draft-ietf-rats-eat-06.txt   draft-ietf-rats-eat-07.txt 
RATS Working Group G. Mandyam RATS Working Group G. Mandyam
Internet-Draft Qualcomm Technologies Inc. Internet-Draft Qualcomm Technologies Inc.
Intended status: Standards Track L. Lundblade Intended status: Standards Track L. Lundblade
Expires: 4 June 2021 Security Theory LLC Expires: August 7, 2021 Security Theory LLC
M. Ballesteros M. Ballesteros
J. O'Donoghue J. O'Donoghue
Qualcomm Technologies Inc. Qualcomm Technologies Inc.
1 December 2020 February 03, 2021
The Entity Attestation Token (EAT) The Entity Attestation Token (EAT)
draft-ietf-rats-eat-06 draft-ietf-rats-eat-07
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.
skipping to change at page 1, line 45 skipping to change at page 1, line 45
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. CWT, JWT and UCCS . . . . . . . . . . . . . . . . . . . . 5 1.1. CWT, JWT and UCCS . . . . . . . . . . . . . . . . . . . . 5
1.2. CDDL . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2. CDDL . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Entity Overview . . . . . . . . . . . . . . . . . . . . . 5 1.3. Entity Overview . . . . . . . . . . . . . . . . . . . . . 6
1.4. EAT Operating Models . . . . . . . . . . . . . . . . . . 6 1.4. EAT Operating Models . . . . . . . . . . . . . . . . . . 6
1.5. What is Not Standardized . . . . . . . . . . . . . . . . 7 1.5. What is Not Standardized . . . . . . . . . . . . . . . . 7
1.5.1. Transmission Protocol . . . . . . . . . . . . . . . . 7 1.5.1. Transmission Protocol . . . . . . . . . . . . . . . . 8
1.5.2. Signing Scheme . . . . . . . . . . . . . . . . . . . 8 1.5.2. Signing Scheme . . . . . . . . . . . . . . . . . . . 8
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 8 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 8
3. The Claims . . . . . . . . . . . . . . . . . . . . . . . . . 9 3. The Claims . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1. Token ID Claim (cti and jti) . . . . . . . . . . . . . . 10 3.1. Token ID Claim (cti and jti) . . . . . . . . . . . . . . 10
3.2. Timestamp claim (iat) . . . . . . . . . . . . . . . . . . 10 3.2. Timestamp claim (iat) . . . . . . . . . . . . . . . . . . 10
3.3. Nonce Claim (nonce) . . . . . . . . . . . . . . . . . . . 10 3.3. Nonce Claim (nonce) . . . . . . . . . . . . . . . . . . . 10
3.3.1. nonce CDDL . . . . . . . . . . . . . . . . . . . . . 11 3.3.1. nonce CDDL . . . . . . . . . . . . . . . . . . . . . 11
3.4. Universal Entity ID Claim (ueid) . . . . . . . . . . . . 11 3.4. Universal Entity ID Claim (ueid) . . . . . . . . . . . . 11
3.4.1. ueid CDDL . . . . . . . . . . . . . . . . . . . . . . 13 3.4.1. ueid CDDL . . . . . . . . . . . . . . . . . . . . . . 13
3.5. Origination Claim (origination) . . . . . . . . . . . . . 13 3.5. Origination Claim (origination) . . . . . . . . . . . . . 13
3.5.1. origination CDDL . . . . . . . . . . . . . . . . . . 14 3.5.1. origination CDDL . . . . . . . . . . . . . . . . . . 14
3.6. OEM Identification by IEEE (oemid) . . . . . . . . . . . 14 3.6. OEM Identification by IEEE (oemid) . . . . . . . . . . . 14
3.6.1. oemid CDDL . . . . . . . . . . . . . . . . . . . . . 15 3.6.1. oemid CDDL . . . . . . . . . . . . . . . . . . . . . 14
3.7. Hardware Version Claims (hardware-version-claims) . . . . 15 3.7. Hardware Version Claims (hardware-version-claims) . . . . 14
3.8. Software Description and Version . . . . . . . . . . . . 16 3.8. Software Description and Version . . . . . . . . . . . . 16
3.9. The Security Level Claim (security-level) . . . . . . . . 17 3.9. The Security Level Claim (security-level) . . . . . . . . 16
3.9.1. security-level CDDL . . . . . . . . . . . . . . . . . 18 3.9.1. security-level CDDL . . . . . . . . . . . . . . . . . 17
3.10. Secure Boot Claim (secure-boot) . . . . . . . . . . . . . 18 3.10. Secure Boot Claim (secure-boot) . . . . . . . . . . . . . 17
3.10.1. secure-boot CDDL . . . . . . . . . . . . . . . . . . 18 3.10.1. secure-boot CDDL . . . . . . . . . . . . . . . . . . 17
3.11. Debug Status Claim (debug-status) . . . . . . . . . . . . 18 3.11. Debug Status Claim (debug-status) . . . . . . . . . . . . 18
3.11.1. Enabled . . . . . . . . . . . . . . . . . . . . . . 19 3.11.1. Enabled . . . . . . . . . . . . . . . . . . . . . . 19
3.11.2. Disabled . . . . . . . . . . . . . . . . . . . . . . 19 3.11.2. Disabled . . . . . . . . . . . . . . . . . . . . . . 19
3.11.3. Disabled Since Boot . . . . . . . . . . . . . . . . 20 3.11.3. Disabled Since Boot . . . . . . . . . . . . . . . . 19
3.11.4. Disabled Permanently . . . . . . . . . . . . . . . . 20 3.11.4. Disabled Permanently . . . . . . . . . . . . . . . . 19
3.11.5. Disabled Fully and Permanently . . . . . . . . . . . 20 3.11.5. Disabled Fully and Permanently . . . . . . . . . . . 19
3.11.6. debug-status CDDL . . . . . . . . . . . . . . . . . 20 3.11.6. debug-status CDDL . . . . . . . . . . . . . . . . . 19
3.12. Including Keys . . . . . . . . . . . . . . . . . . . . . 20 3.12. Including Keys . . . . . . . . . . . . . . . . . . . . . 20
3.13. The Location Claim (location) . . . . . . . . . . . . . . 21 3.13. The Location Claim (location) . . . . . . . . . . . . . . 21
3.13.1. location CDDL . . . . . . . . . . . . . . . . . . . 22 3.13.1. location CDDL . . . . . . . . . . . . . . . . . . . 21
3.14. The Uptime Claim (uptime) . . . . . . . . . . . . . . . . 22 3.14. The Uptime Claim (uptime) . . . . . . . . . . . . . . . . 22
3.14.1. uptime CDDL . . . . . . . . . . . . . . . . . . . . 22 3.14.1. uptime CDDL . . . . . . . . . . . . . . . . . . . . 22
3.14.2. The Boot Seed Claim (boot-seed) . . . . . . . . . . 22
3.15. The Intended Use Claim (intended-use) . . . . . . . . . . 23 3.15. The Intended Use Claim (intended-use) . . . . . . . . . . 23
3.15.1. intended-use CDDL . . . . . . . . . . . . . . . . . 23 3.15.1. intended-use CDDL . . . . . . . . . . . . . . . . . 23
3.16. The Submodules Part of a Token (submods) . . . . . . . . 24 3.16. The Profile Claim (profile) . . . . . . . . . . . . . . . 24
3.16.1. Two Types of Submodules . . . . . . . . . . . . . . 24 3.17. The Submodules Part of a Token (submods) . . . . . . . . 24
3.16.1.1. Non-token Submodules . . . . . . . . . . . . . . 24 3.17.1. Two Types of Submodules . . . . . . . . . . . . . . 25
3.16.1.2. Nested EATs . . . . . . . . . . . . . . . . . . 25 3.17.1.1. Non-token Submodules . . . . . . . . . . . . . . 25
3.16.1.3. Unsecured JWTs and UCCS Tokens as Submodules . . 26 3.17.1.2. Nested EATs . . . . . . . . . . . . . . . . . . 25
3.16.2. No Inheritance . . . . . . . . . . . . . . . . . . . 26 3.17.1.3. Unsecured JWTs and UCCS Tokens as Submodules . . 26
3.16.3. Security Levels . . . . . . . . . . . . . . . . . . 27 3.17.2. No Inheritance . . . . . . . . . . . . . . . . . . . 27
3.16.4. Submodule Names . . . . . . . . . . . . . . . . . . 27 3.17.3. Security Levels . . . . . . . . . . . . . . . . . . 27
3.16.5. submods CDDL . . . . . . . . . . . . . . . . . . . . 27 3.17.4. Submodule Names . . . . . . . . . . . . . . . . . . 27
3.17.5. submods CDDL . . . . . . . . . . . . . . . . . . . . 27
4. Endorsements and Verification Keys . . . . . . . . . . . . . 28 4. Endorsements and Verification Keys . . . . . . . . . . . . . 28
5. Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.1. Common CDDL Types . . . . . . . . . . . . . . . . . . . . 29 5.1. List of Profile Issues . . . . . . . . . . . . . . . . . 29
5.2. CDDL for CWT-defined Claims . . . . . . . . . . . . . . . 29 5.1.1. Use of JSON, CBOR or both . . . . . . . . . . . . . . 29
5.3. JSON . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.1.2. CBOR Map and Array Encoding . . . . . . . . . . . . . 29
5.3.1. JSON Labels . . . . . . . . . . . . . . . . . . . . . 29 5.1.3. CBOR String Encoding . . . . . . . . . . . . . . . . 29
5.3.2. JSON Interoperability . . . . . . . . . . . . . . . . 30 5.1.4. COSE/JOSE Protection . . . . . . . . . . . . . . . . 29
5.4. CBOR . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.1.5. COSE/JOSE Algorithms . . . . . . . . . . . . . . . . 30
5.4.1. CBOR Interoperability . . . . . . . . . . . . . . . . 30 5.1.6. Verification Key Identification . . . . . . . . . . . 30
5.5. Collected CDDL . . . . . . . . . . . . . . . . . . . . . 32 5.1.7. Endorsement Identification . . . . . . . . . . . . . 30
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 38 5.1.8. Required Claims . . . . . . . . . . . . . . . . . . . 30
6.1. Reuse of CBOR Web Token (CWT) Claims Registry . . . . . . 38 5.1.9. Prohibited Claims . . . . . . . . . . . . . . . . . . 30
6.2. Claim Characteristics . . . . . . . . . . . . . . . . . . 38 5.1.10. Additional Claims . . . . . . . . . . . . . . . . . . 31
6.2.1. Interoperability and Relying Party Orientation . . . 38 5.1.11. Refined Claim Definition . . . . . . . . . . . . . . 31
6.2.2. Operating System and Technology Neutral . . . . . . . 39 5.1.12. CBOR Tags . . . . . . . . . . . . . . . . . . . . . . 31
6.2.3. Security Level Neutral . . . . . . . . . . . . . . . 39 6. Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.2.4. Reuse of Extant Data Formats . . . . . . . . . . . . 39 6.1. Common CDDL Types . . . . . . . . . . . . . . . . . . . . 31
6.2.5. Proprietary Claims . . . . . . . . . . . . . . . . . 40 6.2. CDDL for CWT-defined Claims . . . . . . . . . . . . . . . 31
6.3. Claims Registered by This Document . . . . . . . . . . . 40 6.3. JSON . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 40 6.3.1. JSON Labels . . . . . . . . . . . . . . . . . . . . . 32
7.1. UEID Privacy Considerations . . . . . . . . . . . . . . . 41 6.3.2. JSON Interoperability . . . . . . . . . . . . . . . . 33
7.2. Location Privacy Considerations . . . . . . . . . . . . . 41 6.4. CBOR . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8. Security Considerations . . . . . . . . . . . . . . . . . . . 42 6.4.1. CBOR Interoperability . . . . . . . . . . . . . . . . 33
8.1. Key Provisioning . . . . . . . . . . . . . . . . . . . . 42 6.4.1.1. EAT Constrained Device Serialization . . . . . . 33
8.1.1. Transmission of Key Material . . . . . . . . . . . . 42 6.5. Collected CDDL . . . . . . . . . . . . . . . . . . . . . 34
8.2. Transport Security . . . . . . . . . . . . . . . . . . . 42 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 40
8.3. Multiple EAT Consumers . . . . . . . . . . . . . . . . . 43 7.1. Reuse of CBOR Web Token (CWT) Claims Registry . . . . . . 40
