]. They are encoded without the tag number. For
JSON-encoded tokens, OIDs are a text string in the common form of JSON-encoded tokens, OIDs are text strings in the common form of
"nn.nn.nn...". "nn.nn.nn...".
Unless expliclity indicated, URIs are not the URI tag defined in Unless explicitly indicated, URIs are not the URI tag defined in
[RFC8949]. They are just text strings that contain a URI conforming [RFC8949]. They are just text strings that contain a URI conforming
to the format defined in [RFC3986]. to the format defined in [RFC3986].
time-int = #6.1(int) time-int = #6.1(int)
binary-data = JC< base64-url-text, bstr> binary-data = JC< base64-url-text, bstr>
base64-url-text = tstr .regexp "[A-Za-z0-9_-]+" base64-url-text = tstr .regexp "[A-Za-z0-9_-]+"
general-oid = JC< json-oid, ~oid > general-oid = JC< json-oid, ~oid >
json-oid = tstr .regexp "([0-2])((\\.0)|(\\.[1-9][0-9]*))*" json-oid = tstr .regexp "([0-2])((\\.0)|(\\.[1-9][0-9]*))*"
general-uri = JC< text, ~uri > general-uri = JC< text, ~uri >
coap-content-format = uint .le 65535 coap-content-format = uint .le 65535
7.2.2. JSON Interoperability 7.2.2. JSON Interoperability
JSON should be encoded per [RFC8610], Appendix E. In addition, the JSON should be encoded per Appendix E of [RFC8610]. In addition, the
following CDDL types are encoded in JSON as follows: following CDDL types are encoded in JSON as follows:
* bstr -- MUST be base64url-encoded * bstr -- MUST be base64url encoded.
* time -- MUST be encoded as NumericDate as described in Section 2 * time -- MUST be encoded as NumericDate as described in Section 2
of [RFC7519]. of [RFC7519].
* string-or-uri -- MUST be encoded as StringOrURI as described in * string-or-uri -- MUST be encoded as StringOrURI as described in
Section 2 of [RFC7519]. Section 2 of [RFC7519].
* uri -- MUST be a URI [RFC3986]. * uri -- MUST be a URI [RFC3986].
* oid -- MUST be encoded as a string using the well established * oid -- MUST be encoded as a string using the well-established
dotted-decimal notation (e.g., the text "1.2.250.1") [RFC4517]. dotted-decimal notation (e.g., the text "1.2.250.1") [RFC4517].
The CDDL generic "JC<>" is used in most places where there is a The CDDL generic "JC<>" is used in most places where there is a
variance between CBOR and JSON. The first argument is the CDDL for variance between CBOR and JSON. The first argument is the CDDL for
JSON and the second is CDDL for CBOR. JSON, and the second is CDDL for CBOR.
7.2.3. Labels 7.2.3. Labels
Most map labels, Claims-Keys, Claim-Names and enumerated-type values Most map labels, Claims-Keys, Claim-Names, and enumerated-type values
are integers for CBOR-encoded tokens and strings for JSON-encoded are integers for CBOR-encoded tokens and strings for JSON-encoded
tokens. When this is the case the "JC<>" CDDL construct is used to tokens. When this is the case, the JC<> CDDL construct is used to
give both the integer and string values. give both the integer and string values.
7.2.4. CBOR Interoperability 7.2.4. CBOR Interoperability
CBOR allows data items to be serialized in more than one form to CBOR allows data items to be serialized in more than one form to
accommodate a variety of use cases. This is addressed in Section 6. accommodate a variety of use cases. This is addressed in Section 6.
7.3. Collected CDDL 7.3. Collected CDDL
7.3.1. Payload CDDL 7.3.1. Payload CDDL
This CDDL defines all the EAT Claims that are added to the main The payload CDDL defines all the EAT claims that are added to the
definition of a Claim-Set in Appendix D. Claims-Set is the payload main definition of a Claims-Set in Appendix D. Claims-Set is the
for CWT, JWT and potentially other token types. This is for both payload for CWT, JWT, and potentially other token types. This is for
CBOR and JSON. When there is variation between CBOR and JSON, the both CBOR and JSON. When there is variation between CBOR and JSON,
JC<> CDDL generic defined in Appendix D. Note that the JC<> generic the JC<> CDDL generic defined in Appendix D. Note that the JC<>
uses the CDDL ".feature" control operator defined in [RFC9165]. generic uses the CDDL ".feature" control operator defined in
[RFC9165].
This CDDL uses, but does not define Submodule or nested tokens This CDDL uses, but does not define, Submodule or nested tokens
because the definition for these types varies between CBOR and JSON because the definition for these types varies between CBOR and JSON
and the JC<> generic cannot be used to define it. The submodule and the JC<> generic cannot be used to define it. The submodule
claim is the one place where a CBOR token can be nested inside a JSON claim is the one place where a CBOR token can be nested inside a JSON
token and vice versa. Encoding-specific definitions are provided in token and vice versa. Encoding-specific definitions are provided in
the following sections. the following sections.
time-int = #6.1(int) time-int = #6.1(int)
binary-data = JC< base64-url-text, bstr> binary-data = JC< base64-url-text, bstr>
skipping to change at page 56, line 15 skipping to change at line 2517
8. Privacy Considerations 8. Privacy Considerations
Certain EAT claims can be used to track the owner of an entity; Certain EAT claims can be used to track the owner of an entity;
therefore, implementations should consider privacy-preserving options therefore, implementations should consider privacy-preserving options
dependent on the usage of the EAT. For example, the location claim dependent on the usage of the EAT. For example, the location claim
might be suppressed in EATs sent to unauthenticated consumers. might be suppressed in EATs sent to unauthenticated consumers.
8.1. UEID and SUEID Privacy Considerations 8.1. UEID and SUEID Privacy Considerations
A UEID is usually not privacy-preserving. Relying parties receiving A UEID is usually not privacy-preserving. Relying parties receiving
tokens from a particular entity will be able to know the tokens are tokens from a particular entity will be able to know that the tokens
from the same entity and be able to identify the entity issuing those are from the same entity and identify the entity issuing those
tokens. tokens.
Thus the use of the claim may violate privacy policies. In other Thus, the use of the claim may violate privacy policies. In other
usage situations a UEID will not be allowed for certain products like usage situations, a UEID will not be allowed for certain products
browsers that give privacy for the end user. It will often be the such as browsers that give privacy for the end user. It will often
case that tokens will not have a UEID for these reasons. be the case that tokens will not have a UEID for these reasons.
An SUEID is also usually not privacy-preserving. In some cases it An SUEID is also usually not privacy-preserving. In some cases, it
may have fewer privacy issues than a UEID depending on when and how may have fewer privacy issues than a UEID depending on when and how
and when it is generated. it is generated.
There are several strategies that can be used to still be able to put There are several strategies that can be used to still be able to put
UEIDs and SUEIDs in tokens: UEIDs and SUEIDs in tokens:
* The entity obtains explicit permission from the user of the entity * The entity obtains explicit permission from the user of the entity
to use the UEID/SUEID. This may be through a prompt. It may also to use the UEID/SUEID; this may be through a prompt or through a
be through a license agreement. For example, agreements for some license agreement. For example, agreements for some online
online banking and brokerage services might already cover use of a banking and brokerage services might already cover use of a UEID/
UEID/SUEID. SUEID.
* The UEID/SUEID is used only in a particular context or particular * The UEID/SUEID is used only in a particular context or use case.
use case. It is used only by one relying party. It is used only by one relying party.
* The entity authenticates the relying party and generates a derived * The entity authenticates the relying party and generates a derived
UEID/SUEID just for that particular relying party. For example, UEID/SUEID just for that particular relying party. For example,
the relying party could prove their identity cryptographically to the relying party could prove their identity cryptographically to
the entity, then the entity generates a UEID just for that relying the entity, then the entity generates a UEID just for that relying
party by hashing a proofed relying party ID with the main entity party by hashing a proofed relying party ID with the main entity
UEID/SUEID. UEID/SUEID.
Note that some of these privacy preservation strategies result in Note that some of these privacy preservation strategies result in
multiple UEIDs and SUEIDs per entity. Each UEID/SUEID is used in a multiple UEIDs and SUEIDs per entity. Each UEID/SUEID is used in a
different context, use case or system on the entity. However, from different context, use case, or system on the entity. However, from
the view of the relying party, there is just one UEID and it is still the view of the relying party, there is just one UEID and it is still
globally universal across manufacturers. globally universal across manufacturers.
8.2. Location Privacy Considerations 8.2. Location Privacy Considerations
Geographic location is most always considered personally identifiable Geographic location is almost always considered personally
information. Implementers should consider laws and regulations identifiable information. Implementors should consider laws and
governing the transmission of location data from end user devices to regulations governing the transmission of location data from end-user
servers and services. Implementers should consider using location devices to servers and services. Implementors should consider using
management facilities offered by the operating system on the entity location management facilities offered by the operating system on the
generating the attestation. For example, many mobile phones prompt entity generating the attestation. For example, many mobile phones
the user for permission before sending location data. prompt the user for permission before sending location data.
8.3. Boot Seed Privacy Considerations 8.3. Boot Seed Privacy Considerations
The "bootseed" claim is effectively a stable entity identifier within The "bootseed" claim is effectively a stable entity identifier within
a given boot epoch. Therefore, it is not suitable for use in a given boot epoch. Therefore, it is not suitable for use in
attestation schemes that are privacy-preserving. attestation schemes that are privacy-preserving.
8.4. Replay Protection and Privacy 8.4. Replay Protection and Privacy
EAT defines the EAT nonce claim for replay protection and token EAT defines the EAT nonce claim for replay protection and token
freshness. The nonce claim is based on a value usually derived freshness. The nonce claim is based on a value usually derived
remotely (outside of the entity). This claim might be used to remotely (outside of the entity). This claim might be used to
extract and convey personally identifying information either extract and convey personally identifying information either
inadvertently or by intention. For instance, an implementor may inadvertently or by intention. For instance, an implementor may
choose a nonce equivalent to a username associated with the device choose a nonce equivalent to a username associated with the device
(e.g., account login). If the token is inspected by a 3rd-party then (e.g., account login). If the token is inspected by a third party,
this information could be used to identify the source of the token or then this information could be used to identify the source of the
an account associated with the token. To avoid the conveyance of token or an account associated with the token. To avoid the
privacy-related information in the nonce claim, it should be derived conveyance of privacy-related information in the nonce claim, it
using a salt that originates from a true and reliable random number should be derived using a salt that originates from a true and
generator or any other source of randomness that would still meet the reliable random number generator or any other source of randomness
target system requirements for replay protection and token freshness. that would still meet the target system requirements for replay
protection and token freshness.
9. Security Considerations 9. Security Considerations
The security considerations provided in Section 8 of [RFC8392] and The security considerations provided in Section 8 of [RFC8392] and of
Section 11 of [RFC7519] apply to EAT in its CWT and JWT form, Section 11 of [RFC7519] apply to EAT in its CWT and JWT form,
respectively. Moreover, Chapter 12 of [RFC9334] is also applicable respectively. Moreover, Section 12 of [RFC9334] is also applicable
to implementations of EAT. In addition, implementors should consider to implementations of EAT. In addition, implementors should consider
the following. the information in the following subsections.
9.1. Claim Trustworthiness 9.1. Claim Trustworthiness
This specification defines semantics for each claim. It does not This specification defines semantics for each claim. It does not
require any particular level of security in the implementation of the require any particular level of security in the implementation of the
claims or even the attester itself. Such specification is far beyond claims or even for the attester itself. Such specification is far
the scope of this document which is about a message format not the beyond the scope of this document, which is about a message format
security level of an implementation. not the security level of an implementation.
The receiver of an EAT comes to know the trustworthiness of the The receiver of an EAT knows the trustworthiness of the claims in it
claims in it by understanding the implementation made by the attester by understanding the implementation made by the attester vendor and/
vendor and/or understanding the checks and processing performed by or understanding the checks and processing performed by the verifier.
the verifier.
For example, this document says that a UEID is permanent and that it For example, this document says that a UEID is permanent and that it
must not change, but it does not say what degree of attack to change must not change, but it does not say what degree of attack to change
it must be defended. it must be defended.
The degree of security will vary from use case to use case. In some The degree of security will vary from use case to use case. In some
cases the receiver may only need to know something of the cases, the receiver may only need to know something of the
implementation such as that it was implemented in a TEE. In other implementation such as that it was implemented in a TEE. In other
cases the receiver may require the attester be certified by a cases, the receiver may require the attester to be certified by a
particular certification program. Or perhaps the receiver is content particular certification program. Or perhaps the receiver is content
with very little security. with very little security.
9.2. Key Provisioning 9.2. Key Provisioning
Private key material can be used to sign and/or encrypt the EAT, or Private key material can be used to sign and/or encrypt the EAT or to
can be used to derive the keys used for signing and/or encryption. derive the keys used for signing and/or encryption. In some
In some instances, the manufacturer of the entity may create the key instances, the manufacturer of the entity may create the key material
material separately and provision the key material in the entity separately and provision the key material in the entity itself. The
itself. The manufacturer of any entity that is capable of producing manufacturer of any entity that is capable of producing an EAT should
an EAT should take care to ensure that any private key material be take care to ensure that any private key material be suitably
suitably protected prior to provisioning the key material in the protected prior to provisioning the key material in the entity
entity itself. This can require creation of key material in an itself. This can require creation of key material in an enclave (see
enclave (see [RFC4949] for definition of "enclave"), secure [RFC4949] for definition of "enclave"), secure transmission of the
transmission of the key material from the enclave to the entity using key material from the enclave to the entity using an appropriate
an appropriate protocol, and persistence of the private key material protocol, and persistence of the private key material in some form of
in some form of secure storage to which (preferably) only the entity secure storage to which (preferably) only the entity has access.
has access.
9.2.1. Transmission of Key Material 9.2.1. Transmission of Key Material
Regarding transmission of key material from the enclave to the Regarding transmission of key material from the enclave to the
entity, the key material may pass through one or more intermediaries. entity, the key material may pass through one or more intermediaries.
Therefore some form of protection ("key wrapping") may be necessary. Therefore, some form of protection (e.g., key wrapping) may be
The transmission itself may be performed electronically, but can also necessary. The transmission itself may be performed electronically,
be done by human courier. In the latter case, there should be but it can also be done by human courier. In the latter case, there
minimal to no exposure of the key material to the human (e.g. should be minimal to no exposure of the key material to the human
encrypted portable memory). Moreover, the human should transport the (e.g., encrypted portable memory). Moreover, the human should
key material directly from the secure enclave where it was created to transport the key material directly from the secure enclave where it
a destination secure enclave where it can be provisioned. was created to a destination secure enclave where it can be
provisioned.
