draft-ietf-rats-eat-10.txt   draft-ietf-rats-eat-11.txt 
RATS Working Group G. Mandyam RATS Working Group L. Lundblade
Internet-Draft Qualcomm Technologies Inc. Internet-Draft Security Theory LLC
Intended status: Standards Track L. Lundblade Intended status: Standards Track G. Mandyam
Expires: December 9, 2021 Security Theory LLC Expires: April 26, 2022 J. O'Donoghue
M. Ballesteros
J. O'Donoghue
Qualcomm Technologies Inc. Qualcomm Technologies Inc.
June 07, 2021 October 23, 2021
The Entity Attestation Token (EAT) The Entity Attestation Token (EAT)
draft-ietf-rats-eat-10 draft-ietf-rats-eat-11
Abstract Abstract
An Entity Attestation Token (EAT) provides a signed (attested) set of An Entity Attestation Token (EAT) provides a signed (attested) set of
claims that describe state and characteristics of an entity, claims that describe state and characteristics of an entity,
typically a device like a phone or an IoT device. These claims are typically a device like a phone or an IoT device. These claims are
used by a relying party to determine how much it wishes to trust the used by a Relying Party to determine how much it wishes to trust the
entity. entity.
An EAT is either a CWT or JWT with some attestation-oriented claims. An EAT is either a CWT or JWT with some attestation-oriented claims.
To a large degree, all this document does is extend CWT and JWT. To a large degree, all this document does is extend CWT and JWT.
Contributing
TBD
Status of This Memo Status of This Memo
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. CWT, JWT and UCCS . . . . . . . . . . . . . . . . . . . . 6 1.1. CWT, JWT, UCCS, UJCS and DEB . . . . . . . . . . . . . . 5
1.2. CDDL . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2. CDDL, CBOR and JSON . . . . . . . . . . . . . . . . . . . 6
1.3. Entity Overview . . . . . . . . . . . . . . . . . . . . . 6 1.3. Operating Model and RATS Architecture . . . . . . . . . . 7
1.4. Use as Evidence and Attestation Results . . . . . . . . . 7 1.3.1. Use as Attestation Evidence . . . . . . . . . . . . . 8
1.5. EAT Operating Models . . . . . . . . . . . . . . . . . . 7 1.3.2. Use as Attestation Results . . . . . . . . . . . . . 8
1.6. What is Not Standardized . . . . . . . . . . . . . . . . 9 1.4. Entity Overview . . . . . . . . . . . . . . . . . . . . . 9
1.6.1. Transmission Protocol . . . . . . . . . . . . . . . . 9 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.6.2. Signing Scheme . . . . . . . . . . . . . . . . . . . 9
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 10
3. The Claims . . . . . . . . . . . . . . . . . . . . . . . . . 10 3. The Claims . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1. Token ID Claim (cti and jti) . . . . . . . . . . . . . . 11 3.1. Token ID Claim (cti and jti) . . . . . . . . . . . . . . 11
3.2. Timestamp claim (iat) . . . . . . . . . . . . . . . . . . 11 3.2. Timestamp claim (iat) . . . . . . . . . . . . . . . . . . 11
3.3. Nonce Claim (nonce) . . . . . . . . . . . . . . . . . . . 12 3.3. Nonce Claim (nonce) . . . . . . . . . . . . . . . . . . . 11
3.3.1. nonce CDDL . . . . . . . . . . . . . . . . . . . . . 12
3.4. Universal Entity ID Claim (ueid) . . . . . . . . . . . . 12 3.4. Universal Entity ID Claim (ueid) . . . . . . . . . . . . 12
3.4.1. ueid CDDL . . . . . . . . . . . . . . . . . . . . . . 15 3.5. Semi-permanent UEIDs (SUEIDs) . . . . . . . . . . . . . . 14
3.5. Semi-permanent UEIDs (SUEIDs) . . . . . . . . . . . . . . 15 3.6. Hardware OEM Identification (oemid) . . . . . . . . . . . 15
3.6. OEM Identification by IEEE (oemid) . . . . . . . . . . . 16 3.6.1. Random Number Based . . . . . . . . . . . . . . . . . 15
3.6.1. oemid CDDL . . . . . . . . . . . . . . . . . . . . . 16 3.6.2. IEEE Based . . . . . . . . . . . . . . . . . . . . . 15
3.6.3. IANA Private Enterprise Number . . . . . . . . . . . 16
3.7. Hardware Version Claims (hardware-version-claims) . . . . 16 3.7. Hardware Version Claims (hardware-version-claims) . . . . 16
3.8. Software Description and Version . . . . . . . . . . . . 17 3.8. Software Name Claim . . . . . . . . . . . . . . . . . . . 17
3.9. The Security Level Claim (security-level) . . . . . . . . 17 3.9. Software Version Claim . . . . . . . . . . . . . . . . . 17
3.9.1. security-level CDDL . . . . . . . . . . . . . . . . . 18 3.10. The Security Level Claim (security-level) . . . . . . . . 17
3.10. Secure Boot Claim (secure-boot) . . . . . . . . . . . . . 19 3.11. Secure Boot Claim (secure-boot) . . . . . . . . . . . . . 19
3.10.1. secure-boot CDDL . . . . . . . . . . . . . . . . . . 19 3.12. Debug Status Claim (debug-status) . . . . . . . . . . . . 19
3.11. Debug Status Claim (debug-status) . . . . . . . . . . . . 19 3.12.1. Enabled . . . . . . . . . . . . . . . . . . . . . . 20
3.11.1. Enabled . . . . . . . . . . . . . . . . . . . . . . 20 3.12.2. Disabled . . . . . . . . . . . . . . . . . . . . . . 20
3.11.2. Disabled . . . . . . . . . . . . . . . . . . . . . . 21 3.12.3. Disabled Since Boot . . . . . . . . . . . . . . . . 21
3.11.3. Disabled Since Boot . . . . . . . . . . . . . . . . 21 3.12.4. Disabled Permanently . . . . . . . . . . . . . . . . 21
3.11.4. Disabled Permanently . . . . . . . . . . . . . . . . 21 3.12.5. Disabled Fully and Permanently . . . . . . . . . . . 21
3.11.5. Disabled Fully and Permanently . . . . . . . . . . . 21 3.13. Including Keys . . . . . . . . . . . . . . . . . . . . . 21
3.11.6. debug-status CDDL . . . . . . . . . . . . . . . . . 21 3.14. The Location Claim (location) . . . . . . . . . . . . . . 22
3.12. Including Keys . . . . . . . . . . . . . . . . . . . . . 22 3.15. The Uptime Claim (uptime) . . . . . . . . . . . . . . . . 23
3.13. The Location Claim (location) . . . . . . . . . . . . . . 22 3.16. The Boot Seed Claim (boot-seed) . . . . . . . . . . . . . 23
3.13.1. location CDDL . . . . . . . . . . . . . . . . . . . 23 3.17. The Intended Use Claim (intended-use) . . . . . . . . . . 24
3.14. The Uptime Claim (uptime) . . . . . . . . . . . . . . . . 24 3.18. The Profile Claim (profile) . . . . . . . . . . . . . . . 25
3.14.1. uptime CDDL . . . . . . . . . . . . . . . . . . . . 24 3.19. The DLOA (Digital Letter or Approval) Claim (dloas) . . . 26
3.15. The Boot Seed Claim (boot-seed) . . . . . . . . . . . . . 24 3.20. The Software Manifests Claim (manifests) . . . . . . . . 27
3.16. The Intended Use Claim (intended-use) . . . . . . . . . . 24 3.21. The Software Evidence Claim (swevidence) . . . . . . . . 28
3.16.1. intended-use CDDL . . . . . . . . . . . . . . . . . 25 3.22. The SW Measurement Results Claim (swresults) . . . . . . 29
3.17. The Profile Claim (profile) . . . . . . . . . . . . . . . 25 3.22.1. Scheme . . . . . . . . . . . . . . . . . . . . . . . 29
3.18. The Software Manifests Claim (manifests) . . . . . . . . 26 3.22.2. Objective . . . . . . . . . . . . . . . . . . . . . 30
3.19. The Software Evidence Claim {swevidence} . . . . . . . . 27 3.22.3. Results . . . . . . . . . . . . . . . . . . . . . . 30
3.20. The Submodules Part of a Token (submods) . . . . . . . . 28 3.22.4. Objective Name . . . . . . . . . . . . . . . . . . . 31
3.20.1. Two Types of Submodules . . . . . . . . . . . . . . 28 3.23. Submodules (submods) . . . . . . . . . . . . . . . . . . 33
3.20.1.1. Non-token Submodules . . . . . . . . . . . . . . 29 3.23.1. Submodule Types . . . . . . . . . . . . . . . . . . 33
3.20.1.2. Nested EATs . . . . . . . . . . . . . . . . . . 29 3.23.1.1. Submodule Claims-Set . . . . . . . . . . . . . . 33
3.20.1.3. Unsecured JWTs and UCCS Tokens as Submodules . . 30 3.23.1.2. Nested Token . . . . . . . . . . . . . . . . . . 34
3.20.2. No Inheritance . . . . . . . . . . . . . . . . . . . 30 3.23.1.3. Detached Submodule Digest . . . . . . . . . . . 36
3.20.3. Security Levels . . . . . . . . . . . . . . . . . . 31 3.23.2. No Inheritance . . . . . . . . . . . . . . . . . . . 37
3.20.4. Submodule Names . . . . . . . . . . . . . . . . . . 31 3.23.3. Security Levels . . . . . . . . . . . . . . . . . . 37
3.20.5. submods CDDL . . . . . . . . . . . . . . . . . . . . 31 3.23.4. Submodule Names . . . . . . . . . . . . . . . . . . 37
4. Endorsements and Verification Keys . . . . . . . . . . . . . 32 3.23.5. CDDL for submods . . . . . . . . . . . . . . . . . . 38
4.1. Identification Methods . . . . . . . . . . . . . . . . . 33 4. Unprotected JWT Claims-Sets . . . . . . . . . . . . . . . . . 38
4.1.1. COSE/JWS Key ID . . . . . . . . . . . . . . . . . . . 33 5. Detached EAT Bundles . . . . . . . . . . . . . . . . . . . . 39
4.1.2. JWS and COSE X.509 Header Parameters . . . . . . . . 34 6. Endorsements and Verification Keys . . . . . . . . . . . . . 40
4.1.3. CBOR Certificate COSE Header Parameters . . . . . . . 34 6.1. Identification Methods . . . . . . . . . . . . . . . . . 41
4.1.4. Claim-Based Key Identification . . . . . . . . . . . 34 6.1.1. COSE/JWS Key ID . . . . . . . . . . . . . . . . . . . 41
4.2. Other Considerations . . . . . . . . . . . . . . . . . . 34 6.1.2. JWS and COSE X.509 Header Parameters . . . . . . . . 41
5. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . 35 6.1.3. CBOR Certificate COSE Header Parameters . . . . . . . 42
5.1. Format of a Profile Document . . . . . . . . . . . . . . 35 6.1.4. Claim-Based Key Identification . . . . . . . . . . . 42
5.2. List of Profile Issues . . . . . . . . . . . . . . . . . 35 6.2. Other Considerations . . . . . . . . . . . . . . . . . . 42
5.2.1. Use of JSON, CBOR or both . . . . . . . . . . . . . . 35 7. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.2.2. CBOR Map and Array Encoding . . . . . . . . . . . . . 35 7.1. Format of a Profile Document . . . . . . . . . . . . . . 43
5.2.3. CBOR String Encoding . . . . . . . . . . . . . . . . 36 7.2. List of Profile Issues . . . . . . . . . . . . . . . . . 43
5.2.4. CBOR Preferred Serialization . . . . . . . . . . . . 36 7.2.1. Use of JSON, CBOR or both . . . . . . . . . . . . . . 43
5.2.5. COSE/JOSE Protection . . . . . . . . . . . . . . . . 36 7.2.2. CBOR Map and Array Encoding . . . . . . . . . . . . . 43
5.2.6. COSE/JOSE Algorithms . . . . . . . . . . . . . . . . 36 7.2.3. CBOR String Encoding . . . . . . . . . . . . . . . . 44
5.2.7. Verification Key Identification . . . . . . . . . . . 37 7.2.4. CBOR Preferred Serialization . . . . . . . . . . . . 44
5.2.8. Endorsement Identification . . . . . . . . . . . . . 37 7.2.5. COSE/JOSE Protection . . . . . . . . . . . . . . . . 44
5.2.9. Freshness . . . . . . . . . . . . . . . . . . . . . . 37 7.2.6. COSE/JOSE Algorithms . . . . . . . . . . . . . . . . 44
5.2.10. Required Claims . . . . . . . . . . . . . . . . . . . 37 7.2.7. DEB Support . . . . . . . . . . . . . . . . . . . . . 44
5.2.11. Prohibited Claims . . . . . . . . . . . . . . . . . . 37 7.2.8. Verification Key Identification . . . . . . . . . . . 45
5.2.12. Additional Claims . . . . . . . . . . . . . . . . . . 37 7.2.9. Endorsement Identification . . . . . . . . . . . . . 45
5.2.13. Refined Claim Definition . . . . . . . . . . . . . . 37 7.2.10. Freshness . . . . . . . . . . . . . . . . . . . . . . 45
5.2.14. CBOR Tags . . . . . . . . . . . . . . . . . . . . . . 38 7.2.11. Required Claims . . . . . . . . . . . . . . . . . . . 45
5.2.15. Manifests and Software Evidence Claims . . . . . . . 38 7.2.12. Prohibited Claims . . . . . . . . . . . . . . . . . . 45
6. Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7.2.13. Additional Claims . . . . . . . . . . . . . . . . . . 45
6.1. Common CDDL Types . . . . . . . . . . . . . . . . . . . . 38 7.2.14. Refined Claim Definition . . . . . . . . . . . . . . 45
6.2. CDDL for CWT-defined Claims . . . . . . . . . . . . . . . 38 7.2.15. CBOR Tags . . . . . . . . . . . . . . . . . . . . . . 46
6.3. JSON . . . . . . . . . . . . . . . . . . . . . . . . . . 39 7.2.16. Manifests and Software Evidence Claims . . . . . . . 46
6.3.1. JSON Labels . . . . . . . . . . . . . . . . . . . . . 39 8. Encoding and Collected CDDL . . . . . . . . . . . . . . . . . 46
6.3.2. JSON Interoperability . . . . . . . . . . . . . . . . 40 8.1. Claims-Set and CDDL for CWT and JWT . . . . . . . . . . . 46
6.4. CBOR . . . . . . . . . . . . . . . . . . . . . . . . . . 41 8.2. Encoding Data Types . . . . . . . . . . . . . . . . . . . 47
6.4.1. CBOR Interoperability . . . . . . . . . . . . . . . . 41 8.2.1. Common Data Types . . . . . . . . . . . . . . . . . . 47
6.4.1.1. EAT Constrained Device Serialization . . . . . . 41 8.2.2. JSON Interoperability . . . . . . . . . . . . . . . . 47
6.5. Collected CDDL . . . . . . . . . . . . . . . . . . . . . 42 8.2.3. Labels . . . . . . . . . . . . . . . . . . . . . . . 47
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 47 8.3. CBOR Interoperability . . . . . . . . . . . . . . . . . . 48
7.1. Reuse of CBOR Web Token (CWT) Claims Registry . . . . . . 47 8.3.1. EAT Constrained Device Serialization . . . . . . . . 48
7.2. Claim Characteristics . . . . . . . . . . . . . . . . . . 48
7.2.1. Interoperability and Relying Party Orientation . . . 48 8.4. Collected Common CDDL . . . . . . . . . . . . . . . . . . 49
7.2.2. Operating System and Technology Neutral . . . . . . . 48 8.5. Collected CDDL for CBOR . . . . . . . . . . . . . . . . . 55
7.2.3. Security Level Neutral . . . . . . . . . . . . . . . 49 8.6. Collected CDDL for JSON . . . . . . . . . . . . . . . . . 57
7.2.4. Reuse of Extant Data Formats . . . . . . . . . . . . 49 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 59
7.2.5. Proprietary Claims . . . . . . . . . . . . . . . . . 49 9.1. Reuse of CBOR and JSON Web Token (CWT and JWT) Claims
7.3. Claims Registered by This Document . . . . . . . . . . . 49 Registries . . . . . . . . . . . . . . . . . . . . . . . 59
7.3.1. Claims for Early Assignment . . . . . . . . . . . . . 50 9.2. Claim Characteristics . . . . . . . . . . . . . . . . . . 59
7.3.2. To be Assigned Claims . . . . . . . . . . . . . . . . 53 9.2.1. Interoperability and Relying Party Orientation . . . 59
7.3.3. Version Schemes Registered by this Document . . . . . 53 9.2.2. Operating System and Technology Neutral . . . . . . . 59
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 53 9.2.3. Security Level Neutral . . . . . . . . . . . . . . . 60
8.1. UEID and SUEID Privacy Considerations . . . . . . . . . . 53 9.2.4. Reuse of Extant Data Formats . . . . . . . . . . . . 60
8.2. Location Privacy Considerations . . . . . . . . . . . . . 54 9.2.5. Proprietary Claims . . . . . . . . . . . . . . . . . 60
9. Security Considerations . . . . . . . . . . . . . . . . . . . 54 9.3. Claims Registered by This Document . . . . . . . . . . . 61
9.1. Key Provisioning . . . . . . . . . . . . . . . . . . . . 55 9.3.1. Claims for Early Assignment . . . . . . . . . . . . . 61
9.1.1. Transmission of Key Material . . . . . . . . . . . . 55 9.3.2. To be Assigned Claims . . . . . . . . . . . . . . . . 64
9.2. Transport Security . . . . . . . . . . . . . . . . . . . 55 9.3.3. Version Schemes Registered by this Document . . . . . 64
9.3. Multiple EAT Consumers . . . . . . . . . . . . . . . . . 56 9.3.4. UEID URN Registered by this Document . . . . . . . . 64
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 56 9.3.5. Tag for Detached EAT Bundle . . . . . . . . . . . . . 65
10.1. Normative References . . . . . . . . . . . . . . . . . . 56 10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 65
10.2. Informative References . . . . . . . . . . . . . . . . . 59 10.1. UEID and SUEID Privacy Considerations . . . . . . . . . 65
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 61 10.2. Location Privacy Considerations . . . . . . . . . . . . 66
A.1. Very Simple EAT . . . . . . . . . . . . . . . . . . . . . 61 11. Security Considerations . . . . . . . . . . . . . . . . . . . 66
A.2. Example with Submodules, Nesting and Security Levels . . 61 11.1. Key Provisioning . . . . . . . . . . . . . . . . . . . . 66
Appendix B. UEID Design Rationale . . . . . . . . . . . . . . . 61 11.1.1. Transmission of Key Material . . . . . . . . . . . . 67
B.1. Collision Probability . . . . . . . . . . . . . . . . . . 62 11.2. Transport Security . . . . . . . . . . . . . . . . . . . 67
B.2. No Use of UUID . . . . . . . . . . . . . . . . . . . . . 64 11.3. Multiple EAT Consumers . . . . . . . . . . . . . . . . . 67
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 68
12.1. Normative References . . . . . . . . . . . . . . . . . . 68
12.2. Informative References . . . . . . . . . . . . . . . . . 70
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 73
A.1. Simple TEE Attestation . . . . . . . . . . . . . . . . . 73
A.2. EAT Produced by Attestation Hardware Block . . . . . . . 74
A.3. Detached EAT Bundle . . . . . . . . . . . . . . . . . . . 75
A.4. Key / Key Store Attestation . . . . . . . . . . . . . . . 76
A.5. SW Measurements of an IoT Device . . . . . . . . . . . . 78
A.6. Attestation Results in JSON format . . . . . . . . . . . 81
Appendix B. UEID Design Rationale . . . . . . . . . . . . . . . 82
B.1. Collision Probability . . . . . . . . . . . . . . . . . . 82
B.2. No Use of UUID . . . . . . . . . . . . . . . . . . . . . 84
Appendix C. EAT Relation to IEEE.802.1AR Secure Device Identity Appendix C. EAT Relation to IEEE.802.1AR Secure Device Identity
(DevID) . . . . . . . . . . . . . . . . . . . . . . 65 (DevID) . . . . . . . . . . . . . . . . . . . . . . 85
C.1. DevID Used With EAT . . . . . . . . . . . . . . . . . . . 65 C.1. DevID Used With EAT . . . . . . . . . . . . . . . . . . . 85
C.2. How EAT Provides an Equivalent Secure Device Identity . . 66 C.2. How EAT Provides an Equivalent Secure Device Identity . . 86
C.3. An X.509 Format EAT . . . . . . . . . . . . . . . . . . . 66 C.3. An X.509 Format EAT . . . . . . . . . . . . . . . . . . . 86
C.4. Device Identifier Permanence . . . . . . . . . . . . . . 67 C.4. Device Identifier Permanence . . . . . . . . . . . . . . 87
Appendix D. Changes from Previous Drafts . . . . . . . . . . . . 67 Appendix D. Changes from Previous Drafts . . . . . . . . . . . . 87
D.1. From draft-rats-eat-01 . . . . . . . . . . . . . . . . . 67 D.1. From draft-rats-eat-01 . . . . . . . . . . . . . . . . . 87
D.2. From draft-mandyam-rats-eat-00 . . . . . . . . . . . . . 67 D.2. From draft-mandyam-rats-eat-00 . . . . . . . . . . . . . 87
D.3. From draft-ietf-rats-eat-01 . . . . . . . . . . . . . . . 67 D.3. From draft-ietf-rats-eat-01 . . . . . . . . . . . . . . . 87
D.4. From draft-ietf-rats-eat-02 . . . . . . . . . . . . . . . 68 D.4. From draft-ietf-rats-eat-02 . . . . . . . . . . . . . . . 88
D.5. From draft-ietf-rats-eat-03 . . . . . . . . . . . . . . . 68 D.5. From draft-ietf-rats-eat-03 . . . . . . . . . . . . . . . 88
D.6. From draft-ietf-rats-eat-04 . . . . . . . . . . . . . . . 68 D.6. From draft-ietf-rats-eat-04 . . . . . . . . . . . . . . . 88
D.7. From draft-ietf-rats-05 . . . . . . . . . . . . . . . . . 69 D.7. From draft-ietf-rats-eat-05 . . . . . . . . . . . . . . . 89
D.8. From draft-ietf-rats-06 . . . . . . . . . . . . . . . . . 69 D.8. From draft-ietf-rats-eat-06 . . . . . . . . . . . . . . . 89
D.9. From draft-ietf-rats-07 . . . . . . . . . . . . . . . . . 69 D.9. From draft-ietf-rats-eat-07 . . . . . . . . . . . . . . . 89
D.10. From draft-ietf-rats-08 . . . . . . . . . . . . . . . . . 69 D.10. From draft-ietf-rats-eat-08 . . . . . . . . . . . . . . . 89
D.11. From draft-ietf-rats-09 . . . . . . . . . . . . . . . . . 69 D.11. From draft-ietf-rats-eat-09 . . . . . . . . . . . . . . . 89
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 70 D.12. From draft-ietf-rats-eat-10 . . . . . . . . . . . . . . . 90
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 91
1. Introduction 1. Introduction
Remote device attestation is a fundamental service that allows a Remote device attestation is a fundamental service that allows a
remote device such as a mobile phone, an Internet-of-Things (IoT) remote device such as a mobile phone, an Internet-of-Things (IoT)
device, or other endpoint to prove itself to a relying party, a device, or other endpoint to prove itself to a Relying Party, a
server or a service. This allows the relying party to know some server or a service. This allows the Relying Party to know some
characteristics about the device and decide whether it trusts the characteristics about the device and decide whether it trusts the
device. device.