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 43 7.2. Claim Characteristics . . . . . . . . . . . . . . . . . . 40
9.1. Normative References . . . . . . . . . . . . . . . . . . 43 7.2.1. Interoperability and Relying Party Orientation . . . 40
9.2. Informative References . . . . . . . . . . . . . . . . . 45 7.2.2. Operating System and Technology Neutral . . . . . . . 41
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 47 7.2.3. Security Level Neutral . . . . . . . . . . . . . . . 41
A.1. Very Simple EAT . . . . . . . . . . . . . . . . . . . . . 47 7.2.4. Reuse of Extant Data Formats . . . . . . . . . . . . 41
A.2. Example with Submodules, Nesting and Security Levels . . 47 7.2.5. Proprietary Claims . . . . . . . . . . . . . . . . . 42
Appendix B. UEID Design Rationale . . . . . . . . . . . . . . . 48 7.3. Claims Registered by This Document . . . . . . . . . . . 42
B.1. Collision Probability . . . . . . . . . . . . . . . . . . 48 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 42
B.2. No Use of UUID . . . . . . . . . . . . . . . . . . . . . 51 8.1. UEID Privacy Considerations . . . . . . . . . . . . . . . 43
Appendix C. Changes from Previous Drafts . . . . . . . . . . . . 51 8.2. Location Privacy Considerations . . . . . . . . . . . . . 43
C.1. From draft-rats-eat-01 . . . . . . . . . . . . . . . . . 51 9. Security Considerations . . . . . . . . . . . . . . . . . . . 44
C.2. From draft-mandyam-rats-eat-00 . . . . . . . . . . . . . 52 9.1. Key Provisioning . . . . . . . . . . . . . . . . . . . . 44
C.3. From draft-ietf-rats-eat-01 . . . . . . . . . . . . . . . 52 9.1.1. Transmission of Key Material . . . . . . . . . . . . 44
C.4. From draft-ietf-rats-eat-02 . . . . . . . . . . . . . . . 52 9.2. Transport Security . . . . . . . . . . . . . . . . . . . 44
C.5. From draft-ietf-rats-eat-03 . . . . . . . . . . . . . . . 52 9.3. Multiple EAT Consumers . . . . . . . . . . . . . . . . . 45
C.6. From draft-ietf-rats-eat-04 . . . . . . . . . . . . . . . 52 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 45
C.7. From draft-ietf-rats-eat-05 . . . . . . . . . . . . . . . 53 10.1. Normative References . . . . . . . . . . . . . . . . . . 45
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 53 10.2. Informative References . . . . . . . . . . . . . . . . . 47
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 49
A.1. Very Simple EAT . . . . . . . . . . . . . . . . . . . . . 49
A.2. Example with Submodules, Nesting and Security Levels . . 49
Appendix B. UEID Design Rationale . . . . . . . . . . . . . . . 50
B.1. Collision Probability . . . . . . . . . . . . . . . . . . 50
B.2. No Use of UUID . . . . . . . . . . . . . . . . . . . . . 52
Appendix C. Changes from Previous Drafts . . . . . . . . . . . . 53
C.1. From draft-rats-eat-01 . . . . . . . . . . . . . . . . . 53
C.2. From draft-mandyam-rats-eat-00 . . . . . . . . . . . . . 53
C.3. From draft-ietf-rats-eat-01 . . . . . . . . . . . . . . . 53
C.4. From draft-ietf-rats-eat-02 . . . . . . . . . . . . . . . 53
C.5. From draft-ietf-rats-eat-03 . . . . . . . . . . . . . . . 54
C.6. From draft-ietf-rats-eat-04 . . . . . . . . . . . . . . . 54
C.7. From draft-ietf-rats-05 . . . . . . . . . . . . . . . . . 54
C.8. From draft-ietf-rats-06 . . . . . . . . . . . . . . . . . 55
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 55
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.
skipping to change at page 4, line 42 skipping to change at page 5, line 13
The relying party needs to know that the device is one that is known The relying party needs to know that the device is one that is known
to do biometric matching correctly. Another example is content to do biometric matching correctly. Another example is content
protection where the relying party wants to know the device will protection where the relying party wants to know the device will
protect the data. This generalizes on to corporate enterprises that protect the data. This generalizes on to corporate enterprises that
might want to know that a device is trustworthy before allowing might want to know that a device is trustworthy before allowing
corporate data to be accessed by it. 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:
* Proof of the make and model of the device hardware (HW) o Proof of the make and model of the device hardware (HW)
* 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
* Measurement of the software (SW) running on the device o Measurement of the software (SW) running on the device
* Configuration and state of the device o Configuration and state of the device
* Environmental characteristics of the device such as its GPS
o Environmental characteristics of the device such as its GPS
location location
TODO: mention use for Attestation Evidence and Results. TODO: mention use for Attestation Evidence and Results.
1.1. CWT, JWT and UCCS 1.1. CWT, JWT and UCCS
For flexibility and ease of imlpementation in a wide variety of For flexibility and ease of imlpementation in a wide variety of
environments, EATs can be either CBOR [RFC7049] or JSON [ECMAScript] environments, EATs can be either CBOR [RFC8949] or JSON [ECMAScript]
format. This specification simultaneously describes both formats. 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 either a CWT as defined in [RFC8392], a UCCS as defined in
[UCCS.Draft], or a JWT as defined in [RFC7519]. This specification [UCCS.Draft], or a JWT as defined in [RFC7519]. This specification
extends those specifications with additional claims for attestation. extends those specifications with additional claims for attestation.
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 format, 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 1.2. CDDL
This specification uses CDDL, [RFC8610], as the primary formalism to This specification uses CDDL, [RFC8610], as the primary formalism to
define each claim. The implementor then interprets the CDDL to come define each claim. The implementor then interprets the CDDL to come
to either the CBOR [RFC7049] or JSON [ECMAScript] representation. In to either the CBOR [RFC8949] or JSON [ECMAScript] representation. In
the case of JSON, Appendix E of [RFC8610] is followed. Additional the case of JSON, Appendix E of [RFC8610] is followed. Additional
rules are given in Section 5.3.2 of this document where Appendix E is 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 insufficient. (Note that this is not to define a general means to
translate between CBOR and JSON, but only to define enough such that translate between CBOR and JSON, but only to define enough such that
the claims defined in this document can be rendered unambiguously in the claims defined in this document can be rendered unambiguously in
JSON). JSON).
The CWT specification was authored before CDDL was available and did The CWT specification was authored before CDDL was available and did
not use it. This specification includes a CDDL definition of most of not use it. This specification includes a CDDL definition of most of
what is described in [RFC8392]. what is described in [RFC8392].
1.3. Entity Overview 1.3. Entity Overview
skipping to change at page 7, line 5 skipping to change at page 7, line 22
In all operating models, hardware and/or software on the entity In all operating models, hardware and/or software on the entity
create an EAT of the format described in this document. The EAT is create an EAT of the format described in this document. The EAT is
always signed by the attestation key material provisioned by the always signed by the attestation key material provisioned by the
manufacturer. manufacturer.
In all operating models, the relying party must end up knowing that In all operating models, the relying party must end up knowing that
the signature on the EAT is valid and consistent with data from the signature on the EAT is valid and consistent with data from
claims in the EAT. This can happen in many different ways. Here are claims in the EAT. This can happen in many different ways. Here are
some examples. some examples.
* The EAT is transmitted to the relying party. The relying party o The EAT is transmitted to the relying party. The relying party
gets corresponding key material (e.g. a root certificate) from the gets corresponding key material (e.g. a root certificate) from the
manufacturer. The relying party performs the verification. manufacturer. The relying party performs the verification.
* The EAT is transmitted to the relying party. The relying party o The EAT is transmitted to the relying party. The relying party
transmits the EAT to a verification service offered by the transmits the EAT to a verification service offered by the
manufacturer. The server returns the validated claims. manufacturer. The server returns the validated claims.
* The EAT is transmitted directly to a verification service, perhaps o The EAT is transmitted directly to a verification service, perhaps
operated by the manufacturer or perhaps by another party. It operated by the manufacturer or perhaps by another party. It
verifies the EAT and makes the validated claims available to the verifies the EAT and makes the validated claims available to the
relying party. It may even modify the claims in some way and re- relying party. It may even modify the claims in some way and re-
sign the EAT (with a different signing key). sign the EAT (with a different signing key).
All these operating models are supported and there is no preference All these operating models are supported and there is no preference
of one over the other. It is important to support this variety of of one over the other. It is important to support this variety of
operating models to generally facilitate deployment and to allow for operating models to generally facilitate deployment and to allow for
some special scenarios. One special scenario has a validation some special scenarios. One special scenario has a validation
service that is monetized, most likely by the manufacturer. In service that is monetized, most likely by the manufacturer. In
skipping to change at page 9, line 26 skipping to change at page 9, line 37
3. The Claims 3. The Claims
This section describes new claims defined for attestation. It also This section describes new claims defined for attestation. It also
mentions several claims defined by CWT and JWT that are particularly mentions several claims defined by CWT and JWT that are particularly
important for EAT. important for EAT.
