--- 1/draft-ietf-rats-eat-00.txt 2019-07-04 01:13:11.732736450 -0700 +++ 2/draft-ietf-rats-eat-01.txt 2019-07-04 01:13:11.860739681 -0700 @@ -1,137 +1,141 @@ RATS Working Group G. Mandyam Internet-Draft Qualcomm Technologies Inc. Intended status: Standards Track L. Lundblade -Expires: December 24, 2019 Security Theory LLC +Expires: January 5, 2020 Security Theory LLC M. Ballesteros J. O'Donoghue Qualcomm Technologies Inc. - June 22, 2019 + July 04, 2019 The Entity Attestation Token (EAT) - draft-ietf-rats-eat-00 + draft-ietf-rats-eat-01 Abstract - An attestation format based on concise binary object representation - (CBOR) is proposed that is suitable for inclusion in a CBOR Web Token - (CWT), know as the Entity Attestation Token (EAT). The associated - data can be used by a relying party to assess the security state of a - remote device or module. + An Entity Attestation Token (EAT) provides a signed (attested) set of + claims that describe state and characteristics of an entity, + 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 + entity. + + An EAT is either a CWT or JWT with some attestation-oriented claims. + To a large degree, all this document does is extend CWT and JWT. Contributing TBD Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on December 24, 2019. + This Internet-Draft will expire on January 5, 2020. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 - 1.1. Entity Overview . . . . . . . . . . . . . . . . . . . . . 4 - 1.2. Use of CBOR and COSE . . . . . . . . . . . . . . . . . . 5 + 1.1. CDDL, CWT and JWT . . . . . . . . . . . . . . . . . . . . 4 + 1.2. Entity Overview . . . . . . . . . . . . . . . . . . . . . 4 1.3. EAT Operating Models . . . . . . . . . . . . . . . . . . 5 1.4. What is Not Standardized . . . . . . . . . . . . . . . . 6 1.4.1. Transmission Protocol . . . . . . . . . . . . . . . . 6 - 1.4.2. Signing Scheme . . . . . . . . . . . . . . . . . . . 7 + 1.4.2. Signing Scheme . . . . . . . . . . . . . . . . . . . 6 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 3. The Claims . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 3.1. Universal Entity ID (UEID) Claim . . . . . . . . . . . . 8 - 3.2. Origination (origination) Claims . . . . . . . . . . . . 11 - 3.3. OEM identification by IEEE OUI . . . . . . . . . . . . . 11 - 3.4. Security Level (seclevel) Claim . . . . . . . . . . . . . 12 - 3.5. Nonce (nonce) Claim . . . . . . . . . . . . . . . . . . . 13 - 3.6. Secure Boot and Debug Enable State Claims . . . . . . . . 13 - 3.6.1. Secure Boot Enabled (secbootenabled) Claim . . . . . 13 - 3.6.2. Debug Disabled (debugdisabled) Claim . . . . . . . . 13 - 3.6.3. Debug Disabled Since Boot (debugdisabledsincebboot) - Claim . . . . . . . . . . . . . . . . . . . . . . . . 13 - 3.6.4. Debug Permanent Disable (debugpermanentdisable) Claim 13 - 3.6.5. Debug Full Permanent Disable - (debugfullpermanentdisable) Claim . . . . . . . . . . 14 - 3.7. Location (loc) Claim . . . . . . . . . . . . . . . . . . 14 - 3.7.1. lat (latitude) claim . . . . . . . . . . . . . . . . 14 - 3.7.2. long (longitude) claim . . . . . . . . . . . . . . . 14 - 3.7.3. alt (altitude) claim . . . . . . . . . . . . . . . . 14 - 3.7.4. acc (accuracy) claim . . . . . . . . . . . . . . . . 14 - 3.7.5. altacc (altitude accuracy) claim . . . . . . . . . . 15 - 3.7.6. heading claim . . . . . . . . . . . . . . . . . . . . 15 - 3.7.7. speed claim . . . . . . . . . . . . . . . . . . . . . 15 - 3.8. ts (timestamp) claim . . . . . . . . . . . . . . . . . . 15 - 3.9. age claim . . . . . . . . . . . . . . . . . . . . . . . . 15 - 3.10. uptime claim . . . . . . . . . . . . . . . . . . . . . . 15 - 3.11. The submods Claim . . . . . . . . . . . . . . . . . . . . 16 - 3.11.1. The submod_name Claim . . . . . . . . . . . . . . . 16 - 3.11.2. Nested EATs, the eat Claim . . . . . . . . . . . . . 16 - - 4. CBOR Interoperability . . . . . . . . . . . . . . . . . . . . 16 - 4.1. Integer Encoding (major type 0 and 1) . . . . . . . . . . 17 - 4.2. String Encoding (major type 2 and 3) . . . . . . . . . . 17 - 4.3. Map and Array Encoding (major type 4 and 5) . . . . . . . 