Remote attestation is a fundamental service that can underlie other
protocols and services that need to know about the trustworthiness of
the device before proceeding. One good example is biometric
authentication where the biometric matching is done on the device.
The relying party needs to know that the device is one that is known
to do biometric matching correctly. Another example is content
protection where the relying party wants to know the device will
protect the data. This generalizes on to corporate enterprises that
might want to know that a device is trustworthy before allowing
corporate data to be accessed by it.
The notion of attestation here is large and may include, but is not The notion of attestation here is large and may include, but is not
limited to the following: limited to the following:
o Proof of the make and model of the device hardware (HW) o Proof of the make and model of the device hardware (HW)
o Proof of the make and model of the device processor, particularly o Proof of the make and model of the device processor, particularly
for security-oriented chips for security-oriented chips
o Measurement of the software (SW) running on the device o Measurement of the software (SW) running on the device
o Configuration and state of the device o Configuration and state of the device
o Environmental characteristics of the device such as its GPS o Environmental characteristics of the device such as its GPS
location location
1.1. CWT, JWT and UCCS This document uses the terminology and main operational model defined
in [RATS.Architecture]. In particular it is a format that can be
used for Attestation Evidence or Attestation Results as defined in
the RATS architecture.
For flexibility and ease of imlpementation in a wide variety of 1.1. CWT, JWT, UCCS, UJCS and DEB
environments, EATs can be either CBOR [RFC8949] or JSON [ECMAScript]
format. This specification simultaneously describes both formats.
An EAT is either a CWT as defined in [RFC8392], a UCCS as defined in An EAT is a set of claims about an entity/device based on one of the
[UCCS.Draft], or a JWT as defined in [RFC7519]. This specification following:
extends those specifications with additional claims for attestation.
o CBOR Web Token (CWT), [RFC8392]
o Unprotected CWT Claims Sets (UCCS), [UCCS.Draft]
o JSON Web Token (JWT), [RFC7519]
All definitions, requirements, creation and validation procedures,
security considerations, IANA registrations and so on from these
carry over to EAT.
This specification extends those specifications by defining
additional claims for attestation. This specification also describes
the notion of a "profile" that can narrow the definition of an EAT,
ensure interoperability and fill in details for specific usage
scenarios. This specification also adds some considerations for
registration of future EAT-related claims.
The identification of a protocol element as an EAT, whether CBOR or The identification of a protocol element as an EAT, whether CBOR or
JSON format, follows the general conventions used by CWT, JWT and JSON encoded, follows the general conventions used by CWT, JWT and
UCCS. Largely this depends on the protocol carrying the EAT. In UCCS. Largely this depends on the protocol carrying the EAT. In
some cases it may be by content type (e.g., MIME type). In other some cases it may be by content type (e.g., MIME type). In other
cases it may be through use of CBOR tags. There is no fixed cases it may be through use of CBOR tags. There is no fixed
mechanism across all use cases. mechanism across all use cases.
1.2. CDDL This specification adds two more top-level messages:
This specification uses CDDL, [RFC8610], as the primary formalism to
define each claim. The implementor then interprets the CDDL to come
to either the CBOR [RFC8949] or JSON [ECMAScript] representation. In
the case of JSON, Appendix E of [RFC8610] is followed. Additional
rules are given in Section 6.3.2 of this document where Appendix E is
insufficient. (Note that this is not to define a general means to
translate between CBOR and JSON, but only to define enough such that
the claims defined in this document can be rendered unambiguously in
JSON).
The CWT specification was authored before CDDL was available and did
not use it. This specification includes a CDDL definition of most of
what is described in [RFC8392].
1.3. Entity Overview
An "entity" can be any device or device subassembly ("submodule")
that can generate its own attestation in the form of an EAT. The
attestation should be cryptographically verifiable by the EAT
consumer. An EAT at the device-level can be composed of several
submodule EAT's.
Modern devices such as a mobile phone have many different execution
environments operating with different security levels. For example,
it is common for a mobile phone to have an "apps" environment that
runs an operating system (OS) that hosts a plethora of downloadable
apps. It may also have a TEE (Trusted Execution Environment) that is
distinct, isolated, and hosts security-oriented functionality like
biometric authentication. Additionally, it may have an eSE (embedded
Secure Element) - a high security chip with defenses against HW
attacks that is used to produce attestations. This device
attestation format allows the attested data to be tagged at a
security level from which it originates. In general, any discrete
execution environment that has an identifiable security level can be
considered an entity.
1.4. Use as Evidence and Attestation Results
Here, normative reference is made to [RATS-Architecture], o Unprotected JWT Claims Set (UJCS), Section 4
particularly the definition of Evidence, the Verifier, Attestation
Results and the Relying Party. Per Figure 1 in [RATS-Architecture],
Evidence is a protocol message that goes from the Attester to the
Verifier and Attestation Results a message that goes from the
Verifier to the Relying Party. EAT is defined such that it can be
used to represent either Evidence, Attestation Results or both. No
claims defined here are considered exclusive to or are prohibited in
either use. It is useful to create EAT profiles as described in
Section 5 for either use.
It is useful to characterize the relationship of claims in Evidence o Detached EAT Bundle (DEB), Section 5
to those in Attestation Results.
Many claims in Evidence simply will pass through the Verifier to the A DEB is simple structure to hold a collection of detached claims-
Relying Party without modification. They will be verified as sets and the EAT that separately provides integrity and authenticity
authentic from the device by the Verifier just through normal protection for them. It can be either CBOR or JSON encoded.
verification of the Attester's signature. They will be protected
from modification when they are conveyed to the Relying Party by
whatever means is used to protect Attestation Results. (The details
of that protection are out of scope of this document.)
Some claims in Evidence will be verified by the Verifier by 1.2. CDDL, CBOR and JSON
comparison to Reference Values. In this case the claims in Evidence
will not likely be conveyed to the Relying Party. Instead, some
claim indicating they were checked may be added to the Attestation
Results or it may be tacitly known that the Verifier always does this
check.
In some cases the Verifier may provide privacy-preserving An EAT can be encoded in either CBOR or JSON. The definition of each
functionality by stripping or modifying claims that do not posses claim is such that it can be encoded either. Each token is either
sufficient privacy-preserving characteristics. entirely CBOR or JSON, with only an exception for nested tokens.
1.5. EAT Operating Models To implement composite attestation as described in the RATS
architecture document, one token has to be nested inside another. It
is also possible to construct composite Attestation Results (see
below) which may be expressed as one token nested inside another. So
as to not force each end-end attestation system to be all JSON or all
CBOR, nesting of JSON-encoded tokens in CBOR-encoded tokens and vice
versa is accommodated by this specification. This is the only place
that CBOR and JSON can be mixed.
TODO: Rewrite (or eliminate) this section in light of the RATS This specification formally uses CDDL, [RFC8610], to define each
architecture draft. claim. The implementor interprets the CDDL to come to either the
CBOR [RFC8949] or JSON [ECMAScript] representation. In the case of
JSON, Appendix E of [RFC8610] is followed. Additional rules are
given in Section 8.2.2 where Appendix E is insufficient.
At least the following three participants exist in all EAT operating The CWT and JWT specifications were authored before CDDL was
models. Some operating models have additional participants. available and did not use CDDL. This specification includes a CDDL
definition of most of what is defined in [RFC8392]. Similarly, this
specification includes CDDL for most of what is defined in [RFC7519].
The Entity. This is the phone, the IoT device, the sensor, the sub- The UCCS specification does not include CDDL. This specification
assembly or such that the attestation provides information about. provides CDDL for it.
The Manufacturer. The company that made the entity. This may be a (TODO: The authors are open to modifications to this specification
chip vendor, a circuit board module vendor or a vendor of finished and the UCCS specification to include CDDL for UCCS and UJCS there
consumer products. instead of here.)
The Relying Party. The server, service or company that makes use of 1.3. Operating Model and RATS Architecture
the information in the EAT about the entity.
In all operating models, the manufacturer provisions some secret While it is not required that EAT be used with the RATS operational
attestation key material (AKM) into the entity during manufacturing. model described in Figure 1 in [RATS.Architecture], or even that it
This might be during the manufacturer of a chip at a fabrication be used for attestation, this document is authored with an
facility (fab) or during final assembly of a consumer product or any orientation around that model.
time in between. This attestation key material is used for signing
EATs.
In all operating models, hardware and/or software on the entity To summarize, an Attester on an entity/device generates Attestation
create an EAT of the format described in this document. The EAT is Evidence. Attestation Evidence is a Claims Set describing various
always signed by the attestation key material provisioned by the characteristics of the entity/device. Attestation Evidence also is
manufacturer. usually signed by a key that proves the entity/device and the
evidence it produces are authentic. The Claims Set includes a nonce
or some other means to provide freshness. EAT is designed to carry
Attestation Evidence. The Attestation Evidence goes to a Verifier
where the signature is validated. Some of the Claims may also be
validated against Reference Values. The Verifier then produces
Attestation Results which is also usually a Claims Set. EAT is also
designed to carry Attestation Results. The Attestation Results go to
the Relying Party which is the ultimate consumer of the "Remote
Attestaton Procedures", RATS. The Relying Party uses the Attestation
Results as needed for the use case, perhaps allowing a device on the
network, allowing a financial transaction or such.
In all operating models, the relying party must end up knowing that Note that sometimes the Verifier and Relying Party are not separate
the signature on the EAT is valid and consistent with data from and thus there is no need for a protocol to carry Attestation
claims in the EAT. This can happen in many different ways. Here are Results.
some examples.
o The EAT is transmitted to the relying party. The relying party 1.3.1. Use as Attestation Evidence
gets corresponding key material (e.g. a root certificate) from the
manufacturer. The relying party performs the verification.
o The EAT is transmitted to the relying party. The relying party Any claim defined in this document or in the IANA CWT or JWT registry
transmits the EAT to a verification service offered by the may be used in Attestation Evidence.
manufacturer. The server returns the validated claims.
o The EAT is transmitted directly to a verification service, perhaps Attestation Evidence nearly always has to be signed or otherwise have
operated by the manufacturer or perhaps by another party. It authenticity and integrity protection because the Attester is remote
verifies the EAT and makes the validated claims available to the relative to the Verifier. Usually, this is by using COSE/JOSE
relying party. It may even modify the claims in some way and re- signing where the signing key is an attestation key provisioned into
sign the EAT (with a different signing key). the entity/device by its manufacturer. The details of how this is
achieved are beyond this specification, but see Section 6. If there
is already a suitable secure channel between the Attester and
Verifier, UCCS may be used.
All these operating models are supported and there is no preference 1.3.2. Use as Attestation Results
of one over the other. It is important to support this variety of
operating models to generally facilitate deployment and to allow for
some special scenarios. One special scenario has a validation
service that is monetized, most likely by the manufacturer. In
another, a privacy proxy service processes the EAT before it is
transmitted to the relying party. In yet another, symmetric key
material is used for signing. In this case the manufacturer should
perform the verification, because any release of the key material
would enable a participant other than the entity to create valid
signed EATs.
1.6. What is Not Standardized Any claim defined in this document or in the IANA CWT or JWT registry
may be used in Attestation Results.
The following is not standardized for EAT, just the same they are not It is useful to characterize the relationship of claims in Evidence
standardized for CWT or JWT. to those in Attestation Results.
1.6.1. Transmission Protocol Many claims in Attestation Evidence simply will pass through the
Verifier to the Relying Party without modification. They will be
verified as authentic from the device by the Verifier just through
normal verification of the Attester's signature. The UEID,
Section 3.4, and Location, Section 3.14, are examples of claims that
may be passed through.
EATs may be transmitted by any protocol the same as CWTs and JWTs. Some claims in Attestation Evidence will be verified by the Verifier
For example, they might be added in extension fields of other by comparison to Reference Values. These claims will not likely be
protocols, bundled into an HTTP header, or just transmitted as files. conveyed to the Relying Party. Instead, some claim indicating they
This flexibility is intentional to allow broader adoption. This were checked may be added to the Attestation Results or it may be
flexibility is possible because EAT's are self-secured with signing tacitly known that the Verifier always does this check. For example,
(and possibly additionally with encryption and anti-replay). The the Verifier receives the Software Evidence claim, Section 3.21,
transmission protocol is not required to fulfill any additional compares it to Reference Values and conveys the results to the
security requirements. Relying Party in a Software Measurement Results Claim, Section 3.22.
For certain devices, a direct connection may not exist between the In some cases the Verifier may provide privacy-preserving
EAT-producing device and the Relying Party. In such cases, the EAT functionality by stripping or modifying claims that do not posses
should be protected against malicious access. The use of COSE and sufficient privacy-preserving characteristics. For example, the data
JOSE allows for signing and encryption of the EAT. Therefore, even in the Location claim, Section 3.14, may be modified to have a
if the EAT is conveyed through intermediaries between the device and precision of a few kilometers rather than a few meters.
Relying Party, such intermediaries cannot easily modify the EAT
payload or alter the signature.
1.6.2. Signing Scheme When the Verifier is remote from the Relying Party, the Attestation
Results must be protected for integrity, authenticity and possibly
confidentiality. Often this will simply be HTTPS as per a normal web
service, but COSE or JOSE may also be used. The details of this
protection are beyond the scope of this document.
The term "signing scheme" is used to refer to the system that 1.4. Entity Overview
includes end-end process of establishing signing attestation key
material in the entity, signing the EAT, and verifying it. This
might involve key IDs and X.509 certificate chains or something
similar but different. The term "signing algorithm" refers just to
the algorithm ID in the COSE signing structure. No particular
signing algorithm or signing scheme is required by this standard.
There are three main implementation issues driving this. First, An "entity" can be any device or device subassembly ("submodule")
secure non-volatile storage space in the entity for the attestation that can generate its own attestation in the form of an EAT. The
key material may be highly limited, perhaps to only a few hundred attestation should be cryptographically verifiable by the EAT
bits, on some small IoT chips. Second, the factory cost of consumer. An EAT at the device-level can be composed of several
provisioning key material in each chip or device may be high, with submodule EAT's.
even millisecond delays adding to the cost of a chip. Third,
privacy-preserving signing schemes like ECDAA (Elliptic Curve Direct
Anonymous Attestation) are complex and not suitable for all use
cases.
Over time to faciliate interoperability, some signing schemes may be Modern devices such as a mobile phone have many different execution
defined in EAT profiles or other documents either in the IETF or environments operating with different security levels. For example,
outside. it is common for a mobile phone to have an "apps" environment that
runs an operating system (OS) that hosts a plethora of downloadable
apps. It may also have a TEE (Trusted Execution Environment) that is
distinct, isolated, and hosts security-oriented functionality like
biometric authentication. Additionally, it may have an eSE (embedded
Secure Element) - a high security chip with defenses against HW
attacks that is used to produce attestations. This device
attestation format allows the attested data to be tagged at a
security level from which it originates. In general, any discrete
execution environment that has an identifiable security level can be
considered an entity.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
This document reuses terminology from JWT [RFC7519], COSE [RFC8152], This document reuses terminology from JWT [RFC7519] and CWT
and CWT [RFC8392]. [RFC8392].
Claim Name. The human-readable name used to identify a claim. Claim: A piece of information asserted about a subject. A claim is
represented as pair with a value and either a name or key to
identify it.
Claim Key. The CBOR map key or JSON name used to identify a claim. Claim Name: A unique text string that identifies the claim. It is
used as the claim name for JSON encoding.
Claim Value. The value portion of the claim. A claim value can be Claim Key: The CBOR map key used to identify a claim.
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.
CWT Claims Set. The CBOR map or JSON object that contains the claims CWT/JWT Claims Set: The CBOR map or JSON object that contains the
conveyed by the CWT or JWT. claims conveyed by the CWT or JWT.
Attestation Key Material (AKM). The key material used to sign the This document reuses terminology from RATS Architecure
EAT token. If it is done symmetrically with HMAC, then this is a [RATS.Architecture]
simple symmetric key. If it is done with ECC, such as an IEEE
DevID [IEEE.802.1AR], then this is the private part of the EC key
pair. If ECDAA is used, (e.g., as used by Enhanced Privacy ID,
i.e. EPID) then it is the key material needed for ECDAA.
3. The Claims Attester: A role performed by an entity (typically a device) whose
Evidence must be appraised in order to infer the extent to which
the Attester is considered trustworthy, such as when deciding
whether it is authorized to perform some operation.
This section describes new claims defined for attestation. It also Verifier: A role that appraises the validity of Attestation Evidence
mentions several claims defined by CWT and JWT that are particularly about an Attester and produces Attestation Results to be used by a
important for EAT. Relying Party.
Note also: * Any claim defined for CWT or JWT may be used in an EAT Relying Party: A role that depends on the validity of information
including those in the CWT [IANA.CWT.Claims] and JWT IANA about an Attester, for purposes of reliably applying application
[IANA.JWT.Claims] claims registries. specific actions. Compare /relying party/ in [RFC4949].
o All claims are optional Attestation Evidence: A Claims Set generated by an Attester to be
o No claims are mandatory appraised by a Verifier. Attestation Evidence may include
configuration data, measurements, telemetry, or inferences.
o All claims that are not understood by implementations MUST be Attestation Results: The output generated by a Verifier, typically
ignored including information about an Attester, where the Verifier
vouches for the validity of the results
There are no default values or meanings assigned to absent claims Reference Values: A set of values against which values of Claims can
other than they are not reported. The reason for a claim's absence be compared as part of applying an Appraisal Policy for
may be the implementation not supporting the claim, an inability to Attestation Evidence. Reference Values are sometimes referred to
determine its value, or a preference to report in a different way in other documents as known-good values, golden measurements, or
such as a proprietary claim. nominal values, although those terms typically assume comparison
for equality, whereas here Reference Values might be more general
and be used in any sort of comparison.
CDDL along with text descriptions is used to define each claim 3. The Claims
indepdent of encoding. Each claim is defined as a CDDL group (the
group is a general aggregation and type definition feature of CDDL).
In the encoding section Section 6, the CDDL groups turn into CBOR map
entries and JSON name/value pairs.
Map labels are assigned both an integer and string value. CBOR This section describes new claims defined for attestation that are to
encoded tokens MUST use only integer labels. JSON encoded tokens be added to the CWT [IANA.CWT.Claims] and JWT [IANA.JWT.Claims] IANA
MUST use only string labels. registries.
TODO: add paragraph here about use for Attestation Evidence and for This section also describes how several extant CWT and JWT claims
Results. apply in EAT.
CDDL, along with a text description, is used to define each claim
independent of encoding. Each claim is defined as a CDDL group. In
Section 8 on encoding, the CDDL groups turn into CBOR map entries and
JSON name/value pairs.
Each claim described has a unique text string and integer that
identifies it. CBOR encoded tokens MUST use only the integer for
Claim Keys. JSON encoded tokens MUST use only the text string for
Claim Names.
3.1. Token ID Claim (cti and jti) 3.1. Token ID Claim (cti and jti)
CWT defines the "cti" claim. JWT defines the "jti" claim. These are CWT defines the "cti" claim. JWT defines the "jti" claim. These are
equivalent to each other in EAT and carry a unique token identifier equivalent to each other in EAT and carry a unique token identifier
as they do in JWT and CWT. They may be used to defend against re use as they do in JWT and CWT. They may be used to defend against re use
of the token but are distinct from the nonce that is used by the of the token but are distinct from the nonce that is used by the
relying party to guarantee freshness and defend against replay. Relying Party to guarantee freshness and defend against replay.
3.2. Timestamp claim (iat) 3.2. Timestamp claim (iat)
The "iat" claim defined in CWT and JWT is used to indicate the date- The "iat" claim defined in CWT and JWT is used to indicate the date-
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
skipping to change at page 12, line 12 skipping to change at page 11, line 42
use of floating-point. No token may contain an iat claim in float- use of floating-point. No token may contain an iat claim in float-
point format. Any recipient of a token with a floating-point format point format. Any recipient of a token with a floating-point format
iat claim may consider it an error. A 64-bit integer representation iat claim may consider it an error. A 64-bit integer representation
of epoch time can represent a range of +/- 500 billion years, so the of epoch time can represent a range of +/- 500 billion years, so the
only point of a floating-point timestamp is to have precession only point of a floating-point timestamp is to have precession
greater than one second. This is not needed for EAT. greater than one second. This is not needed for EAT.
3.3. Nonce Claim (nonce) 3.3. Nonce Claim (nonce)
All EATs should have a nonce to prevent replay attacks. The nonce is All EATs should have a nonce to prevent replay attacks. The nonce is
generated by the relying party, the end consumer of the token. It is generated by the Relying Party, the end consumer of the token. It is
conveyed to the entity over whatever transport is in use before the conveyed to the entity over whatever transport is in use before the
token is generated and then included in the token as the nonce claim. token is generated and then included in the token as the nonce claim.
This documents the nonce claim for registration in the IANA CWT This documents the nonce claim for registration in the IANA CWT
claims registry. This is equivalent to the JWT nonce claim that is claims registry. This is equivalent to the JWT nonce claim that is
already registered. already registered.
The nonce must be at least 8 bytes (64 bits) as fewer are unlikely to The nonce must be at least 8 bytes (64 bits) as fewer are unlikely to
be secure. A maximum of 64 bytes is set to limit the memory a be secure. A maximum of 64 bytes is set to limit the memory a
constrained implementation uses. This size range is not set for the constrained implementation uses. This size range is not set for the
already-registered JWT nonce, but it should follow this size already-registered JWT nonce, but it should follow this size
recommendation when used in an EAT. recommendation when used in an EAT.
Multiple nonces are allowed to accommodate multistage verification Multiple nonces are allowed to accommodate multistage verification
and consumption. and consumption.
3.3.1. nonce CDDL $$claims-set-claims //=
(nonce-label => nonce-type / [ 2* nonce-type ])
nonce-type = bstr .size (8..64) nonce-type = bstr .size (8..64)
nonce-claim = (
nonce => nonce-type / [ 2* nonce-type ]
)
3.4. Universal Entity ID Claim (ueid) 3.4. Universal Entity ID Claim (ueid)
UEID's identify individual manufactured entities / devices such as a UEID's identify individual manufactured entities / devices such as a
mobile phone, a water meter, a Bluetooth speaker or a networked mobile phone, a water meter, a Bluetooth speaker or a networked
security camera. It may identify the entire device or a submodule or security camera. It may identify the entire device or a submodule or
subsystem. It does not identify types, models or classes of devices. subsystem. It does not identify types, models or classes of devices.
It is akin to a serial number, though it does not have to be It is akin to a serial number, though it does not have to be
sequential. sequential.