Note also: * Any claim defined for CWT or JWT may be used in an EAT Note also: * Any claim defined for CWT or JWT may be used in an EAT
including those in the CWT [IANA.CWT.Claims] and JWT IANA including those in the CWT [IANA.CWT.Claims] and JWT IANA
[IANA.JWT.Claims] claims registries. [IANA.JWT.Claims] claims registries.
* All claims are optional o All claims are optional
* No claims are mandatory o No claims are mandatory
* All claims that are not understood by implementations MUST be o All claims that are not understood by implementations MUST be
ignored ignored
There are no default values or meanings assigned to absent claims There are no default values or meanings assigned to absent claims
other than they are not reported. The reason for a claim's absence other than they are not reported. The reason for a claim's absence
may be the implementation not supporting the claim, an inability to may be the implementation not supporting the claim, an inability to
determine its value, or a preference to report in a different way determine its value, or a preference to report in a different way
such as a proprietary claim. such as a proprietary claim.
CDDL along with text descriptions is used to define each claim CDDL along with text descriptions is used to define each claim
indepdent of encoding. Each claim is defined as a CDDL group (the indepdent of encoding. Each claim is defined as a CDDL group (the
group is a general aggregation and type definition feature of CDDL). group is a general aggregation and type definition feature of CDDL).
In the encoding section Section 5, the CDDL groups turn into CBOR map In the encoding section Section 6, the CDDL groups turn into CBOR map
entries and JSON name/value pairs. entries and JSON name/value pairs.
TODO: add paragraph here about use for Attestation Evidence and for TODO: add paragraph here about use for Attestation Evidence and for
Results. Results.
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
skipping to change at page 11, line 32 skipping to change at page 11, line 41
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 7.1. There are privacy considerations for UEID's. See Section 8.1.
The UEID should be permanent. It should never change for a given The UEID should be permanent. It should never change for a given
device / entity. In addition, it should not be reprogrammable. device / entity. In addition, it should not be reprogrammable.
UEID's are variable length. All implementations MUST be able to UEID's are variable length. All implementations MUST be able to
receive UEID's that are 33 bytes long (1 type byte and 256 bits). receive UEID's that are 33 bytes long (1 type byte and 256 bits).
The recommended maximum sent is also 33 bytes. The 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
processes and to give options to avoid paying fees for certain types processes and to give options to avoid paying fees for certain types
of manufacturer registrations. of manufacturer registrations.
Creation of new types requires a Standards Action [RFC8126]. Creation of new types requires a Standards Action [RFC8126].
+======+======+===================================================+ +------+------+-----------------------------------------------------+
| Type | Type | Specification | | Type | Type | Specification |
| Byte | Name | | | Byte | Name | |
+======+======+===================================================+ +------+------+-----------------------------------------------------+
| 0x01 | RAND | This is a 128, 192 or 256 bit random number | | 0x01 | RAND | This is a 128, 192 or 256 bit random number |
| | | generated once and stored in the device. This | | | | generated once and stored in the device. This may |
| | | may be constructed by concatenating enough | | | | be constructed by concatenating enough identifiers |
| | | identifiers to make up an equivalent number of | | | | to make up an equivalent number of random bits and |
| | | random bits and then feeding the concatenation | | | | then feeding the concatenation through a |
| | | through a cryptographic hash function. It may | | | | cryptographic hash function. It may also be a |
| | | also be a cryptographic quality random number | | | | cryptographic quality random number generated once |
| | | generated once at the beginning of the life of | | | | at the beginning of the life of the device and |
| | | the device and stored. It may not be smaller | | | | stored. It may not be smaller than 128 bits. |
| | | than 128 bits. | | 0x02 | IEEE | This makes use of the IEEE company identification |
+------+------+---------------------------------------------------+ | | EUI | registry. An EUI is either an EUI-48, EUI-60 or |
| 0x02 | IEEE | This makes use of the IEEE company identification | | | | EUI-64 and made up of an OUI, OUI-36 or a CID, |
| | EUI | registry. An EUI is either an EUI-48, EUI-60 or | | | | different registered company identifiers, and some |
| | | EUI-64 and made up of an OUI, OUI-36 or a CID, | | | | unique per-device identifier. EUIs are often the |
| | | different registered company identifiers, and | | | | same as or similar to MAC addresses. This type |
| | | some unique per-device identifier. EUIs are | | | | includes MAC-48, an obsolete name for EUI-48. (Note |
| | | often the same as or similar to MAC addresses. | | | | that while devices with multiple network interfaces |
| | | This type includes MAC-48, an obsolete name for | | | | may have multiple MAC addresses, there is only one |
| | | EUI-48. (Note that while devices with multiple | | | | UEID for a device) [IEEE.802-2001], [OUI.Guide] |
| | | network interfaces may have multiple MAC | | 0x03 | IMEI | This is a 14-digit identifier consisting of an |
| | | addresses, there is only one UEID for a device) | | | | 8-digit Type Allocation Code and a 6-digit serial |
| | | [IEEE.802-2001], [OUI.Guide] | | | | number allocated by the manufacturer, which SHALL |
+------+------+---------------------------------------------------+ | | | be encoded as byte string of length 14 with each |
| 0x03 | IMEI | This is a 14-digit identifier consisting of an | | | | byte as the digit's value (not the ASCII encoding |
| | | 8-digit Type Allocation Code and a 6-digit serial | | | | of the digit; the digit 3 encodes as 0x03, not |
| | | number allocated by the manufacturer, which SHALL | | | | 0x33). The IMEI value encoded SHALL NOT include |
| | | be encoded as byte string of length 14 with each | | | | Luhn checksum or SVN information. [ThreeGPP.IMEI] |
| | | byte as the digit's value (not the ASCII encoding | +------+------+-----------------------------------------------------+
| | | of the digit; the digit 3 encodes as 0x03, not |
| | | 0x33). The IMEI value encoded SHALL NOT include |
| | | 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:
* UEIDs types may vary freely from one manufacturer to the next. o UEIDs types may vary freely from one manufacturer to the next.
* 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.
* 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 3.4.1. ueid CDDL
ueid-type = bstr .size (7..33) ueid-type = bstr .size (7..33)
ueid-claim = ( ueid-claim = (
skipping to change at page 14, line 5 skipping to change at page 13, line 36
3.5. Origination Claim (origination) 3.5. Origination Claim (origination)
TODO: this claim is likely to be dropped in favor of Endorsement TODO: this claim is likely to be dropped in favor of Endorsement
identifier and locators. identifier and locators.
This claim describes the parts of the device or entity that are This claim describes the parts of the device or entity that are
creating the EAT. Often it will be tied back to the device or chip creating the EAT. Often it will be tied back to the device or chip
manufacturer. The following table gives some examples: manufacturer. The following table gives some examples:
+===================+=========================================+ +-------------------+-----------------------------------------------+
| Name | Description | | Name | Description |
+===================+=========================================+ +-------------------+-----------------------------------------------+
| Acme-TEE | The EATs are generated in the TEE | | Acme-TEE | The EATs are generated in the TEE authored |
| | authored and configured by "Acme" | | | and configured by "Acme" |
+-------------------+-----------------------------------------+ | Acme-TPM | The EATs are generated in a TPM manufactured |
| Acme-TPM | The EATs are generated in a TPM | | | by "Acme" |
| | manufactured by "Acme" | | Acme-Linux-Kernel | The EATs are generated in a Linux kernel |
+-------------------+-----------------------------------------+ | | configured and shipped by "Acme" |
| Acme-Linux-Kernel | The EATs are generated in a Linux | | Acme-TA | The EATs are generated in a Trusted |
| | kernel configured and shipped by "Acme" | | | Application (TA) authored by "Acme" |
+-------------------+-----------------------------------------+ +-------------------+-----------------------------------------------+
| Acme-TA | The EATs are generated in a Trusted |
| | Application (TA) authored by "Acme" |
+-------------------+-----------------------------------------+
Table 2
TODO: consider a more structure approach where the name and the URI TODO: consider a more structure approach where the name and the URI
and other are in separate fields. and other are in separate fields.
TODO: This needs refinement. It is somewhat parallel to issuer claim TODO: This needs refinement. It is somewhat parallel to issuer claim
in CWT in that it describes the authority that created the token. in CWT in that it describes the authority that created the token.
3.5.1. origination CDDL 3.5.1. origination CDDL
origination-claim = ( origination-claim = (
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3.8. Software Description and Version 3.8. Software Description and Version
TODO: Add claims that reference CoSWID. TODO: Add claims that reference CoSWID.
3.9. The Security Level Claim (security-level) 3.9. 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 done by defining four security levels as
described below. This is similar to the key protection types defined described below. This is similar to the key protection types defined
by the Fast Identity Online (FIDO) Alliance [FIDO.Registry]). 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. reside 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 the
EAT provides no meaningful security assurances. EAT provides no meaningful security assurances.
2- Restricted Entities at this level should not be general-purpose 2- Restricted Entities at this level should not be general-purpose
skipping to change at page 22, line 11 skipping to change at page 21, line 35
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 Section 7.2 below. See location-related privacy considerations in Section 8.2 below.
3.13.1. location CDDL 3.13.1. location CDDL
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,
? age => uint ? age => uint
skipping to change at page 23, line 5 skipping to change at page 22, line 41
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 3.14.1. uptime CDDL
uptime-claim = ( uptime-claim = (
uptime => uint uptime => uint
) )
3.14.2. The Boot Seed Claim (boot-seed)
The Boot Seed claim is a random value created at system boot time
that will allow differentiation of reports from different boot
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
secret.
boot-seed-claim = (
boot-seed => bytes
)
3.15. The Intended Use Claim (intended-use) 3.15. 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
skipping to change at page 24, line 9 skipping to change at page 24, line 9
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.
3.15.1. intended-use CDDL 3.15.1. intended-use CDDL
intended-use-type = &( intended-use-type = &(
generic: 1, generic: 1,
registration: 2, registration: 2,
provisioning: 3, provisioning: 3,
csr: 4, csr: 4,
pop: 5 pop: 5
) )
intended-use-claim = ( intended-use-claim = (
intended-use => intended-use-type intended-use => intended-use-type
)
3.16. The Profile Claim (profile)
The profile claim is a text string that simply gives the name of the
profile to which the token purports to adhere to. It may name an
IETF document, some other document or no particular document. There
is no requirement that the named document be publicly accessible.
See Section 5 for a detailed description of a profile.
Note that this named "eat-profile" for JWT and is distinct from the
already registered "profile" claim in the JWT claims registry.
profile-claim = (
profile => tstr
) )
3.16. The Submodules Part of a Token (submods) 3.17. The Submodules Part of a Token (submods)
Some devices are complex, having many subsystems or submodules. A Some devices are complex, having many subsystems or submodules. A
mobile phone is a good example. It may have several connectivity mobile phone is a good example. It may have several connectivity
submodules for communications (e.g., Wi-Fi and cellular). It may submodules for communications (e.g., Wi-Fi and cellular). It may
have subsystems for low-power audio and video playback. It may have have subsystems for low-power audio and video playback. It may have
one or more security-oriented subsystems like a TEE or a Secure one or more security-oriented subsystems like a TEE or a Secure
Element. Element.