9.3. Freshness 9.3. Freshness
All EAT use MUST provide a freshness mechanism to prevent replay and All EAT use MUST provide a freshness mechanism to prevent replay and
related attacks. The extensive discussions on freshness in [RFC9334] related attacks. The extensive discussions in [RFC9334] on
including security considerations apply here. The EAT nonce claim, freshness, as well as the security considerations, apply here. One
in Section 4.1, is one option to provide freshness. option to provide freshness is the EAT nonce claim (Section 4.1).
9.4. Multiple EAT Consumers 9.4. Multiple EAT Consumers
In many cases, more than one EAT consumer may be required to fully In many cases, more than one EAT consumer may be required to fully
verify the entity attestation. Examples include individual consumers verify the entity attestation. Examples include individual consumers
for nested EATs, or consumers for individual claims with an EAT. for nested EATs or consumers for individual claims with an EAT. When
When multiple consumers are required for verification of an EAT, it multiple consumers are required for verification of an EAT, it is
is important to minimize information exposure to each consumer. In important to minimize information exposure to each consumer. In
addition, the communication between multiple consumers should be addition, the communication between multiple consumers should be
secure. secure.
For instance, consider the example of an encrypted and signed EAT For instance, consider the example of an encrypted and signed EAT
with multiple claims. A consumer may receive the EAT (denoted as the with multiple claims. A consumer may receive the EAT (denoted as the
"receiving consumer"), decrypt its payload, verify its signature, but "receiving consumer"), decrypt its payload, and verify its signature
then pass specific subsets of claims to other consumers for but then pass specific subsets of claims to other consumers for
evaluation ("downstream consumers"). Since any COSE encryption will evaluation ("downstream consumers"). Since any COSE encryption will
be removed by the receiving consumer, the communication of claim be removed by the receiving consumer, the communication of claim
subsets to any downstream consumer MUST leverage an equivalent subsets to any downstream consumer MUST leverage an equivalent
communication security protocol (e.g. Transport Layer Security). communication security protocol (e.g., TLS).
However, assume the EAT of the previous example is hierarchical and However, assume the EAT of the previous example is hierarchical and
each claim subset for a downstream consumer is created in the form of each claim subset for a downstream consumer is created in the form of
a nested EAT. Then the nested EAT is itself encrypted and a nested EAT. Then, the nested EAT itself is encrypted and
cryptographically verifiable (due to its COSE envelope) by a cryptographically verifiable (due to its COSE envelope) by a
downstream consumer (unlike the previous example where a claims set downstream consumer (unlike the previous example where a claims set
without a COSE envelope is sent to a downstream consumer). without a COSE envelope is sent to a downstream consumer).
Therefore, Transport Layer Security between the receiving and Therefore, TLS between the receiving and downstream consumers is not
downstream consumers is not strictly required. Nevertheless, strictly required. Nevertheless, downstream consumers of a nested
downstream consumers of a nested EAT should provide a nonce unique to EAT should provide a nonce unique to the EAT they are consuming.
the EAT they are consuming.
9.5. Detached EAT Bundle Digest Security Considerations 9.5. Detached EAT Bundle Digest Security Considerations
A detached EAT bundle is composed of a nested EAT and a claims set as A detached EAT bundle is composed of a nested EAT and a claims set as
per Section 5. Although the attached claims set is vulnerable to per Section 5. Although the attached claims set is vulnerable to
modification in transit, any modification can be detected by the modification in transit, any modification can be detected by the
receiver through the associated digest, which is a claim fully receiver through the associated digest, which is a claim fully
contained within an EAT. Moreover, the digest itself can only be contained within an EAT. Moreover, the digest itself can only be
derived using an appropriate COSE hash algorithm, implying that an derived using an appropriate COSE hash algorithm, implying that an
attacker cannot induce false detection of modified detached claims attacker cannot induce false detection of modified detached claims
because the algorithms in the COSE registry are assumed to be of because the algorithms in the COSE registry are assumed to be of
sufficient cryptographic strength. sufficient cryptographic strength.
9.6. Verification Keys 9.6. Verification Keys
In all cases there must be some way that the verification key is In all cases, there must be some way that the verification key itself
itself verified or determined to be trustworthy. The key is verified or determined to be trustworthy. The key identification
identification itself is never enough. This will always be by some itself is never enough. This will always be by some out-of-band
out-of-band mechanism that is not described here. For example, the mechanism that is not described here. For example, the verifier may
verifier may be configured with a root certificate or a master key by be configured with a root certificate or a master key by the verifier
the verifier system administrator. system administrator.
Often an X.509 certificate or an endorsement carries more than just Often, an X.509 certificate or an endorsement carries more than just
the verification key. For example, an X.509 certificate might have the verification key. For example, an X.509 certificate might have
key usage constraints, and an endorsement might have reference key usage constraints, and an endorsement might have reference
values. When this is the case, the key identifier must be either a values. When this is the case, the key identifier must be either a
protected header or in the payload, such that it is cryptographically protected header or in the payload, such that it is cryptographically
bound to the EAT. This is in line with the requirements in section 6 bound to the EAT. This is in line with the requirements in "Key
on Key Identification in JSON Web Signature [RFC7515]. Identification" of JSON Web Signature (Section 6 of [RFC7515]).
10. IANA Considerations 10. IANA Considerations
10.1. Reuse of CBOR and JSON Web Token (CWT and JWT) Claims Registries 10.1. Reuse of CBOR and JSON Web Token (CWT and JWT) Claims Registries
Claims defined for EAT are compatible with those of CWT and JWT so Claims defined for EAT are compatible with those of CWT and JWT, so
the CWT and JWT Claims Registries, [IANA.CWT.Claims] and the CWT and JWT Claims registries, [IANA.CWT.Claims] and
[IANA.JWT.Claims], are re-used. No new IANA registry is created. [IANA.JWT.Claims], are reused. No new IANA registry is created.
All EAT claims defined in this document are placed in both All EAT claims defined in this document have been placed in both
registries. All new EAT claims defined subsequently should be placed registries. All new EAT claims defined subsequently should be placed
in both registries. in both registries.
Appendix E describes some considerations when defining new claims. Appendix E describes some considerations when defining new claims.
10.2. CWT and JWT Claims Registered by This Document 10.2. CWT and JWT Claims Registered by This Document
This specification adds the following values to the "JSON Web Token Per this specification, the following values have been added to the
Claims" registry established by [RFC7519] and the "CBOR Web Token "JSON Web Token Claims" registry established by [RFC7519] and the
Claims Registry" established by [RFC8392]. Each entry below is an "CBOR Web Token (CWT) Claims" registry established by [RFC8392].
addition to both registries. Each entry below has been added to both registries.
The "Claim Description", "Change Controller" and "Specification
Documents" are common and equivalent for the JWT and CWT registries.
The "Claim Key" and "Claim Value Types(s)" are for the CWT registry
only. The "Claim Name" is as defined for the CWT registry, not the
JWT registry. The "JWT Claim Name" is equivalent to the "Claim Name"
in the JWT registry.
IANA is requested to register the following claims. The "Claim Value
Type(s)" here all name CDDL definitions and are only for the CWT
registry.
// RFC editor: please see instructions in followg paragraph and
// remove for final publication
RFC Editor: Please make the following adjustments and remove this
paragraph. Replace "*this document*" with this RFC number. In the
following, the claims with "Claim Key: TBD" need to be assigned a
value in the Specification Required Range, preferably starting around
267. Those below already with a Claim Key number were given early
assignment. No change is requested for them except for Claim Key
262. Claim 262 should be renamed from "secboot" to "oemboot" in the
JWT registry and its description changed in both the CWT and JWT
registries.
* Claim Name: Nonce
* Claim Description: Nonce
* JWT Claim Name: "eat_nonce"
* Claim Key: 10
* Claim Value Type(s): bstr or array
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: UEID
* Claim Description: The Universal Entity ID
* JWT Claim Name: "ueid"
* CWT Claim Key: 256
* Claim Value Type(s): bstr
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: SUEIDs
* Claim Description: Semi-permanent UEIDs
* JWT Claim Name: "sueids"
* CWT Claim Key: 257
* Claim Value Type(s): map
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Hardware OEM ID
* Claim Description: Hardware OEM ID
* JWT Claim Name: "oemid"
* Claim Key: 258
* Claim Value Type(s): bstr or int
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Hardware Model
* Claim Description: Model identifier for hardware
* JWT Claim Name: "hwmodel"
* Claim Key: 259
* Claim Value Type(s): bstr
* Change Controller: IETF The "Claim Description", "Change Controller", and "Reference" fields
are common and equivalent for the JWT and CWT registries. The "Claim
Key" and "Claim Value Type" fields are for the CWT registry only.
The "Claim Name" field is as defined for the CWT registry, not the
JWT registry. The "JWT Claim Name" field is equivalent to the "Claim
Name" field in the JWT registry.
* Specification Document(s): *this document* IANA has registered the following claims. Here, the "Claim Value
Type" fields name CDDL definitions and are only for the CWT registry.
* Claim Name: Hardware Version Claim Name: Nonce
Claim Description: Nonce
JWT Claim Name: "eat_nonce"
Claim Key: 10
Claim Value Type: bstr or array
Change Controller: IETF
Reference: [OIDCC], RFC 9711
* Claim Description: Hardware Version Identifier Claim Name: UEID
Claim Description: The Universal Entity ID
JWT Claim Name: "ueid"
CWT Claim Key: 256
Claim Value Type: bstr
Change Controller: IETF
Reference: RFC 9711
* JWT Claim Name: "hwversion" Claim Name: SUEIDs
Claim Description: Semi-permanent UEIDs
JWT Claim Name: "sueids"
CWT Claim Key: 257
Claim Value Type: map
Change Controller: IETF
Reference: RFC 9711
* Claim Key: 260 Claim Name: Hardware OEM ID
Claim Description: Hardware OEM ID
JWT Claim Name: "oemid"
Claim Key: 258
Claim Value Type: bstr or int
Change Controller: IETF
Reference: RFC 9711
* Claim Value Type(s): array Claim Name: Hardware Model
* Change Controller: IETF Claim Description: Model identifier for hardware
JWT Claim Name: "hwmodel"
Claim Key: 259
Claim Value Type: bstr
Change Controller: IETF
Reference: RFC 9711
* Specification Document(s): *this document* Claim Name: Hardware Version
Claim Description: Hardware Version Identifier
JWT Claim Name: "hwversion"
Claim Key: 260
Claim Value Type: array
Change Controller: IETF
Reference: RFC 9711
* Claim Name: OEM Authorized Boot Claim Name: Uptime
Claim Description: Uptime
JWT Claim Name: "uptime"
Claim Key: 261
Claim Value Type: uint
Change Controller: IETF
Reference: RFC 9711
* Claim Description: Indicates whether the software booted was OEM Claim Name: OEM Authorized Boot
Claim Description: Indicates whether the software booted was OEM
authorized authorized
JWT Claim Name: "oemboot"
Claim Key: 262
Claim Value Type: bool
Change Controller: IETF
Reference: RFC 9711
* JWT Claim Name: "oemboot" Claim Name: Debug Status
Claim Description: Indicates status of debug facilities
* Claim Key: 262 JWT Claim Name: "dbgstat"
Claim Key: 263
* Claim Value Type(s): bool Claim Value Type: uint
Change Controller: IETF
* Change Controller: IETF Reference: RFC 9711
* Specification Document(s): *this document*
* Claim Name: Debug Status
* Claim Description: Indicates status of debug facilities
* JWT Claim Name: "dbgstat"
* Claim Key: 263
* Claim Value Type(s): uint
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Location
* Claim Description: The geographic location
* JWT Claim Name: "location"
* Claim Key: 264
* Claim Value Type(s): map
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: EAT Profile
* Claim Description: Indicates the EAT profile followed
* JWT Claim Name: "eat_profile"
* Claim Key: 265
* Claim Value Type(s): uri or oid
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Submodules Section
* Claim Description: The section containing submodules
* JWT Claim Name: "submods"
* Claim Key: 266
* Claim Value Type(s): map
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Uptime
* Claim Description: Uptime
* JWT Claim Name: "uptime"
* Claim Key: 261
* Claim Value Type(s): uint Claim Name: Location
Claim Description: The geographic location
JWT Claim Name: "location"
Claim Key: 264
Claim Value Type: map
Change Controller: IETF
Reference: RFC 9711
* Change Controller: IETF Claim Name: EAT Profile
Claim Description: Indicates the EAT profile followed
JWT Claim Name: "eat_profile"
Claim Key: 265
Claim Value Type: uri or oid
Change Controller: IETF
Reference: RFC 9711
* Specification Document(s): *this document* Claim Name: Submodules Section
* Claim Name: Boot Count Claim Description: The section containing submodules
JWT Claim Name: "submods"
Claim Key: 266
Claim Value Type: map
Change Controller: IETF
Reference: RFC 9711
* Claim Description: The number times the entity or submodule has Claim Name: Boot Count
Claim Description: The number of times the entity or submodule has
been booted been booted
JWT Claim Name: "bootcount"
Claim Key: 267
Claim Value Type: uint
Change Controller: IETF
Reference: RFC 9711
* JWT Claim Name: "bootcount" Claim Name: Boot Seed
Claim Description: Identifies a boot cycle
* Claim Key: 267 JWT Claim Name: "bootseed"
Claim Key: 268
* Claim Value Type(s): uint Claim Value Type: bstr
Change Controller: IETF
* Change Controller: IETF Reference: RFC 9711
* Specification Document(s): *this document*
* Claim Name: Boot Seed
* Claim Description: Identifies a boot cycle
* JWT Claim Name: "bootseed"
* Claim Key: 268
* Claim Value Type(s): bstr
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: DLOAs
* Claim Description: Certifications received as Digital Letters of Claim Name: DLOAs
Claim Description: Certifications received as Digital Letters of
Approval Approval
JWT Claim Name: "dloas"
Claim Key: 269
Claim Value Type: array
Change Controller: IETF
Reference: RFC 9711
* JWT Claim Name: "dloas" Claim Name: Software Name
Claim Description: The name of the software running in the entity
* Claim Key: 269 JWT Claim Name: "swname"
Claim Key: 270
* Claim Value Type(s): array Claim Value Type: tstr
Change Controller: IETF
* Change Controller: IETF Reference: RFC 9711
* Specification Document(s): *this document*
* Claim Name: Software Name
* Claim Description: The name of the software running in the entity
* JWT Claim Name: "swname"
* Claim Key: 270
* Claim Value Type(s): tstr
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Software Version
* Claim Description: The version of software running in the entity
* JWT Claim Name: "swversion"
* Claim Key: 271
* Claim Value Type(s): array
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Software Manifests Claim Name: Software Version
Claim Description: The version of software running in the entity
JWT Claim Name: "swversion"
Claim Key: 271
Claim Value Type: array
Change Controller: IETF
Reference: RFC 9711
* Claim Description: Manifests describing the software installed on Claim Name: Software Manifests
Claim Description: Manifests describing the software installed on
the entity the entity
JWT Claim Name: "manifests"
Claim Key: 272
Claim Value Type: array
Change Controller: IETF
Reference: RFC 9711
* JWT Claim Name: "manifests" Claim Name: Measurements
Claim Description: Measurements of the software, memory
* Claim Key: 272 configuration, and such on the entity
JWT Claim Name: "measurements"
* Claim Value Type(s): array Claim Key: 273
Claim Value Type: array
* Change Controller: IETF Change Controller: IETF
Reference: RFC 9711
* Specification Document(s): *this document*
* Claim Name: Measurements
* Claim Description: Measurements of the software, memory
configuration and such on the entity
* JWT Claim Name: "measurements"
* Claim Key: 273
* Claim Value Type(s): array
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Software Measurement Results
* Claim Description: The results of comparing software measurements
to reference values
* JWT Claim Name: "measres"
* Claim Key: 274
* Claim Value Type(s): array
* Change Controller: IETF
* Specification Document(s): *this document*
* Claim Name: Intended Use
* Claim Description: Indicates intended use of the EAT
* JWT Claim Name: "intuse"
* Claim Key: 275
* Claim Value Type(s): uint
* Change Controller: IETF Claim Name: Software Measurement Results
Claim Description: The results of comparing software measurements to
reference values
JWT Claim Name: "measres"
Claim Key: 274
Claim Value Type: array
Change Controller: IETF
Reference: RFC 9711
* Specification Document(s): *this document* Claim Name: Intended Use
Claim Description: Indicates intended use of the EAT
JWT Claim Name: "intuse"
Claim Key: 275
Claim Value Type: uint
Change Controller: IETF
Reference: RFC 9711
10.3. UEID URN Registered by this Document 10.3. UEID URNs Registered by This Document
IANA is requested to register the following new subtypes in the "DEV IANA has registered the following new subtypes in the "DEV URN
URN Subtypes" registry under "Device Identification". See [RFC9039]. Subtypes" registry [IANA.DEV-URNs] under the "Device Identification"
registry group; see [RFC9039].