UEID's must be universally and globally unique across manufacturers UEID's must be universally and globally unique across manufacturers
and countries. UEIDs must also be unique across protocols and and countries. UEIDs must also be unique across protocols and
systems, as tokens are intended to be embedded in many different systems, as tokens are intended to be embedded in many different
protocols and systems. No two products anywhere, even in completely protocols and systems. No two products anywhere, even in completely
different industries made by two different manufacturers in two different industries made by two different manufacturers in two
different countries should have the same UEID (if they are not global different countries should have the same UEID (if they are not global
and universal in this way, then relying parties receiving them will and universal in this way, then Relying Parties receiving them will
have to track other characteristics of the device to keep devices have to track other characteristics of the device to keep devices
distinct between manufacturers). distinct between manufacturers).
There are privacy considerations for UEID's. See Section 8.1. There are privacy considerations for UEID's. See Section 10.1.
The UEID is permanent. It never change for a given device / entity. The UEID is permanent. It never change for a given device / entity.
UEIDs are variable length. All implementations MUST be able to UEIDs are variable length. All implementations MUST be able to
receive UEIDs that are 33 bytes long (1 type byte and 256 bits). The receive UEIDs that are 33 bytes long (1 type byte and 256 bits). The
recommended maximum sent is also 33 bytes. recommended maximum sent is also 33 bytes.
When the entity constructs the UEID, the first byte is a type and the When the entity constructs the UEID, the first byte is a type and the
following bytes the ID for that type. Several types are allowed to following bytes the ID for that type. Several types are allowed to
accommodate different industries and different manufacturing accommodate different industries and different manufacturing
skipping to change at page 14, line 43 skipping to change at page 13, line 43
| | | of the digit; the digit 3 encodes as 0x03, not | | | | of the digit; the digit 3 encodes as 0x03, not |
| | | 0x33). The IMEI value encoded SHALL NOT include | | | | 0x33). The IMEI value encoded SHALL NOT include |
| | | Luhn checksum or SVN information. [ThreeGPP.IMEI] | | | | Luhn checksum or SVN information. [ThreeGPP.IMEI] |
+------+------+-----------------------------------------------------+ +------+------+-----------------------------------------------------+
Table 1: UEID Composition Types Table 1: UEID Composition Types
UEID's are not designed for direct use by humans (e.g., printing on UEID's are not designed for direct use by humans (e.g., printing on
the case of a device), so no textual representation is defined. the case of a device), so no textual representation is defined.
The consumer (the relying party) of a UEID MUST treat a UEID as a The consumer (the Relying Party) of a UEID MUST treat a UEID as a
completely opaque string of bytes and not make any use of its completely opaque string of bytes and not make any use of its
internal structure. For example, they should not use the OUI part of internal structure. For example, they should not use the OUI part of
a type 0x02 UEID to identify the manufacturer of the device. Instead a type 0x02 UEID to identify the manufacturer of the device. Instead
they should use the oemid claim that is defined elsewhere. The they should use the oemid claim that is defined elsewhere. The
reasons for this are: reasons for this are:
o UEIDs types may vary freely from one manufacturer to the next. o UEIDs types may vary freely from one manufacturer to the next.
o New types of UEIDs may be created. For example, a type 0x07 UEID o New types of UEIDs may be created. For example, a type 0x07 UEID
may be created based on some other manufacturer registration may be created based on some other manufacturer registration
scheme. scheme.
o Device manufacturers are allowed to change from one type of UEID o Device manufacturers are allowed to change from one type of UEID
to another anytime they want. For example, they may find they can to another anytime they want. For example, they may find they can
optimize their manufacturing by switching from type 0x01 to type optimize their manufacturing by switching from type 0x01 to type
0x02 or vice versa. The main requirement on the manufacturer is 0x02 or vice versa. The main requirement on the manufacturer is
that UEIDs be universally unique. that UEIDs be universally unique.
3.4.1. ueid CDDL A Device Indentifier URN is registered for UEIDs. See Section 9.3.4.
ueid-type = bstr .size (7..33) $$claims-set-claims //= (ueid-label => ueid-type)
ueid-claim = ( ueid-type = bstr .size (7..33)
ueid => ueid-type
)
3.5. Semi-permanent UEIDs (SUEIDs) 3.5. Semi-permanent UEIDs (SUEIDs)
An SEUID is of the same format as a UEID, but it may change to a An SEUID is of the same format as a UEID, but it may change to a
different value on device life-cycle events. Examples of these different value on device life-cycle events. Examples of these
events are change of ownership, factory reset and on-boarding into an events are change of ownership, factory reset and on-boarding into an
IoT device management system. A device may have both a UEID and IoT device management system. A device may have both a UEID and
SUEIDs, neither, one or the other. SUEIDs, neither, one or the other.
There may be multiple SUEIDs. Each one has a text string label the There may be multiple SUEIDs. Each one has a text string label the
purpose of which is to distinguish it from others in the token. The purpose of which is to distinguish it from others in the token. The
label may name the purpose, application or type of the SUEID. label may name the purpose, application or type of the SUEID.
Typically, there will be few SUEDs so there is no need for a formal Typically, there will be few SUEDs so there is no need for a formal
labeling mechanism like a registry. The EAT profile may describe how labeling mechanism like a registry. The EAT profile may describe how
SUEIDs should be labeled. If there is only one SUEID, the claim SUEIDs should be labeled. If there is only one SUEID, the claim
remains a map and there still must be a label. For example, the remains a map and there still must be a label. For example, the
label for the SUEID used by FIDO Onboarding Protocol could simply be label for the SUEID used by FIDO Onboarding Protocol could simply be
"FDO". "FDO".
There are privacy considerations for SUEID's. See Section 8.1. There are privacy considerations for SUEID's. See Section 10.1.
A Device Indentifier URN is registered for SUEIDs. See
Section 9.3.4.
$$claims-set-claims //= (sueids-label => sueids-type)
sueids-type = { sueids-type = {
+ tstr => ueid-type + tstr => ueid-type
} }
sueids-claim = ( 3.6. Hardware OEM Identification (oemid)
sueids => sueids-type
)
3.6. OEM Identification by IEEE (oemid) This claim identifies the OEM of the hardware. Any of the three
forms may be used at the convenience of the attester implementation.
The receiver of this claim MUST be able to handle all three forms.
3.6.1. Random Number Based
This format is always 16 bytes in size (128 bits).
The OEM may create their own ID by using a cryptographic-quality
random number generator. They would perform this only once in the
life of the company to generate the single ID for said company. They
would use that same ID in every device they make. This uniquely
identifies the OEM on a statistical basis and is large enough should
there be ten billion companies.
The OEM may also use a hash like SHA-256 and truncate the output to
128 bits. The input to the hash should be somethings that have at
least 96 bits of entropy, but preferably 128 bits of entropy. The
input to the hash may be something whose uniqueness is managed by a
central registry like a domain name.
This is to be base64url encoded in JSON.
3.6.2. IEEE Based
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 an IEEE 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. MA-M similarly is a 28-bit value
uses as the first part of a MAC address, and MA-S, formerly known as uses as the first part of a MAC address, and MA-S, formerly known as
OUI-36, a 36-bit value. Many companies already have purchased one of OUI-36, a 36-bit value. Many companies already have purchased one of
these. A CID is also a 24-bit value from the same space as an MA-L, these. A CID is also a 24-bit value from the same space as an MA-L,
but not for use as a MAC address. IEEE has published Guidelines for but not for use as a MAC address. IEEE has published Guidelines for
Use of EUI, OUI, and CID [OUI.Guide] and provides a lookup services Use of EUI, OUI, and CID [OUI.Guide] and provides a lookup services
[OUI.Lookup] [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 pick one and prefer that for all their devices. should pick one and prefer that for all their devices.
Commonly, these are expressed in Hexadecimal Representation Commonly, these are expressed in Hexadecimal Representation
[IEEE.802-2001] also called the Canonical format. When this claim is [IEEE.802-2001] also called the Canonical format. When this claim is
encoded the order of bytes in the bstr are the same as the order in encoded the order of bytes in the bstr are the same as the order in
the Hexadecimal Representation. For example, an MA-L like "AC-DE-48" the Hexadecimal Representation. For example, an MA-L like "AC-DE-48"
would be encoded in 3 bytes with values 0xAC, 0xDE, 0x48. For JSON would be encoded in 3 bytes with values 0xAC, 0xDE, 0x48. For JSON
encoded tokens, this is further base64url encoded. encoded tokens, this is further base64url encoded.
3.6.1. oemid CDDL This format is always 3 bytes in size in CBOR.
oemid-claim = ( 3.6.3. IANA Private Enterprise Number
oemid => bstr
IANA maintains a simple integer-based company registry called the
Private Enterprise Number (PEN) [PEN].
PENs are often used to create an OID. That is not the case here.
They are used only as a simple integer.
In CBOR this is encoded as a major type 0 integer in CBOR and is
typically 3 bytes. It is encoded as a number in JSON.
oemid-pen = int
oemid-ieee = bstr .size 3
oemid-random = bstr .size 16
$$claims-set-claims //= (
oemid-label =>
oemid-random / oemid-ieee / oemid-pen
) )
3.7. Hardware Version Claims (hardware-version-claims) 3.7. Hardware Version Claims (hardware-version-claims)
The hardware version can be claimed at three different levels, the The hardware version can be claimed at three different levels, the
chip, the circuit board and the final device assembly. An EAT can chip, the circuit board and the final device assembly. An EAT can
include any combination these claims. include any combination these claims.
The hardware version is a simple text string the format of which is The hardware version is a simple text string the format of which is
set by each manufacturer. The structure and sorting order of this set by each manufacturer. The structure and sorting order of this
text string can be specified using the version-scheme item from text string can be specified using the version-scheme item from
CoSWID [CoSWID]. CoSWID [CoSWID].
The hardware version can also be given by a 13-digit [EAN-13]. A new The hardware version can also be given by a 13-digit [EAN-13]. A new
CoSWID version scheme is registered with IANA by this document in CoSWID version scheme is registered with IANA by this document in
Section 7.3.3. An EAN-13 is also known as an International Article Section 9.3.3. An EAN-13 is also known as an International Article
Number or most commonly as a bar code. Number or most commonly as a bar code.
chip-version-claim = ( $$claims-set-claims //= (
chip-version => tstr chip-version-label => hw-version-type
) )
chip-version-scheme-claim = ( $$claims-set-claims //= (
chip-version-scheme => $version-scheme board-version-label => hw-version-type
) )
board-version-claim = ( $$claims-set-claims //= (
board-version => tstr device-version-label => hw-version-type
) )
board-version-scheme-claim = ( hw-version-type = [
board-version-scheme => $version-scheme version: tstr,
) scheme: $version-scheme
]
device-version-claim = ( 3.8. Software Name Claim
device-version => tstr
)
device-version-scheme-claim = ( This is a simple free-form text claim for the name of the software.
device-version-scheme => $version-scheme A CoSWID manifest or other type of manifest can be used instead if
) this is too simple.
hardware-version-claims = ( $$claims-set-claims //= ( sw-name-label => tstr )
? chip-version-claim,
? board-version-claim,
? device-version-claim,
? chip-version-scheme-claim,
? board-version-scheme-claim,
? device-version-scheme-claim,
)
3.8. Software Description and Version 3.9. Software Version Claim
TODO: Add claims that reference CoSWID. This makes use of the CoSWID version scheme data type to give a
simple version for the software. A full CoSWID manifest or other
type of manifest can be instead if this is too simple.
3.9. The Security Level Claim (security-level) $$claims-set-claims //= (sw-version-label => sw-version-type)
sw-version-type = [
version: tstr,
scheme: $version-scheme / As defined by CoSWID /
]
3.10. The Security Level Claim (security-level)
This claim characterizes the device/entity ability to defend against This claim characterizes the device/entity ability to defend against
attacks aimed at capturing the signing key, forging claims and at attacks aimed at capturing the signing key, forging claims and at
forging EATs. This is done by defining four security levels as forging EATs. This is by defining four security levels as described
described below. This is similar to the key protection types defined below.
by the Fast Identity Online (FIDO) Alliance [FIDO.Registry].
These claims describe security environment and countermeasures These claims describe security environment and countermeasures
available on the end-entity / client device where the attestation key available on the end-entity/client device where the attestation key
reside and the claims originate. resides and the claims originate.
1 - Unrestricted There is some expectation that implementor will 1 - Unrestricted: There is some expectation that implementor will
protect the attestation signing keys at this level. Otherwise the protect the attestation signing keys at this level. Otherwise,
EAT provides no meaningful security assurances. the EAT provides no meaningful security assurances.
2- Restricted Entities at this level should not be general-purpose 2 - Restricted: Entities at this level are not general-purpose
operating environments that host features such as app download operating environments that host features such as app download
systems, web browsers and complex productivity applications. It systems, web browsers and complex productivity applications. It
is akin to the Secure Restricted level (see below) without the is akin to the secure-restricted level (see below) without the
security orientation. Examples include a Wi-Fi subsystem, an IoT security orientation. Examples include a Wi-Fi subsystem, an IoT
camera, or sensor device. camera, or sensor device. Often these can be considered more
secure than unrestricted just because they are much simpler and a
smaller attack surface, but this won't always be the case. Some
unrestricted devices may be implemented in a way that provides
poor protection of signing keys.
3 - Secure Restricted Entities at this level must meet the criteria 3 - Secure-Restricted: Entities at this level must meet the criteria
defined by FIDO Allowed Restricted Operating Environments defined in section 4 of FIDO Allowed Restricted Operating
[FIDO.AROE]. Examples include TEE's and schemes using Environments [FIDO.AROE]. Examples include TEE's and schemes
virtualization-based security. Like the FIDO security goal, using virtualization-based security. Like the FIDO security goal,
security at this level is aimed at defending well against large- security at this level is aimed at defending well against large-
scale network / remote attacks against the device. scale network/remote attacks against the device.
4 - Hardware Entities at this level must include substantial defense 4 - Hardware: Entities at this level must include substantial
against physical or electrical attacks against the device itself. defense against physical or electrical attacks against the device
It is assumed any potential attacker has captured the device and itself. It is assumed any potential attacker has captured the
can disassemble it. Example include TPMs and Secure Elements. device and can disassemble it. Examples include TPMs and Secure
Elements.
The entity should claim the highest security level it achieves and no The entity should claim the highest security level it achieves and no
higher. This set is not extensible so as to provide a common higher. This set is not extensible so as to provide a common
interoperable description of security level to the relying party. If interoperable description of security level to the Relying Party. If
a particular implementation considers this claim to be inadequate, it a particular implementation considers this claim to be inadequate, it
can define its own proprietary claim. It may consider including both can define its own proprietary claim. It may consider including both
this claim as a coarse indication of security and its own proprietary this claim as a coarse indication of security and its own proprietary
claim as a refined indication. claim as a refined indication.
This claim is not intended as a replacement for a proper end-device This claim is not intended as a replacement for a proper end-device
security certification schemes such as those based on FIPS 140 security certification scheme such as those based on FIPS 140
[FIPS-140] or those based on Common Criteria [Common.Criteria]. The [FIPS-140] or those based on Common Criteria [Common.Criteria]. The
claim made here is solely a self-claim made by the Entity Originator. claim made here is solely a self-claim made by the Attester.
3.9.1. security-level CDDL $$claims-set-claims //= (
security-level-cbor-type = &( security-level-label =>
unrestricted: 1, security-level-cbor-type /
restricted: 2, security-level-json-type
secure-restricted: 3, )
hardware: 4
)
security-level-json-type = security-level-cbor-type = &(
"unrestricted" / unrestricted: 1,
"restricted" / restricted: 2,
"secure-restricted" / secure-restricted: 3,
"hardware" hardware: 4
)
security-level-claim = ( security-level-json-type =
security-level => security-level-cbor-type / security-level-json-type "unrestricted" /
) "restricted" /
"secure-restricted" /
"hardware"
3.10. Secure Boot Claim (secure-boot) 3.11. Secure Boot Claim (secure-boot)
The value of true indicates secure boot is enabled. Secure boot is The value of true indicates secure boot is enabled. Secure boot is
considered enabled when base software, the firmware and operating considered enabled when base software, the firmware and operating
system, are under control of the entity manufacturer identified in system, are under control of the entity manufacturer identified in
the oemid claimd described in Section 3.6. This may because the the OEMID claim described in Section 3.6. This may because the
software is in ROM or because it is cryptographically authenticated software is in ROM or because it is cryptographically authenticated
or some combination of the two or other. or some combination of the two or other.
3.10.1. secure-boot CDDL $$claims-set-claims //= (secure-boot-label => bool)
secure-boot-claim = (
secure-boot => bool
)
3.11. Debug Status Claim (debug-status) 3.12. Debug Status Claim (debug-status)
This applies to system-wide or submodule-wide debug facilities of the This applies to system-wide or submodule-wide debug facilities of the
target device / submodule like JTAG and diagnostic hardware built target device / submodule 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
root, operating system or privileged software that allow system-wide root, operating system or privileged software that allow system-wide
memory inspection, tracing or modification of non-system software memory inspection, tracing or modification of non-system software
like user mode applications. like user mode 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
skipping to change at page 20, line 13 skipping to change at page 20, line 11
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-device public keys. or by per-device public keys.
As with all claims, the absence of the debug level claim means it is As with all claims, the absence of the debug level claim means it is
not reported. A conservative interpretation might assume the Not not reported. A conservative interpretation might assume the Not
Disabled state. It could however be that it is reported in a Disabled state. It could however be that it is reported in a
proprietary claim. proprietary claim.
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 to the relying party. If a particular description of debug status to the Relying Party. If a particular
implementation considers this claim to be inadequate, it can define implementation considers this claim to be inadequate, it can define
its own proprietary claim. It may consider including both this claim its own 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. as a refined indication.
The higher levels of debug disabling requires that all debug The higher levels of debug disabling requires that all debug
disabling of the levels below it be in effect. Since the lowest disabling of the levels below it be in effect. Since the lowest
level requires that all of the target's debug be currently disabled, level requires that all of the target's debug be currently disabled,
all other levels require that too. all other 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 verifier or relying party describe its own debug state. The Verifier or Relying Party
receiving an EAT cannot assume that debug is turned off in a receiving an EAT cannot assume that debug is turned off in a
submodule because there is a claim indicating it is turned off in a submodule because there is a claim indicating it is turned off in a
superior module. superior module.
An individual target device / submodule may have multiple debug An individual target device / submodule may have multiple debug
facilities. The use of plural in the description of the states facilities. The use of plural in the description of the states
refers to that, not to any aggregation or inheritance. refers to that, not to any aggregation or inheritance.
The architecture of some chips or devices may be such that a debug The architecture of some chips or devices may be such that a debug
facility operates for the whole chip or device. If the EAT for such facility operates for the whole chip or device. If the EAT for such
a chip includes submodules, then each submodule should independently a chip includes submodules, then each submodule should independently
report the status of the whole-chip or whole-device debug facility. report the status of the whole-chip or whole-device debug facility.
This is the only way the relying party can know the debug status of This is the only way the Relying Party can know the debug status of
the submodules since there is no inheritance. the submodules since there is no inheritance.
3.11.1. Enabled 3.12.1. 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.
3.11.2. Disabled 3.12.2. 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, and it may also be may be possible to enable them in the future, and it may also be
possible that they were enabled in the past after the target device/ possible that they were enabled in the past after the target device/
sub-system booted/started, but they are currently disabled. sub-system booted/started, but they are currently disabled.
3.11.3. Disabled Since Boot 3.12.3. 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 target device/sub-system booted/started. have been so since the target device/sub-system booted/started.
3.11.4. Disabled Permanently 3.12.4. 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 cannot enable them. Only disabled such that no end user or developer cannot enable them. Only
the manufacturer indicated in the OEMID claim can enable them. This the manufacturer indicated in the OEMID claim can enable them. This
also indicates that all debug facilities are currently disabled and also indicates that all debug facilities are currently disabled and
have been so since boot/start. have been so since boot/start.
3.11.5. Disabled Fully and Permanently 3.12.5. Disabled Fully and Permanently
This level indicates that all debug capabilities for the target This level indicates that all debug capabilities for the target
device/sub-module are permanently disabled. device/sub-module are permanently disabled.
3.11.6. debug-status CDDL $$claims-set-claims //= (
debug-status-label =>
debug-status-cbor-type / debug-status-json-type
)
debug-status-cbor-type = &( debug-status-cbor-type = &(
enabled: 0, enabled: 0,
disabled: 1, disabled: 1,
disabled-since-boot: 2, disabled-since-boot: 2,
disabled-permanently: 3, disabled-permanently: 3,
disabled-fully-and-permanently: 4 disabled-fully-and-permanently: 4
) )
debug-status-json-type = debug-status-json-type =
"enabled" / "enabled" /
"disabled" / "disabled" /
"disabled-since-boot" / "disabled-since-boot" /
"disabled-permanently" / "disabled-permanently" /
"disabled-fully-and-permanently" "disabled-fully-and-permanently"
debug-status-claim = ( 3.13. Including Keys
debug-status => debug-status-cbor-type / debug-status-json-type
)
3.12. Including Keys
An EAT may include a cryptographic key such as a public key. The An EAT may include a cryptographic key such as a public key. The
signing of the EAT binds the key to all the other claims in the signing of the EAT binds the key to all the other claims in the
token. token.
The purpose for inclusion of the key may vary by use case. For The purpose for inclusion of the key may vary by use case. For
example, the key may be included as part of an IoT device onboarding example, the key may be included as part of an IoT device onboarding
protocol. When the FIDO protocol includes a pubic key in its protocol. When the FIDO protocol includes a pubic key in its
attestation message, the key represents the binding of a user, device attestation message, the key represents the binding of a user, device
and relying party. This document describes how claims containing and Relying Party. This document describes how claims containing
keys should be defined for the various use cases. It does not define keys should be defined for the various use cases. It does not define
specific claims for specific use cases. specific claims for specific use cases.
Keys in CBOR format tokens SHOULD be the COSE_Key format [RFC8152] Keys in CBOR format tokens SHOULD be the COSE_Key format [RFC8152]
and keys in JSON format tokens SHOULD be the JSON Web Key format and keys in JSON format tokens SHOULD be the JSON Web Key format
[RFC7517]. These two formats support many common key types. Their [RFC7517]. These two formats support many common key types. Their
use avoids the need to decode other serialization formats. These two use avoids the need to decode other serialization formats. These two
formats can be extended to support further key types through their formats can be extended to support further key types through their
IANA registries. IANA registries.
skipping to change at page 22, line 40 skipping to change at page 22, line 29
case. case.
When the actual confirmation claim is included in an EAT, this When the actual confirmation claim is included in an EAT, this
document associates no use case semantics other than proof of document associates no use case semantics other than proof of
posession. Different EAT use cases may choose to associate further posession. Different EAT use cases may choose to associate further
semantics. The key in the confirmation claim MUST be protected the semantics. The key in the confirmation claim MUST be protected the
same as the key used to sign the EAT. That is, the same, equivalent same as the key used to sign the EAT. That is, the same, equivalent
or better hardware defenses, access controls, key generation and such or better hardware defenses, access controls, key generation and such
must be used. must be used.