The claims for each these can be grouped together in a submodule. The claims for each these can be grouped together in a submodule.
The submods part of a token are in a single map/object with many The submods part of a token are in a single map/object with many
entries, one per submodule. There is only one submods map in a entries, one per submodule. There is only one submods map in a
token. It is identified by its specific label. It is a peer to 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 other claims, but it is not called a claim because it is a container
for a claim set rather than an individual claim. This submods part for a claim set rather than an individual claim. This submods part
of a token allows what might be called recursion. It allows claim of a token allows what might be called recursion. It allows claim
sets inside of claim sets inside of claims sets... sets inside of claim sets inside of claims sets...
3.16.1. Two Types of Submodules 3.17.1. Two Types of Submodules
Each entry in the submod map is one of two types: Each entry in the submod map is one of two types:
* A non-token submodule that is a map or object directly containing o A non-token submodule that is a map or object directly containing
claims for the submodule. claims for the submodule.
* A nested EAT that is a fully formed, independently signed EAT o A nested EAT that is a fully formed, independently signed EAT
token token
3.16.1.1. Non-token Submodules 3.17.1.1. Non-token Submodules
This is simply a map or object containing claims about the submodule. This is simply a map or object containing claims about the submodule.
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 It is signed/encrypted along with the rest of the token and thus the
claims are secured by the same Attester with the same signing key as claims are secured by the same Attester with the same signing key as
the rest of the token. the rest of the token.
If a token is in CBOR format (a CWT or a UCCS), all non-token If a token is in CBOR format (a CWT or a UCCS), all non-token
submodules must be CBOR format. If a token in in JSON format (a submodules must be CBOR format. If a token in in JSON format (a
JWT), all non-token submodules must be in JSON format. JWT), all non-token submodules must be in JSON format.
When decoding, this type of submodule is recognized from the other When decoding, this type of submodule is recognized from the other
type by being a data item of type map for CBOR or type object for type by being a data item of type map for CBOR or type object for
JSON. JSON.
3.16.1.2. Nested EATs 3.17.1.2. Nested EATs
This type of submodule is a fully formed secured EAT as defined in This type of submodule is a fully formed secured EAT as defined in
this document except that it MUST NOT be a UCCS or an unsecured JWT. this document except that it MUST NOT be a UCCS or an unsecured JWT.
A nested token that is one that is always secured using COSE or JOSE, A nested token that is one that is always secured using COSE or JOSE,
usually by an independent Attester. When the surrounding EAT is a usually by an independent Attester. When the surrounding EAT is a
CWT or secured JWT, the nested token becomes securely bound with the CWT or secured JWT, the nested token becomes securely bound with the
other claims in the surrounding token. other claims in the surrounding token.
It is allowed to have a CWT as a submodule in a JWT and vice versa, It is allowed to have a CWT as a submodule in a JWT and vice versa,
but this SHOULD be avoided unless necessary. but this SHOULD be avoided unless necessary.
3.16.1.2.1. Surrounding EAT is CBOR format 3.17.1.2.1. Surrounding EAT is CBOR format
They type of an EAT nested in a CWT is determined by whether the CBOR They type of an EAT nested in a CWT is determined by whether the CBOR
type is a text string or a byte string. If a text string, then it is type is a text string or a byte string. If a text string, then it is
a JWT. If a byte string, then it is a CWT. 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 A CWT nested in a CBOR-format token is always wrapped by a byte
string for easier handling with standard CBOR decoders and token string for easier handling with standard CBOR decoders and token
processing APIs that will typically take a byte buffer as input. processing APIs that will typically take a byte buffer as input.
Nested CWTs may be either a CWT CBOR tag or a CWT Protocol Message. Nested CWTs may be either a CWT CBOR tag or a CWT Protocol Message.
COSE layers in nested CWT EATs MUST be a COSE_Tagged_Message, never a 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_Untagged_Message. If a nested EAT has more than one level of
COSE, for example one that is both encrypted and signed, a COSE, for example one that is both encrypted and signed, a
COSE_Tagged_message must be used at every level. COSE_Tagged_message must be used at every level.
3.16.1.2.2. Surrounding EAT is JSON format 3.17.1.2.2. Surrounding EAT is JSON format
When a CWT is nested in a JWT, it must be as a 55799 tag in order to When a CWT is nested in a JWT, it must be as a 55799 tag in order to
distinguish it from a nested JWT. distinguish it from a nested JWT.
When a nested EAT in a JWT is decoded, first remove the base64url When a nested EAT in a JWT is decoded, first remove the base64url
encoding. Next, check to see if it starts with the bytes 0xd9d9f7. encoding. Next, check to see if it starts with the bytes 0xd9d9f7.
If so, then it is a CWT as a JWT will never start with these four If so, then it is a CWT as a JWT will never start with these four
bytes. If not if it is a JWT. bytes. If not if it is a JWT.
Other than the 55799 tag requirement, tag usage for CWT's nested in a Other than the 55799 tag requirement, tag usage for CWT's nested in a
JSON format token follow the same rules as for CWTs nested in CBOR- JSON format token follow the same rules as for CWTs nested in CBOR-
format tokens. It may be a CWT CBOR tag or a CWT Protocol Message format tokens. It may be a CWT CBOR tag or a CWT Protocol Message
and COSE_Tagged_Message MUST be used at all COSE layers. and COSE_Tagged_Message MUST be used at all COSE layers.
3.16.1.3. Unsecured JWTs and UCCS Tokens as Submodules 3.17.1.3. Unsecured JWTs and UCCS Tokens as Submodules
To incorporate a UCCS token as a submodule, it MUST be as a non-token To incorporate a UCCS token as a submodule, it MUST be as a non-token
submodule. This can be accomplished inserting the content of the submodule. This can be accomplished inserting the content of the
UCCS Tag into the submodule map. The content of a UCCS tag is UCCS Tag into the submodule map. The content of a UCCS tag is
exactly a map of claims as required for a non-token submodule. If 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 the UCCS is not a UCCS tag, then it can just be inserted into the
submodule map directly. submodule map directly.
The definition of a nested EAT type of submodule is that it is one The definition of a nested EAT type of submodule is that it is one
that is secured (signed) by an Attester. Since UCCS tokens are that is secured (signed) by an Attester. Since UCCS tokens are
skipping to change at page 26, line 44 skipping to change at page 27, line 5
To incorporate an Unsecured JWT as a submodule, the null-security To incorporate an Unsecured JWT as a submodule, the null-security
JOSE wrapping should be removed. The resulting claims set should be JOSE wrapping should be removed. The resulting claims set should be
inserted as a non-token submodule. inserted as a non-token submodule.
To incorporate a UCCS token in a surrounding JSON token, the UCCS To incorporate a UCCS token in a surrounding JSON token, the UCCS
token claims should be translated from CBOR to JSON. To incorporate token claims should be translated from CBOR to JSON. To incorporate
an Unsecured JWT into a surrounding CBOR-format token, the null- an Unsecured JWT into a surrounding CBOR-format token, the null-
security JOSE should be removed and the claims translated from JSON security JOSE should be removed and the claims translated from JSON
to CBOR. to CBOR.
3.16.2. No Inheritance 3.17.2. 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 and age.
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.
3.16.3. Security Levels 3.17.3. 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.
3.16.4. Submodule Names 3.17.4. 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.
3.16.5. submods CDDL 3.17.5. submods CDDL
; The part of a token that contains all the submodules. It is a peer ; 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 ; with the claims in the token, but not a claim, only a map/object to
; hold all the submodules. ; hold all the submodules.
submods-part = ( submods-part = (
submods => submods-type submods => submods-type
) )
submods-type = { + submod-type } submods-type = { + submod-type }
skipping to change at page 28, line 39 skipping to change at page 28, line 39
submod-name = tstr submod-name = tstr
4. Endorsements and Verification Keys 4. Endorsements and Verification Keys
TODO: fill this section in. It will discuss key IDs, endorsement ID TODO: fill this section in. It will discuss key IDs, endorsement ID
and such that are needed as input needed to by the Verifier to verify and such that are needed as input needed to by the Verifier to verify
the signature. This will NOT discuss the contents of an Endorsement, the signature. This will NOT discuss the contents of an Endorsement,
just and ID/locator. just and ID/locator.
5. Encoding 5. Profiles
This EAT specification does not gaurantee that implementations of it
will interoperate. The variability in this specification is
necessary to accommodate the widely varying use cases. An EAT
profile narrows the specification for a specific use case. An ideal
EAT profile will gauarantee interoperability.
The profile can be named in the token using the profile claim
described in Section 3.16.
5.1. List of Profile Issues
The following is a list of EAT, CWT, UCCS, JWS, COSE, JOSE and CBOR
options that a profile should address.
5.1.1. Use of JSON, CBOR or both
The profile should indicate whether the token format should be CBOR,
JSON, both or even some other encoding. If some other encoding, a
specification for how the CDDL described here is serialized in that
encoding is necessary.
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
of the same encoding of the top level token.
5.1.2. CBOR Map and Array Encoding
The profile should indicate whether definite-length arrays/maps,
indefinite-length arrays/maps or both are allowed. A good default is
to allow only definite-length arrays/maps.
An alternate is to allow both definite and indefinite-length arrays/
maps. The decoder should accept either. Encoders that need to fit
on very small hardware or be actually implement in hardware can use
indefinite-length encoding.
This applies to individual EAT claims, CWT and COSE parts of the
implementation.
5.1.3. CBOR String Encoding
The profile should indicate whether definite-length strings,
indefinite-length strings or both are allowed. A good default is to
allow only definite-length strings. As with map and array encoding,
allowing indefinite-length strings can be beneficial for some smaller
implementations.
5.1.4. COSE/JOSE Protection
COSE and JOSE have several options for signed, MACed and encrypted
messages. EAT/CWT has the option to have no protection using UCCS
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
combinations allowed by COSE, JOSE, JWT, CWT and UCCS are allowed by
EAT.
The profile should list the protections that must be supported by all
decoders implementing the profile. The encoders them must implement
a subset of what is listed for the decoders, perhaps only one.
Implementations may choose to sign or MAC before encryption so that
the implementation layer doing the signing or MACing can be the
smallest. It is often easier to make smaller implementations more
secure, perhaps even implementing in solely in hardware. The key
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
requires less protection.
5.1.5. COSE/JOSE Algorithms
The profile document should list the COSE algorithms that a Verifier
must implement. The Attester will select one of them. Since there
is no negotiation, the Verifier should implement all algorithms
listed in the profile.