+=========+=============================+===============+ +=========+============================================+===========+
| Subtype | Description | Reference | | Subtype | Description | Reference |
+=========+=============================+===============+ +=========+============================================+===========+
| ueid | Universal Entity Identifier | This document | | ueid | Universal Entity Identifier | RFC 9711 |
+---------+-----------------------------+---------------+ +---------+--------------------------------------------+-----------+
| sueid | Semi-permanent Universal | This document | | sueid | Semi-permanent Universal Entity Identifier | RFC 9711 |
| | Entity Identifier | | +---------+--------------------------------------------+-----------+
+---------+-----------------------------+---------------+
Table 3: UEID URN Registration Table 3: UEID URN Registration
ABNF for these two URNs is as follows where b64ueid is the base64url- The ABNF [RFC5234] [RFC7405] for these two URNs is as follows, where
encoded binary byte-string for the UEID or SUEID: b64ueid is the base64url-encoded binary byte string for the UEID or
SUEID:
body =/ ueidbody body =/ ueidbody
ueidbody = %s"ueid:" b64ueid ueidbody = %s"ueid:" b64ueid
10.4. CBOR Tag for Detached EAT Bundle Registered by this Document 10.4. CBOR Tag for Detached EAT Bundle Registered by This Document
In the registry [IANA.cbor-tags], IANA is requested to allocate the In the "CBOR Tags" registry [IANA.cbor-tags], IANA has allocated the
following tag from the Specification Required space, with the present following tag from the Specification Required range, with the present
document as the specification reference. document as the reference.
+=====+============+===============================+ +=====+===========+=====================+=====================+
| Tag | Data Items | Semantics | | Tag | Data Item | Semantics | Reference |
+=====+============+===============================+ +=====+===========+=====================+=====================+
| 602 | array | Detached EAT Bundle Section 5 | | 602 | array | Detached EAT Bundle | RFC 9711, Section 5 |
+-----+------------+-------------------------------+ +-----+-----------+---------------------+---------------------+
Table 4: Detached EAT Bundle Tag Registration Table 4: Detached EAT Bundle Tag Registration
10.5. Intended Use Registry 10.5. Intended Use Registry
IANA is requested to create a new registry titled "Entity Attestation IANA has created a new registry titled "Entity Attestation Token
Token (EAT) Intended Uses" in a new registry group called "Remote (EAT) Intended Uses" under the new "Remote Attestation Procedures
Attestation Procedures (RATS)." The registry uses the "Expert (RATS)" registry group. The registry uses the Expert Review
Review" registration procedure [RFC8126]. registration procedure [RFC8126].
Guidelines for experts: Guidelines for designated experts:
* Each intended use should be clearly described so a user of it can * Each intended use should be clearly described so a user knows what
know what it means. it means.
* Each intended use should be distinct from others that are * Each intended use should be distinct from others that are
registered. registered.
* Point squatting is discouraged. * Point squatting is discouraged.
The three columns for the registry are: The three columns for the registry are:
Integer: This is a unique integer used to identify the intended use 1. Integer: This is a unique integer that is used to identify the
in CBOR-encoded tokens. intended use in CBOR-encoded tokens.
Name: This is unique short descriptive string that is used to 2. Name: This is unique short descriptive string that is used to
identify the use in JSON-encoded tokens. identify the use in JSON-encoded tokens.
Description: This is a text paragraph or more that sufficiently 3. Description: This is one or more text paragraphs that
defines what the intended use means. It may also be a reference sufficiently define what the intended use means. It may also be
to another document. a reference to another document.
The following 5 values represent the initial content of the registry. The following 5 values represent the initial content of the registry.
Note that 0 will be marked as "reserved" for the CBOR value, and the Note that 0 will be marked as "reserved" for the CBOR value, and the
maximum CBOR value for assignment is 255. maximum CBOR value for assignment is 255.
1 -- Generic: Generic attestation describes an application where the 1 -- Generic: Generic attestation describes an application where the
EAT consumer requires the most up-to-date security assessment of EAT consumer requires the most up-to-date security assessment of
the attesting entity. It is expected that this is the most the attesting entity. It is expected that this is the most
commonly-used application of EAT. commonly used application of EAT.
2-- Registration: Entities that are registering for a new service 2 -- Registration: Entities that are registering for a new service
may be expected to provide an attestation as part of the may be expected to provide an attestation as part of the
registration process. This "intuse" setting indicates that the registration process. This "intuse" setting indicates that the
attestation is not intended for any use but registration. attestation is not intended for any use but registration.
3 -- Provisioning: Entities may be provisioned with different values 3 -- Provisioning: Entities may be provisioned with different values
or settings by an EAT consumer. Examples include key material or or settings by an EAT consumer. Examples include key material or
device management trees. The consumer may require an EAT to device management trees. The consumer may require an EAT to
assess entity security state of the entity prior to provisioning. assess entity security state of the entity prior to provisioning.
4 -- Certificate Issuance: Certification Authorities (CAs) may 4 -- Certificate Issuance: Certification Authorities (CAs) may
require attestation results (which in a background check model require attestation results (which in a background check model
might require receiving evidence to be passed to a verifier) to might require receiving evidence to be passed to a verifier) to
make decisions about the issuance of certificates. An EAT may be make decisions about the issuance of certificates. An EAT may be
used as part of the certificate signing request (CSR). used as part of the certificate signing request (CSR).
5 -- Proof-of-Possession: An EAT consumer may require an attestation 5 -- Proof of Possession: An EAT consumer may require an attestation
as part of an accompanying proof-of-possession (PoP) application. as part of an accompanying proof-of-possession (PoP) application.
More precisely, a PoP transaction is intended to provide to the More precisely, a PoP transaction is intended to provide the
recipient cryptographically-verifiable proof that the sender has recipient with cryptographically verifiable proof that the sender
possession of a key. This kind of attestation may be necessary to has possession of a key. This kind of attestation may be
verify the security state of the entity storing the private key necessary to verify the security state of the entity storing the
used in a PoP application. private key used in a PoP application.
11. References 11. References
11.1. Normative References 11.1. Normative References
[DLOA] "Digital Letter of Approval", November 2015, [DLOA] GlobalPlatform, "GlobalPlatform Card: Digital Letter of
<https://globalplatform.org/wp-content/uploads/2015/12/ Approval", Public Release Version 1.0, Document Reference:
GPC_SPE_095, November 2015, <https://globalplatform.org/
wp-content/uploads/2015/12/
GPC_DigitalLetterOfApproval_v1.0.pdf>. GPC_DigitalLetterOfApproval_v1.0.pdf>.
[IANA.cbor-tags] [IANA.cbor-tags]
IANA, "Concise Binary Object Representation (CBOR) Tags", IANA, "CBOR Tags",
<https://www.iana.org/assignments/cbor-tags>. <https://www.iana.org/assignments/cbor-tags>.
[IANA.COSE.Algorithms] [IANA.COSE.Algorithms]
IANA, "CBOR Object Signing and Encryption (COSE)", IANA, "COSE Algorithms",
<https://www.iana.org/assignments/cose>. <https://www.iana.org/assignments/cose>.
[IANA.CWT.Claims] [IANA.CWT.Claims]
IANA, "CBOR Web Token (CWT) Claims", IANA, "CBOR Web Token (CWT) Claims",
<https://www.iana.org/assignments/cwt>. <https://www.iana.org/assignments/cwt>.
[IANA.DEV-URNs]
IANA, "DEV URN Subtypes",
<https://www.iana.org/assignments/device-identification>.
[IANA.JWT.Claims] [IANA.JWT.Claims]
IANA, "JSON Web Token (JWT)", IANA, "JSON Web Token Claims",
<https://www.iana.org/assignments/jwt>. <https://www.iana.org/assignments/jwt>.
[PEN] "Private Enterprise Number (PEN) Request", n.d., [PEN] IANA, "Application for a Private Enterprise Number",
<https://pen.iana.org/pen/PenApplication.page>. <https://pen.iana.org/pen/PenApplication.page>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005, RFC 3986, DOI 10.17487/RFC3986, January 2005,
skipping to change at page 70, line 47 skipping to change at line 3068
[RFC4517] Legg, S., Ed., "Lightweight Directory Access Protocol [RFC4517] Legg, S., Ed., "Lightweight Directory Access Protocol
(LDAP): Syntaxes and Matching Rules", RFC 4517, (LDAP): Syntaxes and Matching Rules", RFC 4517,
DOI 10.17487/RFC4517, June 2006, DOI 10.17487/RFC4517, June 2006,
<https://www.rfc-editor.org/info/rfc4517>. <https://www.rfc-editor.org/info/rfc4517>.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>. <https://www.rfc-editor.org/info/rfc4648>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252, Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014, DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>. <https://www.rfc-editor.org/info/rfc7252>.
[RFC7405] Kyzivat, P., "Case-Sensitive String Support in ABNF",
RFC 7405, DOI 10.17487/RFC7405, December 2014,
<https://www.rfc-editor.org/info/rfc7405>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web [RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>. 2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>. <https://www.rfc-editor.org/info/rfc7519>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
skipping to change at page 72, line 21 skipping to change at line 3145
W. Pan, "Remote ATtestation procedureS (RATS) W. Pan, "Remote ATtestation procedureS (RATS)
Architecture", RFC 9334, DOI 10.17487/RFC9334, January Architecture", RFC 9334, DOI 10.17487/RFC9334, January
2023, <https://www.rfc-editor.org/info/rfc9334>. 2023, <https://www.rfc-editor.org/info/rfc9334>.
[RFC9393] Birkholz, H., Fitzgerald-McKay, J., Schmidt, C., and D. [RFC9393] Birkholz, H., Fitzgerald-McKay, J., Schmidt, C., and D.
Waltermire, "Concise Software Identification Tags", Waltermire, "Concise Software Identification Tags",
RFC 9393, DOI 10.17487/RFC9393, June 2023, RFC 9393, DOI 10.17487/RFC9393, June 2023,
<https://www.rfc-editor.org/info/rfc9393>. <https://www.rfc-editor.org/info/rfc9393>.
[ThreeGPP.IMEI] [ThreeGPP.IMEI]
3GPP, "3rd Generation Partnership Project; Technical 3GPP, "Numbering, addressing and identification", 3GPP
Specification Group Core Network and Terminals; Numbering, TS 23.003, Version 19, September 2024,
addressing and identification", 2019,
<https://portal.3gpp.org/desktopmodules/Specifications/ <https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=729>. SpecificationDetails.aspx?specificationId=729>.
[WGS84] National Geospatial-Intelligence Agency (NGA), "WORLD [WGS84] National Geospatial-Intelligence Agency (NGA), "Department
GEODETIC SYSTEM 1984, NGA.STND.0036_1.0.0_WGS84", 8 July of Defense World Geodetic System 1984: Its Definition and
2014, <https://earth-info.nga.mil/php/ Relationships with Local Geodetic Systems",
download.php?file=coord-wgs84>. NGA.STND.0036_1.0.0_WGS84, July 2014,
<https://nsgreg.nga.mil/doc/view?i=4085>.
11.2. Informative References 11.2. Informative References
[BirthdayAttack] [BirthdayAttack]
"Birthday attack", Wikipedia, "Birthday attack", October 2024,
<https://en.wikipedia.org/wiki/Birthday_attack.>. <https://en.wikipedia.org/w/
index.php?title=Birthday_attack&oldid=1249270346>.
[CBOR.Cert.Draft] [CBOR.Certs]
Mattsson, J. P., Selander, G., Raza, S., Höglund, J., and Mattsson, J. P., Selander, G., Raza, S., Höglund, J., and
M. Furuhed, "CBOR Encoded X.509 Certificates (C509 M. Furuhed, "CBOR Encoded X.509 Certificates (C509
Certificates)", Work in Progress, Internet-Draft, draft- Certificates)", Work in Progress, Internet-Draft, draft-
ietf-cose-cbor-encoded-cert-11, 8 July 2024, ietf-cose-cbor-encoded-cert-12, 8 January 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-cose- <https://datatracker.ietf.org/doc/html/draft-ietf-cose-
cbor-encoded-cert-11>. cbor-encoded-cert-12>.