3.13. The Location Claim (location) 3.14. The Location Claim (location)
The location claim gives the location of the device entity from which The location claim gives the location of the device entity from which
the attestation originates. It is derived from the W3C Geolocation the attestation originates. It is derived from the W3C Geolocation
API [W3C.GeoLoc]. The latitude, longitude, altitude and accuracy API [W3C.GeoLoc]. The latitude, longitude, altitude and accuracy
must conform to [WGS84]. The altitude is in meters above the [WGS84] must conform to [WGS84]. The altitude is in meters above the [WGS84]
ellipsoid. The two accuracy values are positive numbers in meters. ellipsoid. The two accuracy values are positive numbers in meters.
The heading is in degrees relative to true north. If the device is The heading is in degrees relative to true north. If the device is
stationary, the heading is NaN (floating-point not-a-number). The stationary, the heading is NaN (floating-point not-a-number). The
speed is the horizontal component of the device velocity in meters speed is the horizontal component of the device velocity in meters
per second. per second.
skipping to change at page 23, line 23 skipping to change at page 23, line 11
since the last contact with a GPS satellite. Either the timestamp or since the last contact with a GPS satellite. Either the timestamp or
age data item can be used to quantify the cached period. The age data item can be used to quantify the cached period. The
timestamp data item is preferred as it a non-relative time. timestamp data item is preferred as it a non-relative time.
The age data item can be used when the entity doesn't know what time The age data item can be used when the entity doesn't know what time
it is either because it doesn't have a clock or it isn't set. The it is either because it doesn't have a clock or it isn't set. The
entity must still have a "ticker" that can measure a time interval. entity must still have a "ticker" that can measure a time interval.
The age is the interval between acquisition of the location data and The age is the interval between acquisition of the location data and
token creation. token creation.
See location-related privacy considerations in Section 8.2 below. See location-related privacy considerations in Section 10.2 below.
3.13.1. location CDDL $$claims-set-claims //= (location-label => location-type)
location-type = { location-type = {
latitude => number, latitude => number,
longitude => number, longitude => number,
? altitude => number, ? altitude => number,
? accuracy => number, ? accuracy => number,
? altitude-accuracy => number, ? altitude-accuracy => number,
? heading => number, ? heading => number,
? speed => number, ? speed => number,
? timestamp => ~time-int, ? timestamp => ~time-int,
skipping to change at page 23, line 49 skipping to change at page 23, line 37
latitude = 1 / "latitude" latitude = 1 / "latitude"
longitude = 2 / "longitude" longitude = 2 / "longitude"
altitude = 3 / "altitude" altitude = 3 / "altitude"
accuracy = 4 / "accuracy" accuracy = 4 / "accuracy"
altitude-accuracy = 5 / "altitude-accuracy" altitude-accuracy = 5 / "altitude-accuracy"
heading = 6 / "heading" heading = 6 / "heading"
speed = 7 / "speed" speed = 7 / "speed"
timestamp = 8 / "timestamp" timestamp = 8 / "timestamp"
age = 9 / "age" age = 9 / "age"
location-claim = ( 3.15. The Uptime Claim (uptime)
location-label => location-type
)
3.14. The Uptime Claim (uptime)
The "uptime" claim contains a value that represents the number of The "uptime" claim contains a value that represents the number of
seconds that have elapsed since the entity or submod was last booted. seconds that have elapsed since the entity or submod was last booted.
3.14.1. uptime CDDL $$claims-set-claims //= (uptime-label => uint)
uptime-claim = (
uptime => uint
)
3.15. The Boot Seed Claim (boot-seed) 3.16. The Boot Seed Claim (boot-seed)
The Boot Seed claim is a random value created at system boot time The Boot Seed claim is a random value created at system boot time
that will allow differentiation of reports from different boot that will allow differentiation of reports from different boot
sessions. This value is usually public and not protected. It is not sessions. This value is usually public and not protected. It is not
the same as a seed for a random number generator which must be kept the same as a seed for a random number generator which must be kept
secret. secret.
boot-seed-claim = ( $$claims-set-claims //= (boot-seed-label => bytes)
boot-seed => bytes
)
3.16. The Intended Use Claim (intended-use) 3.17. The Intended Use Claim (intended-use)
EAT's may be used in the context of several different applications. EAT's may be used in the context of several different applications.
The intended-use claim provides an indication to an EAT consumer The intended-use claim provides an indication to an EAT consumer
about the intended usage of the token. This claim can be used as a about the intended usage of the token. This claim can be used as a
way for an application using EAT to internally distinguish between way for an application using EAT to internally distinguish between
different ways it uses EAT. different ways it uses EAT.
1 - Generic Generic attestation describes an application where the 1 - Generic Generic attestation describes an application where the
EAT consumer requres the most up-to-date security assessment of EAT consumer requres 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
skipping to change at page 25, line 15 skipping to change at page 25, line 5
may be used as part of the certificate signing request (CSR). may be 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) appication. as part of an accompanying proof-of-possession (PoP) appication.
More precisely, a PoP transaction is intended to provide to the More precisely, a PoP transaction is intended to provide to the
recipient cryptographically-verifiable proof that the sender has recipient cryptographically-verifiable proof that the sender has
posession of a key. This kind of attestation may be neceesary to posession of a key. This kind of attestation may be neceesary to
verify the security state of the entity storing the private key verify the security state of the entity storing the private key
used in a PoP application. used in a PoP application.
3.16.1. intended-use CDDL $$claims-set-claims //= (
intended-use-label =>
intended-use-cbor-type / intended-use-json-type
)
intended-use-cbor-type = &( intended-use-cbor-type = &(
generic: 1, generic: 1,
registration: 2, registration: 2,
provisioning: 3, provisioning: 3,
csr: 4, csr: 4,
pop: 5 pop: 5
) )
intended-use-json-type = intended-use-json-type =
"generic" / "generic" /
"registration" / "registration" /
"provisioning" / "provisioning" /
"csr" / "csr" /
"pop" "pop"
intended-use-claim = ( 3.18. The Profile Claim (profile)
intended-use => intended-use-cbor-type / intended-use-json-type
)
3.17. The Profile Claim (profile)
See Section 5 for the detailed description of a profile. See Section 7 for the detailed description of a profile.
A profile is identified by either a URL or an OID. Typically, the A profile is identified by either a URL or an OID. Typically, the
URI will reference a document describing the profile. An OID is just URI will reference a document describing the profile. An OID is just
a unique identifier for the profile. It may exist anywhere in the a unique identifier for the profile. It may exist anywhere in the
OID tree. There is no requirement that the named document be OID tree. There is no requirement that the named document be
publicly accessible. The primary purpose of the profile claim is to publicly accessible. The primary purpose of the profile claim 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 encoded in CBOR according to [CBOR-OID] and the URI The OID is encoded in CBOR according to [CBOR.OID] and the URI
according to [RFC8949]. Both are unwrapped and thus not tags. The according to [RFC8949]. Both are unwrapped and thus not tags. The
OID is always absolute and never relative. If the claims CBOR type OID is always absolute and never relative. If the claims CBOR type
is a text string it is a URI and if a byte string it is an OID. is a text string it is a URI and if a byte string it is an OID.
Note that this named "eat_profile" for JWT and is distinct from the Note that this named "eat_profile" for JWT and is distinct from the
already registered "profile" claim in the JWT claims registry. already registered "profile" claim in the JWT claims registry.
oid = #6.4000(bstr) ; TODO: fill this in with correct CDDL from OID RFC $$claims-set-claims //= (profile-label => ~uri / ~oid)
profile-claim = ( oid = #6.4000(bstr) ; TODO: Replace with CDDL from OID RFC
profile => ~uri / ~oid
)
3.18. The Software Manifests Claim (manifests) 3.19. The DLOA (Digital Letter or Approval) Claim (dloas)
A DLOA (Digital Letter of Approval) [DLOA] is an XML document that
describes a certification that a device or entity has received.
Examples of certifications represented by a DLOA include those issued
by Global Platform and those based on Common Criteria. The DLOA is
unspecific to any particular certification type or those issued by
any particular organization.
This claim is typically issued by a Verifier, not an Attester. When
this claim is issued by a Verifier, it MUST be because the entity,
device or submodule has received the certification in the DLOA.
This claim can contain more than one DLOA. If multiple DLOAs are
present, it MUST be because the entity, device or submodule received
all of the certifications.
DLOA XML documents are always fetched from a registrar that stores
them. This claim contains several data items used to construct a URL
for fetching the DLOA from the particular registrar.
The first data item is a URI for the registrar. The second data item
is a platform label to indicate the particular platform that was
certified. For platform certifications only these two are needed.
A DLOA may equally apply to an application. In that case it has the
URI for the registrar, a platform label and additionally an
application label.
The method of combining the registrar URI, platform label and
possibly application label is specified in [DLOA].
$$claims-set-claims //= (
dloas-label => [ + dloa-type ]
)
dloa-type = [
dloa_registrar: ~uri
dloa_platform_label: text
? dloa_application_label: text
]
3.20. The Software Manifests Claim (manifests)
This claim contains descriptions of software that is present on the This claim contains descriptions of software that is present on the
device. These manifests are installed on the device when the device. These manifests are installed on the device 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 device, process. Installation is anything that adds software to the device,
possibly factory installation, the user installing elective possibly factory installation, the user installing elective
applications and so on. The defining characteristic is that they are applications and so on. The defining characteristic is that they are
created by the software manufacturer. The purpose of these claims in created by the software manufacturer. The purpose of these claims in
an EAT is to relay them without modification to the Verifier and/or an EAT is to relay them without modification to the Verifier and/or
the Relying Party. the Relying Party.
skipping to change at page 27, line 25 skipping to change at page 28, line 17
text sets the encoding requirement. text sets the encoding requirement.
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 multiple formats. In some cases EAT submodules may be used may be of multiple formats. In some cases EAT submodules may be used
instead of the array structure in this claim for multiple manifests. instead of the array structure in this claim for multiple manifests.
When the [CoSWID] format is used, it MUST be a payload CoSWID, not an When the [CoSWID] format is used, it MUST be a payload CoSWID, not an
evidence CoSWID. evidence CoSWID.
manifests-claim = ( $$claims-set-claims //= (
manifests => manifests-type manifests-label => manifests-type
) )
manifests-type = [+ $manifest-formats] manifests-type = [+ $$manifest-formats]
; Must be a CoSWID payload type ; Must be a CoSWID payload type
$manifest-formats /= bytes .cbor concise-swid-tag ; TODO: signed CoSWIDs
coswid-that-is-a-cbor-tag-xx = tagged-coswid<concise-swid-tag>
$manifest-formats /= bytes .cbor SUIT_Envelope_Tagged $$manifest-formats /= bytes .cbor coswid-that-is-a-cbor-tag-xx
3.19. The Software Evidence Claim {swevidence} ; TODO: make this work too
;$$manifest-formats /= bytes .cbor SUIT_Envelope_Tagged
3.21. The Software Evidence Claim (swevidence)
This claim contains descriptions, lists, evidence or measurements of This claim contains descriptions, lists, evidence or measurements of
the software that exists on the device. The defining characteristic the software that exists on the device. The defining characteristic
of this claim is that its contents are created by processes on the of this claim is that its contents are created by processes on the
device that inventory, measure or otherwise characterize the software device that inventory, measure or otherwise characterize the software
on the device. The contents of this claim do not originate from the on the device. The contents of this claim do not originate from the
software manufacturer. software manufacturer.
In most cases the contents of this claim are signed as part of In most cases the contents of this claim are signed as part of
attestation signing, but independent signing in addition to the attestation signing, but independent signing in addition to the
skipping to change at page 28, line 11 skipping to change at page 29, line 8
This claim uses the same mechanism for identification of the type of This claim uses the same mechanism for identification of the type of
the swevidence as is used for the type of the manifest in the the swevidence as is used for the type of the manifest in the
manifests claim. It also uses the same byte string based mechanism manifests claim. It also uses the same byte string based mechanism
for containing the claim and easing the hand off to a processing for containing the claim and easing the hand off to a processing
library. See the discussion above in the manifests claim. library. See the discussion above in the manifests claim.
When the [CoSWID] format is used, it MUST be evidence CoSWIDs, not When the [CoSWID] format is used, it MUST be evidence CoSWIDs, not
payload CoSWIDS. payload CoSWIDS.
swevidence-claim = ( $$claims-set-claims //= (
swevidence => swevidence-type swevidence-label => swevidence-type
) )
swevidence-type = [+ $swevidence-formats] swevidence-type = [+ $$swevidence-formats]
; Must be a CoSWID evidence type ; Must be a CoSWID evidence type that is a CBOR tag
$swevidence-formats /= bytes .cbor concise-swid-tag ; TODO: fix the CDDL so a signed CoSWID is allowed too
coswid-that-is-a-cbor-tag = tagged-coswid<concise-swid-tag>
$$swevidence-formats /= bytes .cbor coswid-that-is-a-cbor-tag
3.20. The Submodules Part of a Token (submods) 3.22. The SW Measurement Results Claim (swresults)
Some devices are complex, having many subsystems or submodules. A This claims reports the outcome of the comparison of a measurement on
mobile phone is a good example. It may have several connectivity some software to the expected Reference Values. It may report a
submodules for communications (e.g., Wi-Fi and cellular). It may successful comparison, failed comparison or other.
have subsystems for low-power audio and video playback. It may have
one or more security-oriented subsystems like a TEE or a Secure
Element.
The claims for each these can be grouped together in a submodule. This claim may be generated by the Verifier and sent to the Relying
Party. For example, it could be the results of the Verifier
comparing the contents of the swevidence claim to Reference Values.
The submods part of a token are in a single map/object with many This claim can also be generated on the device if the device has the
entries, one per submodule. There is only one submods map in a ability for one subsystem to measure another subsystem. For example,
token. It is identified by its specific label. It is a peer to a TEE might have the ability to measure the software of the rich OS
other claims, but it is not called a claim because it is a container and may have the Reference Values for the rich OS.
for a claim set rather than an individual claim. This submods part
of a token allows what might be called recursion. It allows claim
sets inside of claim sets inside of claims sets...
3.20.1. Two Types of Submodules Within an attestation target or submodule, multiple results can be
reported. For example, it may be desirable to report the results for
the kernel and each individual application separately.
Each entry in the submod map is one of two types: For each software objective, the following can be reported.
o A non-token submodule that is a map or object directly containing 3.22.1. Scheme
claims for the submodule.
o A nested EAT that is a fully formed, independently signed EAT This is the free-form text name of the verification system or scheme
token that performed the verification. There is no official registry of
schemes or systems. It may be the name of a commercial product or
such.
3.20.1.1. Non-token Submodules 3.22.2. Objective
This is simply a map or object containing claims about the submodule. This roughly characterizes the coverage of the software measurement
software. This corresponds to the attestation target or the
submodule. If all of the indicated target is not covered, the
measurement must indicate partial.
1 - all Indicates all the software has been verified, for example,
all the software in the attestation target or the submodule
2 - firmware Indicates all of and only the firmware
3 - kernel Refers to all of the most-privileged software, for
example the Linux kernel
4 - privileged Refers to all of the software used by the root,
system or administrative account
5 - system-libs Refers to all of the system libraries that are
broadly shared and used by applications and such
6 - partial Some other partial set of the software
3.22.3. Results
This describes the result of the measurement and also the comparison
to Reference Values.
1 - verificaton-not-run Indicates no attempt was made to run the
verification
2 - verification-indeterminite The verification was attempted, but
it did not produce a result; perhaps it ran out of memory, the
battery died or such
3 - verification-failed The verification ran to completion, the
comparison was completed and did not compare correctly to the
Reference Values
4 - fully-verified The verification ran to completion and all
measurements compared correctly to Reference Values
5 - partially-verified The verification ran to completion and some,
but not all measurements compared correctly to Reference Values
3.22.4. Objective Name
This is a free-form text string that describes the objective. For
example, "Linux kernel" or "Facebook App"
$$claims-set-claims //= (swresults-label => [ + swresult-type ])
verification-result-cbor-type = &(
verification-not-run: 1,
verification-indeterminate: 2,
verification-failed: 3,
fully-verified: 4,
partially-verified: 5,
)
verification-result-json-type =
"verification-not-run" /
"verification-indeterminate" /
"verification-failed" /
"fully-verified" /
"partially-verified"
verification-objective-cbor-type = &(
all: 1,
firmware: 2,
kernel: 3,
privileged: 4,
system-libs: 5,
partial: 6,
)
verification-objective-json-type =
"all" /
"firmware" /
"kernel" /
"privileged" /
"system-libs" /
"partial"
swresult-type = [
verification-system: tstr,
objective: verification-objective-cbor-type /
verification-objective-json-type,
result: verification-result-cbor-type /
verification-result-json-type,
? objective-name: tstr
]
3.23. Submodules (submods)
Some devices are complex, having many subsystems. A mobile phone is
a good example. It may have several connectivity subsystems for
communications (e.g., Wi-Fi and cellular). It may have subsystems
for low-power audio and video playback. It may have one or more
security-oriented subsystems like a TEE or a Secure Element.
The claims for a subsystem can be grouped together in a submodule or
submod.
The submods are in a single map/object, one entry per submodule.
There is only one submods map/object in a token. It is identified by
its specific label. It is a peer to other claims, but it is not
called a claim because it is a container for a claims set rather than
an individual claim. This submods part of a token allows what might
be called recursion. It allows claims sets inside of claims sets
inside of claims sets...
3.23.1. Submodule Types
The following sections define the three major types of submodules:
o A submodule Claims-Set
o A nested token, which can be any valid EAT token, CBOR or JSON
o The digest of a detached Claims-Set
These are distinguished primarily by their data type which may be a
map/object, string or array.
3.23.1.1. Submodule Claims-Set
This is simply a subordinate Claims-Set containing claims about the
submodule.
The submodule claims-set is produced by the same Attester as the
surrounding token. It is secured using the same mechanism as the
enclosing token (e.g., it is signed by the same attestation key). It
roughly corresponds to an Attester Target Environment as described in
the RATS architecture.
It may contain claims that are the same as its surrounding token or It may contain claims that are the same as its surrounding token or
superior submodules. For example, the top-level of the token may superior submodules. For example, the top-level of the token may
have a UEID, a submod may have a different UEID and a further have a UEID, a submod may have a different UEID and a further
subordinate submodule may also have a UEID. subordinate submodule may also have a UEID.
It is signed/encrypted along with the rest of the token and thus the The encoding of a submodule Claims-Set is always the same as the
claims are secured by the same Attester with the same signing key as encoding as the token it is part of.
the rest of the token.
If a token is in CBOR format (a CWT or a UCCS), all non-token This data type for this type of submodule is a map/object as that is
submodules must be CBOR format. If a token in in JSON format (a the type of a Claims-Set.
JWT), all non-token submodules must be in JSON format.
When decoding, this type of submodule is recognized from the other 3.23.1.2. Nested Token
type by being a data item of type map for CBOR or type object for
JSON.
3.20.1.2. Nested EATs This type of submodule is a fully formed complete token. It is
typically produced by a separate Attester. It is typically used by a
Composite Device as described in RATS Architecture
[RATS.Architecture]
This type of submodule is a fully formed secured EAT as defined in In being a submodule of the surrounding token, it is
this document except that it MUST NOT be a UCCS or an unsecured JWT. cryptographically bound to the surrounding token. If it was conveyed
A nested token that is one that is always secured using COSE or JOSE, in parallel with the surrounding token, there would be no such
usually by an independent Attester. When the surrounding EAT is a binding and attackers could substitute a good attestation from
CWT or secured JWT, the nested token becomes securely bound with the another device for the attestation of an errant subsystem.
other claims in the surrounding token.
It is allowed to have a CWT as a submodule in a JWT and vice versa, A nested token does NOT need to use the same encoding as the
but this SHOULD be avoided unless necessary. enclosing token. This is to allow Composite Devices to be built
without regards to the encoding supported by their Attesters.
3.20.1.2.1. Surrounding EAT is CBOR format Thus a CBOR-encoded token like a CWT or UCCS can have a JWT as a
nested token submodule and a JSON-encoded token can have a CWT or
UCCS as a nested token submodule.
They type of an EAT nested in a CWT is determined by whether the CBOR The data type for this type of submodule is either a text or byte
type is a text string or a byte string. If a text string, then it is string.
a JWT. If a byte string, then it is a CWT.
A CWT nested in a CBOR-format token is always wrapped by a byte Mechanisms are defined for identifying the encoding and type of the
string for easier handling with standard CBOR decoders and token nested token. These mechanisms are different for CBOR and JSON
processing APIs that will typically take a byte buffer as input. encoding. The type of a CBOR-encoded nested token is identified
using the CBOR tagging mechanism and thus is in common with
identification used when any CBOR-encoded token is part of a CBOR-
based protocol. A new simple type mechanism is defined for
indication of the type of a JSON-encoded token since there is no JSON
equivalent of tagging.
Nested CWTs may be either a CWT CBOR tag or a CWT Protocol Message. 3.23.1.2.1. Surrounding EAT is CBOR-Encoded
COSE layers in nested CWT EATs MUST be a COSE_Tagged_Message, never a
COSE_Untagged_Message. If a nested EAT has more than one level of
COSE, for example one that is both encrypted and signed, a
COSE_Tagged_message must be used at every level.
3.20.1.2.2. Surrounding EAT is JSON format If the submodule is a byte string, then the nested token is CBOR-
encoded. The byte string always wraps a token that is a tag. The
tag identifies whether the nested token is a CWT, a UCCS or a CBOR-
encoded DEB.
When a CWT is nested in a JWT, it must be as a 55799 tag in order to If the submodule is a text string, then the nested token is JSON-
distinguish it from a nested JWT. encoded. The text string contains JSON. That JSON is the exactly
the JSON described in the next section with one exception. The token
can't be CBOR-encoded.
When a nested EAT in a JWT is decoded, first remove the base64url ; This specifies how one fully-formed token is nested inside a
encoding. Next, check to see if it starts with the bytes 0xd9d9f7. ; CBOR-format token. The fully-formed nested token is any valid
If so, then it is a CWT as a JWT will never start with these four ; token, CBOR or JSON (JWT, CWT, UCCS, DEB...) The mechanism for
bytes. If not if it is a JWT. ; identifying the type of the nested token is specific to the format
; of the surrounding token, CBOR in this case.
;
; A primary reason this is encoding-specific is that JSON does not
; have an equivalent to CBOR tags.
;
; If the data type here is text, then the nested token is JSON
; format, one of a JWT, UJCS or JSON-encoded DEB. The means for
; distinguishing which is in the definition of JSON-encoded
; Nested-Token. If the data type is bstr, then the nested token
; is CBOR format. It is byte-string wrapped and identified by a
;CBOR tag.
Other than the 55799 tag requirement, tag usage for CWT's nested in a Nested-Token =
JSON format token follow the same rules as for CWTs nested in CBOR- tstr / ; A JSON-encoded Nested-Token (see json-nested-token.cddl)
format tokens. It may be a CWT CBOR tag or a CWT Protocol Message bstr .cbor Tagged-CBOR-Token
and COSE_Tagged_Message MUST be used at all COSE layers.