5.1.6. Verification Key Identification
Section Section 4 describes a number of methods for identifying a
verification key. The profile document should specify one of these
or one that is not described. The ones described in this document
are only roughly described. The profile document should go into the
full detail.
5.1.7. Endorsement Identification
Similar to, or perhaps the same as Verification Key Identification,
the profile may wish to specify how Endorsements are to be
identified. However note that Endorsement Identification is
optional, where as key identification is not.
5.1.8. Required Claims
The profile can list claims whose absence results in Verification
failure.
5.1.9. Prohibited Claims
The profile can list claims whose presence results in Verification
failure.
5.1.10. Additional Claims
The profile may describe entirely new claims. These claims can be
required or optional.
5.1.11. Refined Claim Definition
The profile may lock down optional aspects of individual claims. For
example, it may require altitude in the location claim, or it may
require that HW Versions always be described using EAN-13.
5.1.12. CBOR Tags
The profile should specify whether the token should be a CWT Tag or
not. Similarly, the profile should specify whether the token should
be a UCCS tag or not.
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
in a CWT tag.
Often a tag is unncessary because the surrounding or carrying
protocol identifies the object as an EAT.
6. Encoding
This makes use of the types defined in CDDL Appendix D, Standard This makes use of the types defined in CDDL Appendix D, Standard
Prelude. Prelude.
Some of the CDDL included here is for claims that are defined in CWT Some of the CDDL included here is for claims that are defined in CWT
[RFC8392] or JWT [RFC7519] or are in the IANA CWT or JWT registries. [RFC8392] or JWT [RFC7519] or are in the IANA CWT or JWT registries.
CDDL was not in use when these claims where defined. CDDL was not in use when these claims where defined.
5.1. Common CDDL Types 6.1. Common CDDL Types
time-int is identical to the epoch-based time, but disallows time-int is identical to the epoch-based time, but disallows
floating-point representation. floating-point representation.
string-or-uri = tstr string-or-uri = tstr
time-int = #6.1(int) time-int = #6.1(int)
5.2. CDDL for CWT-defined Claims 6.2. CDDL for CWT-defined Claims
This section provides CDDL for the claims defined in CWT. It is non- This section provides CDDL for the claims defined in CWT. It is non-
normative as [RFC8392] is the authoritative definition of these normative as [RFC8392] is the authoritative definition of these
claims. claims.
$$eat-extension //= ( $$eat-extension //= (
? issuer => text, ? issuer => text,
? subject => text, ? subject => text,
? audience => text, ? audience => text,
? expiration => time, ? expiration => time,
skipping to change at page 29, line 38 skipping to change at page 32, line 23
) )
issuer = 1 issuer = 1
subject = 2 subject = 2
audience = 3 audience = 3
expiration = 4 expiration = 4
not-before = 5 not-before = 5
issued-at = 6 issued-at = 6
cwt-id = 7 cwt-id = 7
5.3. JSON 6.3. JSON
6.3.1. JSON Labels
5.3.1. JSON Labels
ueid /= "ueid" ueid /= "ueid"
nonce /= "nonce" nonce /= "nonce"
origination /= "origination" origination /= "origination"
oemid /= "oemid" oemid /= "oemid"
security-level /= "security-level" security-level /= "security-level"
secure-boot /= "secure-boot" secure-boot /= "secure-boot"
debug-status /= "debug-status" debug-status /= "debug-status"
location /= "location" location /= "location"
age /= "age" age /= "age"
uptime /= "uptime" uptime /= "uptime"
profile /= "eat-profile"
boot-seed /= "bootseed"
submods /= "submods" submods /= "submods"
timestamp /= "timestamp" timestamp /= "timestamp"
latitude /= "lat" latitude /= "lat"
longitude /= "long" longitude /= "long"
altitude /= "alt" altitude /= "alt"
accuracy /= "accry" accuracy /= "accry"
altitude-accuracy /= "alt-accry" altitude-accuracy /= "alt-accry"
heading /= "heading" heading /= "heading"
speed /= "speed" speed /= "speed"
5.3.2. JSON Interoperability 6.3.2. JSON Interoperability
JSON should be encoded per RFC 8610 Appendix E. In addition, the JSON should be encoded per RFC 8610 Appendix E. In addition, the
following CDDL types are encoded in JSON as follows: following CDDL types are encoded in JSON as follows:
* bstr - must be base64url encoded o bstr - must be base64url encoded
* 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].
* 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].
5.4. CBOR 6.4. CBOR
5.4.1. CBOR Interoperability
Variations in the CBOR serializations supported in CBOR encoding and
decoding are allowed and suggests that CBOR-based protocols specify
how this variation is handled. This section specifies what formats
MUST be supported in order to achieve interoperability.
The assumption is that the entity is likely to be a constrained
device and relying party is likely to be a very capable server. The
approach taken is that the entity generating the token can use
whatever encoding it wants, specifically encodings that are easier to
implement such as indefinite lengths. The relying party receiving
the token must support decoding all encodings.
These rules cover all types used in the claims in this document.
They also are recommendations for additional claims.
Canonical CBOR encoding, Preferred Serialization and
Deterministically Encoded CBOR are explicitly NOT required as they
would place an unnecessary burden on the entity implementation,
particularly if the entity implementation is implemented in hardware.
* Integer Encoding (major type 0, 1) - The entity may use any
integer encoding allowed by CBOR. The server MUST accept all
integer encodings allowed by CBOR.
* String Encoding (major type 2 and 3) - The entity can use any
string encoding allowed by CBOR including indefinite lengths. It
may also encode the lengths of strings in any way allowed by CBOR.
The server must accept all string encodings.
* Major type 2, bstr, SHOULD have tag 21 to indicate conversion to
base64url in case that conversion is performed.
* Map and Array Encoding (major type 4 and 5) - The entity can use
any array or map encoding allowed by CBOR including indefinite
lengths. Sorting of map keys is not required. Duplicate map keys
are not allowed. The server must accept all array and map
encodings. The server may reject maps with duplicate map keys.
* Date and Time - The entity should send dates as tag 1 encoded as 6.4.1. CBOR Interoperability
64-bit or 32-bit integers. The entity may not send floating-point
dates. The server must support tag 1 epoch-based dates encoded as
64-bit or 32-bit integers. The entity may send tag 0 dates,
however tag 1 is preferred. The server must support tag 0 UTC
dates.
* URIs - URIs should be encoded as text strings and marked with tag CBOR allows data items to be serialized in more than one form. If
32. the sender uses a form that the receiver can't decode, there will not
be interoperability.
* Floating Point - The entity may use any floating-point encoding. This specification gives no blanket requirements to narrow CBOR
The relying party must support decoding of all types of floating- serialization for all uses of EAT. This allows individual uses to
point. tailor serialization to the environment. It also may result in EAT
implementations that don't interoperate.
* Other types - Other types like bignums, regular expressions and One way to guarantee interoperability is to clearly specify CBOR
such, SHOULD NOT be used. The server MAY support them but is not serialization in a profile document. See Section 5 for a list of
required to so interoperability is not guaranteed. serialization issues that should be addressed.
5.5. Collected CDDL EAT will be commonly used where the device generating the attestation
is constrained and the receiver/verifier of the attestation is a
capacious server. Following is a set of serialization requirements
that work well for that use case and are guaranteed to interoperate.
Use of this serialization is recommended where possible, but not
required. An EAT profile may just reference the following section
rather than spell out serialization details.
; This is the top-level definition of the claims in EAT tokens. To 6.4.1.1. EAT Constrained Device Serialization
; form an actual EAT Token, this claim set is enclosed in a COSE, JOSE
; or UCCS message.
; TO-DO: Add intended-use claim
eat-claim-set = { o Preferred serialization described in section 4.1 of [RFC8949] is
? ueid-claim, not required. The EAT decoder must accept all forms of number
? nonce-claim, serialization. The EAT encoder may use any form it wishes.
? origination-claim,
? oemid-claim,
? hardware-version-claims,
? security-level-claim,
? secure-boot-claim,
? debug-status-claim,
? location-claim,
? uptime-claim,
? submods-part,
* $$eat-extension,
}
; This is the top-level definition of an EAT Token. It is a CWT, JWT o The EAT decoder must accept indefinite length arrays and maps as
; or UCSS where the payload is an eat-claim-set. A JWT_Message is what described in section 3.2.2 of [RFC8949]. The EAT encoder may use
; is defined by JWT in RFC 7519. (RFC 7519 doesn't use CDDL so a there indefinite length arrays and maps if it wishes.
; is no actual CDDL definition of JWT_Message).
eat-token = EAT_Tagged_Message / EAT_Untagged_Message / JWT_Message o The EAT decoder must accept indefinite length strings as described
in section 3.2.3 of [RFC8949]. The EAT encoder may use indefinite
length strings if it wishes.
; This is CBOR-format EAT token in the CWT or UCCS format that is a o Sorting of maps by key is not required. The EAT decoder must not
; tag. COSE_Tagged_message is defined in RFC 8152. Tag 601 is rely on sorting.
; proposed by the UCCS draft, but not yet assigned.
EAT_Tagged_Message = #6.61(COSE_Tagged_Message) / #6.601(eat-claim-set) o Deterministic encoding described in Section 4.2 of [RFC8949] is
not required.
; This is a CBOR-format EAT token that is a CWT or UCSS that is not a o Basic validity described in section 5.3.1 of [RFC8949] must be
; tag COSE_Tagged_message and COSE_Untagged_Message are defined in RFC followed. The EAT encoder must not send duplicate map keys/labels
; 8152. or invalid UTF-8 strings.
EAT_Untagged_Message = COSE_Tagged_Message / COSE_Untagged_Message / UCCS_Untagged_Message 6.5. Collected CDDL
; 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 ; This is the top-level definition of the claims in EAT tokens. To
; form an actual EAT Token, this claim set is enclosed in a COSE, JOSE
; or UCCS message.
; The following Claim Keys (labels) are temporary. They are not eat-claim-set = {
; assigned by IANA ? ueid-claim,
? nonce-claim,
? origination-claim,
? oemid-claim,
? hardware-version-claims,
? security-level-claim,
? secure-boot-claim,
? debug-status-claim,
? location-claim,
? profile-claim,
? uptime-claim,
? boot-seed-claim,
? submods-part,
* $$eat-extension,
}
nonce = 10 ; This is the top-level definition of an EAT Token. It is a CWT, JWT
ueid = 11 ; or UCSS where the payload is an eat-claim-set. A JWT_Message is what
origination = 12 ; is defined by JWT in RFC 7519. (RFC 7519 doesn't use CDDL so a there
oemid = 13 ; is no actual CDDL definition of JWT_Message).
security-level = 14
secure-boot = 15
debug-status = 16
location = 17
uptime = 19
submods = 20
chip-version = 21 eat-token = EAT_Tagged_Message / EAT_Untagged_Message / JWT_Message
board-version = 22
device-version = 23
chip-version-scheme = 24
board-version-scheme = 25
device-version-scheme = 26
ean-chip-version = 27
ean-board-version = 28
ean-device-version = 29
string-or-uri = tstr ; This is CBOR-format EAT token in the CWT or UCCS format that is a
; tag. COSE_Tagged_message is defined in RFC 8152. Tag 601 is
; proposed by the UCCS draft, but not yet assigned.
time-int = #6.1(int) EAT_Tagged_Message = #6.61(COSE_Tagged_Message) / #6.601(eat-claim-set)
$$eat-extension //= ( ; This is a CBOR-format EAT token that is a CWT or UCSS that is not a
? issuer => text, ; tag COSE_Tagged_message and COSE_Untagged_Message are defined in RFC
? subject => text, ; 8152.