[CC-Example] [CC-Example]
"Secure Sub-System in System-on-Chip (3S in SoC) Eurosmart, "Secure Sub-System in System-on-Chip (3S in
Protection Profile", SoC) Protection Profile", Version 1.8, October 2023,
<https://commoncriteriaportal.org/nfs/ccpfiles/files/ <https://commoncriteriaportal.org/nfs/ccpfiles/files/
ppfiles/pp0117V2b_pdf.pdf>. ppfiles/pp0117V2b_pdf.pdf>.
[COSE.X509.Draft]
Schaad, J., "CBOR Object Signing and Encryption (COSE):
Header Parameters for Carrying and Referencing X.509
Certificates", Work in Progress, Internet-Draft, draft-
ietf-cose-x509-09, 13 October 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-cose-
x509-09>.
[EAT.media-types] [EAT.media-types]
Lundblade, L., Birkholz, H., and T. Fossati, "EAT Media Lundblade, L., Birkholz, H., and T. Fossati, "EAT Media
Types", Work in Progress, Internet-Draft, draft-ietf-rats- Types", Work in Progress, Internet-Draft, draft-ietf-rats-
eat-media-type-09, 21 August 2024, eat-media-type-12, 3 November 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-rats- <https://datatracker.ietf.org/doc/html/draft-ietf-rats-
eat-media-type-09>. eat-media-type-12>.
[GP-Example] [GP-Example]
"GlobalPlatform Technology TEE Certification Process", GlobalPlatform, "GlobalPlatform Technology: TEE
Certification Process", Public Release Version 2.0,
Document Reference: GP_PRO_023, January 2021,
<https://globalplatform.org/wp-content/uploads/2021/01/ <https://globalplatform.org/wp-content/uploads/2021/01/
GP_TEECertificationProcess_v2.0_PublicRelease.pdf>. GP_TEECertificationProcess_v2.0_PublicRelease.pdf>.
[IEEE-RA] "IEEE Registration Authority", [IEEE-RA] IEEE, "IEEE Registration Authority",
<https://standards.ieee.org/products-services/regauth/ <https://standards.ieee.org/products-services/regauth/
index.html>. index.html>.
[IEEE.802-2001] [IEEE.802-2001]
"IEEE Standard for Local and Metropolitan Area Networks: IEEE, "IEEE Standard for Local and Metropolitan Area
Overview and Architecture", IEEE standard, Networks: Overview and Architecture", IEEE Std 802-2014,
DOI 10.1109/ieeestd.2014.6847097, July 2014, DOI 10.1109/IEEESTD.2014.6847097, June 2014,
<https://doi.org/10.1109/ieeestd.2014.6847097>. <https://ieeexplore.ieee.org/document/6847097>.
[IEEE.802.1AR] [IEEE.802.1AR]
"IEEE Standard for Local and Metropolitan Area Networks - IEEE, "IEEE Standard for Local and Metropolitan Area
Secure Device Identity", IEEE standard, Networks - Secure Device Identity", IEEE Std 802.1AR-2018,
DOI 10.1109/ieeestd.2018.8423794, July 2018, DOI 10.1109/IEEESTD.2018.8423794, August 2018,
<https://doi.org/10.1109/ieeestd.2018.8423794>. <https://ieeexplore.ieee.org/document/8423794>.
[JTAG] "IEEE Standard for Reduced-Pin and Enhanced-Functionality [JTAG] IEEE, "IEEE Standard for Reduced-Pin and Enhanced-
Test Access Port and Boundary-Scan Architecture", February Functionality Test Access Port and Boundary-Scan
2010, <https://ieeexplore.ieee.org/document/5412866>. Architecture", IEEE Std 1149.7-2009,
DOI 10.1109/IEEESTD.2010.5412866, February 2010,
<https://ieeexplore.ieee.org/document/5412866>.
[OIDCC] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
C. Mortimore, "OpenID Connect Core 1.0 incorporating
errata set 2", December 2023,
<https://openid.net/specs/openid-connect-core-1_0.html>.
[OUI.Guide] [OUI.Guide]
"Guidelines for Use of Extended Unique Identifier (EUI), IEEE, "Guidelines for Use of Extended Unique Identifier
Organizationally Unique Identifier (OUI), and Company ID (EUI), Organizationally Unique Identifier (OUI), and
(CID)", August 2017, Company ID (CID)", August 2017,
<https://standards.ieee.org/content/dam/ieee- <https://standards.ieee.org/content/dam/ieee-
standards/standards/web/documents/tutorials/eui.pdf>. standards/standards/web/documents/tutorials/eui.pdf>.
[OUI.Lookup] [OUI.Lookup]
"IEEE Registration Authority Assignments", IEEE, "IEEE Registration Authority: Assignments",
<https://regauth.standards.ieee.org/standards-ra-web/pub/ <https://regauth.standards.ieee.org/standards-ra-web/pub/
view.html#registries>. view.html#registries>.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2", [RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007, FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
<https://www.rfc-editor.org/info/rfc4949>. <https://www.rfc-editor.org/info/rfc4949>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC9039] Arkko, J., Jennings, C., and Z. Shelby, "Uniform Resource [RFC9039] Arkko, J., Jennings, C., and Z. Shelby, "Uniform Resource
Names for Device Identifiers", RFC 9039, Names for Device Identifiers", RFC 9039,
DOI 10.17487/RFC9039, June 2021, DOI 10.17487/RFC9039, June 2021,
<https://www.rfc-editor.org/info/rfc9039>. <https://www.rfc-editor.org/info/rfc9039>.
[RFC9360] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Header Parameters for Carrying and Referencing X.509
Certificates", RFC 9360, DOI 10.17487/RFC9360, February
2023, <https://www.rfc-editor.org/info/rfc9360>.
[RFC9562] Davis, K., Peabody, B., and P. Leach, "Universally Unique [RFC9562] Davis, K., Peabody, B., and P. Leach, "Universally Unique
IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, May IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, May
2024, <https://www.rfc-editor.org/info/rfc9562>. 2024, <https://www.rfc-editor.org/info/rfc9562>.
[UCCS] Birkholz, H., O'Donoghue, J., Cam-Winget, N., and C. [UCCS] Birkholz, H., O'Donoghue, J., Cam-Winget, N., and C.
Bormann, "A CBOR Tag for Unprotected CWT Claims Sets", Bormann, "A CBOR Tag for Unprotected CWT Claims Sets",
Work in Progress, Internet-Draft, draft-ietf-rats-uccs-10, Work in Progress, Internet-Draft, draft-ietf-rats-uccs-12,
4 July 2024, <https://datatracker.ietf.org/doc/html/draft- 3 November 2024, <https://datatracker.ietf.org/doc/html/
ietf-rats-uccs-10>. draft-ietf-rats-uccs-12>.
[W3C.GeoLoc] [W3C.GeoLoc]
Popescu, A., Ed., "Geolocation API Specification", W3C Popescu, A., Ed., "Geolocation API Specification", W3C
REC REC-geolocation-API-20131024, W3C REC-geolocation-API- Recommendation, 24 October 2013,
20131024, 24 October 2013, <https://www.w3.org/TR/2013/ <https://www.w3.org/TR/2013/REC-geolocation-API-
REC-geolocation-API-20131024/>. 20131024/>.
Appendix A. Examples Appendix A. Examples
Most examples are shown as just a Claims-Set that would be a payload Most examples are shown as a Claims-Set that would be a payload for a
for a CWT, JWT, detached EAT bundle or future token types. The CWT, a JWT, a detached EAT bundle, or future token types. The
signing is left off so the Claims-Set is easier to see. Some signing is left off so the Claims-Set is easier to see. Some
examples of signed tokens are also given. examples of signed tokens are also given.
// RFC Editor: When the IANA values are permanently assigned, please
// contact the authors so the examples can be regenerated.
// Regeneration is required because IANA-assigned values are inside
// hex and based-64 encoded data and some of these are signed.
A.1. Claims Set Examples A.1. Claims Set Examples
A.1.1. Simple TEE Attestation A.1.1. Simple TEE Attestation
This is a simple attestation of a TEE that includes a manifest that This is a simple attestation of a TEE; it includes a manifest that is
is a payload CoSWID to describe the TEE's software. a payload CoSWID to describe the TEE's software.
/ This is an EAT payload that describes a simple TEE. / / This is an EAT payload that describes a simple TEE. /
{ {
/ eat_nonce / 10: h'48df7b172d70b5a18935d0460a73dd71', / eat_nonce / 10: h'48df7b172d70b5a18935d0460a73dd71',
/ oemboot / 262: true, / oemboot / 262: true,
/ dbgstat / 263: 2, / disabled-since-boot / / dbgstat / 263: 2, / disabled-since-boot /
/ manifests / 272: [ / manifests / 272: [
[ [
258, / CoAP Content ID for CoSWID / 258, / CoAP Content ID for CoSWID /
/ This is byte-string wrapped / / This is a byte-string-wrapped /
/ payload CoSWID. It gives the TEE / / payload CoSWID. It gives the TEE /
/ software name, the version and / / software name, the version, and /
/ the name of the file it is in. / / the name of the file it is in. /
/ {0: "3a24", / / {0: "3a24", /
/ 12: 1, / / 12: 1, /
/ 1: "Acme TEE OS", / / 1: "Acme TEE OS", /
/ 13: "3.1.4", / / 13: "3.1.4", /
/ 2: [{31: "Acme TEE OS", 33: 1}, / / 2: [{31: "Acme TEE OS", 33: 1}, /
/ {31: "Acme TEE OS", 33: 2}], / / {31: "Acme TEE OS", 33: 2}], /
/ 6: { / / 6: { /
/ 17: { / / 17: { /
/ 24: "acme_tee_3.exe" / / 24: "acme_tee_3.exe" /
skipping to change at page 76, line 4 skipping to change at line 3314
/ } / / } /
h' a60064336132340c01016b h' a60064336132340c01016b
41636d6520544545204f530d65332e31 41636d6520544545204f530d65332e31
2e340282a2181f6b41636d6520544545 2e340282a2181f6b41636d6520544545
204f53182101a2181f6b41636d652054 204f53182101a2181f6b41636d652054
4545204f5318210206a111a118186e61 4545204f5318210206a111a118186e61
636d655f7465655f332e657865' 636d655f7465655f332e657865'
] ]
] ]
} }
/ A payload CoSWID created by the SW vendor. All this really does /
/ is name the TEE SW, its version and lists the one file that / / This is a payload CoSWID created by the software (SW) vendor. All /
/ makes up the TEE. / / this does is name the TEE SW, name its version, and list the one /
/ file that makes up the TEE. /
1398229316({ 1398229316({
/ Unique CoSWID ID / 0: "3a24", / Unique CoSWID ID / 0: "3a24",
/ tag-version / 12: 1, / tag-version / 12: 1,
/ software-name / 1: "Acme TEE OS", / software-name / 1: "Acme TEE OS",
/ software-version / 13: "3.1.4", / software-version / 13: "3.1.4",
/ entity / 2: [ / entity / 2: [
{ {
/ entity-name / 31: "Acme TEE OS", / entity-name / 31: "Acme TEE OS",
/ role / 33: 1 / tag-creator / / role / 33: 1 / tag-creator /
skipping to change at page 77, line 4 skipping to change at line 3342
} }
], ],
/ payload / 6: { / payload / 6: {
/ ...file / 17: { / ...file / 17: {
/ ...fs-name / 24: "acme_tee_3.exe" / ...fs-name / 24: "acme_tee_3.exe"
} }
} }
}) })
A.1.2. Submodules for Board and Device A.1.2. Submodules for Board and Device
/ This example shows use of submodules to give information / / This example shows use of submodules to give information /
/ about the chip, board and overall device. / / about the chip, board, and overall device. /
/ / / /
/ The main attestation is associated with the chip with the / / The main attestation is associated with the chip /
/ CPU and running the main OS. It is what has the keys and / / containing the CPU and running the main OS. It is what /
/ produces the token. / / has the keys and produces the token. /
/ / / /
/ The board is made by a different vendor than the chip. / / The board is made by a different vendor than the chip; /
/ Perhaps it is some generic IoT board. / / perhaps it is some generic IoT board. /
/ / / /
/ The device is some specific appliance that is made by a / / The device is some specific appliance that is made by a /
/ different vendor than either the chip or the board. / / different vendor than either the chip or the board. /
/ / / /
/ Here the board and device submodules aren't the typical / / Here, the board and device submodules aren't the typical /
/ target environments as described by the RATS architecture / / target environments as described by RATS Architecture /
/ document, but they are a valid use of submodules. / / (RFC 9334), but they are a valid use of submodules. /
{ {
/ eat_nonce / 10: h'e253cabedc9eec24ac4e25bcbeaf7765', / eat_nonce / 10: h'e253cabedc9eec24ac4e25bcbeaf7765',
/ ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea', / ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea',
/ oemid / 258: h'894823', / IEEE OUI format OEM ID / / oemid / 258: h'894823', / IEEE OUI format OEM ID /
/ hwmodel / 259: h'549dcecc8b987c737b44e40f7c635ce8' / hwmodel / 259: h'549dcecc8b987c737b44e40f7c635ce8'
/ Hash of chip model name /, / Hash of chip model name /,
/ hwversion / 260: ["1.3.4", 1], / Multipartnumeric / / hwversion / 260: ["1.3.4", 1], / Multipartnumeric /
/ swname / 270: "Acme OS", / swname / 270: "Acme OS",
/ swversion / 271: ["3.5.5", 1], / swversion / 271: ["3.5.5", 1],
skipping to change at page 77, line 50 skipping to change at line 3389
}, },
/ A submodule to hold claims about the overall device / / A submodule to hold claims about the overall device /
"device" : { "device" : {
/ oemid / 258: 61234, / PEN Format OEM ID / / oemid / 258: 61234, / PEN Format OEM ID /
/ hwversion / 260: ["4.0", 1] / Multipartnumeric / / hwversion / 260: ["4.0", 1] / Multipartnumeric /
} }
} }
} }
A.1.3. EAT Produced by Attestation Hardware Block A.1.3. EAT Produced by an Attestation Hardware Block
/ This is an example of a token produced by a HW block /
/ purpose-built for attestation. Only the nonce claim changes / / This is an example of a token produced by a hardware block /
/ from one attestation to the next as the rest either come / / purposely built for attestation. Only the nonce claim changes /
/ directly from the hardware or from one-time-programmable memory / / from one attestation to the next as the rest come from either /
/ (e.g. a fuse). 47 bytes encoded in CBOR (8 byte nonce, 16 byte / / the hardware directly or from one-time-programmable memory /
/ UEID). / / (e.g., a fuse). 47 bytes are encoded in CBOR (8-byte nonce, /
/ 16-byte UEID). /
{ {
/ eat_nonce / 10: h'd79b964ddd5471c1393c8888', / eat_nonce / 10: h'd79b964ddd5471c1393c8888',
/ ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea', / ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea',
/ oemid / 258: 64242, / Private Enterprise Number / / oemid / 258: 64242, / Private Enterprise Number /
/ oemboot / 262: true, / oemboot / 262: true,
/ dbgstat / 263: 3, / disabled-permanently / / dbgstat / 263: 3, / disabled-permanently /
/ hwversion / 260: [ "3.1", 1 ] / Type is multipartnumeric / / hwversion / 260: [ "3.1", 1 ] / Type is multipartnumeric /
} }
A.1.4. Key / Key Store Attestation A.1.4. Key / Key Store Attestation
/ This is an attestation of a public key and the key store / / This is an attestation of a public key and the key store /
/ implementation that protects and manages it. The key store / / implementation that protects and manages it. The key store /
/ implementation is in a security-oriented execution / / implementation is in a security-oriented execution /
/ environment separate from the high-level OS (HLOS), for / / environment separate from the high-level OS (HLOS), for /
/ example a Trusted Execution Environment (TEE). The key store / / example, a Trusted Execution Environment (TEE). The key /
/ is the Attester. / / store is the attester. /
/ / / /
/ There is some attestation of the high-level OS, just version / / There is some attestation of the HLOS, just version and /
/ and boot & debug status. It is a Claims-Set submodule because/ / boot and debug status. It is a Claims-Set submodule because /
/ it has lower security level than the key store. The key / / it has a lower security level than the key store. The key /
/ store's implementation has access to info about the HLOS, so / / store's implementation has access to info about the HLOS, so /
/ it is able to include it. / / it is able to include it. /
/ / / /
/ A key and an indication of the user authentication given to / / A key and an indication of the user authentication given to /
/ allow access to the key is given. The labels for these are / / allow access to the key is given. The labels for these are /
/ in the private space since this is just a hypothetical / / in the private space as this is a hypothetical example, /
/ example, not part of a standard protocol. / / not part of a standard protocol. /
{ {
/ eat_nonce / 10: h'99b67438dba40743266f70bf75feb1026d5134 / eat_nonce / 10: h'99b67438dba40743266f70bf75feb1026d5134
97a229bfe8', 97a229bfe8',
/ oemboot / 262: true, / oemboot / 262: true,
/ dbgstat / 263: 2, / disabled-since-boot / / dbgstat / 263: 2, / disabled-since-boot /
/ manifests / 272: [ / manifests / 272: [
[ 258, / CoAP Content ID. / [ 258, / CoAP Content ID. /
h'a600683762623334383766 h'a600683762623334383766
0c000169436172626f6e6974650d6331 0c000169436172626f6e6974650d6331
skipping to change at page 80, line 8 skipping to change at line 3488
/ SW Creator: / / SW Creator: /
/ "Industrial Automation"/ / "Industrial Automation"/
] ]
} }
} }
} }
A.1.5. Software Measurements of an IoT Device A.1.5. Software Measurements of an IoT Device
This is a simple token that might be for an IoT device. It includes This is a simple token that might be for an IoT device. It includes
CoSWID format measurments of the SW. The CoSWID is in byte-string CoSWID format measurements of the SW. The CoSWID is byte string
wrapped in the token and also shown in diagnostic form. wrapped in the token and is also shown in diagnostic form.