3.20.1.3. Unsecured JWTs and UCCS Tokens as Submodules 3.23.1.2.2. Surrounding EAT is JSON-Encoded
To incorporate a UCCS token as a submodule, it MUST be as a non-token A nested token in a JSON-encoded token is an array of two items. The
submodule. This can be accomplished inserting the content of the first is a string that indicates the type of the second item as
UCCS Tag into the submodule map. The content of a UCCS tag is follows:
exactly a map of claims as required for a non-token submodule. If
the UCCS is not a UCCS tag, then it can just be inserted into the
submodule map directly.
The definition of a nested EAT type of submodule is that it is one "JWT" A JWT formatted according to [RFC7519]
that is secured (signed) by an Attester. Since UCCS tokens are
unsecured, they do not fulfill this definition and must be non-token
submodules.
To incorporate an Unsecured JWT as a submodule, the null-security "CBOR" Some base64url-encoded CBOR that is a tag that is either a
JOSE wrapping should be removed. The resulting claims set should be CWT, UCCS or CBOR-encoded DEB
inserted as a non-token submodule.
To incorporate a UCCS token in a surrounding JSON token, the UCCS "UJCS" A UJCS-Message. (A UJCS-Message is identical to a JSON-
token claims should be translated from CBOR to JSON. To incorporate encoded Claims-Set)
an Unsecured JWT into a surrounding CBOR-format token, the null-
security JOSE should be removed and the claims translated from JSON
to CBOR.
3.20.2. No Inheritance "DEB" A JSON-encoded Detached EAT Bundle.
; This describes a nested token that occurs inside a JSON-encoded
; token. It uses an array that is made up of a type indicator and the
; actual token. This is a substitute for the CBOR tag mechanism that
; JSON does not have.
Nested-Token = [
type : "JWT" / "CBOR" / "UJCS" / "DEB",
nested-token : JWT-Message /
B64URL-Tagged-CBOR-Token /
DEB-JSON-Message /
UJCS-Message
]
; This text is a Tagged-CBOR-Token (see cbor-token.cddl) that is
; base64url encoded. For example, it is a CWT that is a COSE_Sign1
; that is a CBOR tag that has been base64url encoded.
B64URL-Tagged-CBOR-Token = tstr .regexp "[A-Za-z0-9_=-]+"
3.23.1.3. Detached Submodule Digest
This is type of submodule equivalent to a Claims-Set submodule,
except the Claims-Set is conveyed separately outside of the token.
This type of submodule consists of a digest made using a
cryptographic hash of a Claims-Set. The Claims-Set is not included
in the token. It is conveyed to the Verifier outside of the token.
The submodule containing the digest is called a detached digest. The
separately conveyed Claims-Set is called a detached claims set.
The input to the digest is exactly the byte-string wrapped encoded
form of the Claims-Set for the submodule. That Claims-Set can
include other submodules including nested tokens and detached
digests.
The primary use for this is to facilitate the implementation of a
small and secure attester, perhaps purely in hardware. This small,
secure attester implements COSE signing and only a few claims,
perhaps just UEID and hardware identification. It has inputs for
digests of submodules, perhaps 32-byte hardware registers. Software
running on the device constructs larger claim sets, perhaps very
large, encodes them and digests them. The digests are written into
the small secure attesters registers. The EAT produced by the small
secure attester only contains the UEID, hardware identification and
digests and is thus simple enough to be implemented in hardware.
Probably, every data item in it is of fixed length.
The integrity protection for the larger Claims Sets will not be as
secure as those originating in hardware block, but the key material
and hardware-based claims will be. It is possible for the hardware
to enforce hardware access control (memory protection) on the digest
registers so that some of the larger claims can be more secure. For
example, one register may be writable only by the TEE, so the
detached claims from the TEE will have TEE-level security.
The data type for this type of submodule is an array It contains two
data items, an algorithm identifier and a byte string containing the
digest.
A DEB, described in Section 5, may be used to convey detached claims
sets and the token with their detached digests. EAT, however,
doesn't require use of a DEB. Any other protocols may be used to
convey detached claims sets and the token with their detached
digests. Note that since detached Claims-Sets are usually signed,
protocols conveying them must make sure they are not modified in
transit.
3.23.2. No Inheritance
The subordinate modules do not inherit anything from the containing The subordinate modules do not inherit anything from the containing
token. The subordinate modules must explicitly include all of their token. The subordinate modules must explicitly include all of their
claims. This is the case even for claims like the nonce and age. claims. This is the case even for claims like the nonce.
This rule is in place for simplicity. It avoids complex inheritance This rule is in place for simplicity. It avoids complex inheritance
rules that might vary from one type of claim to another. rules that might vary from one type of claim to another.
3.20.3. Security Levels 3.23.3. Security Levels
The security level of the non-token subordinate modules should always The security level of the non-token subordinate modules should always
be less than or equal to that of the containing modules in the case be less than or equal to that of the containing modules in the case
of non-token submodules. It makes no sense for a module of lesser of non-token submodules. It makes no sense for a module of lesser
security to be signing claims of a module of higher security. An security to be signing claims of a module of higher security. An
example of this is a TEE signing claims made by the non-TEE parts example of this is a TEE signing claims made by the non-TEE parts
(e.g. the high-level OS) of the device. (e.g. the high-level OS) of the device.
The opposite may be true for the nested tokens. They usually have The opposite may be true for the nested tokens. They usually have
their own more secure key material. An example of this is an their own more secure key material. An example of this is an
embedded secure element. embedded secure element.
3.20.4. Submodule Names 3.23.4. Submodule Names
The label or name for each submodule in the submods map is a text The label or name for each submodule in the submods map is a text
string naming the submodule. No submodules may have the same name. string naming the submodule. No submodules may have the same name.
3.20.5. submods CDDL 3.23.5. CDDL for submods
; The part of a token that contains all the submodules. It is a peer
; with the claims in the token, but not a claim, only a map/object to
; hold all the submodules.
submods-part = ( ; This is the part of a token that contains all the submodules. It
submods => submods-type ; is a peer with the claims in the token, but not a claim, only a
) ; map/object to hold all the submodules.
submods-type = { + submod-type } $$claims-set-claims //= (submods-label => { + text => Submodule })
; The type of a submodule which can either be a nested claim set or a ; A submodule can be:
; nested separately signed token. Nested tokens are wrapped in a bstr ; - A simple Claims-Set (encoded in the same format as the token)
; or a tstr. ; - A digest of a detached Claims-Set (encoded in the same format as
; the token)
; - A nested token which may be either CBOR or JSON format. Further,
; the mechanism for identifying and containing the nested token
; depends on the format of the surrounding token, particularly
; because JSON doesn't have any equivalent of a CBOR tag so a
; JSON-specific mechanism is invented. Also, there is the issue
; that binary data must be B64 encoded when carried in
; JSON. Nested-Token is defined in the format specific CDDL, not
; here.
submod-type = ( ; Note that at nested token can either be a signed token like a CWT
submod-name => eat-claim-set / nested-token ; or JWT, an unsigned token like a UCCS or UJCS, or a DEB (detached
) ; EAT bundle). The specific encoding of these is format-specific
; so it doesn't appear here.
; When this is a bstr, the contents are an eat-token in CWT or UCCS Submodule = Claims-Set / Nested-Token / Detached-Submodule-Digest
; format. When this is a tstr, the contents are an eat-token in JWT
; format.
nested-token = bstr / tstr; ; This is for both JSON and CBOR. JSON uses text label for
; algorithm from JOSE registry. CBOR uses integer label for
; algorithm from COSE registry. In JSON the digest is base64
; encoded.
; Each submodule has a unique text string name. Detached-Submodule-Digest = [
algorithm : int / text,
digest : bstr
]
submod-name = tstr 4. Unprotected JWT Claims-Sets
4. Endorsements and Verification Keys This is simply the JSON equivalent of an Unprotected CWT Claims-Set
[UCCS.Draft].
It has no protection of its own so protections must be provided by
the protocol carrying it. These are extensively discussed in
[UCCS.Draft]. All the security discussion and security
considerations in [UCCS.Draft] apply to UJCS.
(Note: The EAT author is open to this definition being moved into the
UCCS draft, perhaps along with the related CDDL. It is place here
for now so that the current UCCS draft plus this document are
complete. UJCS is needed for the same use cases that a UCCS is
needed. Further, JSON will commonly be used to convey Attestation
Results since JSON is common for server to server communications.
Server to server communications will often have established security
(e.g., TLS) therefore the signing and encryption from JWS and JWE are
unnecssary and burdensome).
5. Detached EAT Bundles
A detached EAT bundle is a structure to convey a fully-formed and
signed token plus detached claims set that relate to that token. It
is a top-level EAT message like a CWT, JWT, UCCS and UJCS. It can be
used any place that CWT, JWT, UCCS or UJCS messages are used. It may
also be sent as a submodule.
A DEB has two main parts.
The first part is a full top-level token. This top-level token must
have at least one submodule that is a detached digest. This top-
level token may be either CBOR or JSON-encoded. It may be a CWT,
JWT, UCCS or UJCS, but not a DEB. The same mechanism for
distinguishing the type for nested token submodules is used here.
The second part is a map/object containing the detached Claims-Sets
corresponding to the detached digests in the full token. When the
DEB is CBOR-encoded, each Claims-Set is wrapped in a byte string.
When the DEB is JSON-encoded, each Claims-Set is base64url encoded.
All the detached Claims-Sets MUST be encoded in the same format as
the DEB. No mixing of encoding formats is allowed for the Claims-
Sets in a DEB.
For CBOR-encoded DEBs, tag TBD602 can be used to identify it. The
normal 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 distinguish it from the
other types of nested tokens.
The digests of the detached claims sets are associated with detached
claims-sets by label/name. It is up to the constructor of the
detached EAT bundle to ensure the names uniquely identify the
detached claims sets. Since the names are used only in the detached
EAT bundle, they can be very short, perhaps one byte.
; Top-level definition of a DEB for CBOR and JSON
Detached-EAT-Bundle = [
main-token : Nested-Token,
detached-claims-sets: {
+ tstr => cbor-wrapped-claims-set / json-wrapped-claims-set
}
]
; text content is a base64url encoded JSON-format Claims-Set
json-wrapped-claims-set = tstr .regexp "[A-Za-z0-9_=-]+"
cbor-wrapped-claims-set = bstr .cbor Claims-Set
6. 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/
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 like Direct Anonymous
Attestation (DAA). Attestation (DAA).
RATS Architecture [RATS.Architecture] describes what is called an RATS Architecture [RATS.Architecture] describes what is called an
Endorsement. This is an input to the Verifier that is usually the Endorsement. This is an input to the Verifier that is usually the
basis of the trust placed in an EAT and the Attester that generated basis of the trust placed in an EAT and the Attester that generated
it. It may contain the public key for verification of the signature it. It may contain the public key for verification of the signature
skipping to change at page 33, line 26 skipping to change at page 41, line 15
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,...) of a
particular end-end attestation system to reliably interoperate, its particular end-end attestation system to reliably interoperate, its
definition should specify how the verification key is identified. 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.
4.1. Identification Methods 6.1. 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.
4.1.1. COSE/JWS Key ID 6.1.1. 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
[RFC8152] and [RFC7515] [RFC8152] 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
KDF, an authority key identifier (AKI) for an X.509 certificate or KDF, an authority key identifier (AKI) for an X.509 certificate or
other. The profile document should specify what the key ID's other. The profile document should specify what the key ID's
semantics are. semantics are.
4.1.2. JWS and COSE X.509 Header Parameters 6.1.2. JWS and COSE X.509 Header Parameters
COSE X.509 [COSE.X509.Draft] and JSON Web Siganture [RFC7515] define COSE X.509 [COSE.X509.Draft] and JSON Web Siganture [RFC7515] define
several header parameters (x5t, x5u,...) for referencing or carrying several header parameters (x5t, x5u,...) for referencing or carrying
X.509 certificates any of which may be used. X.509 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. It is up to the attestation system design and the
Verifier to determine which. Verifier to determine which.
4.1.3. CBOR Certificate COSE Header Parameters 6.1.3. 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.Cert.Draft]. These are semantically compatible
with X.509 and therefore can be used as an equivalent to X.509 as with 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,...).
4.1.4. Claim-Based Key Identification 6.1.4. 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 re-used as a key
identifier. For example, the UEID uniquely identifies the device and identifier. For example, the UEID uniquely identifies the device 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 This has the advantage that key identification requires no additional
bytes in the EAT and makes the EAT smaller. bytes in the EAT and makes the EAT smaller.
This has the disadvantage that the unverified EAT must be This has the disadvantage 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.
4.2. Other Considerations 6.2. Other Considerations
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 is
itself verified or determined to be trustworthy. The key itself verified or determined to be trustworthy. The key
identification itself is never enough. This will always be by some identification itself is never enough. This will always be by some
out-of-band mechanism that is not described here. For example, the out-of-band mechanism that is not described here. For example, the
Verifier may be configured with a root certificate or a master key by Verifier may be configured with a root certificate or a master key by
the Verifier system administrator. the Verifier 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 Values. key usage constraints and an Endorsement might have Reference Values.
When this is the case, the key identifier must be either a protected When this is the case, the key identifier must be either a protected
header or in the payload such that it is cryptographically bound to header or in the payload such that it is cryptographically bound to
the EAT. This is in line with the requirements in section 6 on Key the EAT. This is in line with the requirements in section 6 on Key
Identification in JSON Web Signature [RFC7515]. Identification in JSON Web Signature [RFC7515].
5. Profiles 7. Profiles
This EAT specification does not gaurantee that implementations of it This EAT specification does not gaurantee that implementations of it
will interoperate. The variability in this specification is will interoperate. The variability in this specification is
necessary to accommodate the widely varying use cases. An EAT necessary to accommodate the widely varying use cases. An EAT
profile narrows the specification for a specific use case. An ideal profile narrows the specification for a specific use case. An ideal
EAT profile will gauarantee interoperability. EAT profile will guarantee interoperability.
The profile can be named in the token using the profile claim The profile can be named in the token using the profile claim
described in Section 3.17. described in Section 3.18.
5.1. Format of a Profile Document A profile can apply to Attestation Evidence or to Attestation Results
or both.
7.1. Format of a Profile Document
A profile document doesn't have to be in any particular format. It A profile document doesn't 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.
In some cases CDDL may be created that replaces CDDL in this or other In some cases CDDL may be created that replaces CDDL in this or other
document to express some profile requirements. For example, to document to express some profile requirements. For example, to
require the altitude data item in the location claim, CDDL can be require the altitude data item in the location claim, CDDL can be
written that replicates the location claim with the altitude no written that replicates the location claim with the altitude no
longer optional. longer optional.
5.2. List of Profile Issues 7.2. List of Profile Issues
The following is a list of EAT, CWT, UCCS, JWS, COSE, JOSE and CBOR The following is a list of EAT, CWT, UCCS, JWS, UJCS, COSE, JOSE and
options that a profile should address. CBOR options that a profile should address.
5.2.1. Use of JSON, CBOR or both 7.2.1. Use of JSON, CBOR or both
The profile should indicate whether the token format should be CBOR, The profile should indicate whether the token format should be CBOR,
JSON, both or even some other encoding. If some other encoding, a JSON, both or even some other encoding. If some other encoding, a
specification for how the CDDL described here is serialized in that specification for how the CDDL described here is serialized in that
encoding is necessary. encoding is necessary.
This should be addressed for the top-level token and for any nested This should be addressed for the top-level token and for any nested
tokens. For example, a profile might require all nested tokens to be tokens. For example, a profile might require all nested tokens to be
of the same encoding of the top level token. of the same encoding of the top level token.
5.2.2. CBOR Map and Array Encoding 7.2.2. CBOR Map and Array Encoding
The profile should indicate whether definite-length arrays/maps, The profile should indicate whether definite-length arrays/maps,
indefinite-length arrays/maps or both are allowed. A good default is indefinite-length arrays/maps or both are allowed. A good default is
to allow only definite-length arrays/maps. to allow only definite-length arrays/maps.
An alternate is to allow both definite and indefinite-length arrays/ An alternate is to allow both definite and indefinite-length arrays/
maps. The decoder should accept either. Encoders that need to fit maps. The decoder should accept either. Encoders that need to fit
on very small hardware or be actually implement in hardware can use on very small hardware or be actually implement in hardware can use
indefinite-length encoding. indefinite-length encoding.
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.
5.2.3. CBOR String Encoding 7.2.3. CBOR String Encoding
The profile should indicate whether definite-length strings, The profile should indicate whether definite-length strings,
indefinite-length strings or both are allowed. A good default is to indefinite-length strings or both are allowed. A good default is to
allow only definite-length strings. As with map and array encoding, allow only definite-length strings. As with map and array encoding,
allowing indefinite-length strings can be beneficial for some smaller allowing indefinite-length strings can be beneficial for some smaller
implementations. implementations.
5.2.4. CBOR Preferred Serialization 7.2.4. CBOR Preferred Serialization
The profile should indicate whether encoders must use preferred The profile should indicate whether encoders must use preferred
serialization. The profile should indicate whether decoders must serialization. The profile should indicate whether decoders must
accept non-preferred serialization. accept non-preferred serialization.
5.2.5. COSE/JOSE Protection 7.2.5. 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. EAT/CWT has the option to have no protection using UCCS messages. EAT/CWT has the option to have no protection using UCCS
and JOSE has a NULL protection option. It is possible to implement and JOSE has a NULL protection option. It is possible to implement
no protection, sign only, MAC only, sign then encrypt and so on. All no protection, sign only, MAC only, sign then encrypt and so on. All
combinations allowed by COSE, JOSE, JWT, CWT and UCCS are allowed by combinations allowed by COSE, JOSE, JWT, CWT, UCCS and UJCS are
EAT. allowed by EAT.
The profile should list the protections that must be supported by all The profile should list the protections that must be supported by all
decoders implementing the profile. The encoders them must implement decoders implementing the profile. The encoders them must implement
a subset of what is listed for the decoders, perhaps only one. a subset of what is listed for the decoders, perhaps only one.
Implementations may choose to sign or MAC before encryption so that Implementations may choose to sign or MAC before encryption so that
the implementation layer doing the signing or MACing can be the the implementation layer doing the signing or MACing can be the
smallest. It is often easier to make smaller implementations more smallest. It is often easier to make smaller implementations more
secure, perhaps even implementing in solely in hardware. The key secure, perhaps even implementing in solely in hardware. The key
material for a signature or MAC is a private key, while for material for a signature or MAC is a private key, while for
encryption it is likely to be a public key. The key for encryption encryption it is likely to be a public key. The key for encryption
requires less protection. requires less protection.
5.2.6. COSE/JOSE Algorithms 7.2.6. COSE/JOSE Algorithms
The profile document should list the COSE algorithms that a Verifier The profile document should list the COSE algorithms that a Verifier
must implement. The Attester will select one of them. Since there must implement. The Attester will select one of them. Since there
is no negotiation, the Verifier should implement all algorithms is no negotiation, the Verifier should implement all algorithms
listed in the profile. listed in the profile. If detached submodules are used, the COSE
algorithms allowed for their digests should also be in the profile.
5.2.7. Verification Key Identification 7.2.7. DEB Support
Section Section 4 describes a number of methods for identifying a A Detatched EAT Bundle Section 5 is a special case message that will
not often be used. A profile may prohibit its use.
7.2.8. Verification Key Identification
Section Section 6 describes a number of methods for identifying a
verification key. The profile document should specify one of these verification key. The profile document should specify one of these
or one that is not described. The ones described in this document or one that is not described. The ones described in this document
are only roughly described. The profile document should go into the are only roughly described. The profile document should go into the
full detail. full detail.
5.2.8. Endorsement Identification 7.2.9. 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, where as key identification is not. optional, where as key identification is not.
5.2.9. Freshness 7.2.10. Freshness
Just about every use case will require some means of knowing the EAT Just about every use case will require some means of knowing the EAT
is recent enough and not a replay of an old token. The profile is recent enough and not a replay of an old token. The profile
should describe how freshness is achieved. The section on Freshness should describe how freshness is achieved. The section on Freshness
in [RATS-Architecture] describes some of the possible solutions to in [RATS.Architecture] describes some of the possible solutions to
achieve this. achieve this.
5.2.10. Required Claims 7.2.11. Required Claims
The profile can list claims whose absence results in Verification The profile can list claims whose absence results in Verification
failure. failure.
5.2.11. Prohibited Claims 7.2.12. Prohibited Claims
The profile can list claims whose presence results in Verification The profile can list claims whose presence results in Verification
failure. failure.
5.2.12. Additional Claims 7.2.13. Additional Claims
The profile may describe entirely new claims. These claims can be The profile may describe entirely new claims. These claims can be
required or optional. required or optional.
5.2.13. Refined Claim Definition 7.2.14. Refined Claim Definition
The profile may lock down optional aspects of individual claims. For The profile may lock down optional aspects of individual claims. For
example, it may require altitude in the location claim, or it may example, it may require altitude in the location claim, or it may
require that HW Versions always be described using EAN-13. require that HW Versions always be described using EAN-13.
5.2.14. CBOR Tags 7.2.15. 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. Similarly, the profile should specify whether the token should not. Similarly, the profile should specify whether the token should
be a UCCS tag or not. be a UCCS tag or 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 unncessary because the surrounding or carrying Often a tag is unncessary because the surrounding or carrying
protocol identifies the object as an EAT. protocol identifies the object as an EAT.
5.2.15. Manifests and Software Evidence Claims 7.2.16. Manifests and Software Evidence Claims
The profile should specify which formats are allowed for the The profile should specify which formats are allowed for the
manifests and software evidence claims. The profile may also go on manifests and software evidence claims. The profile may also go on
to say which parts and options of these formats are used, allowed and to say which parts and options of these formats are used, allowed and
prohibited. prohibited.
6. Encoding 8. Encoding and Collected CDDL
This makes use of the types defined in CDDL Appendix D, Standard
Prelude.
Some of the CDDL included here is for claims that are defined in CWT An EAT is fundamentally defined using CDDL. This document specifies
[RFC8392] or JWT [RFC7519] or are in the IANA CWT or JWT registries. how to encode the CDDL in CBOR or JSON. Since CBOR can express some
CDDL was not in use when these claims where defined. things that JSON can't (e.g., tags) or that are expressed differently
(e.g., labels) there is some CDDL that is specific to the encoding
format.
6.1. Common CDDL Types 8.1. Claims-Set and CDDL for CWT and JWT
time-int is identical to the epoch-based time, but disallows CDDL was not used to define CWT or JWT. It was not available at the
floating-point representation. time.
Note that unless expliclity indicated, URIs are not the URI tag This document defines CDDL for both CWT and JWT as well as UCCS.
defined in [RFC8949]. They are just text strings that contain a URI. This document does not change the encoding or semantics of anything
in a CWT or JWT.
string-or-uri = tstr A Claims-Set is the central data structure for EAT, CWT, JWT and
UCCS. It holds all the claims and is the structure that is secured
by signing or other means. It is not possible to define EAT, CWT,
JWT or UCCS in CDDL without it. The CDDL definition of Claims-Set
here is applicable to EAT, CWT, JWT and UCCS.
time-int = #6.1(int) This document specifies how to encode a Claims-Set in CBOR or JSON.