? audience => text,
? expiration => time,
? not-before => time,
? issued-at => time,
? cwt-id => bytes,
)
issuer = 1 EAT_Untagged_Message = COSE_Tagged_Message /
subject = 2 COSE_Untagged_Message /
audience = 3 UCCS_Untagged_Message
expiration = 4
not-before = 5
issued-at = 6
cwt-id = 7
debug-status-type = &( ; This is an "unwrapped" UCCS tag. Unwrapping a tag means to use the
enabled: 0, ; definition of its content without the preceding type 6 tag
disabled: 1, ; integer. Since a UCCS is nothing but a tag for an unsecured CWT
disabled-since-boot: 2, ; claim set, unwrapping reduces to a bare eat-claim-set.
disabled-permanently: 3,
disabled-fully-and-permanently: 4
)
debug-status-claim = ( UCCS_Untagged_Message = eat-claim-set
debug-status => debug-status-type
)
location-type = { ; The following Claim Keys (labels) are temporary. They are not
latitude => number, ; assigned by IANA
longitude => number,
? altitude => number,
? accuracy => number,
? altitude-accuracy => number,
? heading => number,
? speed => number,
? timestamp => ~time-int,
? age => uint
}
latitude = 1 nonce = 10
longitude = 2 ueid = 11
altitude = 3 origination = 12
accuracy = 4 oemid = 13
altitude-accuracy = 5 security-level = 14
heading = 6 secure-boot = 15
speed = 7 debug-status = 16
timestamp = 8 location = 17
age = 9 profile = 18
uptime = 19
submods = 20
boot-seed = 21
location-claim = ( chip-version = 21
location => location-type board-version = 22
) device-version = 23
chip-version-scheme = 24
board-version-scheme = 25
device-version-scheme = 26
ean-chip-version = 27
ean-board-version = 28
ean-device-version = 29
string-or-uri = tstr
time-int = #6.1(int)
$$eat-extension //= (
? issuer => text,
? subject => text,
? audience => text,
? expiration => time,
? not-before => time,
? issued-at => time,
? cwt-id => bytes,
)
nonce-type = bstr .size (8..64) issuer = 1
subject = 2
audience = 3
expiration = 4
not-before = 5
issued-at = 6
cwt-id = 7
nonce-claim = ( debug-status-type = &(
nonce => nonce-type / [ 2* nonce-type ] enabled: 0,
) disabled: 1,
disabled-since-boot: 2,
disabled-permanently: 3,
disabled-fully-and-permanently: 4
)
oemid-claim = ( debug-status-claim = (
oemid => bstr debug-status => debug-status-type
) )
location-type = {
latitude => number,
longitude => number,
? altitude => number,
? accuracy => number,
? altitude-accuracy => number,
? heading => number,
? speed => number,
? timestamp => ~time-int,
? age => uint
}
; copied from CoSWID latitude = 1
; TODO: how to properly make reference to CoSWID and have tool validate longitude = 2
altitude = 3
accuracy = 4
altitude-accuracy = 5
heading = 6
speed = 7
timestamp = 8
age = 9
$version-scheme /= multipartnumeric location-claim = (
$version-scheme /= multipartnumeric-suffix location => location-type
$version-scheme /= alphanumeric )
$version-scheme /= decimal nonce-type = bstr .size (8..64)
$version-scheme /= semver
$version-scheme /= uint / text
multipartnumeric = 1
multipartnumeric-suffix = 2
alphanumeric = 3
decimal = 4
semver = 16384
chip-version-claim = ( nonce-claim = (
chip-version => tstr nonce => nonce-type / [ 2* nonce-type ]
) )
oemid-claim = (
oemid => bstr
)
; copied from CoSWID
; TODO: how to properly make reference to CoSWID and have tool validate
chip-version-scheme-claim = ( $version-scheme /= multipartnumeric
chip-version-scheme => $version-scheme $version-scheme /= multipartnumeric-suffix
) $version-scheme /= alphanumeric
$version-scheme /= decimal
$version-scheme /= semver
$version-scheme /= uint / text
multipartnumeric = 1
multipartnumeric-suffix = 2
alphanumeric = 3
decimal = 4
semver = 16384
board-version-claim = ( chip-version-claim = (
board-version => tstr chip-version => tstr
) )
board-version-scheme-claim = ( chip-version-scheme-claim = (
board-version-scheme => $version-scheme chip-version-scheme => $version-scheme
) )
device-version-claim = ( board-version-claim = (
device-version => tstr board-version => tstr
) )
device-version-scheme-claim = ( board-version-scheme-claim = (
device-version-scheme => $version-scheme board-version-scheme => $version-scheme
) )
ean-type = text .regexp "[0-9]{13}"
ean-chip-version-claim = ( device-version-claim = (
ean-chip-version => ean-type device-version => tstr
)
ean-board-version-claim = ( )
ean-board-version => ean-type
)
ean-device-version-claim = ( device-version-scheme-claim = (
ean-device-version => ean-type device-version-scheme => $version-scheme
) )
hardware-version-claims = ( ean-type = text .regexp "[0-9]{13}"
? chip-version-claim,
? board-version-claim,
? device-version-claim,
? chip-version-scheme-claim,
? board-version-scheme-claim,
? device-version-scheme-claim,
? ean-chip-version-claim,
? ean-board-version-claim,
? ean-device-version-claim,
)
origination-claim = ( ean-chip-version-claim = (
origination => string-or-uri ean-chip-version => ean-type
) )
secure-boot-claim = ( ean-board-version-claim = (
secure-boot => bool ean-board-version => ean-type
) )
security-level-type = &( ean-device-version-claim = (
unrestricted: 1, ean-device-version => ean-type
restricted: 2, )
secure-restricted: 3,
hardware: 4
)
security-level-claim = ( hardware-version-claims = (
security-level => security-level-type ? chip-version-claim,
) ? board-version-claim,
? device-version-claim,
? chip-version-scheme-claim,
? board-version-scheme-claim,
? device-version-scheme-claim,
? ean-chip-version-claim,
? ean-board-version-claim,
? ean-device-version-claim,
)
; The part of a token that contains all the submodules. It is a peer origination-claim = (
; with the claims in the token, but not a claim, only a map/object to origination => string-or-uri
; hold all the submodules. )
secure-boot-claim = (
secure-boot => bool
)
security-level-type = &(
unrestricted: 1,
restricted: 2,
secure-restricted: 3,
hardware: 4
)
submods-part = ( security-level-claim = (
submods => submods-type security-level => security-level-type
)
submods-type = { + submod-type } )
; 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.
; The type of a submodule which can either be a nested claim set or a submods-part = (
; nested separately signed token. Nested tokens are wrapped in a bstr submods => submods-type
; or a tstr. )
submod-type = ( submods-type = { + submod-type }
submod-name => eat-claim-set / nested-token
)
; When this is a bstr, the contents are an eat-token in CWT or UCCS ; The type of a submodule which can either be a nested claim set or a
; format. When this is a tstr, the contents are an eat-token in JWT ; nested separately signed token. Nested tokens are wrapped in a bstr
; format. ; or a tstr.
nested-token = bstr / tstr; submod-type = (
submod-name => eat-claim-set / nested-token
)
; Each submodule has a unique text string name. ; When this is a bstr, the contents are an eat-token in CWT or UCCS
; format. When this is a tstr, the contents are an eat-token in JWT
; format.
submod-name = tstr nested-token = bstr / tstr;
ueid-type = bstr .size (7..33) ; Each submodule has a unique text string name.
ueid-claim = ( submod-name = tstr
ueid => ueid-type
)
uptime-claim = ( ueid-type = bstr .size (7..33)
uptime => uint
)
ueid /= "ueid" ueid-claim = (
nonce /= "nonce" ueid => ueid-type
origination /= "origination" )
oemid /= "oemid" uptime-claim = (
security-level /= "security-level" uptime => uint
secure-boot /= "secure-boot" )
debug-status /= "debug-status" profile-claim = (
location /= "location" profile => tstr
age /= "age" )
uptime /= "uptime" boot-seed-claim = (
submods /= "submods" boot-seed => bytes
timestamp /= "timestamp" )
ueid /= "ueid"
nonce /= "nonce"
origination /= "origination"
oemid /= "oemid"
security-level /= "security-level"
secure-boot /= "secure-boot"
debug-status /= "debug-status"
location /= "location"
age /= "age"
uptime /= "uptime"
profile /= "eat-profile"
boot-seed /= "bootseed"
submods /= "submods"
timestamp /= "timestamp"
latitude /= "lat" latitude /= "lat"
longitude /= "long" longitude /= "long"
altitude /= "alt" altitude /= "alt"
accuracy /= "accry" accuracy /= "accry"
altitude-accuracy /= "alt-accry" altitude-accuracy /= "alt-accry"
heading /= "heading" heading /= "heading"
speed /= "speed" speed /= "speed"
6. IANA Considerations 7. IANA Considerations
6.1. Reuse of CBOR Web Token (CWT) Claims Registry 7.1. Reuse of CBOR Web Token (CWT) Claims Registry
Claims defined for EAT are compatible with those of CWT so the CWT Claims defined for EAT are compatible with those of CWT so the CWT
Claims Registry is re used. No new IANA registry is created. All Claims Registry is re used. No new IANA registry is created. All
EAT claims should be registered in the CWT and JWT Claims Registries. EAT claims should be registered in the CWT and JWT Claims Registries.