/ This EAT payload is for an IoT device with a TEE. The attestation / / This EAT payload is for an IoT device with a TEE. The attestation /
/ is produced by the TEE. There is a submodule for the IoT OS (the / / is produced by the TEE. There is a submodule for the IoT OS (the /
/ main OS of the IoT device that is not as secure as the TEE). The / / main OS of the IoT device that is not as secure as the TEE). The /
/ submodule contains claims for the IoT OS. The TEE also measures / / submodule contains claims for the IoT OS. The TEE also measures /
/ the IoT OS and puts the measurements in the submodule. / / the IoT OS and puts the measurements in the submodule. /
{ {
/ eat_nonce / 10: h'5e19fba4483c7896', / eat_nonce / 10: h'5e19fba4483c7896',
/ oemboot / 262: true, / oemboot / 262: true,
skipping to change at page 81, line 25 skipping to change at line 3511
/ oemid / 258: h'8945ad', / IEEE CID based / / oemid / 258: h'8945ad', / IEEE CID based /
/ ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea', / ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea',
/ submods / 266: { / submods / 266: {
"OS" : { "OS" : {
/ oemboot / 262: true, / oemboot / 262: true,
/ dbgstat / 263: 2, / disabled-since-boot / / dbgstat / 263: 2, / disabled-since-boot /
/ measurements / 273: [ / measurements / 273: [
[ [
258, / CoAP Content ID / 258, / CoAP Content ID /
/ This is a byte-string wrapped / / This is a byte-string-wrapped /
/ evidence CoSWID. It has / / evidence CoSWID. It has /
/ hashes of the main files of / / hashes of the main files of /
/ the IoT OS. / / the IoT OS. /
h'a600663463613234350c h'a600663463613234350c
17016d41636d6520522d496f542d4f 17016d41636d6520522d496f542d4f
530d65332e312e3402a2181f724163 530d65332e312e3402a2181f724163
6d6520426173652041747465737465 6d6520426173652041747465737465
7218210103a11183a318187161636d 7218210103a11183a318187161636d
655f725f696f745f6f732e65786514 655f725f696f745f6f732e65786514
1a0044b349078201582005f6b327c1 1a0044b349078201582005f6b327c1
skipping to change at page 82, line 4 skipping to change at line 3537
be529571f5569bb7dc542f98a31818 be529571f5569bb7dc542f98a31818
6a636f6d6d6f6e2e6c6962141a0023 6a636f6d6d6f6e2e6c6962141a0023
3d3b0782015820a6a9dcdfb3884da5 3d3b0782015820a6a9dcdfb3884da5
f884e4e1e8e8629958c2dbc7027414 f884e4e1e8e8629958c2dbc7027414
43a913e34de9333be6' 43a913e34de9333be6'
] ]
] ]
} }
} }
} }
/ An evidence CoSWID created for the "Acme R-IoT-OS" created by /
/ the "Acme Base Attester" (both fictious names). It provides / / This is an evidence CoSWID created for the "Acme R-IoT-OS" /
/ measurements of the SW (other than the attester SW) on the / / that is created by the "Acme Base Attester" (both fictitious /
/ device. / / names). It provides measurements of the SW (other than the /
/ attester SW) on the device. /
1398229316({ 1398229316({
/ Unique CoSWID ID / 0: "4ca245", / Unique CoSWID ID / 0: "4ca245",
/ tag-version / 12: 23, / Attester-maintained counter / / tag-version / 12: 23, / Attester-maintained counter /
/ software-name / 1: "Acme R-IoT-OS", / software-name / 1: "Acme R-IoT-OS",
/ software-version / 13: "3.1.4", / software-version / 13: "3.1.4",
/ entity / 2: { / entity / 2: {
/ entity-name / 31: "Acme Base Attester", / entity-name / 31: "Acme Base Attester",
/ role / 33: 1 / tag-creator / / role / 33: 1 / tag-creator /
}, },
skipping to change at page 83, line 4 skipping to change at line 3586
{ {
/ ...fs-name / 24: "common.lib", / ...fs-name / 24: "common.lib",
/ ...size / 20: 2309435, / ...size / 20: 2309435,
/ ...hash / 7: [ / ...hash / 7: [
1, / SHA-256 / 1, / SHA-256 /
h'a6a9dcdfb3884da5 h'a6a9dcdfb3884da5
f884e4e1e8e86299 f884e4e1e8e86299
58c2dbc702741443 58c2dbc702741443
a913e34de9333be6' a913e34de9333be6'
] ]
} }
] ]
} }
}) })
A.1.6. Attestation Results in JSON A.1.6. Attestation Results in JSON
This is a JSON-encoded payload that might be the output of a verifier This is a JSON-encoded payload that might be the output of a verifier
that evaluated the IoT Attestation example immediately above. that evaluated the IoT Attestation example immediately above.
This particular verifier knows enough about the TEE attester to be This particular verifier knows enough about the TEE attester to be
able to pass claims like debug status directly through to the relying able to pass claims such as debug status directly through to the
party. The verifier also knows the reference values for the measured relying party. The verifier also knows the reference values for the
software components and is able to check them. It informs the measured software components and is able to check them. It informs
relying party that they were correct in the "measres" claim. the relying party that they were correct in the "measres" claim.
"Trustus Verifications" is the name of the services that verifies the "Trustus Verifications" is the name of the service that verifies the
software component measurements. software component measurements.
{ {
"eat_nonce": "jkd8KL-8xQk", "eat_nonce": "jkd8KL-8xQk",
"oemboot": true, "oemboot": true,
"dbgstat": "disabled-since-boot", "dbgstat": "disabled-since-boot",
"oemid": "iUWt", "oemid": "iUWt",
"ueid": "AZj1Ck_2wFhhyIYNE6Y4", "ueid": "AZj1Ck_2wFhhyIYNE6Y4",
"swname": "Acme R-IoT-OS", "swname": "Acme R-IoT-OS",
"swversion": [ "swversion": [
skipping to change at page 83, line 46 skipping to change at line 3627
[ [
[ [
"all", "all",
"success" "success"
] ]
] ]
] ]
] ]
} }
A.1.7. JSON-encoded Token with Submodules A.1.7. JSON-Encoded Token with Submodules
This example has its lines wrapped per [RFC8792]. The lines in this example are wrapped per [RFC8792].
{ {
"eat_nonce": "lI-IYNE6Rj6O", "eat_nonce": "lI-IYNE6Rj6O",
"ueid": "AJj1Ck_2wFhhyIYNE6Y46g==", "ueid": "AJj1Ck_2wFhhyIYNE6Y46g==",
"secboot": true, "secboot": true,
"dbgstat": "disabled-permanently", "dbgstat": "disabled-permanently",
"iat": 1526542894, "iat": 1526542894,
"submods": { "submods": {
"Android App Foo": { "Android App Foo": {
"swname": "Foo.app" "swname": "Foo.app"
skipping to change at page 84, line 38 skipping to change at line 3664
GVyIiwiaWF0IjoxNjUxNzc0ODY4LCJleHAiOm51bGwsImF1ZCI6IiIsInN1YiI6IiJ9.\ GVyIiwiaWF0IjoxNjUxNzc0ODY4LCJleHAiOm51bGwsImF1ZCI6IiIsInN1YiI6IiJ9.\
gjw4nFMhLpJUuPXvMPzK1GMjhyJq2vWXg1416XKszwQ" gjw4nFMhLpJUuPXvMPzK1GMjhyJq2vWXg1416XKszwQ"
] ]
} }
} }
A.2. Signed Token Examples A.2. Signed Token Examples
A.2.1. Basic CWT Example A.2.1. Basic CWT Example
This is a simple CWT-format token signed with the ECDSA algorithm. This is a simple CWT-format token signed with the Elliptic Curve
Digital Signature Algorithm (ECDSA).
/ This is a full CWT-format token. The payload is the / / This is a full CWT-format token. The payload is the /
/ attestation hardware block above. The main structure / / attestation hardware block above. The visible main /
/ visible is that of the COSE_Sign1. / / structure is that of the COSE_Sign1. /
61( 18( [ 61( 18( [
h'A10126', / protected headers / h'A10126', / protected headers /
{}, / empty unprotected headers / {}, / empty unprotected headers /
h'A60A4CD79B964DDD5471C1393C88881901005001 h'A60A4CD79B964DDD5471C1393C88881901005001
98F50A4FF6C05861C8860D13A638EA19010219FA 98F50A4FF6C05861C8860D13A638EA19010219FA
F2190106F5190107031901048263332E3101', / payload / F2190106F5190107031901048263332E3101', / payload /
h'9B9B2F5E470000F6A20C8A4157B5763FC45BE759 h'9B9B2F5E470000F6A20C8A4157B5763FC45BE759
9A5334028517768C21AFFB845A56AB557E0C8973 9A5334028517768C21AFFB845A56AB557E0C8973
A07417391243A79C478562D285612E292C622162 A07417391243A79C478562D285612E292C622162
AB233787' / signature / AB233787' / signature /
] ) ) ] ) )
A.2.2. CBOR-encoded Detached EAT Bundle A.2.2. CBOR-Encoded Detached EAT Bundle
In this detached EAT bundle, the main token is produced by a HW In this detached EAT bundle, the main token is produced by a hardware
attestation block. The detached Claims-Set is produced by a TEE and (HW) attestation block. The detached Claims-Set is produced by a TEE
is largely identical to the Simple TEE examples above. The TEE and is largely identical to the simple TEE examples above. The TEE
digests its Claims-Set and feeds that digest to the HW block. digests its Claims-Set and feeds that digest to the HW block.
In a better example the attestation produced by the HW block would be In a better example, the attestation produced by the HW block would
a CWT and thus signed and secured by the HW block. Since the be a CWT and thus signed and secured by the HW block. Since the
signature covers the digest from the TEE that Claims-Set is also signature covers the digest from the TEE, that Claims-Set is also
secured. secured.
The detached EAT bundle itself can be assembled by untrusted The detached EAT bundle itself can be assembled by untrusted
software. software.