6.2. CDDL for CWT-defined Claims With the exception of nested tokens and some other externally defined
structures (e.g., SWIDs) an entire Claims-Set must be in encoded in
either CBOR or JSON, never a mixture.
This section provides CDDL for the claims defined in CWT. It is non- CDDL for the seven claims defined by [RFC8392] and [RFC7519] is
normative as [RFC8392] is the authoritative definition of these included here.
claims.
Note that the subject, issue and audience claims may be a text string 8.2. Encoding Data Types
containing a URI per [RFC8392] and [RFC7519]. These are never the
URI tag defined in [RFC8949].
$$eat-extension //= ( This makes use of the types defined in [RFC8610] Appendix D, Standard
? issuer => text, Prelude.
? subject => text,
? audience => text,
? expiration => time,
? not-before => time,
? issued-at => time,
? cwt-id => bytes,
)
issuer = 1 8.2.1. Common Data Types
subject = 2
audience = 3
expiration = 4
not-before = 5
issued-at = 6
cwt-id = 7
6.3. JSON time-int is identical to the epoch-based time, but disallows
floating-point representation.
6.3.1. JSON Labels Unless expliclity indicated, URIs are not the URI tag defined in
; The following are Claim Keys (labels) assigned for JSON-encoded tokens. [RFC8949]. They are just text strings that contain a URI.
ueid /= "ueid" string-or-uri = tstr
sueids /= "sueids"
nonce /= "nonce"
oemid /= "oemid"
security-level /= "seclevel"
secure-boot /= "secboot"
debug-status /= "dbgstat"
location /= "location"
uptime /= "uptime"
profile /= "eat-profile"
intended-use /= "intuse"
boot-seed /= "bootseed"
submods /= "submods"
timestamp /= "timestamp"
manifests /= "manifests"
swevidence /= "swevidence"
latitude /= "lat" time-int = #6.1(int)
longitude /= "long"
altitude /= "alt"
accuracy /= "accry"
altitude-accuracy /= "alt-accry"
heading /= "heading"
speed /= "speed"
6.3.2. JSON Interoperability 8.2.2. JSON Interoperability
JSON should be encoded per RFC 8610 Appendix E. In addition, the JSON should be encoded per [RFC8610] Appendix E. In addition, the
following CDDL types are encoded in JSON as follows: following CDDL types are encoded in JSON as follows:
o bstr - must be base64url encoded o bstr - must be base64url encoded
o time - must be encoded as NumericDate as described section 2 of o time - must be encoded as NumericDate as described section 2 of
[RFC7519]. [RFC7519].
o string-or-uri - must be encoded as StringOrURI as described o string-or-uri - must be encoded as StringOrURI as described
section 2 of [RFC7519]. section 2 of [RFC7519].
o uri - must be a URI [RFC3986]. o uri - must be a URI [RFC3986].
o oid - encoded as a string using the well established dotted- o oid - encoded as a string using the well established dotted-
decimal notation (e.g., the text "1.2.250.1"). decimal notation (e.g., the text "1.2.250.1").
6.4. CBOR 8.2.3. Labels
6.4.1. CBOR Interoperability Map labels, including Claims-Keys and Claim-Names, and enumerated-
type values are always integers when encoding in CBOR and strings
when encoding in JSON. There is an exception to this for naming
submodules and detached claims sets in a DEB. These are strings in
CBOR.
The CDDL in most cases gives both the integer label and the string
label as it is not convenient to have conditional CDDL for such.
8.3. CBOR Interoperability
CBOR allows data items to be serialized in more than one form. If CBOR allows data items to be serialized in more than one form. If
the sender uses a form that the receiver can't decode, there will not the sender uses a form that the receiver can't decode, there will not
be interoperability. be interoperability.
This specification gives no blanket requirements to narrow CBOR This specification gives no blanket requirements to narrow CBOR
serialization for all uses of EAT. This allows individual uses to serialization for all uses of EAT. This allows individual uses to
tailor serialization to the environment. It also may result in EAT tailor serialization to the environment. It also may result in EAT
implementations that don't interoperate. implementations that don't interoperate.
One way to guarantee interoperability is to clearly specify CBOR One way to guarantee interoperability is to clearly specify CBOR
serialization in a profile document. See Section 5 for a list of serialization in a profile document. See Section 7 for a list of
serialization issues that should be addressed. serialization issues that should be addressed.
EAT will be commonly used where the device generating the attestation EAT will be commonly used where the device generating the attestation
is constrained and the receiver/verifier of the attestation is a is constrained and the receiver/Verifier of the attestation is a
capacious server. Following is a set of serialization requirements capacious server. Following is a set of serialization requirements
that work well for that use case and are guaranteed to interoperate. that work well for that use case and are guaranteed to interoperate.
Use of this serialization is recommended where possible, but not Use of this serialization is recommended where possible, but not
required. An EAT profile may just reference the following section required. An EAT profile may just reference the following section
rather than spell out serialization details. rather than spell out serialization details.
6.4.1.1. EAT Constrained Device Serialization 8.3.1. EAT Constrained Device Serialization
o Preferred serialization described in section 4.1 of [RFC8949] is o Preferred serialization described in section 4.1 of [RFC8949] is
not required. The EAT decoder must accept all forms of number not required. The EAT decoder must accept all forms of number
serialization. The EAT encoder may use any form it wishes. serialization. The EAT encoder may use any form it wishes.
o The EAT decoder must accept indefinite length arrays and maps as o The EAT decoder must accept indefinite length arrays and maps as
described in section 3.2.2 of [RFC8949]. The EAT encoder may use described in section 3.2.2 of [RFC8949]. The EAT encoder may use
indefinite length arrays and maps if it wishes. indefinite length arrays and maps if it wishes.
o The EAT decoder must accept indefinite length strings as described o The EAT decoder must accept indefinite length strings as described
skipping to change at page 42, line 5 skipping to change at page 49, line 5
o Sorting of maps by key is not required. The EAT decoder must not o Sorting of maps by key is not required. The EAT decoder must not
rely on sorting. rely on sorting.
o Deterministic encoding described in Section 4.2 of [RFC8949] is o Deterministic encoding described in Section 4.2 of [RFC8949] is
not required. not required.
o Basic validity described in section 5.3.1 of [RFC8949] must be o Basic validity described in section 5.3.1 of [RFC8949] must be
followed. The EAT encoder must not send duplicate map keys/labels followed. The EAT encoder must not send duplicate map keys/labels
or invalid UTF-8 strings. or invalid UTF-8 strings.
6.5. Collected CDDL 8.4. Collected Common CDDL
; This is the top-level definition of the claims in EAT tokens. To ; This is the fundamental definition of a Claims-Set for both CBOR
; form an actual EAT Token, this claim set is enclosed in a COSE, JOSE ; and JSON. It is a set of label-value pairs each of which is a
; or UCCS message. ; claim.
;
; In CBOR the labels can be integers or strings with a strong
; preference for integers. For JSON, the labels are always strings.
;
; The values can be anything, with some consideration for types that
; can work in both CBOR and JSON.
eat-claim-set = { Claims-Set = {
? ueid-claim, * $$claims-set-claims,
? sueids-claim, * Claim-Label .feature "extended-label" => any
? nonce-claim, }
? oemid-claim,
? hardware-version-claims,
? security-level-claim,
? secure-boot-claim,
? debug-status-claim,
? location-claim,
? intended-use-claim,
? profile-claim,
? uptime-claim,
? manifests-claim,
? swevidence-claim,
? submods-part,
* $$eat-extension,
}
; This is the top-level definition of an EAT Token. It is a CWT, JWT Claim-Label = int / text
; or UCSS where the payload is an eat-claim-set. A JWT_Message is what string-or-uri = tstr
; is defined by JWT in RFC 7519. (RFC 7519 doesn't use CDDL so a there
; is no actual CDDL definition of JWT_Message).
eat-token = EAT_Tagged_Message / EAT_Untagged_Message / JWT_Message time-int = #6.1(int)
; This is CDDL for the 7 individual claims that are defined in CWT
; and JWT. This CDDL works for either CBOR format CWT or JSON format
; JWT The integer format CWT Claim Keys (the labels) are defined in
; cwt-labels.cddl. The string format JWT Claim Names (the labels)
; are defined in jwt-labels.cddl.
; This is CBOR-format EAT token in the CWT or UCCS format that is a ; $$claims-set-claims is defined in claims-set.cddl
; tag. COSE_Tagged_message is defined in RFC 8152. Tag 601 is
; proposed by the UCCS draft, but not yet assigned.
EAT_Tagged_Message = #6.61(COSE_Tagged_Message) / #6.601(eat-claim-set) $$claims-set-claims //= (iss-label => text)
$$claims-set-claims //= (sub-label => text)
$$claims-set-claims //= (aud-label => text)
$$claims-set-claims //= (exp-label => ~time)
$$claims-set-claims //= (nbf-label => ~time)
$$claims-set-claims //= (iat-label => ~time)
; This is a CBOR-format EAT token that is a CWT or UCSS that is not a ; TODO: how does the bstr get handled in JSON validation with the
; tag COSE_Tagged_message and COSE_Untagged_Message are defined in RFC ; cddl tool? TODO: should this be a text for JSON?
; 8152. ; $$claims-set-claims //= (cti-label : bytes)
$$claims-set-claims //=
(nonce-label => nonce-type / [ 2* nonce-type ])
EAT_Untagged_Message = COSE_Tagged_Message / COSE_Untagged_Message / UCCS_Untagged_Message nonce-type = bstr .size (8..64)
; This is an "unwrapped" UCCS tag. Unwrapping a tag means to use the
; definition of its content without the preceding type 6 tag
; integer. Since a UCCS is nothing but a tag for an unsecured CWT
; claim set, unwrapping reduces to a bare eat-claim-set.
UCCS_Untagged_Message = eat-claim-set $$claims-set-claims //= (ueid-label => ueid-type)
string-or-uri = tstr ueid-type = bstr .size (7..33)
$$claims-set-claims //= (sueids-label => sueids-type)
sueids-type = {
+ tstr => ueid-type
}
time-int = #6.1(int) oemid-pen = int
$$eat-extension //= (
? issuer => text,
? subject => text,
? audience => text,
? expiration => time,
? not-before => time,
? issued-at => time,
? cwt-id => bytes,
)
issuer = 1 oemid-ieee = bstr .size 3
subject = 2
audience = 3
expiration = 4
not-before = 5
issued-at = 6
cwt-id = 7
debug-status-cbor-type = &( oemid-random = bstr .size 16
enabled: 0,
disabled: 1,
disabled-since-boot: 2,
disabled-permanently: 3,
disabled-fully-and-permanently: 4
)
debug-status-json-type = $$claims-set-claims //= (
"enabled" / oemid-label =>
"disabled" / oemid-random / oemid-ieee / oemid-pen
"disabled-since-boot" / )
"disabled-permanently" / $$claims-set-claims //= (
"disabled-fully-and-permanently" chip-version-label => hw-version-type
)
debug-status-claim = ( $$claims-set-claims //= (
debug-status => debug-status-cbor-type / debug-status-json-type board-version-label => hw-version-type
) )
location-type = {
latitude => number,
longitude => number,
? altitude => number,
? accuracy => number,
? altitude-accuracy => number,
? heading => number,
? speed => number,
? timestamp => ~time-int,
? age => uint
}
latitude = 1 / "latitude" $$claims-set-claims //= (
longitude = 2 / "longitude" device-version-label => hw-version-type
altitude = 3 / "altitude" )
accuracy = 4 / "accuracy"
altitude-accuracy = 5 / "altitude-accuracy"
heading = 6 / "heading"
speed = 7 / "speed"
timestamp = 8 / "timestamp"
age = 9 / "age"
location-claim = ( hw-version-type = [
location-label => location-type version: tstr,
) scheme: $version-scheme
nonce-type = bstr .size (8..64) ]
$$claims-set-claims //= ( sw-name-label => tstr )
nonce-claim = ( $$claims-set-claims //= (
nonce => nonce-type / [ 2* nonce-type ] security-level-label =>
) security-level-cbor-type /
oemid-claim = ( security-level-json-type
oemid => bstr )
)
chip-version-claim = (
chip-version => tstr
)
chip-version-scheme-claim = ( security-level-cbor-type = &(
chip-version-scheme => $version-scheme unrestricted: 1,
) restricted: 2,
secure-restricted: 3,
hardware: 4
)
board-version-claim = ( security-level-json-type =
board-version => tstr "unrestricted" /
) "restricted" /
"secure-restricted" /
"hardware"
$$claims-set-claims //= (secure-boot-label => bool)
$$claims-set-claims //= (
debug-status-label =>
debug-status-cbor-type / debug-status-json-type
)
board-version-scheme-claim = ( debug-status-cbor-type = &(
board-version-scheme => $version-scheme enabled: 0,
) disabled: 1,
disabled-since-boot: 2,
disabled-permanently: 3,
disabled-fully-and-permanently: 4
)
device-version-claim = ( debug-status-json-type =
device-version => tstr "enabled" /
) "disabled" /
"disabled-since-boot" /
"disabled-permanently" /
"disabled-fully-and-permanently"
$$claims-set-claims //= (location-label => location-type)
device-version-scheme-claim = ( location-type = {
device-version-scheme => $version-scheme latitude => number,
) longitude => number,
? altitude => number,
? accuracy => number,
? altitude-accuracy => number,
? heading => number,
? speed => number,
? timestamp => ~time-int,
? age => uint
}
hardware-version-claims = ( latitude = 1 / "latitude"
? chip-version-claim, longitude = 2 / "longitude"
? board-version-claim, altitude = 3 / "altitude"
? device-version-claim, accuracy = 4 / "accuracy"
? chip-version-scheme-claim, altitude-accuracy = 5 / "altitude-accuracy"
? board-version-scheme-claim, heading = 6 / "heading"
? device-version-scheme-claim, speed = 7 / "speed"
) timestamp = 8 / "timestamp"
age = 9 / "age"
secure-boot-claim = ( $$claims-set-claims //= (uptime-label => uint)
secure-boot => bool $$claims-set-claims //= (boot-seed-label => bytes)
) $$claims-set-claims //= (
security-level-cbor-type = &( intended-use-label =>
unrestricted: 1, intended-use-cbor-type / intended-use-json-type
restricted: 2, )
secure-restricted: 3,
hardware: 4
)
security-level-json-type = intended-use-cbor-type = &(
"unrestricted" / generic: 1,
"restricted" / registration: 2,
"secure-restricted" / provisioning: 3,
"hardware" csr: 4,
pop: 5
)
security-level-claim = ( intended-use-json-type =
security-level => security-level-cbor-type / security-level-json-type "generic" /
) "registration" /
; The part of a token that contains all the submodules. It is a peer "provisioning" /
; with the claims in the token, but not a claim, only a map/object to "csr" /
; hold all the submodules. "pop"
submods-part = ( $$claims-set-claims //= (
submods => submods-type dloas-label => [ + dloa-type ]
) )
submods-type = { + submod-type } dloa-type = [
dloa_registrar: ~uri
dloa_platform_label: text
? dloa_application_label: text
]
; The type of a submodule which can either be a nested claim set or a $$claims-set-claims //= (profile-label => ~uri / ~oid)
; nested separately signed token. Nested tokens are wrapped in a bstr
; or a tstr.
submod-type = ( oid = #6.4000(bstr) ; TODO: Replace with CDDL from OID RFC
submod-name => eat-claim-set / nested-token
)
; When this is a bstr, the contents are an eat-token in CWT or UCCS $$claims-set-claims //= (
; format. When this is a tstr, the contents are an eat-token in JWT manifests-label => manifests-type
; format. )
nested-token = bstr / tstr; manifests-type = [+ $$manifest-formats]
; Each submodule has a unique text string name. ; Must be a CoSWID payload type
; TODO: signed CoSWIDs
coswid-that-is-a-cbor-tag-xx = tagged-coswid<concise-swid-tag>
submod-name = tstr $$manifest-formats /= bytes .cbor coswid-that-is-a-cbor-tag-xx
; TODO: make this work too
;$$manifest-formats /= bytes .cbor SUIT_Envelope_Tagged
ueid-type = bstr .size (7..33) $$claims-set-claims //= (
swevidence-label => swevidence-type
)
ueid-claim = ( swevidence-type = [+ $$swevidence-formats]
ueid => ueid-type
)
sueids-type = {
+ tstr => ueid-type
}
sueids-claim = ( ; Must be a CoSWID evidence type that is a CBOR tag
sueids => sueids-type ; TODO: fix the CDDL so a signed CoSWID is allowed too
) coswid-that-is-a-cbor-tag = tagged-coswid<concise-swid-tag>
intended-use-cbor-type = &( $$swevidence-formats /= bytes .cbor coswid-that-is-a-cbor-tag
generic: 1,
registration: 2,
provisioning: 3,
csr: 4,
pop: 5
)
intended-use-json-type = $$claims-set-claims //= (swresults-label => [ + swresult-type ])
"generic" /
"registration" /
"provisioning" /
"csr" /
"pop"
intended-use-claim = ( verification-result-cbor-type = &(
intended-use => intended-use-cbor-type / intended-use-json-type verification-not-run: 1,
) verification-indeterminate: 2,
oid = #6.4000(bstr) ; TODO: fill this in with correct CDDL from OID RFC verification-failed: 3,
fully-verified: 4,
partially-verified: 5,
)
uptime-claim = ( verification-result-json-type =
uptime => uint "verification-not-run" /
) "verification-indeterminate" /
"verification-failed" /
"fully-verified" /
"partially-verified"
manifests-claim = ( verification-objective-cbor-type = &(
manifests => manifests-type all: 1,
) firmware: 2,
kernel: 3,
privileged: 4,
system-libs: 5,
partial: 6,
)
manifests-type = [+ $manifest-formats] verification-objective-json-type =
"all" /
"firmware" /
"kernel" /
"privileged" /
"system-libs" /
"partial"
; Must be a CoSWID payload type swresult-type = [
$manifest-formats /= bytes .cbor concise-swid-tag verification-system: tstr,
objective: verification-objective-cbor-type /
verification-objective-json-type,
result: verification-result-cbor-type /
verification-result-json-type,
? objective-name: tstr
]
; This is the part of a token that contains all the submodules. It
; is a peer with the claims in the token, but not a claim, only a
; map/object to hold all the submodules.
$manifest-formats /= bytes .cbor SUIT_Envelope_Tagged $$claims-set-claims //= (submods-label => { + text => Submodule })
swevidence-claim = ( ; A submodule can be:
swevidence => swevidence-type ; - A simple Claims-Set (encoded in the same format as the token)
) ; - A digest of a detached Claims-Set (encoded in the same format as
; the token)
; - A nested token which may be either CBOR or JSON format. Further,
; the mechanism for identifying and containing the nested token
; depends on the format of the surrounding token, particularly
; because JSON doesn't have any equivalent of a CBOR tag so a
; JSON-specific mechanism is invented. Also, there is the issue
; that binary data must be B64 encoded when carried in
; JSON. Nested-Token is defined in the format specific CDDL, not
; here.
swevidence-type = [+ $swevidence-formats] ; Note that at nested token can either be a signed token like a CWT
; or JWT, an unsigned token like a UCCS or UJCS, or a DEB (detached
; EAT bundle). The specific encoding of these is format-specific
; so it doesn't appear here.
; Must be a CoSWID evidence type Submodule = Claims-Set / Nested-Token / Detached-Submodule-Digest
$swevidence-formats /= bytes .cbor concise-swid-tag
oid = #6.4000(bstr) ; TODO: fill this in with correct CDDL from OID RFC ; This is for both JSON and CBOR. JSON uses text label for
; algorithm from JOSE registry. CBOR uses integer label for
; algorithm from COSE registry. In JSON the digest is base64
; encoded.
profile-claim = ( Detached-Submodule-Digest = [
profile => ~uri / ~oid algorithm : int / text,
) digest : bstr
]
; Top-level definition of a DEB for CBOR and JSON
boot-seed-claim = ( Detached-EAT-Bundle = [
boot-seed => bytes main-token : Nested-Token,
) detached-claims-sets: {
+ tstr => cbor-wrapped-claims-set / json-wrapped-claims-set
}
]
7. IANA Considerations ; text content is a base64url encoded JSON-format Claims-Set
7.1. Reuse of CBOR Web Token (CWT) Claims Registry json-wrapped-claims-set = tstr .regexp "[A-Za-z0-9_=-]+"
Claims defined for EAT are compatible with those of CWT so the CWT cbor-wrapped-claims-set = bstr .cbor Claims-Set
Claims Registry is re used. No new IANA registry is created. All
EAT claims should be registered in the CWT and JWT Claims Registries.
7.2. Claim Characteristics 8.5. Collected CDDL for CBOR
; The top-level definition of a CBOR-encoded token.
CBOR-Token = Tagged-CBOR-Token / Untagged-CBOR-Token
; All forms of a CBOR-encoded token that are a CBOR tag.
Tagged-CBOR-Token = CWT-Tagged-Message
Tagged-CBOR-Token /= UCCS-Tagged-Message
Tagged-CBOR-Token /= DEB-Tagged-Message
; All forms of a CBOR-encoded token that are not a CBOR tag.
Untagged-CBOR-Token = CWT-Untagged-Message
Untagged-CBOR-Token /= UCCS-Untagged-Message
Untagged-CBOR-Token /= DEB-Untagged-Message
; The payload of the COSE message is always a Claims-Set
CWT-Tagged-Message = COSE_Tagged_Message
CWT-Untagged-Message = COSE_Untagged_Message
UCCS-Message = UCCS-Tagged-Message / UCCS-Untagged-Message
UCCS-Tagged-Message = #6.601(UCCS-Untagged-Message)
UCCS-Untagged-Message = Claims-Set
DEB-Tagged-Message = #6.602(DEB-Untagged-Message)
DEB-Untagged-Message = Detached-EAT-Bundle
; This specifies how one fully-formed token is nested inside a
; CBOR-format token. The fully-formed nested token is any valid
; token, CBOR or JSON (JWT, CWT, UCCS, DEB...) The mechanism for
; identifying the type of the nested token is specific to the format
; of the surrounding token, CBOR in this case.
;
; A primary reason this is encoding-specific is that JSON does not
; have an equivalent to CBOR tags.
;
; If the data type here is text, then the nested token is JSON
; format, one of a JWT, UJCS or JSON-encoded DEB. The means for
; distinguishing which is in the definition of JSON-encoded
; Nested-Token. If the data type is bstr, then the nested token
; is CBOR format. It is byte-string wrapped and identified by a
;CBOR tag.
Nested-Token =
tstr / ; A JSON-encoded Nested-Token (see json-nested-token.cddl)
bstr .cbor Tagged-CBOR-Token
; This is the CDDL definition of the labels for a CBOR format web
; token, a CWT. The CDDL for the claims is in web-token-claims.cddl
iss-label = 1
sub-label = 2
aud-label = 3
exp-label = 4
nbf-label = 5
iat-label = 6
cti-label = 7; The following Claim Keys (labels) are pre-assigned by IANA.