17 - 4.4. Date and Time . . . . . . . . . . . . . . . . . . . . . . 17 - 4.5. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 17 - 4.6. Floating Point . . . . . . . . . . . . . . . . . . . . . 17 - 4.7. Other types . . . . . . . . . . . . . . . . . . . . . . . 17 - 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 - 5.1. Reuse of CBOR Web Token (CWT) Claims Registry . . . . . . 18 - 5.1.1. Claims Registered by This Document . . . . . . . . . 18 - 5.2. EAT CBOR Tag Registration . . . . . . . . . . . . . . . . 18 - 5.2.1. Tag Registered by This Document . . . . . . . . . . . 18 - 6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 19 - 6.1. UEID Privacy Considerations . . . . . . . . . . . . . . . 19 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 20 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 - 8.1. Normative References . . . . . . . . . . . . . . . . . . 20 - 8.2. Informative References . . . . . . . . . . . . . . . . . 21 - Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 22 - A.1. Very Simple EAT . . . . . . . . . . . . . . . . . . . . . 22 - A.2. Example with Submodules, Nesting and Security Levels . . 22 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 + 3. The Claims Information Model . . . . . . . . . . . . . . . . 8 + 3.1. Nonce Claim (cti and jti) . . . . . . . . . . . . . . . . 8 + 3.2. Timestamp claim (iat) . . . . . . . . . . . . . . . . . . 8 + 3.3. Universal Entity ID Claim (ueid) . . . . . . . . . . . . 8 + 3.4. Origination Claim (origination) . . . . . . . . . . . . . 11 + 3.4.1. CDDL . . . . . . . . . . . . . . . . . . . . . . . . 12 + 3.5. OEM identification by IEEE OUI (oemid) . . . . . . . . . 12 + 3.5.1. CDDL . . . . . . . . . . . . . . . . . . . . . . . . 12 + 3.6. The Security Level Claim (security_level) . . . . . . . . 12 + 3.6.1. CDDL . . . . . . . . . . . . . . . . . . . . . . . . 13 + 3.7. Secure Boot and Debug Enable State Claims (boot_state) . 13 + 3.7.1. Secure Boot Enabled . . . . . . . . . . . . . . . . . 13 + 3.7.2. Debug Disabled . . . . . . . . . . . . . . . . . . . 13 + 3.7.3. Debug Disabled Since Boot . . . . . . . . . . . . . . 14 + 3.7.4. Debug Permanent Disable . . . . . . . . . . . . . . . 14 + 3.7.5. Debug Full Permanent Disable . . . . . . . . . . . . 14 + 3.7.6. CDDL . . . . . . . . . . . . . . . . . . . . . . . . 14 + 3.8. The Location Claim (location) . . . . . . . . . . . . . . 14 + 3.8.1. CDDL . . . . . . . . . . . . . . . . . . . . . . . . 15 + 3.9. The Age Claim (age) . . . . . . . . . . . . . . . . . . . 15 + 3.10. The Uptime Claim (uptime) . . . . . . . . . . . . . . . . 15 + 3.10.1. CDDL . . . . . . . . . . . . . . . . . . . . . . . . 15 + 3.11. Nested EATs, the EAT Claim (nested_eat) . . . . . . . . . 15 + 3.11.1. CDDL . . . . . . . . . . . . . . . . . . . . . . . . 16 + 3.12. The Submods Claim (submods) . . . . . . . . . . . . . . . 16 + 3.12.1. The submod_name Claim . . . . . . . . . . . . . . . 16 + 3.12.2. CDDL . . . . . . . . . . . . . . . . . . . . . . . . 16 + 4. Data Model . . . . . . . . . . . . . . . . . . . . . . . . . 17 + 4.1. Common CDDL Types . . . . . . . . . . . . . . . . . . . . 17 + 4.2. CDDL for CWT-defined Claims . . . . . . . . . . . . . . . 17 + 4.3. JSON . . . . . . . . . . . . . . . . . . . . . . . . . . 18 + 4.3.1. JSON Labels . . . . . . . . . . . . . . . . . . . . . 18 + 4.3.2. JSON Interoperability . . . . . . . . . . . . . . . . 19 + 4.4. CBOR . . . . . . . . . . . . . . . . . . . . . . . . . . 19 + 4.4.1. Labels . . . . . . . . . . . . . . . . . . . . . . . 19 + 4.4.2. CBOR Interoperability . . . . . . . . . . . . . . . . 20 + 4.5. Collected CDDL . . . . . . . . . . . . . . . . . . . . . 21 + 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 + 5.1. Reuse of CBOR Web Token (CWT) Claims Registry . . . . . . 21 + 5.1.1. Claims Registered by This Document . . . . . . . . . 22 + 6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22 + 6.1. UEID Privacy Considerations . . . . . . . . . . . . . . . 22 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 23 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 + 8.1. Normative References . . . . . . . . . . . . . . . . . . 