/ This is a detached EAT bundle tag. / / This is a detached EAT bundle tag. /
602([ 602([
/ First part is a full EAT token with claims like nonce and / / The first part is a full EAT token with claims like nonce /
/ UEID. Most importantly, it includes a submodule that is a / / and UEID. Most importantly, it includes a submodule that /
/ detached digest which is the hash of the "TEE" claims set / / is a detached digest, which is the hash of the "TEE" /
/ in the next section. The COSE payload follows: / / claims set in the next section. The COSE payload is as /
/ follows: /
/ { / / { /
/ 10: h'948F8860D13A463E', / / 10: h'948F8860D13A463E', /
/ 256: h'0198F50A4FF6C05861C8860D13A638EA', / / 256: h'0198F50A4FF6C05861C8860D13A638EA', /
/ 258: 64242, / / 258: 64242, /
/ 262: true, / / 262: true, /
/ 263: 3, / / 263: 3, /
/ 260: ["3.1", 1], / / 260: ["3.1", 1], /
/ 266: { / / 266: { /
/ "TEE": [ / / "TEE": [ /
/ -16, / / -16, /
skipping to change at page 86, line 37 skipping to change at line 3731
/ } / / } /
h'D83DD28443A10126A05866A80A48948F8860D13A463E1901 h'D83DD28443A10126A05866A80A48948F8860D13A463E1901
00500198F50A4FF6C05861C8860D13A638EA19010219FAF2 00500198F50A4FF6C05861C8860D13A638EA19010219FAF2
19010504190106F5190107031901048263332E310119010A 19010504190106F5190107031901048263332E310119010A
A163544545822F58208DEF652F47000710D9F466A4C666E2 A163544545822F58208DEF652F47000710D9F466A4C666E2
09DD74F927A1CEA352B03143E188838ABE5840F690CB0388 09DD74F927A1CEA352B03143E188838ABE5840F690CB0388
677FA624A3775FD7CBC4E8409EC9816BE32FA474733B0F98 677FA624A3775FD7CBC4E8409EC9816BE32FA474733B0F98
C27FBAEDBBC9963B9CB5ECC03C3E35B3AFC0B7B35B495DEA C27FBAEDBBC9963B9CB5ECC03C3E35B3AFC0B7B35B495DEA
C0997122EA867F07B8D5EB', C0997122EA867F07B8D5EB',
{ {
/ A CBOR-encoded byte-string wrapped EAT claims-set. It / / A CBOR-encoded byte-string-wrapped EAT claims-set. It /
/ contains claims suitable for a TEE. / / contains claims suitable for a TEE. /
"TEE" : h'a40a48948f8860d13a463e190106f519010702 "TEE" : h'a40a48948f8860d13a463e190106f519010702
190111818218795858a60064336132340c0101 190111818218795858a60064336132340c0101
6b41636d6520544545204f530d65332e312e34 6b41636d6520544545204f530d65332e312e34
0282a2181f6b41636d6520544545204f531821 0282a2181f6b41636d6520544545204f531821
01a2181f6b41636d6520544545204f53182102 01a2181f6b41636d6520544545204f53182102
06a111a118186e61636d655f7465655f332e65 06a111a118186e61636d655f7465655f332e65
7865' 7865'
} }
]) ])
/ This example contains submodule that is a detached digest, / / This example contains a submodule that is a detached digest, /
/ which is the hash of a Claims-Set convey outside this token. / / which is the hash of a Claims-Set conveyed outside this /
/ Other than that is is the other example of a token from an / / token. Additionally, there is an example of a token from an /
/ attestation HW block. / / attestation HW block. /
{ {
/ eat_nonce / 10: h'3515744961254b41a6cf9c02', / eat_nonce / 10: h'3515744961254b41a6cf9c02',
/ ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea', / ueid / 256: h'0198f50a4ff6c05861c8860d13a638ea',
/ oemid / 258: 64242, / Private Enterprise Number / / oemid / 258: 64242, / Private Enterprise Number /
/ oemboot / 262: true, / oemboot / 262: true,
/ dbgstat / 263: 3, / disabled-permanently / / dbgstat / 263: 3, / disabled-permanently /
/ hwversion / 260: [ "3.1", 1 ], / multipartnumeric / / hwversion / 260: [ "3.1", 1 ], / multipartnumeric /
/ submods/ 266: { / submods/ 266: {
"TEE": [ / detached digest submod / "TEE": [ / detached digest submod /
-16, / SHA-256 / -16, / SHA-256 /
h'e5cf95fd24fab7144674 h'e5cf95fd24fab7144674
2dd58d43dae178e55fe2 2dd58d43dae178e55fe2
b94291a9291082ffc263 b94291a9291082ffc263
5a0b' 5a0b'
] ]
} }
} }
A.2.3. JSON-encoded Detached EAT Bundle A.2.3. JSON-Encoded Detached EAT Bundle
In this bundle there are two detached Claims-Sets, "Audio Subsystem" In this bundle, there are two detached Claims-Sets: "Audio Subsystem"
and "Graphics Subsystem". The JWT at the start of the bundle has and "Graphics Subsystem". The JWT at the start of the bundle has
detached signature submodules with hashes that cover these two detached signature submodules with hashes that cover these two
Claims-Sets. The JWT itself is protected using HMAC with a key of Claims-Sets. The JWT itself is protected using the Hashed Message
"xxxxxx". Authentication Code (HMAC) with a key of "xxxxxx".
This example has its lines wrapped per [RFC8792]. The lines in this example are wrapped per [RFC8792].
[ [
[ [
"JWT", "JWT",
"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJlYXRfbm9uY2UiOiJ5dT\ "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJlYXRfbm9uY2UiOiJ5dT\
c2Tk44SXVWNmUiLCJzdWJtb2RzIjp7IkF1ZGlvIFN1YnN5c3RlbSI6WyJESUdFU1QiLF\ c2Tk44SXVWNmUiLCJzdWJtb2RzIjp7IkF1ZGlvIFN1YnN5c3RlbSI6WyJESUdFU1QiLF\
siU0hBLTI1NiIsIkZSRW4yVlR3aTk5cWNNRVFzYmxtTVFnM2I1b2ZYUG5OM1BJYW5CME\ siU0hBLTI1NiIsIkZSRW4yVlR3aTk5cWNNRVFzYmxtTVFnM2I1b2ZYUG5OM1BJYW5CME\
5RT3MiXV0sIkdyYXBoaWNzIFN1YnN5c3RlbSI6WyJESUdFU1QiLFsiU0hBLTI1NiIsIk\ 5RT3MiXV0sIkdyYXBoaWNzIFN1YnN5c3RlbSI6WyJESUdFU1QiLFsiU0hBLTI1NiIsIk\
52M3NqUVU3Q1Z0RFRka0RTUlhWcFZDNUNMVFBCWmVQWWhTLUhoVlZWMXMiXV19fQ.FYs\ 52M3NqUVU3Q1Z0RFRka0RTUlhWcFZDNUNMVFBCWmVQWWhTLUhoVlZWMXMiXV19fQ.FYs\
7R-TKhgAk85NyCOPQlbtGGjFM_3chnhBEOuM6qCo" 7R-TKhgAk85NyCOPQlbtGGjFM_3chnhBEOuM6qCo"
skipping to change at page 88, line 35 skipping to change at line 3806
] ]
Appendix B. UEID Design Rationale Appendix B. UEID Design Rationale
B.1. Collision Probability B.1. Collision Probability
This calculation is to determine the probability of a collision of This calculation is to determine the probability of a collision of
type 0x01 UEIDs given the total possible entity population and the type 0x01 UEIDs given the total possible entity population and the
number of entities in a particular entity management database. number of entities in a particular entity management database.
Three different sized databases are considered. The number of Three different-sized databases are considered. The number of
devices per person roughly models non-personal devices such as devices per person roughly models non-personal devices such as
traffic lights, devices in stores they shop in, facilities they work traffic lights, devices in stores they shop in, facilities they work
in and so on, even considering individual light bulbs. A device may in, and so on, even considering individual light bulbs. A device may
have individually attested subsystems, for example parts of a car or have individually attested subsystems, for example, parts of a car or
a mobile phone. It is assumed that the largest database will have at a mobile phone. It is assumed that the largest database will have at
most 10% of the world's population of devices. Note that databases most 10% of the world's population of devices. Note that databases
that handle more than a trillion records exist today. that handle more than a trillion records exist today.
The trillion-record database size models an easy-to-imagine reality The trillion-record database size models an easy-to-imagine reality
over the next decades. The quadrillion-record database is roughly at over the next decades. The quadrillion-record database is roughly at
the limit of what is imaginable and should probably be accommodated. the limit of what is imaginable and should probably be accommodated.
The 100 quadrillion database is highly speculative perhaps involving The 100 quadrillion database is highly speculative perhaps involving
nanorobots for every person, livestock animal and domesticated bird. nanorobots for every person, livestock animals, and domesticated
It is included to round out the analysis. birds. It is included to round out the analysis.
Note that the items counted here certainly do not have IP address and Note that the items counted here certainly do not have IP addresses
are not individually connected to the network. They may be connected and are not individually connected to the network. They may be
to internal buses, via serial links, Bluetooth and so on. This is connected to internal buses, via serial links, via Bluetooth, and so
not the same problem as sizing IP addresses. on. This is not the same problem as sizing IP addresses.
+=========+===========+============+==========+=================+ +=========+===========+=============+==========+=================+
| People | Devices / | Subsystems | Database | Database Size | | People | Devices/ | Subsystems/ | Database | Database Size |
| | Person | / Device | Portion | | | | Person | Device | Portion | |
+=========+===========+============+==========+=================+ +=========+===========+=============+==========+=================+
| 10 | 100 | 10 | 10% | trillion | | 10 | 100 | 10 | 10% | trillion |
| billion | | | | (10^12) | | billion | | | | (10^12) |
+---------+-----------+------------+----------+-----------------+ +---------+-----------+-------------+----------+-----------------+
| 10 | 100,000 | 10 | 10% | quadrillion | | 10 | 100,000 | 10 | 10% | quadrillion |
| billion | | | | (10^15) | | billion | | | | (10^15) |
+---------+-----------+------------+----------+-----------------+ +---------+-----------+-------------+----------+-----------------+
| 100 | 1,000,000 | 10 | 10% | 100 quadrillion | | 100 | 1,000,000 | 10 | 10% | 100 quadrillion |
| billion | | | | (10^17) | | billion | | | | (10^17) |
+---------+-----------+------------+----------+-----------------+ +---------+-----------+-------------+----------+-----------------+
Table 5: Entity Database Size Examples Table 5: Entity Database Size Examples
This is conceptually similar to the Birthday Problem where m is the This is conceptually similar to the Birthday Problem where m is the
number of possible birthdays, always 365, and k is the number of number of possible birthdays (always 365) and k is the number of
people. It is also conceptually similar to the Birthday Attack where people. It is also conceptually similar to the Birthday Attack where
collisions of the output of hash functions are considered. collisions of the output of hash functions are considered.
The proper formula for the collision calculation is The proper formula for the collision calculation is:
p = 1 - e^{-k^2/(2n)} p = 1 - e^{-k^2/(2n)}
p Collision Probability For this calculation:
n Total possible population
k Actual population p: Collision probability
n: Total possible population
k: Actual population
However, for the very large values involved here, this formula However, for the very large values involved here, this formula
requires floating point precision higher than commonly available in requires floating-point precision higher than commonly available in
calculators and software so this simple approximation is used. See calculators and software, so this simple approximation is used. See
[BirthdayAttack]. [BirthdayAttack].
p = k^2 / 2n p = k^2 / 2n
For this calculation: For this calculation:
p Collision Probability p: Collision probability
n Total population based on number of bits in UEID n: Total population based on number of bits in UEID
k Population in a database k: Population in a database
+=====================+==============+==============+==============+ +=====================+==============+==============+==============+
| Database Size | 128-bit UEID | 192-bit UEID | 256-bit UEID | | Database Size | 128-bit UEID | 192-bit UEID | 256-bit UEID |
+=====================+==============+==============+==============+ +=====================+==============+==============+==============+
| trillion (10^12) | 2 * 10^-15 | 8 * 10^-35 | 5 * 10^-55 | | trillion (10^12) | 2 * 10^-15 | 8 * 10^-35 | 5 * 10^-55 |
+---------------------+--------------+--------------+--------------+ +---------------------+--------------+--------------+--------------+
| quadrillion (10^15) | 2 * 10^-09 | 8 * 10^-29 | 5 * 10^-49 | | quadrillion (10^15) | 2 * 10^-09 | 8 * 10^-29 | 5 * 10^-49 |
+---------------------+--------------+--------------+--------------+ +---------------------+--------------+--------------+--------------+
| 100 quadrillion | 2 * 10^-05 | 8 * 10^-25 | 5 * 10^-45 | | 100 quadrillion | 2 * 10^-05 | 8 * 10^-25 | 5 * 10^-45 |
| (10^17) | | | | | (10^17) | | | |
skipping to change at page 90, line 25 skipping to change at line 3891
Table 6: UEID Size Options Table 6: UEID Size Options
Next, to calculate the probability of a collision occurring in one Next, to calculate the probability of a collision occurring in one
year's operation of a database, it is assumed that the database size year's operation of a database, it is assumed that the database size
is in a steady state and that 10% of the database changes per year. is in a steady state and that 10% of the database changes per year.
For example, a trillion record database would have 100 billion states For example, a trillion record database would have 100 billion states
per year. Each of those states has the above calculated probability per year. Each of those states has the above calculated probability
of a collision. of a collision.
This assumption is a worst-case since it assumes that each state of This assumption is a worst-case scenario since it assumes that each
the database is completely independent from the previous state. In state of the database is completely independent from the previous
reality this is unlikely as state changes will be the addition or state. In reality, this is unlikely as state changes will be the
deletion of a few records. addition or deletion of a few records.
The following tables gives the time interval until there is a The following table gives the time interval until there is a
probability of a collision based on there being one tenth the number probability of a collision, which is based on there being one tenth
of states per year as the number of records in the database. of the number of states per year as the number of records in the
database.
t = 1 / ((k / 10) * p) t = 1 / ((k / 10) * p)
t Time until a collision For this calculation:
p Collision probability for UEID size
k Database size t: Time until a collision
p: Collision probability for UEID size
k: Database size
+=====================+==============+==============+==============+ +=====================+==============+==============+==============+
| Database Size | 128-bit UEID | 192-bit UEID | 256-bit UEID | | Database Size | 128-bit UEID | 192-bit UEID | 256-bit UEID |
+=====================+==============+==============+==============+ +=====================+==============+==============+==============+
| trillion (10^12) | 60,000 years | 10^24 years | 10^44 years | | trillion (10^12) | 60,000 years | 10^24 years | 10^44 years |
+---------------------+--------------+--------------+--------------+ +---------------------+--------------+--------------+--------------+
| quadrillion (10^15) | 8 seconds | 10^14 years | 10^34 years | | quadrillion (10^15) | 8 seconds | 10^14 years | 10^34 years |
+---------------------+--------------+--------------+--------------+ +---------------------+--------------+--------------+--------------+
| 100 quadrillion | 8 | 10^11 years | 10^31 years | | 100 quadrillion | 8 | 10^11 years | 10^31 years |
| (10^17) | microseconds | | | | (10^17) | microseconds | | |
+---------------------+--------------+--------------+--------------+ +---------------------+--------------+--------------+--------------+
Table 7: UEID Collision Probability Table 7: UEID Collision Probability
Clearly, 128 bits is enough for the near future thus the requirement Clearly, 128 bits is enough for the near future, thus the requirement
that type 0x01 UEIDs be a minimum of 128 bits. that type 0x01 UEIDs be a minimum of 128 bits.