; They are for CBOR-based tokens (CWT and UCCS).
; They are not expected to change in the final publication as an RFC.
nonce-label = 10
ueid-label = 11
oemid-label = 13
security-level-label = 14
secure-boot-label = 15
debug-status-label = 16
location-label = 17
profile-label = 18
submods-label = 20
; These are not yet assigned in any way and may change.
; These are intentionally above 24 so as to not use up
; single-byte labels.
sueids-label = <TBD25>
chip-version-label = <TBD26>
board-version-label = <TBD27>
device-version-label = <TBD28>
sw-name-label = <TBD29>
sw-version-label = <TBD30>
uptime-label = <TBD31>
boot-seed-label = <TBD32>
intended-use-label = <TBD33>
dloas-label = <TBD34>
manifests-label = <TBD35>
swevidence-label = <TBD36>
swresults-label = <TBD37>
8.6. Collected CDDL for JSON
; A JWT message is either a JWS or JWE in compact serialization form
; with the payload a Claims-Set. Compact serialization is the
; protected headers, payload and signature, each b64url encoded and
; separated by a ".". This CDDL simply matches top-level syntax of of
; a JWS or JWE since it is not possible to do more in CDDL.
JWT-Message = text .regexp [A-Za-z0-9_=-]+\.[A-Za-z0-9_=-]+\.[A-Za-z0-9_=-]+
; This defines the JSON equivalent of a UCCS message, a token with
; no integrity or authenticity protection.
UJCS-Message = Claims-Set
; This describes a nested token that occurs inside a JSON-encoded
; token. It uses an array that is made up of a type indicator and the
; actual token. This is a substitute for the CBOR tag mechanism that
; JSON does not have.
Nested-Token = [
type : "JWT" / "CBOR" / "UJCS" / "DEB",
nested-token : JWT-Message /
B64URL-Tagged-CBOR-Token /
DEB-JSON-Message /
UJCS-Message
]
; This text is a Tagged-CBOR-Token (see cbor-token.cddl) that is
; base64url encoded. For example, it is a CWT that is a COSE_Sign1
; that is a CBOR tag that has been base64url encoded.
B64URL-Tagged-CBOR-Token = tstr .regexp "[A-Za-z0-9_=-]+"
; This is the CDDL definition of the labels for a JSON format web
; token, a JWT. The CDDL for the claims is in web-token-claims.cddl
iss-label = "iss"
sub-label = "sub"
aud-label = "aud"
exp-label = "exp"
nbf-label = "nbf"
iat-label = "iat"
cti-label = "cti"; The following are claim names for JSON encoded tokens.
ueid-label /= "ueid"
sueids-label /= "sueids"
nonce-label /= "nonce"
oemid-label /= "oemid"
security-level-label /= "seclevel"
secure-boot-label /= "secboot"
debug-status-label /= "dbgstat"
location-label /= "location"
uptime-label /= "uptime"
profile-label /= "eat-profile"
intended-use-label /= "intuse"
boot-seed-label /= "bootseed"
submods-label /= "submods"
timestamp /= "timestamp"
manifests-label /= "manifests"
swevidence-label /= "swevidence"
dloas-label /= "dloas"
swresults-label /= "swresults"
sw-name-label /= "swname"
sw-version-label /= "swversion"
latitude /= "lat"
longitude /= "long"
altitude /= "alt"
accuracy /= "accry"
altitude-accuracy /= "alt-accry"
heading /= "heading"
speed /= "speed"
9. IANA Considerations
9.1. 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
the CWT and JWT Claims Registries, [IANA.CWT.Claims] and
[IANA.JWT.Claims], are re used. No new IANA registry is created.
All EAT claims defined in this document are placed in both
registries. All new EAT claims defined subsequently should be placed
in both registries.
9.2. Claim Characteristics
The following is design guidance for creating new EAT claims, The following is design guidance for creating new EAT claims,
particularly those to be registered with IANA. particularly those to be registered with IANA.
Much of this guidance is generic and could also be considered when Much of this guidance is generic and could also be considered when
designing new CWT or JWT claims. designing new CWT or JWT claims.
7.2.1. Interoperability and Relying Party Orientation 9.2.1. 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 the
device from which they originate. It is a goal that there be 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, encoding
and serialization formats. and serialization formats.
This is a lofty goal and difficult to achieve broadly requiring This is a lofty goal and difficult to achieve broadly requiring
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.
7.2.2. Operating System and Technology Neutral 9.2.2. 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. They should also be
applicable to multiple small embedded operating systems from multiple applicable to multiple small embedded operating systems from multiple
vendors and everything in between. vendors and everything in between.
Claims should not be defined such that they are specific to a SW Claims should not be defined such that they are specific to a SW
environment or programming language. 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.
The boot and debug state claims in this document are an example of a The boot and debug state claims in this document are an example of a
claim that has been defined in this neutral way. claim that has been defined in this neutral way.
7.2.3. Security Level Neutral 9.2.3. 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 on the basis of whether they
are useful and interoperable, not based on security level. In are 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. just used only in low-security environments.
7.2.4. Reuse of Extant Data Formats 9.2.4. Reuse of Extant Data Formats
Where possible, claims should use already standardized data items, Where possible, claims should use already standardized data items,
identifiers and formats. This takes advantage of the expertise put identifiers and formats. This takes advantage of the expertise put
into creating those formats and improves interoperability. 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 format for them so that EAT implementations do not require a and JSON format for them so that EAT implementations do not require a
plethora of encoders and decoders for serialization formats. 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 CRLs can be
carried as-is in a byte string. This retains interoperability with carried as-is in a byte string. This retains interoperability with
the extensive infrastructure for creating and processing X.509 the extensive infrastructure for creating and processing X.509
certificates and CRLs. certificates and CRLs.
7.2.5. Proprietary Claims 9.2.5. Proprietary Claims
EAT allows the definition and use of proprietary claims. EAT allows the definition and use of proprietary claims.
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 obvious
way to proceed, however for better interoperability, use of general way to proceed, however for better interoperability, use of general
standardized claims is preferred. standardized claims is preferred.
7.3. Claims Registered by This Document 9.3. Claims Registered by This Document
This specification adds the following values to the "JSON Web Token This specification adds the following values to the "JSON Web Token
Claims" registry established by [RFC7519] and the "CBOR Web Token Claims" registry established by [RFC7519] and the "CBOR Web Token
Claims Registry" established by [RFC8392]. Each entry below is an Claims Registry" established by [RFC8392]. Each entry below is an
addition to both registries (except for the nonce claim which is addition to both registries (except for the nonce claim which is
already registered for JWT, but not registered for CWT). already registered for JWT, but not registered for CWT).
The "Claim Description", "Change Controller" and "Specification The "Claim Description", "Change Controller" and "Specification
Documents" are common and equivalent for the JWT and CWT registries. Documents" are common and equivalent for the JWT and CWT registries.
The "Claim Key" and "Claim Value Types(s)" are for the CWT registry 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 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" JWT registry. The "JWT Claim Name" is equivalent to the "Claim Name"
in the JWT registry. in the JWT registry.
7.3.1. Claims for Early Assignment 9.3.1. Claims for Early Assignment
RFC Editor: in the final publication this section should be combined RFC Editor: in the final publication this section should be combined
with the following section as it will no longer be necessary to with the following section as it will no longer be necessary to
distinguish claims with early assignment. Also, the following distinguish claims with early assignment. Also, the following
paragraph should be removed. paragraph should be removed.
The claims in this section have been (requested for / given) early The claims in this section have been (requested for / given) early
assignment according to [RFC7120]. They have been assigned values assignment according to [RFC7120]. They have been assigned values
and registered before final publication of this document. While and registered before final publication of this document. While
their semantics is not expected to change in final publication, it is their semantics is not expected to change in final publication, it is
skipping to change at page 53, line 4 skipping to change at page 64, line 16
o Specification Document(s): *this document* o Specification Document(s): *this document*
o Claim Name: Submodules Section o Claim Name: Submodules Section
o Claim Description: The section containing submodules (not actually o Claim Description: The section containing submodules (not actually
a claim) a claim)
o JWT Claim Name: "submods" o JWT Claim Name: "submods"
o Claim Key: 20 o Claim Key: 20
o Claim Value Type(s): map o Claim Value Type(s): map
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): *this document* o Specification Document(s): *this document*
7.3.2. To be Assigned Claims 9.3.2. To be Assigned Claims
TODO: add the rest of the claims in here TODO: add the rest of the claims in here
7.3.3. Version Schemes Registered by this Document 9.3.3. Version Schemes Registered by this Document
IANA is requested to register a new value in the "Software Tag IANA is requested to register a new value in the "Software Tag
Version Scheme Values" established by [CoSWID]. Version Scheme Values" established by [CoSWID].
The new value is a version scheme a 13-digit European Article Number The new value is a version scheme a 13-digit European Article Number
[EAN-13]. An EAN-13 is also known as an International Article Number [EAN-13]. An EAN-13 is also known as an International Article Number
or most commonly as a bar code. This version scheme is the ASCII or most commonly as a bar code. This version scheme is the ASCII
text representation of EAN-13 digits, the same ones often printed text representation of EAN-13 digits, the same ones often printed
with a bar code. This version scheme must comply with the EAN with a bar code. This version scheme must comply with the EAN
allocation and assignment rules. For example, this requires the allocation and assignment rules. For example, this requires the
manufacturer to obtain a manufacture code from GS1. manufacturer to obtain a manufacture code from GS1.
+-------+---------------------+---------------+ +-------+---------------------+---------------+
| Index | Version Scheme Name | Specification | | Index | Version Scheme Name | Specification |
+-------+---------------------+---------------+ +-------+---------------------+---------------+
| 5 | ean-13 | This document | | 5 | ean-13 | This document |
+-------+---------------------+---------------+ +-------+---------------------+---------------+
8. Privacy Considerations 9.3.4. UEID URN Registered by this Document
IANA is requested to register the following new subtypes in the "DEV
URN Subtypes" registry under "Device Identification". See [RFC9039].
+---------+-----------------------------------------+---------------+
| Subtype | Description | Reference |
+---------+-----------------------------------------+---------------+
| ueid | Universal Entity Identifier | This document |
| sueid | Semi-permanent Universal Entity | This document |
| | Identifier | |
+---------+-----------------------------------------+---------------+
9.3.5. Tag for Detached EAT Bundle
In the registry [IANA.cbor-tags], IANA is requested to allocate the
following tag from the FCFS space, with the present document as the
specification reference.
+--------+------------+-------------------------------+
| Tag | Data Items | Semantics |
+--------+------------+-------------------------------+
| TBD602 | array | Detached EAT Bundle Section 5 |
+--------+------------+-------------------------------+
10. Privacy Considerations
Certain EAT claims can be used to track the owner of an entity and Certain EAT claims can be used to track the owner of an entity and
therefore, implementations should consider providing privacy- therefore, implementations should consider providing privacy-
preserving options dependent on the intended usage of the EAT. preserving options dependent on the intended usage of the EAT.
Examples would include suppression of location claims for EAT's Examples would include suppression of location claims for EAT's
provided to unauthenticated consumers. provided to unauthenticated consumers.
8.1. UEID and SUEID Privacy Considerations 10.1. UEID and SUEID Privacy Considerations
A UEID is usually not privacy-preserving. Any set of relying parties A UEID is usually not privacy-preserving. Any set of Relying Parties
that receives tokens that happen to be from a single device will be that receives tokens that happen to be from a single device will be
able to know the tokens are all from the same device and be able to able to know the tokens are all from the same device and be able to
track the device. Thus, in many usage situations UEID violates track the device. Thus, in many usage situations UEID violates
governmental privacy regulation. In other usage situations a UEID governmental privacy regulation. In other usage situations a UEID
will not be allowed for certain products like browsers that give will not be allowed for certain products like browsers that give
privacy for the end user. It will often be the case that tokens will privacy for the end user. It will often be the case that tokens will
not have a UEID for these reasons. 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
skipping to change at page 54, line 19 skipping to change at page 66, line 9
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:
o The device obtains explicit permission from the user of the device o The device obtains explicit permission from the user of the device
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. It may also
be through a license agreement. For example, agreements for some be through a license agreement. For example, agreements for some
online banking and brokerage services might already cover use of a online banking and brokerage services might already cover use of a
UEID/SUEID. UEID/SUEID.
o The UEID/SUEID is used only in a particular context or particular o The UEID/SUEID is used only in a particular context or particular
use case. It is used only by one relying party. use case. It is used only by one Relying Party.
o The device authenticates the relying party and generates a derived o The device 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 device, then the device generates a UEID just for that relying the device, then the device generates a UEID just for that Relying
party by hashing a proofed relying party ID with the main device Party by hashing a proofed Relying Party ID with the main device
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 device. Each UEID/SUEID is used in a multiple UEIDs and SUEIDs per device. Each UEID/SUEID is used in a
different context, use case or system on the device. However, from different context, use case or system on the device. 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 10.2. Location Privacy Considerations
Geographic location is most always considered personally identifiable Geographic location is most always considered personally identifiable
information. Implementers should consider laws and regulations information. Implementers should consider laws and regulations
governing the transmission of location data from end user devices to governing the transmission of location data from end user devices to
servers and services. Implementers should consider using location servers and services. Implementers should consider using location
management facilities offered by the operating system on the device management facilities offered by the operating system on the device
generating the attestation. For example, many mobile phones prompt generating the attestation. For example, many mobile phones prompt
the user for permission when before sending location data. the user for permission when before sending location data.
9. Security Considerations 11. Security Considerations
The security considerations provided in Section 8 of [RFC8392] and The security considerations provided in Section 8 of [RFC8392] and
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. In addition, implementors should consider the respectively. In addition, implementors should consider the
following. following.
9.1. Key Provisioning 11.1. 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
can be used to derive the keys used for signing and/or encryption. can be used to derive the keys used for signing and/or encryption.
In some instances, the manufacturer of the entity may create the key In some instances, the manufacturer of the entity may create the key
material separately and provision the key material in the entity material separately and provision the key material in the entity
itself. The manfuacturer of any entity that is capable of producing itself. The manfuacturer of any entity that is capable of producing
an EAT should take care to ensure that any private key material be an EAT should take care to ensure that any private key material be
suitably protected prior to provisioning the key material in the suitably protected prior to provisioning the key material in the
entity itself. This can require creation of key material in an entity itself. This can require creation of key material in an
enclave (see [RFC4949] for definition of "enclave"), secure enclave (see [RFC4949] for definition of "enclave"), secure
transmission of the key material from the enclave to the entity using transmission of the key material from the enclave to the entity using
an appropriate protocol, and persistence of the private key material an appropriate protocol, and persistence of the private key material
in some form of secure storage to which (preferably) only the entity in some form of secure storage to which (preferably) only the entity
has access. has access.
9.1.1. Transmission of Key Material 11.1.1. 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 ("key wrapping") may be necessary.
The transmission itself may be performed electronically, but can also The transmission itself may be performed electronically, but can also
be done by human courier. In the latter case, there should be be done by human courier. In the latter case, there should be
minimal to no exposure of the key material to the human (e.g. minimal to no exposure of the key material to the human (e.g.
encrypted portable memory). Moreover, the human should transport the encrypted portable memory). Moreover, the human should transport the
key material directly from the secure enclave where it was created to key material directly from the secure enclave where it was created to
a destination secure enclave where it can be provisioned. a destination secure enclave where it can be provisioned.
9.2. Transport Security 11.2. Transport Security
As stated in Section 8 of [RFC8392], "The security of the CWT relies As stated in Section 8 of [RFC8392], "The security of the CWT relies
upon on the protections offered by COSE". Similar considerations upon on the protections offered by COSE". Similar considerations
apply to EAT when sent as a CWT. However, EAT introduces the concept apply to EAT when sent as a CWT. However, EAT introduces the concept
of a nonce to protect against replay. Since an EAT may be created by of a nonce to protect against replay. Since an EAT may be created by
an entity that may not support the same type of transport security as an entity that may not support the same type of transport security as
the consumer of the EAT, intermediaries may be required to bridge the consumer of the EAT, intermediaries may be required to bridge
communications between the entity and consumer. As a result, it is communications between the entity and consumer. As a result, it is
RECOMMENDED that both the consumer create a nonce, and the entity RECOMMENDED that both the consumer create a nonce, and the entity
leverage the nonce along with COSE mechanisms for encryption and/or leverage the nonce along with COSE mechanisms for encryption and/or
signing to create the EAT. signing to create the EAT.
Similar considerations apply to the use of EAT as a JWT. Although Similar considerations apply to the use of EAT as a JWT. Although
the security of a JWT leverages the JSON Web Encryption (JWE) and the security of a JWT leverages the JSON Web Encryption (JWE) and
JSON Web Signature (JWS) specifications, it is still recommended to JSON Web Signature (JWS) specifications, it is still recommended to
make use of the EAT nonce. make use of the EAT nonce.
9.3. Multiple EAT Consumers 11.3. 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 multiple consumers are required for verification of an EAT, it When multiple consumers are required for verification of an EAT, it
is important to minimize information exposure to each consumer. In is 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
skipping to change at page 56, line 31 skipping to change at page 68, line 17
subsets to any downstream consumer should leverage a secure protocol subsets to any downstream consumer should leverage a secure protocol
(e.g.one that uses transport-layer security, i.e. TLS), (e.g.one that uses transport-layer security, i.e. 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 transport security between the receiving and a nested EAT. Then transport security between the receiving and
downstream consumers is not strictly required. Nevertheless, downstream consumers is not strictly required. Nevertheless,
downstream consumers of a nested EAT should provide a nonce unique to downstream consumers of a nested EAT should provide a nonce unique to
the EAT they are consuming. the EAT they are consuming.
10. References 12. References
10.1. Normative References 12.1. Normative References
[CBOR-OID] [CBOR.OID]
Bormann, C., "Concise Binary Object Representation (CBOR) Bormann, C., "Concise Binary Object Representation (CBOR)
Tags for Object Identifiers", draft-ietf-cbor-tags-oid-06 Tags for Object Identifiers", draft-ietf-cbor-tags-oid-08
(work in progress), March 2021. (work in progress), May 2021.
[CBOR.Cert.Draft]
Raza, S., "CBOR Encoding of X.509 Certificates (CBOR
Certificates)", 2020, <https://tools.ietf.org/html/draft-
mattsson-cose-cbor-cert-compress-05>.
[COSE.X509.Draft] [CoSWID] Birkholz, H., Fitzgerald-McKay, J., Schmidt, C., and D.
Schaad, J., "CBOR Object Signing and Encryption (COSE): Waltermire, "Concise Software Identification Tags", draft-
Header parameters for carrying and referencing X.509 ietf-sacm-coswid-19 (work in progress), October 2021.
certificates", 2020,
<https://tools.ietf.org/html/draft-ietf-cose-x509-08>.
[CoSWID] "Concise Software Identification Tags", November 2020, [DLOA] "Digital Letter of Approval", November 2015,
<https://tools.ietf.org/html/draft-ietf-sacm-coswid-16>. <https://globalplatform.org/wp-content/uploads/2015/12/
GPC_DigitalLetterOfApproval_v1.0.pdf>.
[EAN-13] GS1, "International Article Number - EAN/UPC barcodes", [EAN-13] GS1, "International Article Number - EAN/UPC barcodes",
2019, <https://www.gs1.org/standards/barcodes/ean-upc>. 2019, <https://www.gs1.org/standards/barcodes/ean-upc>.
[FIDO.AROE] [FIDO.AROE]
The FIDO Alliance, "FIDO Authenticator Allowed Restricted The FIDO Alliance, "FIDO Authenticator Allowed Restricted
Operating Environments List", November 2019, Operating Environments List", November 2020,
<https://fidoalliance.org/specs/fido-uaf-v1.0-fd-20191115/ <https://fidoalliance.org/specs/fido-security-
fido-allowed-AROE-v1.0-fd-20191115.html>. requirements/fido-authenticator-allowed-restricted-
operating-environments-list-v1.2-fd-20201102.html>.
[IANA.cbor-tags]
"IANA CBOR Tags Registry", n.d.,
<https://www.iana.org/assignments/cbor-tags/cbor-
tags.xhtml>.
[IANA.CWT.Claims] [IANA.CWT.Claims]
IANA, "CBOR Web Token (CWT) Claims", IANA, "CBOR Web Token (CWT) Claims",
<http://www.iana.org/assignments/cwt>. <http://www.iana.org/assignments/cwt>.
[IANA.JWT.Claims] [IANA.JWT.Claims]
IANA, "JSON Web Token (JWT) Claims", IANA, "JSON Web Token (JWT) Claims",
<https://www.iana.org/assignments/jwt>. <https://www.iana.org/assignments/jwt>.
[OpenIDConnectCore] [OpenIDConnectCore]
Sakimura, N., Bradley, J., Jones, M., Medeiros, B. D., and Sakimura, N., Bradley, J., Jones, M., Medeiros, B. D., and
C. Mortimore, "OpenID Connect Core 1.0 incorporating C. Mortimore, "OpenID Connect Core 1.0 incorporating
errata set 1", November 2014, errata set 1", November 2014,
<https://openid.net/specs/openid-connect-core-1_0.html>. <https://openid.net/specs/openid-connect-core-1_0.html>.
[RATS-Architecture] [PEN] "Private Enterprise Number (PEN) Request", n.d.,
Birkholz, H., Thaler, D., Richardson, M., Smith, N., and <https://pen.iana.org/pen/PenApplication.page>.
W. Pan, "Remote Attestation Procedures Architecture",
draft-ietf-rats-architecture-12 (work in progress), April
2021.
[RATS.Architecture]
Birkholz, H., "Remote Attestation Procedures
Architecture", 2020, <https://tools.ietf.org/html/draft-
ietf-rats-architecture-08>.
[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,
<https://www.rfc-editor.org/info/rfc3986>. <https://www.rfc-editor.org/info/rfc3986>.
skipping to change at page 59, line 13 skipping to change at page 70, line 37
<https://www.rfc-editor.org/info/rfc8949>. <https://www.rfc-editor.org/info/rfc8949>.
[ThreeGPP.IMEI] [ThreeGPP.IMEI]
3GPP, "3rd Generation Partnership Project; Technical 3GPP, "3rd Generation Partnership Project; Technical
Specification Group Core Network and Terminals; Numbering, Specification Group Core Network and Terminals; Numbering,
addressing and identification", 2019, addressing and identification", 2019,
<https://portal.3gpp.org/desktopmodules/Specifications/ <https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=729>. SpecificationDetails.aspx?specificationId=729>.
[UCCS.Draft] [UCCS.Draft]
Birkholz, H., "A CBOR Tag for Unprotected CWT Claims Birkholz, H., O'Donoghue, J., Cam-Winget, N., and C.
Sets", 2020, Bormann, "A CBOR Tag for Unprotected CWT Claims Sets",
<https://tools.ietf.org/html/draft-birkholz-rats-uccs-01>. draft-ietf-rats-uccs-01 (work in progress), July 2021.