6.2. Claim Characteristics 7.2. 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.
6.2.1. Interoperability and Relying Party Orientation 7.2.1. 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.
6.2.2. Operating System and Technology Neutral 7.2.2. 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.
6.2.3. Security Level Neutral 7.2.3. 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.
6.2.4. Reuse of Extant Data Formats 7.2.4. 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.
6.2.5. Proprietary Claims 7.2.5. 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.
6.3. Claims Registered by This Document 7.3. Claims Registered by This Document
* Claim Name: UEID o Claim Name: UEID
* Claim Description: The Universal Entity ID o Claim Description: The Universal Entity ID
* JWT Claim Name: N/A o JWT Claim Name: N/A
* Claim Key: 8 o Claim Key: 8
* Claim Value Type(s): byte string o Claim Value Type(s): byte string
* Change Controller: IESG o Change Controller: IESG
* Specification Document(s): *this document* o Specification Document(s): *this document*
TODO: add the rest of the claims in here TODO: add the rest of the claims in here
7. Privacy Considerations 8. 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.
7.1. UEID Privacy Considerations 8.1. UEID 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 UEID will governmental privacy regulation. In other usage situations UEID will
not be allowed for certain products like browsers that give privacy not be allowed for certain products like browsers that give privacy
for the end user. It will often be the case that tokens will not for the end user. It will often be the case that tokens will not
have a UEID for these reasons. have a UEID for these reasons.
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
UEID's in tokens: UEID's in tokens:
* 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. This may be through a prompt. It may also be to use the UEID. This may be through a prompt. It may also be
through a license agreement. For example, agreements for some 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. UEID.
* The UEID is used only in a particular context or particular use o The UEID is used only in a particular context or particular use
case. It is used only by one relying party. case. It is used only by one relying party.
* The device authenticates the relying party and generates a derived o The device authenticates the relying party and generates a derived
UEID just for that particular relying party. For example, the UEID 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 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. UEID.
Note that some of these privacy preservation strategies result in Note that some of these privacy preservation strategies result in
multiple UEIDs per device. Each UEID is used in a different context, multiple UEIDs per device. Each UEID is used in a different context,
use case or system on the device. However, from the view of the use case or system on the device. However, from the view of the
relying party, there is just one UEID and it is still globally relying party, there is just one UEID and it is still globally
universal across manufacturers. universal across manufacturers.
7.2. Location Privacy Considerations 8.2. 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.
8. Security Considerations 9. Security Considerations
The security considerations provided in Section 8 of [RFC8392] and The security considerations provided in Section 8 of [RFC8392] and
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.
8.1. Key Provisioning 9.1. 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.
8.1.1. Transmission of Key Material 9.1.1. 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.
8.2. Transport Security 9.2. 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.
8.3. Multiple EAT Consumers 9.3. 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 43, line 36 skipping to change at page 45, line 36
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.
9. References 10. References
9.1. Normative References 10.1. Normative References
[CoSWID] "Concise Software Identification Tags", November 2020, [CoSWID] "Concise Software Identification Tags", November 2020,
<https://tools.ietf.org/html/draft-ietf-sacm-coswid-16>. <https://tools.ietf.org/html/draft-ietf-sacm-coswid-16>.
[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 2019,
skipping to change at page 44, line 18 skipping to change at page 46, line 18
[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>.
[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>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517, [RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015, DOI 10.17487/RFC7517, May 2015,
<https://www.rfc-editor.org/info/rfc7517>. <https://www.rfc-editor.org/info/rfc7517>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>. <https://www.rfc-editor.org/info/rfc7519>.
[RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of- [RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of-
Possession Key Semantics for JSON Web Tokens (JWTs)", Possession Key Semantics for JSON Web Tokens (JWTs)",
skipping to change at page 45, line 16 skipping to change at page 47, line 10
Definition Language (CDDL): A Notational Convention to Definition Language (CDDL): A Notational Convention to
Express Concise Binary Object Representation (CBOR) and Express Concise Binary Object Representation (CBOR) and
JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
June 2019, <https://www.rfc-editor.org/info/rfc8610>. June 2019, <https://www.rfc-editor.org/info/rfc8610>.
[RFC8747] Jones, M., Seitz, L., Selander, G., Erdtman, S., and H. [RFC8747] Jones, M., Seitz, L., Selander, G., Erdtman, S., and H.
Tschofenig, "Proof-of-Possession Key Semantics for CBOR Tschofenig, "Proof-of-Possession Key Semantics for CBOR
Web Tokens (CWTs)", RFC 8747, DOI 10.17487/RFC8747, March Web Tokens (CWTs)", RFC 8747, DOI 10.17487/RFC8747, March
2020, <https://www.rfc-editor.org/info/rfc8747>. 2020, <https://www.rfc-editor.org/info/rfc8747>.
[RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", STD 94, RFC 8949,
DOI 10.17487/RFC8949, December 2020,
<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>.
[TIME_T] The Open Group Base Specifications, "Vol. 1: Base
Definitions, Issue 7", Section 4.15 'Seconds Since the
Epoch', IEEE Std 1003.1, 2013 Edition, 2013,
<http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/
V1_chap04.html#tag_04_15>.
[UCCS.Draft] [UCCS.Draft]
Birkholz, H., "A CBOR Tag for Unprotected CWT Claims Birkholz, H., "A CBOR Tag for Unprotected CWT Claims
Sets", 2020, Sets", 2020,
<https://tools.ietf.org/html/draft-birkholz-rats-uccs-01>. <https://tools.ietf.org/html/draft-birkholz-rats-uccs-01>.
[WGS84] National Imagery and Mapping Agency, "National Imagery and [WGS84] National Imagery and Mapping Agency, "National Imagery and
Mapping Agency Technical Report 8350.2, Third Edition", Mapping Agency Technical Report 8350.2, Third Edition",
2000, <http://earth- 2000, <http://earth-
info.nga.mil/GandG/publications/tr8350.2/wgs84fin.pdf>. info.nga.mil/GandG/publications/tr8350.2/wgs84fin.pdf>.
9.2. Informative References 10.2. Informative References
[ASN.1] International Telecommunication Union, "Information
Technology -- ASN.1 encoding rules: Specification of Basic
Encoding Rules (BER), Canonical Encoding Rules (CER) and
Distinguished Encoding Rules (DER)", ITU-T Recommendation
X.690, 1994.
[BirthdayAttack] [BirthdayAttack]
"Birthday attack", "Birthday attack",
<https://en.wikipedia.org/wiki/Birthday_attack.>. <https://en.wikipedia.org/wiki/Birthday_attack.>.
[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/>.
skipping to change at page 46, line 21 skipping to change at page 48, line 5
"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] [FIDO.Registry]
The FIDO Alliance, "FIDO Registry of Predefined Values", The FIDO Alliance, "FIDO Registry of Predefined Values",
December 2019, <https://fidoalliance.org/specs/common- December 2019, <https://fidoalliance.org/specs/common-
specs/fido-registry-v2.1-ps-20191217.html>. specs/fido-registry-v2.1-ps-20191217.html>.
[FIPS-140] National Institue of Standards, "Security Requirements for [FIPS-140]
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>.
[IDevID] "IEEE Standard, "IEEE 802.1AR Secure Device Identifier"", [IDevID] "IEEE Standard, "IEEE 802.1AR Secure Device Identifier"",
December 2009, <http://standards.ieee.org/findstds/ December 2009, <http://standards.ieee.org/findstds/
standard/802.1AR-2009.html>. standard/802.1AR-2009.html>.
[IEEE.802-2001] [IEEE.802-2001]
"IEEE Standard For Local And Metropolitan Area Networks "IEEE Standard For Local And Metropolitan Area Networks
skipping to change at page 47, line 19 skipping to change at page 49, line 5
[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>.
[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>.
[Webauthn] Worldwide Web Consortium, "Web Authentication: A Web API
for accessing scoped credentials", 2016.
Appendix A. Examples Appendix A. Examples
A.1. Very Simple EAT A.1. Very Simple EAT
This is shown in CBOR diagnostic form. Only the payload signed by This is shown in CBOR diagnostic form. Only the payload signed by
COSE is shown. COSE is shown.
{ {
/ issuer / 1: "joe", / issuer / 1: "joe",
/ nonce / 10: h'948f8860d13a463e8e', / nonce / 10: h'948f8860d13a463e8e',
/ UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea4fe2fa', / UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea',
/ secure-boot / 15: true, / secure-boot / 15: true,
/ debug-disable / 16: 3, / permanent-disable / / debug-disable / 16: 3, / permanent-disable /
/ timestamp (iat) / 6: 1(1526542894), / timestamp (iat) / 6: 1(1526542894),
/ chip-version / 21: "1.4a", / chip-version / 21: "1.4a",
/ chip-version-scheme / 24: 2 / multipartnumeric+suffix / / chip-version-scheme / 24: 2 / multipartnumeric+suffix /
} }
A.2. Example with Submodules, Nesting and Security Levels A.2. Example with Submodules, Nesting and Security Levels
{
/ nonce / 10: h'948f8860d13a463e8e',
/ UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea4fe2fa',
/ secure-boot / 15: true,
/ 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 / {
"Secure Element Eat" : / nonce / 10: h'948f8860d13a463e8e',
/ an embedded EAT, bytes of which are not shown / / UEID / 11: h'0198f50a4ff6c05861c8860d13a638ea'
h'420123', / secure-boot / 15: true,
/ 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 /
},
/ 3rd submod, information about Linux Android / / 2nd submod, A nested EAT from a secure element /
"Linux Android": { "Secure Element Eat" :
/ security-level / 14: 1 / unrestricted / / an embedded EAT, bytes of which are not shown /
} h'420123',
}
} / 3rd submod, information about Linux Android /
"Linux Android": {
/ security-level / 14: 1 / unrestricted /
}
}
}
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
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the limit of what is imaginable and should probably be accommodated. the limit of what is imaginable and should probably be accommodated.
The 100 quadrillion datadbase is highly speculative perhaps involving The 100 quadrillion datadbase is highly speculative perhaps involving
nanorobots for every person, livestock animal and domesticated bird. nanorobots for every person, livestock animal and domesticated bird.
It is included to round out the analysis. It is included to round out the analysis.
Note that the items counted here certainly do not have IP address and Note that the items counted here certainly do not have IP address and
are not individually connected to the network. They may be connected are not individually connected to the network. They may be connected
to internal buses, via serial links, Bluetooth and so on. This is to internal buses, via serial links, Bluetooth and so on. This is
not the same problem as sizing IP addresses. not the same problem as sizing IP addresses.
+=========+===========+============+==========+=================+ +---------+------------+--------------+------------+----------------+
| People | Devices / | Subsystems | Database | Database Size | | People | Devices / | Subsystems / | Database | Database Size |
| | Person | / Device | Portion | | | | Person | Device | Portion | |
+=========+===========+============+==========+=================+ +---------+------------+--------------+------------+----------------+
| 10 | 100 | 10 | 10% | trillion | | 10 | 100 | 10 | 10% | trillion |
| billion | | | | (10^12) | | billion | | | | (10^12) |
+---------+-----------+------------+----------+-----------------+ | 10 | 100,000 | 10 | 10% | quadrillion |
| 10 | 100,000 | 10 | 10% | quadrillion | | billion | | | | (10^15) |
| billion | | | | (10^15) | | 100 | 1,000,000 | 10 | 10% | 100 |
+---------+-----------+------------+----------+-----------------+ | billion | | | | quadrillion |
| 100 | 1,000,000 | 10 | 10% | 100 quadrillion | | | | | | (10^17) |
| billion | | | | (10^17) | +---------+------------+--------------+------------+----------------+
+---------+-----------+------------+----------+-----------------+
Table 3
This is conceptually similar to the Birthday Problem where m is the This is conceptually similar to the Birthday Problem where m is the
number of possible birthdays, always 365, and k is the number of number of possible birthdays, always 365, and k is the number of
people. It is also conceptually similar to the Birthday Attack where people. It is also conceptually similar to the Birthday Attack where
collisions of the output of hash functions are considered. collisions of the output of hash functions are considered.