There is no requirement for 256 bits today as quadrillion-record There is no requirement for 256 bits today as quadrillion-record
databases are not expected in the near future and because this time- databases are not expected in the near future and because this time-
to-collision calculation is a very worst case. A future update of to-collision calculation is a very worst-case scenario. A future
the standard may increase the requirement to 256 bits, so there is a update of the standard may increase the requirement to 256 bits, so
requirement that implementations be able to receive 256-bit UEIDs. there is a requirement that implementations be able to receive
256-bit UEIDs.
B.2. No Use of UUID B.2. No Use of UUID
A UEID is not a Universally Unique Identifier (UUID) [RFC9562] by A UEID is not a Universally Unique Identifier (UUID) [RFC9562] by
conscious choice for the following reasons. conscious choice for the following reasons.
UUIDs are limited to 128 bits which may not be enough for some future UUIDs are limited to 128 bits, which may not be enough for some
use cases. future use cases.
Today, cryptographic-quality random numbers are available from common Today, cryptographic-quality random numbers are available from common
computing platforms. In particular, hardware randomness sources were computing platforms. In particular, hardware randomness sources were
introduced in CPUs between 2010 and 2015. Operating systems and introduced in CPUs between 2010 and 2015. Operating systems and
cryptographic libraries make use of this hardware. Consequently, cryptographic libraries make use of this hardware. Consequently,
there is little need for protocols to construct random numbers from there is little need for protocols to construct random numbers from
multiple sources on their own. multiple sources on their own.
Version 4 UUIDs do allow for use of such cryptographic-quality random Version 4 UUIDs do allow for the use of such cryptographic-quality
numbers, but do so by mapping into the overall UUID structure of time random numbers, but they do so by mapping into the overall UUID
and clock values. This structure is of no value here yet adds structure of time and clock values. This structure is of no value
complexity. It also slightly reduces the number of actual bits with here yet adds complexity. It also slightly reduces the number of
entropy. actual bits with entropy.
The design of UUID accommodates the construction of a unique The design of UUID accommodates the construction of a unique
identifier by combination of several identifiers that separately do identifier by the combination of several identifiers that separately
not provide sufficient uniqueness. UEID takes the view that this do not provide sufficient uniqueness. UEID takes the view that this
construction is no longer needed, in particular because construction is no longer needed, in particular because
cryptographic-quality random number generators are readily available. cryptographic-quality random number generators are readily available.
It takes the view that hardware, software and/or manufacturing It takes the view that hardware, software, and/or manufacturing
process implement UEID in a simple and direct way. processes implement UEID in a simple and direct way.
Note also that that a type 2 UEID (EUI/MAC) is only 7 bytes compared Note also that a type 2 UEID (EUI/MAC) is only 7 bytes whereas a UUID
to 16 for a UUID. is 16.
Appendix C. EAT Relation to IEEE.802.1AR Secure Device Identity (DevID) Appendix C. EAT Relation to IEEE.802.1AR Secure Device Identity (DevID)
This section describes several distinct ways in which an IEEE IDevID This section describes several distinct ways in which an IEEE Initial
[IEEE.802.1AR] relates to EAT, particularly to UEID and SUEID. Device Identifier (IDevID) [IEEE.802.1AR] relates to EAT,
particularly to UEID and SUEID.
[IEEE.802.1AR] orients around the definition of an implementation [IEEE.802.1AR] orients around the definition of an implementation
called a "DevID Module." It describes how IDevIDs and LDevIDs are called a "DevID Module". It describes how IDevIDs and LDevIDs are
stored, protected and accessed using a DevID Module. A particular stored, protected, and accessed using a DevID Module. A particular
level of defense against attack that should be achieved to be a DevID level of defense against attack that should be achieved to be a DevID
is defined. The intent is that IDevIDs and LDevIDs can be used with is defined here. The intent is that IDevIDs and LDevIDs can be used
any network protocol or message format. In these protocols and with any network protocol or message format. In these protocols and
message formats the DevID secret is used to sign a nonce or similar message formats, the DevID secret is used to sign a nonce or similar
to prove the association of the DevID certificates with the device. to prove the association of the DevID certificates with the device.
By contrast, EAT standardizes a message format that is sent to a By contrast, EAT standardizes a message format that is sent to a
relying party, the very thing that is not defined in [IEEE.802.1AR]. relying party, the very thing that is not defined in [IEEE.802.1AR].
Nor does EAT give details on how keys, data and such are stored, Nor does EAT give details on how keys, data, and such are stored,
protected and accessed. EAT is intended to work with a variety of protected, and accessed. EAT is intended to work with a variety of
different on-device implementations ranging from minimal protection different on-device implementations ranging from minimal protection
of assets to the highest levels of asset protection. It does not of assets to the highest levels of asset protection. It does not
define any particular level of defense against attack, instead define any particular level of defense against attack; instead, it
providing a set of security considerations. provides a set of security considerations.
EAT and DevID can be viewed as complimentary when used together or as EAT and DevID can be viewed as complimentary when used together or as
competing to provide a device identity service. competing to provide a device identity service.
C.1. DevID Used With EAT C.1. DevID Used with EAT
As just described, EAT standardizes a message format and As described above, EAT standardizes a message format, but
[IEEE.802.1AR] does not. Vice versa, EAT does not define a device [IEEE.802.1AR] does not. Vice versa, EAT does not define a device
implementation, but DevID does. implementation, but DevID does.
Hence, EAT can be the message format that a DevID is used with. The Hence, EAT can be the message format that a DevID is used with. The
DevID secret becomes the attestation key used to sign EATs. The DevID secret becomes the attestation key used to sign EATs, and the
DevID and its certificate chain become the endorsement sent to the DevID and its certificate chain become the endorsement sent to the
verifier. verifier.
In this case, the EAT and the DevID are likely to both provide a In this case, the EAT and the DevID are likely to both provide a
device identifier (e.g. a serial number). In the EAT it is the UEID device identifier (e.g., a serial number). In the EAT, it is the
(or SUEID). In the DevID (used as an endorsement), it is a device UEID (or SUEID). In the DevID (used as an endorsement), it is a
serial number included in the subject field of the DevID certificate. device serial number included in the subject field of the DevID
It is probably a good idea in this use for them to be the same serial certificate. For this use, it is a good idea for the serial numbers
number or for the UEID to be a hash of the DevID serial number. to be the same or for the UEID to be a hash of the DevID serial
number.
C.2. How EAT Provides an Equivalent Secure Device Identity C.2. How EAT Provides an Equivalent Secure Device Identity
The UEID, SUEID and other claims like OEM ID are equivalent to the The UEID, SUEID, and other claims such as OEM ID are equivalent to
secure device identity put into the subject field of a DevID the secure device identity that is put into the subject field of a
certificate. These EAT claims can represent all the same fields and DevID certificate. These EAT claims can represent all the same
values that can be put in a DevID certificate subject. EAT fields and values that can be put in a DevID certificate subject.
explicitly and carefully defines a variety of useful claims. EAT explicitly and carefully defines a variety of useful claims.
EAT secures the conveyance of these claims by having them signed on EAT secures the conveyance of these claims by having them signed on
the device by the attestation key when the EAT is generated. EAT the device by the attestation key when the EAT is generated. EAT
also signs the nonce that gives freshness at this time. Since these also signs the nonce that gives freshness at this time. Since these
claims are signed for every EAT generated, they can include things claims are signed for every EAT generated, they can include things
that vary over time like GPS location. that vary over time such as GPS location.
DevID secures the device identity fields by having them signed by the DevID secures the device identity fields when they are signed by the
manufacturer of the device into a certificate. That certificate is manufacturer of the device into a certificate. That certificate is
created once during the manufacturing of the device and never changes created once during the manufacturing of the device and never
so the fields cannot change. changes, so the fields cannot change.
So in one case the signing of the identity happens on the device and So in one case, the signing of the identity happens on the device,
the other in a manufacturing facility, but in both cases the signing and in the other case, it happens in a manufacturing facility.
of the nonce that proves the binding to the actual device happens on However, in both cases, the signing of the nonce that proves the
the device. binding to the actual device happens on the device.
While EAT does not specify how the signing keys, signature process While EAT does not specify how the signing keys, signature process,
and storage of the identity values should be secured against attack, and storage of the identity values should be secured against attack,
an EAT implementation may have equal defenses against attack. One an EAT implementation may have equal defenses against attack. One
reason EAT uses CBOR is because it is simple enough that a basic EAT reason EAT uses CBOR is because it is simple enough that a basic EAT
implementation can be constructed entirely in hardware. This allows implementation can be constructed entirely in hardware. This allows
EAT to be implemented with the strongest defenses possible. EAT to be implemented with the strongest defenses possible.
C.3. An X.509 Format EAT C.3. An X.509 Format EAT
It is possible to define a way to encode EAT claims in an X.509 It is possible to define a way to encode EAT claims in an X.509
certificate. For example, the EAT claims might be mapped to X.509 v3 certificate. For example, the EAT claims might be mapped to X.509 v3
extensions. It is even possible to stuff a whole CBOR-encoded extensions. It is even possible to stuff a whole CBOR-encoded
unsigned EAT token into a X.509 certificate. unsigned EAT token into an X.509 certificate.
If that X.509 certificate is an IDevID or LDevID, this becomes If that X.509 certificate is an IDevID or LDevID, it becomes another
another way to use EAT and DevID together. way to use EAT and DevID together.
Note that the DevID must still be used with an authentication Note that the DevID must still be used with an authentication
protocol that has a nonce or equivalent. The EAT here is not being protocol that has a nonce or equivalent. The EAT here is not being
used as the protocol to interact with the relying party. used as the protocol to interact with the relying party.
C.4. Device Identifier Permanence C.4. Device Identifier Permanence
In terms of permanence, an IDevID is similar to a UEID in that they In terms of permanence, an IDevID is similar to a UEID in that they
do not change over the life of the device. They cease to exist only do not change over the life of the device. They cease to exist only
when the device is destroyed. when the device is destroyed.
skipping to change at page 94, line 15 skipping to change at line 4074
[IEEE.802.1AR] describes much of this permanence as resistant to [IEEE.802.1AR] describes much of this permanence as resistant to
attacks that seek to change the ID. IDevID permanence can be attacks that seek to change the ID. IDevID permanence can be
described this way because [IEEE.802.1AR] is oriented around the described this way because [IEEE.802.1AR] is oriented around the
definition of an implementation with a particular level of defense definition of an implementation with a particular level of defense
against attack. against attack.
EAT is not defined around a particular implementation and must work EAT is not defined around a particular implementation and must work
on a range of devices that have a range of defenses against attack. on a range of devices that have a range of defenses against attack.
EAT thus cannot be defined permanence in terms of defense against EAT thus cannot be defined permanence in terms of defense against
attack. EAT's definition of permanence is in terms of operations and attack. EAT's definition of permanence is in terms of operations and
device lifecycle. device life cycle.
Appendix D. CDDL for CWT and JWT Appendix D. CDDL for CWT and JWT
[RFC8392] was published before CDDL was available and thus is [RFC8392] was published before CDDL was available and thus is
specified in prose, not CDDL. Following is CDDL specifying CWT as it specified in prose, not CDDL. In the following example, CDDL
is needed to complete this specification. This CDDL also covers the specifies CWT as it is needed to complete this specification. This
Claims-Set for JWT. CDDL also covers the Claims-Set for JWT.
Note that Section 4.3.1 requires that the iat claim be the type Note that Section 4.3.1 requires that the "iat" claim be the type
~time-int (Section 7.2.1), not the type ~time when it is used in an ~time-int (Section 7.2.1), not the type ~time when it is used in an
EAT as floating-point values are not allowed for the "iat" claim in EAT as floating-point values are not allowed for the "iat" claim in
EAT. EAT.
The COSE-related types in this CDDL are defined in [RFC9052]. The COSE-related types in this CDDL are defined in [RFC9052].
This however is NOT a normative or standard definition of CWT or JWT This, however, is NOT a normative or standard definition of CWT or
in CDDL. The prose in CWT and JWT remain the normative definition. JWT in CDDL. The prose in CWT and JWT remains the normative
definition.
; This is replicated from draft-ietf-rats-uccs ; This is replicated from draft-ietf-rats-uccs.
Claims-Set = { Claims-Set = {
* $$Claims-Set-Claims * $$Claims-Set-Claims
* Claim-Label .feature "extended-claims-label" => any * Claim-Label .feature "extended-claims-label" => any
} }
Claim-Label = int / text Claim-Label = int / text
string-or-uri = text string-or-uri = text
$$Claims-Set-Claims //= ( iss-claim-label => string-or-uri ) $$Claims-Set-Claims //= ( iss-claim-label => string-or-uri )
$$Claims-Set-Claims //= ( sub-claim-label => string-or-uri ) $$Claims-Set-Claims //= ( sub-claim-label => string-or-uri )
skipping to change at page 95, line 40 skipping to change at line 4129
JSON-ONLY<J> = J .feature "json" JSON-ONLY<J> = J .feature "json"
CBOR-ONLY<C> = C .feature "cbor" CBOR-ONLY<C> = C .feature "cbor"
JC<J,C> = JSON-ONLY<J> / CBOR-ONLY<C> JC<J,C> = JSON-ONLY<J> / CBOR-ONLY<C>
; Same as JC<> but with unwound generic nesting as it seems to cause ; Same as JC<> but with unwound generic nesting as it seems to cause
; problems. Perhaps this is the nesting problem described in RFC ; problems. Perhaps this is the nesting problem described in RFC
; 8610. ; 8610.
JC-NEST-SAFE<J,C> = J .feature "json" / C .feature "cbor" JC-NEST-SAFE<J,C> = J .feature "json" / C .feature "cbor"
; A JWT message is either a JWS or JWE in compact serialization form ; A JWT message is either a JSON Web Signature (JWS) or a JSON Web
; with the payload a Claims-Set. Compact serialization is the ; Encryption (JWE) in compact serialization form with the payload
; protected headers, payload and signature, each b64url encoded and ; as a Claims-Set. Compact serialization is the protected headers,
; separated by a ".". This CDDL simply matches top-level syntax of of ; payload, and signature that are each b64url-encoded and separated
; a JWS or JWE since it is not possible to do more in CDDL. ; by a ".". This CDDL simply matches the top-level syntax of a JWS
; or JWE as it is not possible to do more in CDDL.