[WGS84] National Imagery and Mapping Agency, "National Imagery and [WGS84] National Geospatial-Intelligence Agency (NGA), "WORLD
Mapping Agency Technical Report 8350.2, Third Edition", GEODETIC SYSTEM 1984, NGA.STND.0036_1.0.0_WGS84", July
2000, <http://earth- 2014, <https://earth-info.nga.mil/php/
info.nga.mil/GandG/publications/tr8350.2/wgs84fin.pdf>. download.php?file=coord-wgs84>.
10.2. Informative References 12.2. Informative References
[BirthdayAttack] [BirthdayAttack]
"Birthday attack", "Birthday attack",
<https://en.wikipedia.org/wiki/Birthday_attack.>. <https://en.wikipedia.org/wiki/Birthday_attack.>.
[CBOR.Cert.Draft]
Mattsson, J. P., Selander, G., Raza, S., Hoeglund, J., and
M. Furuhed, "CBOR Encoded X.509 Certificates (C509
Certificates)", draft-ietf-cose-cbor-encoded-cert-02 (work
in progress), July 2021.
[Common.Criteria] [Common.Criteria]
"Common Criteria for Information Technology Security "Common Criteria for Information Technology Security
Evaluation", April 2017, Evaluation", April 2017,
<https://www.commoncriteriaportal.org/cc/>. <https://www.commoncriteriaportal.org/cc/>.
[COSE.X509.Draft]
Schaad, J., "CBOR Object Signing and Encryption (COSE):
Header parameters for carrying and referencing X.509
certificates", draft-ietf-cose-x509-08 (work in progress),
December 2020.
[ECMAScript] [ECMAScript]
"Ecma International, "ECMAScript Language Specification, "Ecma International, "ECMAScript Language Specification,
5.1 Edition", ECMA Standard 262", June 2011, 5.1 Edition", ECMA Standard 262", June 2011,
<http://www.ecma-international.org/ecma-262/5.1/ECMA- <http://www.ecma-international.org/ecma-262/5.1/ECMA-
262.pdf>. 262.pdf>.
[FIDO.Registry]
The FIDO Alliance, "FIDO Registry of Predefined Values",
December 2019, <https://fidoalliance.org/specs/common-
specs/fido-registry-v2.1-ps-20191217.html>.
[FIPS-140] [FIPS-140]
National Institue of Standards, "Security Requirements for National Institue of Standards, "Security Requirements for
Cryptographic Modules", May 2001, Cryptographic Modules", May 2001,
<https://csrc.nist.gov/publications/detail/fips/140/2/ <https://csrc.nist.gov/publications/detail/fips/140/2/
final>. final>.
[IEEE.802-2001] [IEEE.802-2001]
"IEEE Standard For Local And Metropolitan Area Networks "IEEE Standard For Local And Metropolitan Area Networks
Overview And Architecture", 2007, Overview And Architecture", 2007,
<https://webstore.ansi.org/standards/ieee/ <https://webstore.ansi.org/standards/ieee/
skipping to change at page 60, line 32 skipping to change at page 72, line 17
Organizationally Unique Identifier (OUI), and Company ID Organizationally Unique Identifier (OUI), and Company ID
(CID)", August 2017, (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 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>.
[RATS.Architecture]
Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
W. Pan, "Remote Attestation Procedures Architecture",
draft-ietf-rats-architecture-12 (work in progress), April
2021.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122, Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005, DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/info/rfc4122>. <https://www.rfc-editor.org/info/rfc4122>.
[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>.
[RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code [RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code
Points", BCP 100, RFC 7120, DOI 10.17487/RFC7120, January Points", BCP 100, RFC 7120, DOI 10.17487/RFC7120, January
2014, <https://www.rfc-editor.org/info/rfc7120>. 2014, <https://www.rfc-editor.org/info/rfc7120>.
[RFC9039] Arkko, J., Jennings, C., and Z. Shelby, "Uniform Resource
Names for Device Identifiers", RFC 9039,
DOI 10.17487/RFC9039, June 2021,
<https://www.rfc-editor.org/info/rfc9039>.
[W3C.GeoLoc] [W3C.GeoLoc]
Worldwide Web Consortium, "Geolocation API Specification Worldwide Web Consortium, "Geolocation API Specification
2nd Edition", January 2018, <https://www.w3.org/TR/ 2nd Edition", January 2018, <https://www.w3.org/TR/
geolocation-API/#coordinates_interface>. geolocation-API/#coordinates_interface>.
Appendix A. Examples Appendix A. Examples
A.1. Very Simple EAT These examples are either UCCS, shown as CBOR diagnostic, or UJCS
messages. Full CWT and JWT examples with signing and encryption are
not given.
This is shown in CBOR diagnostic form. Only the payload signed by All UCCS examples can be the payload of a CWT. To do so, they must
COSE is shown. be converted from the UCCS message to a Claims-Set, which is achieve
by "removing" the tag.
{ UJCS messages can be directly used as the payload of a JWT.
/ issuer / 1: "joe",
/ nonce / 10: h'948f8860d13a463e8e', WARNING: These examples use tag and label numbers not yet assigned by
IANA.
A.1. Simple TEE Attestation
This is a simple attestation of a TEE that includes a manifest that
is a payload CoSWID to describe the TEE's software.
/ This is a UCCS EAT that describes a simple TEE. /
601({
/ nonce / 10: h'948f8860d13a463e',
/ security-level / 14: 3, / secure-restricted /
/ secure-boot / 15: true,
/ debug-status / 16: 2, / disabled-since-boot /
/ manfests / 35: [
/ This is byte-string wrapped /
/ payload CoSWID. It gives the TEE /
/ software name, the version and /
/ the name of the file it is in. /
h' da53574944a60064336132340c01016b
41636d6520544545204f530d65332e31
2e340282a2181f6b41636d6520544545
204f53182101a2181f6b41636d652054
4545204f5318210206a111a118186e61
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 /
/ makes up the TEE. /
1398229316({
/ Unique CoSWID ID / 0: "3a24",
/ tag-version / 12: 1,
/ software-name / 1: "Acme TEE OS",
/ software-version / 13: "3.1.4",
/ entity / 2: [
{
/ entity-name / 31: "Acme TEE OS",
/ role / 33: 1 / tag-creator /
},
{
/ entity-name / 31: "Acme TEE OS",
/ role / 33: 2 / software-creator /
}
],
/ payload / 6: {
/ ...file / 17: {
/ ...fs-name / 24: "acme_tee_3.exe"
}
}
})
A.2. EAT Produced by Attestation Hardware Block
/ This is an example of a token produced by a HW block /
/ purpose-built for attestation. Only the nonce claim changes /
/ from one attestation to the next as the rest either come /
/ directly from the hardware or from one-time-programmable memory /
/ (e.g. a fuse). 47 bytes encoded in CBOR (8 byte nonce, 16 byte /
/ UEID). /
601({
/ nonce / 10: h'948f8860d13a463e',
/ UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea', / UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea',
/ OEMID / 13: 64242, / Private Enterprise Number /
/ security-level / 14: 4, / hardware level security /
/ secure-boot / 15: true, / secure-boot / 15: true,
/ debug-disable / 16: 3, / permanent-disable / / debug-status / 16: 3, / disabled-permanently /
/ timestamp (iat) / 6: 1(1526542894) / chip-version / 26: [ "3.1", 1 ] / Type is multipartnumeric /
} })
A.2. Example with Submodules, Nesting and Security Levels A.3. Detached EAT Bundle
{ In this DEB main token is produced by a HW attestation block. The
/ nonce / 10: h'948f8860d13a463e8e', detached Claims-Set is produced by a TEE and is largely identical to
/ UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea', the Simple TEE examples above. The TEE digests its Claims-Set and
/ secure-boot / 15: true, feeds that digest to the HW block.
/ debug-disable / 16: 3, / permanent-disable /
/ timestamp (iat) / 6: 1(1526542894),
/ security-level / 14: 3, / secure restricted OS /
/ submods / 20: {
/ first submod, an Android Application /
"Android App Foo" : {
/ security-level / 14: 1 / unrestricted /
},
/ 2nd submod, A nested EAT from a secure element / In a better example the attestation produced by the HW block would be
"Secure Element Eat" : a CWT and thus signed and secured by the HW block. Since the
/ an embedded EAT, bytes of which are not shown / signature covers the digest from the TEE that Claims-Set is also
h'420123', secured.
/ 3rd submod, information about Linux Android / The DEB itself can be assembled by untrusted SW.
"Linux Android": {
/ security-level / 14: 1 / unrestricted / / This is a detached EAT bundle (DEB) tag. /
}
} 602([
}
/ First part is a full EAT token with claims like nonce and /
/ UEID. Most importantly, it includes a submodule that is a /
/ detached digest which is the hash of the "TEE" claims set /
/ in the next section. /
/ /
/ This token here is in UCCS format (unsigned). In a more /
/ realistic example, it would be a signed CWT. /
h'd90259a80a48948f8860d13a463e0b500198f50a4ff6c058
61c8860d13a638ea0d19faf20e040ff51003181a8263332e
310114a163544545822f5820e5cf95fd24fab71446742dd5
8d43dae178e55fe2b94291a9291082ffc2635a0b',
{
/ A CBOR-encoded byte-string wrapped EAT claims-set. It /
/ contains claims suitable for a TEE /
"TEE" : h'a50a48948f8860d13a463e0e030ff51002182381
585dda53574944a60064336132340c01016b4163
6d6520544545204f530d65332e312e340282a218
1f6b41636d6520544545204f53182101a2181f6b
41636d6520544545204f5318210206a111a11818
6e61636d655f7465655f332e657865'
}
])
/ This example contains submodule that is a detached digest, /
/ which is the hash of a Claims-Set convey outside this token. /
/ Other than that is is the other example of a token from an /
/ attestation HW block /
601({
/ nonce / 10: h'948f8860d13a463e',
/ UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea',
/ OEMID / 13: 64242, / Private Enterprise Number /
/ security-level / 14: 4, / hardware level security /
/ secure-boot / 15: true,
/ debug-status / 16: 3, / disabled-permanently /
/ chip-version / 26: [ "3.1", 1 ], / multipartnumeric /
/ submods/ 20: {
"TEE": [ / detached digest submod /
-16, / SHA-256 /
h'e5cf95fd24fab7144674
2dd58d43dae178e55fe2
b94291a9291082ffc2635
a0b'
]
}
})
A.4. Key / Key Store Attestation
/ This is an attestation of a public key and the key store /
/ implementation that protects and manages it. The key store /
/ implementation is in a security-oriented execution /
/ environment separate from the high-level OS, for example a /
/ TEE. The key store is the Attester. /
/ /
/ There is some attestation of the high-level OS, just version /
/ and boot & debug status. It is a Claims-Set submodule because/
/ it has lower security level than the key store. The key /
/ store's implementation has access to info about the HLOS, so /
/ it is able to include it. /
/ /
/ A key and an indication of the user authentication given to /
/ allow access to the key is given. The labels for these are /
/ in the private space since this is just a hypothetical /
/ example, not part of a standard protocol. /
/ /
/ This is similar to Android Key Attestation. /
601({
/ nonce / 10: h'948f8860d13a463e',
/ security-level / 14: 3, / secure-restricted /
/ debug-status / 16: 2, / disabled-since-boot /
/ secure-boot / 15: true,
/ manifests / 35: [
h'da53574944a600683762623334383766
0c000169436172626f6e6974650d6331
2e320e0102a2181f75496e6475737472
69616c204175746f6d6174696f6e1821
02'
/ Above is an encoded CoSWID /
/ with the following data /
/ SW Name: "Carbonite" /
/ SW Vers: "1.2" /
/ SW Creator: /
/ "Industrial Automation" /
],
/ expiration / 4: 1634324274, / 2021-10-15T18:57:54Z /
/ creation time / 6: 1634317080, / 2021-10-15T16:58:00Z /
-80000 : "fingerprint",
-80001 : { / The key -- A COSE_Key /
/ kty / 1: 2, / EC2, eliptic curve with x & y /
/ kid / 2: h'36675c206f96236c3f51f54637b94ced',
/ curve / -1: 2, / curve is P-256 /
/ x-coord / -2: h'65eda5a12577c2bae829437fe338701a
10aaa375e1bb5b5de108de439c08551d',
/ y-coord / -3: h'1e52ed75701163f7f9e40ddf9f341b3d
c9ba860af7e0ca7ca7e9eecd0084d19c'
},
/ submods / 20 : {
"HLOS" : { / submod for high-level OS /
/ nonce / 10: h'948f8860d13a463e',
/ security-level / 14: 1, / unrestricted /
/ secure-boot / 15: true,
/ manifests / 35: [
h'da53574944a600687337
6537346b78380c000168
44726f6964204f530d65
52322e44320e0302a218
1F75496E647573747269
616c204175746f6d6174
696f6e182102'
/ Above is an encoded CoSWID /
/ with the following data: /
/ SW Name: "Droid OS" /
/ SW Vers: "R2.D2" /
/ SW Creator: /
/ "Industrial Automation"/
]
}
}
})
A.5. SW Measurements of an IoT Device
This is a simple token that might be for and IoT device. It includes
CoSWID format measurments of the SW. The CoSWID is in byte-string
wrapped in the token and also shown in diagnostic form.
/ This EAT UCCS is for an IoT device with a TEE. The attestation /
/ 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 /
/ submodule contains claims for the IoT OS. The TEE also measures /
/ the IoT OS and puts the measurements in the submodule. /
601({
/ nonce / 10: h'948f8860d13a463e',
/ security-level / 14: 3, / secure-restricted /
/ secure-boot / 15: true,
/ debug-status / 16: 2, / disabled-since-boot /
/ OEMID / 13: h'8945ad', / IEEE CID based /
/ UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea',
/ sumods / 20: {
"OS" : {
/ security-level / 14: 2, / restricted /
/ secure-boot / 15: true,
/ debug-status / 16: 2, / disabled-since-boot /
/ swevidence / 36: [
/ This is a byte-string wrapped /
/ evidence CoSWID. It has /
/ hashes of the main files of /
/ the IoT OS. /
h'da53574944a600663463613234350c
17016d41636d6520522d496f542d4f
530d65332e312e3402a2181f724163
6d6520426173652041747465737465
7218210103a11183a318187161636d
655f725f696f745f6f732e65786514
1a0044b349078201582005f6b327c1
73b4192bd2c3ec248a292215eab456
611bf7a783e25c1782479905a31818
6d7265736f75726365732e72736314
1a000c38b10782015820c142b9aba4
280c4bb8c75f716a43c99526694caa
be529571f5569bb7dc542f98a31818
6a636f6d6d6f6e2e6c6962141a0023
3d3b0782015820a6a9dcdfb3884da5
f884e4e1e8e8629958c2dbc7027414
43a913e34de9333be6'
]
}
}
})
/ An evidence CoSWID created for the "Acme R-IoT-OS" created by /
/ the "Acme Base Attester" (both fictious names). It provides /
/ measurements of the SW (other than the attester SW) on the /
/ device. /
1398229316({
/ Unique CoSWID ID / 0: "4ca245",
/ tag-version / 12: 23, / Attester-maintained counter /
/ software-name / 1: "Acme R-IoT-OS",
/ software-version / 13: "3.1.4",
/ entity / 2: {
/ entity-name / 31: "Acme Base Attester",
/ role / 33: 1 / tag-creator /
},
/ evidence / 3: {
/ ...file / 17: [
{
/ ...fs-name / 24: "acme_r_iot_os.exe",
/ ...size / 20: 4502345,
/ ...hash / 7: [
1, / SHA-256 /
h'05f6b327c173b419
2bd2c3ec248a2922
15eab456611bf7a7
83e25c1782479905'
]
},
{
/ ...fs-name / 24: "resources.rsc",
/ ...size / 20: 800945,
/ ...hash / 7: [
1, / SHA-256 /
h'c142b9aba4280c4b
b8c75f716a43c995
26694caabe529571
f5569bb7dc542f98'
]
},
{
/ ...fs-name / 24: "common.lib",
/ ...size / 20: 2309435,
/ ...hash / 7: [
1, / SHA-256 /
h'a6a9dcdfb3884da5
f884e4e1e8e86299
58c2dbc702741443
a913e34de9333be6'
]
}
]
}
})
A.6. Attestation Results in JSON format
This is a UJCS format token that might be the output of a Verifier
that evaluated the IoT Attestation example immediately above.
This particular Verifier knows enough about the TEE Attester to be
able to pass claims like security level directly through to the
Relying Party. The Verifier also knows the Reference Values for the
measured SW components and is able to check them. It informs the
Relying Party that they were correct in the swresults claim.
"Trustus Verifications" is the name of the services that verifies the
SW component measurements.
This UJCS is identical to JSON-encoded Claims-Set that could be a JWT
payload.
{
"nonce" : "lI+IYNE6Rj4=",
"seclevel" : "secure-restricted",
"secboot" : true,
"dbgstat" : "disabled-since-boot",
"OEMID" : "iUWt",
"UEID" : "AZj1Ck/2wFhhyIYNE6Y4",
"submods" : {
"seclevel" : "restricted",
"secboot" : true,
"dbgstat" : "disabled-since-boot",
"swname" : "Acme R-IoT-OS",
"sw-version" : [
"3.1.4"
],
"swresults" : [
[
"Trustus Verifications",
"all",
"fully-verified"
]
]
}
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
UEIDs given the total possible entity population and the number of UEIDs given the total possible entity population and the number of
entities in a particular entity management database. 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
skipping to change at page 65, line 24 skipping to change at page 85, line 24
[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 are used with an is defined. The intent is that IDevIDs and LDevIDs are used with an
open set of network protocols for authentication and such. In these open set of network protocols for authentication and such. In these
protocols the DevID secret is used to sign a nonce or similar to protocols the DevID secret is used to sign a nonce or similar to
proof the association of the DevID certificates with the device. proof the association of the DevID certificates with the device.
By contrast, EAT defines network protocol for proving trustworthiness By contrast, EAT defines network protocol for proving trustworthiness
to a relying party, the very thing that is not defined in to a Relying Party, the very thing that is not defined in
[IEEE.802.1AR]. Nor does not give details on how keys, data and such [IEEE.802.1AR]. Nor does not give details on how keys, data and such
are stored protected and accessed. EAT is intended to work with a are stored protected and accessed. EAT is intended to work with a
variety of different on-device implementations ranging from minimal variety of different on-device implementations ranging from minimal
protection of assets to the highest levels of asset protection. It protection of assets to the highest levels of asset protection. It
does not define any particular level of defense against attack, does not define any particular level of defense against attack,
instead providing a set of security considerations. instead providing 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.
skipping to change at page 69, line 12 skipping to change at page 89, line 12
o Rename debug-disable to debug-status; clarify that it is not o Rename debug-disable to debug-status; clarify that it is not
extensible extensible
o Security level claim is not extensible o Security level claim is not extensible
o Improve specification of location claim and added a location o Improve specification of location claim and added a location
privacy section privacy section
o Add intended use claim o Add intended use claim
D.7. From draft-ietf-rats-05 D.7. From draft-ietf-rats-eat-05
o CDDL format issues resolved o CDDL format issues resolved
o Corrected reference to Location Privacy section o Corrected reference to Location Privacy section
D.8. From draft-ietf-rats-06 D.8. From draft-ietf-rats-eat-06
o Added boot-seed claim o Added boot-seed claim
o Rework CBOR interoperability section o Rework CBOR interoperability section
o Added profiles claim and section o Added profiles claim and section
D.9. From draft-ietf-rats-07 D.9. From draft-ietf-rats-eat-07
o Filled in IANA and other sections for possible preassignment of o Filled in IANA and other sections for possible preassignment of
claim keys for well understood claims Claim Keys for well understood claims
D.10. From draft-ietf-rats-08 D.10. From draft-ietf-rats-eat-08
o Change profile claim to be either a URL or an OID rather than a o Change profile claim to be either a URL or an OID rather than a
test string test string
D.11. From draft-ietf-rats-09 D.11. From draft-ietf-rats-eat-09
o Add SUEIDs o Add SUEIDs
o Add appendix comparing IDevID to EAT o Add appendix comparing IDevID to EAT
o Added section on use for Evidence and Attestation Results o Added section on use for Evidence and Attestation Results
o Fill in the key ID and endorsements identificaiton section o Fill in the key ID and endorsements identificaiton section
o Remove origination claim as it is replaced by key IDs and o Remove origination claim as it is replaced by key IDs and
endorsements endorsements
o Added manifests and software evidence claims o Added manifests and software evidence claims
o Add string labels non-claim labels for use with JSON (e.g. labels o Add string labels non-claim labels for use with JSON (e.g. labels
for members of location claim) for members of location claim)
o EAN-13 HW versions are no longer a separate claim. Now they are o EAN-13 HW versions are no longer a separate claim. Now they are
folded in as a CoSWID version scheme. folded in as a CoSWID version scheme.
Authors' Addresses D.12. From draft-ietf-rats-eat-10
Giridhar Mandyam o Hardware version is made into an array of two rather than two
Qualcomm Technologies Inc. claims
5775 Morehouse Drive
San Diego, California
USA
Phone: +1 858 651 7200 o Corrections and wording improvements for security levels claim
EMail: mandyam@qti.qualcomm.com
o Add swresults claim
o Add dloas claim - Digitial Letter of Approvals, a list of
certifications
o CDDL for each claim no longer in a separate sub section
o Consistent use of terminology from RATS architecture document
o Consistent use of terminology from CWT and JWT documents
o Remove operating model and procedures; refer to CWT, JWT and RATS
architecture instead
o Some reorganization of Section 1
o Moved a few references, including RATS Architecture, to
informative.
o Add detached submodule digests and detached eat bundles (DEBs)
o New simpler and more universal scheme for identifying the encoding
of a nested token
o Made clear that CBOR and JSON are only mixed when nesting a token
in another token
o Clearly separate CDDL for JSON and CBOR-specific data items
o Define UJCS (unsigned JWTs)
o Add CDDL for a general Claims-Set used by UCCS, UJCS, CWT, JWT and
EAT
o Top level CDDL for CWT correctly refers to COSE
o OEM ID is specifically for HW, not for SW
o HW OEM ID can now be a PEN
o HW OEM ID can now be a 128-bit random number
o Expand the examples section
o Add software and version claims as easy / JSON alternative to
CoSWID
Authors' Addresses
Laurence Lundblade Laurence Lundblade
Security Theory LLC Security Theory LLC
EMail: lgl@island-resort.com EMail: lgl@securitytheory.com
Miguel Ballesteros Giridhar Mandyam
Qualcomm Technologies Inc. Qualcomm Technologies Inc.
5775 Morehouse Drive 5775 Morehouse Drive
San Diego, California San Diego, California
USA USA
Phone: +1 858 651 4299 Phone: +1 858 651 7200
EMail: mballest@qti.qualcomm.com EMail: mandyam@qti.qualcomm.com
Jeremy O'Donoghue Jeremy O'Donoghue
Qualcomm Technologies Inc. Qualcomm Technologies Inc.
279 Farnborough Road 279 Farnborough Road
Farnborough GU14 7LS Farnborough GU14 7LS
United Kingdom United Kingdom
Phone: +44 1252 363189 Phone: +44 1252 363189
EMail: jodonogh@qti.qualcomm.com EMail: jodonogh@qti.qualcomm.com
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