23 + 8.2. Informative References . . . . . . . . . . . . . . . . . 24 + Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 26 + A.1. Very Simple EAT . . . . . . . . . . . . . . . . . . . . . 26 + A.2. Example with Submodules, Nesting and Security Levels . . 26 + Appendix B. Changes from Previous Drafts . . . . . . . . . . . . 27 + B.1. From draft-mandyam-rats-eat-00 . . . . . . . . . . . . . 27 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27 1. Introduction - Remote device attestation is fundamental service that allows a remote - device such as a mobile phone, an Internet-of-Things (IoT) device, or - other endpoint to prove itself to a relying party, a server or a - service. This allows the relying party to know some characteristics - about the device and decide whether it trusts the device. + Remote device attestation is a fundamental service that allows a + remote device such as a mobile phone, an Internet-of-Things (IoT) + device, or other endpoint to prove itself to a relying party, a + server or a service. This allows the relying party to know some + characteristics about the device and decide whether it trusts the + device. Remote attestation is a fundamental service that can underlie other protocols and services that need to know about the trustworthiness of the device before proceeding. One good example is biometric authentication where the biometric matching is done on the device. The relying party needs to know that the device is one that is known to do biometric matching correctly. Another example is content protection where the relying party wants to know the device will protect the data. This generalizes on to corporate enterprises that might want to know that a device is trustworthy before allowing @@ -134,83 +138,69 @@ to do biometric matching correctly. Another example is content protection where the relying party wants to know the device will protect the data. This generalizes on to corporate enterprises that might want to know that a device is trustworthy before allowing corporate data to be accessed by it. The notion of attestation here is large and may include, but is not limited to the following: o Proof of the make and model of the device hardware (HW) + o Proof of the make and model of the device processor, particularly - for security oriented chips + for security-oriented chips o Measurement of the software (SW) running on the device o Configuration and state of the device o Environmental characteristics of the device such as its GPS location - The required data format should be general purpose and extensible so - that it can work across many use cases. This is why CBOR (see - [RFC7049]) was chosen as the format -- it already supports a rich set - of data types, and is both expressive and extensible. It translates - well to JSON for good interoperation with web technology. It is - compact and can work on very small IoT device. The format proposed - here is small enough that a limited version can be implemented in - pure hardware gates with no software at all. Moreover, the - attestation data is defined in the form of claims that is the same as - CBOR Web Token (CWT, see [RFC8392]). This is the motivation for - defining the Entity Attestation Token, i.e. EAT. +1.1. CDDL, CWT and JWT -1.1. Entity Overview + An EAT token is either a CWT as defined in [RFC8392] or a JWT as + defined in [RFC7519]. This specification defines additional claims + for entity attestation. + + This specification uses CDDL, [RFC8610], as the primary formalism to + define each claim. The implementor then interprets the CDDL to come + to either the CBOR [RFC7049] or JSON [ECMAScript] representation. In + the case of JSON, Appendix E of [RFC8610] is followed. Additional + rules are given in Section 4.3.2 of this document where Appendix E is + insufficient. (Note that this is not to define a general means to + translate between CBOR and JSON, but only to define enough such that + the claims defined in this document can be rendered unambiguously in + JSON). + +1.2. Entity Overview An "entity" can be any device or device subassembly ("submodule") that