The proper formula for the collision calculation is The proper formula for the collision calculation is
p = 1 - e^{-k^2/(2n)} p = 1 - e^{-k^2/(2n)}
p Collision Probability p Collision Probability
n Total possible population n Total possible population
k Actual population k Actual population
However, for the very large values involved here, this formula However, for the very large values involved here, this formula
requires floating point precision higher than commonly available in requires floating point precision higher than commonly available in
calculators and SW so this simple approximation is used. See calculators and SW so this simple approximation is used. See
[BirthdayAttack]. [BirthdayAttack].
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[BirthdayAttack]. [BirthdayAttack].
p = k^2 / 2n p = k^2 / 2n
For this calculation: For this calculation:
p Collision Probability p Collision Probability
n Total population based on number of bits in UEID n Total population based on number of bits in UEID
k Population in a database k Population in a database
+=====================+==============+==============+==============+ +----------------------+--------------+--------------+--------------+
| Database Size | 128-bit UEID | 192-bit UEID | 256-bit UEID | | Database Size | 128-bit UEID | 192-bit UEID | 256-bit UEID |
+=====================+==============+==============+==============+ +----------------------+--------------+--------------+--------------+
| trillion (10^12) | 2 * 10^-15 | 8 * 10^-35 | 5 * 10^-55 | | trillion (10^12) | 2 * 10^-15 | 8 * 10^-35 | 5 * 10^-55 |
+---------------------+--------------+--------------+--------------+ | quadrillion (10^15) | 2 * 10^-09 | 8 * 10^-29 | 5 * 10^-49 |
| quadrillion (10^15) | 2 * 10^-09 | 8 * 10^-29 | 5 * 10^-49 | | 100 quadrillion | 2 * 10^-05 | 8 * 10^-25 | 5 * 10^-45 |
+---------------------+--------------+--------------+--------------+ | (10^17) | | | |
| 100 quadrillion | 2 * 10^-05 | 8 * 10^-25 | 5 * 10^-45 | +----------------------+--------------+--------------+--------------+
| (10^17) | | | |
+---------------------+--------------+--------------+--------------+
Table 4
Next, to calculate the probability of a collision occurring in one Next, to calculate the probability of a collision occurring in one
year's operation of a database, it is assumed that the database size year's operation of a database, it is assumed that the database size
is in a steady state and that 10% of the database changes per year. is in a steady state and that 10% of the database changes per year.
For example, a trillion record database would have 100 billion states For example, a trillion record database would have 100 billion states
per year. Each of those states has the above calculated probability per year. Each of those states has the above calculated probability
of a collision. of a collision.
This assumption is a worst-case since it assumes that each state of This assumption is a worst-case since it assumes that each state of
the database is completely independent from the previous state. In the database is completely independent from the previous state. In
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The following tables gives the time interval until there is a The following tables gives the time interval until there is a
probability of a collision based on there being one tenth the number probability of a collision based on there being one tenth the number
of states per year as the number of records in the database. of states per year as the number of records in the database.
t = 1 / ((k / 10) * p) t = 1 / ((k / 10) * p)
t Time until a collision t Time until a collision
p Collision probability for UEID size p Collision probability for UEID size
k Database size k Database size
+=====================+==============+==============+==============+ +---------------------+---------------+--------------+--------------+
| Database Size | 128-bit UEID | 192-bit UEID | 256-bit UEID | | Database Size | 128-bit UEID | 192-bit UEID | 256-bit UEID |
+=====================+==============+==============+==============+ +---------------------+---------------+--------------+--------------+
| trillion (10^12) | 60,000 years | 10^24 years | 10^44 years | | trillion (10^12) | 60,000 years | 10^24 years | 10^44 years |
+---------------------+--------------+--------------+--------------+ | quadrillion (10^15) | 8 seconds | 10^14 years | 10^34 years |
| quadrillion (10^15) | 8 seconds | 10^14 years | 10^34 years | | 100 quadrillion | 8 | 10^11 years | 10^31 years |
+---------------------+--------------+--------------+--------------+ | (10^17) | microseconds | | |
| 100 quadrillion | 8 | 10^11 years | 10^31 years | +---------------------+---------------+--------------+--------------+
| (10^17) | microseconds | | |
+---------------------+--------------+--------------+--------------+
Table 5
Clearly, 128 bits is enough for the near future thus the requirement Clearly, 128 bits is enough for the near future thus the requirement
that UEIDs be a minimum of 128 bits. that UEIDs be a minimum of 128 bits.
There is no requirement for 256 bits today as quadrillion-record There is no requirement for 256 bits today as quadrillion-record
databases are not expected in the near future and because this time- databases are not expected in the near future and because this time-
to-collision calculation is a very worst case. A future update of to-collision calculation is a very worst case. A future update of
the standard may increase the requirement to 256 bits, so there is a the standard may increase the requirement to 256 bits, so there is a
requirement that implementations be able to receive 256-bit UEIDs. requirement that implementations be able to receive 256-bit UEIDs.
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as they are implemented in commonly used CPU hardware. as they are implemented in commonly used CPU hardware.
Appendix C. Changes from Previous Drafts Appendix C. Changes from Previous Drafts
The following is a list of known changes from the previous drafts. The following is a list of known changes from the previous drafts.
This list is non-authoritative. It is meant to help reviewers see This list is non-authoritative. It is meant to help reviewers see
the significant differences. the significant differences.
C.1. From draft-rats-eat-01 C.1. From draft-rats-eat-01
* Added UEID design rationale appendix o Added UEID design rationale appendix
C.2. From draft-mandyam-rats-eat-00 C.2. From draft-mandyam-rats-eat-00
This is a fairly large change in the orientation of the document, but This is a fairly large change in the orientation of the document, but
no new claims have been added. no new claims have been added.
* Separate information and data model using CDDL. o Separate information and data model using CDDL.
* Say an EAT is a CWT or JWT o Say an EAT is a CWT or JWT
* Use a map to structure the boot_state and location claims o Use a map to structure the boot_state and location claims
C.3. From draft-ietf-rats-eat-01 C.3. From draft-ietf-rats-eat-01
* Clarifications and corrections for OEMID claim o Clarifications and corrections for OEMID claim
* Minor spelling and other fixes o Minor spelling and other fixes
* Add the nonce claim, clarify jti claim o Add the nonce claim, clarify jti claim
C.4. From draft-ietf-rats-eat-02 C.4. From draft-ietf-rats-eat-02
* Roll all EUIs back into one UEID type o Roll all EUIs back into one UEID type
* UEIDs can be one of three lengths, 128, 192 and 256. o UEIDs can be one of three lengths, 128, 192 and 256.
* Added appendix justifying UEID design and size. o Added appendix justifying UEID design and size.
* Submods part now includes nested eat tokens so they can be named o Submods part now includes nested eat tokens so they can be named
and there can be more tha one of them and there can be more tha one of them
* Lots of fixes to the CDDL o Lots of fixes to the CDDL
* Added security considerations o Added security considerations
C.5. From draft-ietf-rats-eat-03 C.5. From draft-ietf-rats-eat-03
* Split boot_state into secure-boot and debug-disable claims o Split boot_state into secure-boot and debug-disable claims
* Debug disable is an enumerated type rather than Booleans o Debug disable is an enumerated type rather than Booleans
C.6. From draft-ietf-rats-eat-04 C.6. From draft-ietf-rats-eat-04
* Change IMEI-based UEIDs to be encoded as a 14-byte string o Change IMEI-based UEIDs to be encoded as a 14-byte string
* CDDL cleaned up some more o CDDL cleaned up some more
* CDDL allows for JWTs and UCCSs o CDDL allows for JWTs and UCCSs
* CWT format submodules are byte string wrapped
* Allows for JWT nested in CWT and vice versa o CWT format submodules are byte string wrapped
* Allows UCCS (unsigned CWTs) and JWT unsecured tokens o Allows for JWT nested in CWT and vice versa
* Clarify tag usage when nesting tokens o Allows UCCS (unsigned CWTs) and JWT unsecured tokens
* Add section on key inclusion o Clarify tag usage when nesting tokens
* Add hardware version claims o Add section on key inclusion
* Collected CDDL is now filled in. Other CDDL corrections. o Add hardware version claims
* Rename debug-disable to debug-status; clarify that it is not o Collected CDDL is now filled in. Other CDDL corrections.
o Rename debug-disable to debug-status; clarify that it is not
extensible extensible
* Security level claim is not extensible o Security level claim is not extensible
* Improve specification of location claim and added a location o Improve specification of location claim and added a location
privacy section privacy section
* Add intended use claim o Add intended use claim
C.7. From draft-ietf-rats-eat-05 C.7. From draft-ietf-rats-05
* CDDL format issues resolved o CDDL format issues resolved
* Corrected reference to Location Privacy section o Corrected reference to Location Privacy section
C.8. From draft-ietf-rats-06
o Added boot-seed claim
o Rework CBOR interoperability section
o Added profiles claim and section
Authors' Addresses Authors' Addresses
Giridhar Mandyam Giridhar Mandyam
Qualcomm Technologies Inc. Qualcomm Technologies Inc.
5775 Morehouse Drive 5775 Morehouse Drive
San Diego, California San Diego, California
United States of America USA
Phone: +1 858 651 7200 Phone: +1 858 651 7200
Email: mandyam@qti.qualcomm.com EMail: mandyam@qti.qualcomm.com
Laurence Lundblade Laurence Lundblade
Security Theory LLC Security Theory LLC
Email: lgl@island-resort.com EMail: lgl@island-resort.com
Miguel Ballesteros Miguel Ballesteros
Qualcomm Technologies Inc. Qualcomm Technologies Inc.
5775 Morehouse Drive 5775 Morehouse Drive
San Diego, California San Diego, California
United States of America USA
Phone: +1 858 651 4299 Phone: +1 858 651 4299
Email: mballest@qti.qualcomm.com EMail: mballest@qti.qualcomm.com
Jeremy O'Donoghue Jeremy O'Donoghue
Qualcomm Technologies Inc. Qualcomm Technologies Inc.
279 Farnborough Road 279 Farnborough Road
Farnborough Farnborough GU14 7LS
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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