JWT-Message = JWT-Message =
text .regexp "[A-Za-z0-9_-]+\\.[A-Za-z0-9_-]+\\.[A-Za-z0-9_-]+" text .regexp "[A-Za-z0-9_-]+\\.[A-Za-z0-9_-]+\\.[A-Za-z0-9_-]+"
; Note that the payload of a JWT is defined in claims-set.cddl. That ; Note that the payload of a JWT is defined in claims-set.cddl. That
; definition is common to CBOR and JSON. ; definition is common to CBOR and JSON.
; This is some CDDL describing a CWT at the top level This is ; This is some CDDL describing a CWT at the top level. This is
; not normative. RFC 8392 is the normative definition of CWT. ; not normative. RFC 8392 is the normative definition of CWT.
CWT-Messages = CWT-Tagged-Message / CWT-Untagged-Message CWT-Messages = CWT-Tagged-Message / CWT-Untagged-Message
; The payload of the COSE_Message is always a Claims-Set ; The payload of the COSE_Message is always a Claims-Set.
; The contents of a CWT Tag must always be a COSE tag ; The contents of a CWT tag must always be a COSE tag.
CWT-Tagged-Message = #6.61(COSE_Tagged_Message) CWT-Tagged-Message = #6.61(COSE_Tagged_Message)
; An untagged CWT may be a COSE tag or not ; An untagged CWT may be a COSE tag or not.
CWT-Untagged-Message = COSE_Messages CWT-Untagged-Message = COSE_Messages
Appendix E. New Claim Design Considerations Appendix E. New Claim Design Considerations
The following are design considerations that may be helpful to take The following are design considerations that may be helpful to take
into account when creating new EAT claims. It is the product of into account when creating new EAT claims. This is the product of
discussion in the working group. discussion in the RAT Working Group.
EAT reuses the CWT and JWT claims registries. There is no registry EAT reuses the CWT and JWT claims registries. There is no registry
exclusively for EAT claims. This is not an update to the expert exclusively for EAT claims. This is not an update to the expert
review criteria for the JWT and CWT claims registries as that would review criteria for the JWT and CWT claims registries as that would
be an overreach for this document. be an overreach for this document.
E.1. Interoperability and Relying Party Orientation E.1. Interoperability and Relying Party Orientation
It is a broad goal that EATs can be processed by relying parties in a It is a broad goal that EATs can be processed by relying parties in a
general way regardless of the type, manufacturer or technology of the general way regardless of the type, manufacturer, or technology of
device from which they originate. It is a goal that there be the device from which they originate. It is a goal that there be
general-purpose verification implementations that can verify tokens general-purpose verification implementations that can verify tokens
for large numbers of use cases with special cases and configurations for large numbers of use cases with special cases and configurations
for different device types. This is a goal of interoperability of for different device types. This is a goal of interoperability of
the semantics of claims themselves, not just of the signing, encoding the semantics of claims themselves, not just of the signing,
and serialization formats. encoding, and serialization formats.
This is a lofty goal and difficult to achieve broadly requiring This is a lofty goal and difficult to achieve broadly as it requires
careful definition of claims in a technology-neutral way. Sometimes careful definition of claims in a technology-neutral way. Sometimes
it will be difficult to design a claim that can represent the it will be difficult to design a claim that can represent the
semantics of data from very different device types. However, the semantics of data from very different device types. However, the
goal remains even when difficult. goal remains even when difficult.
E.2. Operating System and Technology Neutral E.2. Operating System and Technology Neutral
Claims should be defined such that they are not specific to an Claims should be defined such that they are not specific to an
operating system. They should be applicable to multiple large high- operating system. They should be applicable to multiple large high-
level operating systems from different vendors. They should also be level operating systems from different vendors as well as to multiple
applicable to multiple small embedded operating systems from multiple small embedded operating systems from multiple vendors and everything
vendors and everything in between. in between.
Claims should not be defined such that they are specific to a Claims should not be defined such that they are specific to a
software environment or programming language. software environment or programming language.
Claims should not be defined such that they are specific to a chip or Claims should not be defined such that they are specific to a chip or
particular hardware. For example, they should not just be the particular hardware. For example, they should not just be the
contents of some HW status register as it is unlikely that the same contents of some HW status register as it is unlikely that the same
HW status register with the same bits exists on a chip of a different HW status register with the same bits exists on a chip of a different
manufacturer. manufacturer.
skipping to change at page 97, line 25 skipping to change at line 4211
claim that has been defined in this neutral way. claim that has been defined in this neutral way.
E.3. Security Level Neutral E.3. Security Level Neutral
Many use cases will have EATs generated by some of the most secure Many use cases will have EATs generated by some of the most secure
hardware and software that exists. Secure Elements and smart cards hardware and software that exists. Secure Elements and smart cards
are examples of this. However, EAT is intended for use in low- are examples of this. However, EAT is intended for use in low-
security use cases the same as high-security use case. For example, security use cases the same as high-security use case. For example,
an app on a mobile device may generate EATs on its own. an app on a mobile device may generate EATs on its own.
Claims should be defined and registered on the basis of whether they Claims should be defined and registered based on whether they are
are useful and interoperable, not based on security level. In useful and interoperable, not based on security level. In
particular, there should be no exclusion of claims because they are particular, there should be no exclusion of claims because they are
just used only in low-security environments. only used in low-security environments.
E.4. Reuse of Extant Data Formats E.4. Reuse of Extant Data Formats
Where possible, claims should use already standardized data items, Where possible, claims should use data items, identifiers, and
identifiers and formats. This takes advantage of the expertise put formats that are already standardized. This takes advantage of the
into creating those formats and improves interoperability. expertise put into creating those formats and improves
interoperability.
Often extant claims will not be defined in an encoding or Often, extant claims will not be defined in an encoding or
serialization format used by EAT. It is preferred to define a CBOR serialization format used by EAT. It is preferred to define a CBOR
and JSON encoding for them so that EAT implementations do not require and JSON encoding for them so that EAT implementations do not require
a plethora of encoders and decoders for serialization formats. a plethora of encoders and decoders for serialization formats.
In some cases, it may be better to use the encoding and serialization In some cases, it may be better to use the encoding and serialization
as is. For example, signed X.509 certificates and CRLs can be as is. For example, signed X.509 certificates and Certificate
carried as-is in a byte string. This retains interoperability with Revocation Lists (CRLs) can be carried as is in a byte string. This
the extensive infrastructure for creating and processing X.509 retains interoperability with the extensive infrastructure for
certificates and CRLs. creating and processing X.509 certificates and CRLs.
E.5. Proprietary Claims E.5. Proprietary Claims
It is not always possible or convenient to achieve the above goals, It is not always possible or convenient to achieve the above goals,
so the definition and use of proprietary claims is an option. so the definition and use of proprietary claims is an option.
For example, a device manufacturer may generate a token with For example, a device manufacturer may generate a token with
proprietary claims intended only for verification by a service proprietary claims intended only for verification by a service
offered by that device manufacturer. This is a supported use case. offered by that device manufacturer. This is a supported use case.
In many cases proprietary claims will be the easiest and most obvious In many cases, proprietary claims will be the easiest and most
way to proceed, however for better interoperability, use of general obvious way to proceed; however, for better interoperability, use of
standardized claims is preferred. general standardized claims is preferred.
Appendix F. Endorsements and Verification Keys Appendix F. Endorsements and Verification Keys
The verifier must possess the correct key when it performs the The verifier must possess the correct key when it performs the
cryptographic part of an EAT verification (e.g., verifying the COSE/ cryptographic part of an EAT verification (e.g., verifying the COSE/
JOSE signature). This section describes several ways to identify the JOSE signature). This section describes several ways to identify the
verification key. There is not one standard method. verification key. There is not one standard method.
The verification key itself may be a public key, a symmetric key or The verification key itself may be a public key, a symmetric key, or
something complicated in the case of a scheme like Direct Anonymous something complicated in the case of a scheme such as Direct
Attestation (DAA). Anonymous Attestation (DAA).
RATS Architecture [RFC9334] describes what is called an endorsement. RATS Architecture [RFC9334] describes what is called an endorsement.
This is an input to the verifier that is usually the basis of the This is an input to the verifier that is usually the basis of the
trust placed in an EAT and the attester that generated it. It may trust placed in an EAT and the attester that generated it. It may
contain the public key for verification of the signature on the EAT. contain the public key for verification of the signature on the EAT,
It may contain implied claims, those that are passed on to the and it may contain implied claims, i.e., those that are passed on to
relying party in attestation results. the relying party in attestation results.
There is not yet any standard format(s) for an endorsement. One There is not yet any standard format(s) for an endorsement. One
format that may be used for an endorsement is an X.509 certificate. format that may be used for an endorsement is an X.509 certificate.
Endorsement data like reference values and implied claims can be Endorsement data such as reference values and implied claims can be
carried in X.509 v3 extensions. In this use, the public key in the carried in X.509 v3 extensions. In this use, the public key in the
X.509 certificate becomes the verification key, so identification of X.509 certificate becomes the verification key, so identification of
the endorsement is also identification of the verification key. the endorsement is also identification of the verification key.
The verification key identification and establishment of trust in the The verification key identification and establishment of trust in the
EAT and the attester may also be by some other means than an EAT and the attester may also be by some other means than an
endorsement. endorsement.
For the components (attester, verifier, relying party,...) of a For the components (attester, verifier, relying party, etc.) of a
particular end-to-end attestation system to reliably interoperate, particular end-to-end attestation system to reliably interoperate,
its definition should specify how the verification key is identified. its definition should specify how the verification key is identified.
Usually, this will be in the profile document for a particular Usually, this will be in the profile document for a particular
attestation system. attestation system.
See also security consideration in Section 9.6. See also the security considerations in Section 9.6.
F.1. Identification Methods F.1. Identification Methods
Following is a list of possible methods of key identification. A Following is a list of possible methods of key identification. A
specific attestation system may employ any one of these or one not specific attestation system may employ any one of these or one not
listed here. listed here.
The following assumes endorsements are X.509 certificates or The following assumes endorsements are X.509 certificates or
equivalent and thus does not mention or define any identifier for equivalent and thus does not mention or define any identifier for
endorsements in other formats. If such an endorsement format is endorsements in other formats. If such an endorsement format is
created, new identifiers for them will also need to be created. created, new identifiers for them will also need to be created.
F.1.1. COSE/JWS Key ID F.1.1. COSE/JWS Key ID
The COSE standard header parameter for Key ID (kid) may be used. See The COSE standard header parameter for Key ID (kid) may be used; see
[RFC9052] and [RFC7515] [RFC9052] and [RFC7515].
COSE leaves the semantics of the key ID open-ended. It could be a COSE leaves the semantics of the key ID open-ended. It could be a
record locator in a database, a hash of a public key, an input to a record locator in a database, a hash of a public key, an input to a
Key Derivation Function (KDF), an Authority Key Identifier (AKI) for Key Derivation Function (KDF), an Authority Key Identifier (AKI) for
an X.509 certificate or other. The profile document should specify an X.509 certificate, or other. The profile document should specify
what the key ID's semantics are. what the key ID's semantics are.
F.1.2. JWS and COSE X.509 Header Parameters F.1.2. JWS and COSE X.509 Header Parameters
COSE X.509 [COSE.X509.Draft] and JSON Web Signature [RFC7515] define COSE X.509 [RFC9360] and JSON Web Signature [RFC7515] define several
several header parameters (x5t, x5u,...) for referencing or carrying header parameters (x5t, x5u,...) for referencing or carrying X.509
X.509 certificates any of which may be used. certificates, any of which may be used.
The X.509 certificate may be an endorsement and thus carrying The X.509 certificate may be an endorsement and thus carrying
additional input to the verifier. It may be just an X.509 additional input to the verifier. It may be just an X.509
certificate, not an endorsement. The same header parameters are used certificate, not an endorsement. The same header parameters are used
in both cases. It is up to the attestation system design and the in both cases, and it is up to the attestation system design and the
verifier to determine which. verifier to determine which.
F.1.3. CBOR Certificate COSE Header Parameters F.1.3. CBOR Certificate COSE Header Parameters
Compressed X.509 and CBOR Native certificates are defined by CBOR Compressed X.509 and CBOR Native certificates are defined by CBOR
Certificates [CBOR.Cert.Draft]. These are semantically compatible Certificates [CBOR.Certs]. These are semantically compatible with
with X.509 and therefore can be used as an equivalent to X.509 as X.509 and therefore can be used as an equivalent to X.509 as
described above. described above.
These are identified by their own header parameters (c5t, c5u,...). These are identified by their own header parameters (c5t, c5u, etc.).
F.1.4. Claim-Based Key Identification F.1.4. Claim-Based Key Identification
For some attestation systems, a claim may be re-used as a key For some attestation systems, a claim may be reused as a key
identifier. For example, the UEID uniquely identifies the entity and identifier. For example, the UEID uniquely identifies the entity and
therefore can work well as a key identifier or endorsement therefore can work well as a key identifier or endorsement
identifier. identifier.
This has the advantage that key identification requires no additional An advantage of this is that key identification requires no
bytes in the EAT and makes the EAT smaller. additional bytes in the EAT and makes the EAT smaller.
This has the disadvantage that the unverified EAT must be A disadvantage of this is that the unverified EAT must be
substantially decoded to obtain the identifier since the identifier substantially decoded to obtain the identifier since the identifier
is in the COSE/JOSE payload, not in the headers. is in the COSE/JOSE payload, not in the headers.
Appendix G. Changes from Previous Drafts
// RFC editor: please remove this paragraph.
The following is a list of known changes since the immediately
previous drafts. This list is non-authoritative. It is meant to
help reviewers see the significant differences. A comprehensive
history is available via the IETF Datatracker's record for this
document.
G.1. From draft-ietf-rats-eat-30
* Minor typo fixes
Contributors Contributors
Many thanks to the following contributors to draft versions of this Many thanks to the following for their contributions to earlier draft
document: versions of this document:
Henk Birkholz Henk Birkholz
Fraunhofer SIT Fraunhofer SIT
Email: henk.birkholz@sit.fraunhofer.de Email: henk.birkholz@sit.fraunhofer.de
Thomas Fossati Thomas Fossati
Arm Limited Arm Limited
Email: thomas.fossati@arm.com Email: thomas.fossati@arm.com
Miguel Ballesteros Miguel Ballesteros
 End of changes. 448 change blocks. 
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