can generate its own attestation in the form of an EAT. The attestation should be cryptographically verifiable by the EAT consumer. An EAT at the device-level can be composed of several submodule EAT's. It is assumed that any entity that can create an EAT does so by means of a dedicated root-of-trust (RoT). Modern devices such as a mobile phone have many different execution - environments operating with different security levels. For example + environments operating with different security levels. For example, it is common for a mobile phone to have an "apps" environment that runs an operating system (OS) that hosts a plethora of downloadable apps. It may also have a TEE (Trusted Execution Environment) that is distinct, isolated, and hosts security-oriented functionality like - biometric authentication. Additionally it may have an eSE (embedded + biometric authentication. Additionally, it may have an eSE (embedded Secure Element) - a high security chip with defenses against HW attacks that can serve as a RoT. This device attestation format allows the attested data to be tagged at a security level from which it originates. In general, any discrete execution environment that has an identifiable security level can be considered an entity. -1.2. Use of CBOR and COSE - - Fundamentally this attestation format is a verifiable data format. - It is a collection of data items that can be signed by an attestation - key, hashed, and/or encrypted. As per Section 7 of [RFC8392], the - verification method is in the CWT using the CBOR Object Signing and - Encryption (COSE) methodology (see [RFC8152]). - - In addition, the reported attestation data could be determined within - the secure operating environment or written to it from an external - and presumably less trusted entity on the device. In either case, - the source of the reported data must be identifiable by the relying - party. - - This attestation format is a single relatively simple signed message. - It is designed to be incorporated into many other protocols and many - other transports. It is also designed such that other SW and apps - can add their own data to the message such that it is also attested. - 1.3. EAT Operating Models At least the following three participants exist in all EAT operating models. Some operating models have additional participants. The Entity. This is the phone, the IoT device, the sensor, the sub- assembly or such that the attestation provides information about. The Manufacturer. The company that made the entity. This may be a chip vendor, a circuit board module vendor or a vendor of finished @@ -243,52 +233,55 @@ o The EAT is transmitted to the relying party. The relying party transmits the EAT to a verification service offered by the manufacturer. The server returns the validated claims. o The EAT is transmitted directly to a verification service, perhaps operated by the manufacturer or perhaps by another party. It verifies the EAT and makes the validated claims available to the relying party. It may even modify the claims in some way and re- sign the EAT (with a different signing key). - This standard supports all these operating models and does not prefer - one over the other. It is important to support this variety of + All these operating models are supported and there is no preference + of one over the other. It is important to support this variety of operating models to generally facilitate deployment and to allow for some special scenarios. One special scenario has a validation service that is monetized, most likely by the manufacturer. In another, a privacy proxy service processes the EAT before it is transmitted to the relying party. In yet another, symmetric key material is used for signing. In this case the manufacturer should perform the verification, because any release of the key material would enable a participant other than the entity to create valid signed EATs. 1.4. What is Not Standardized + The following is not standardized for EAT, just the same they are not + standardized for CWT or JWT. + 1.4.1. Transmission Protocol - EATs may be transmitted by any protocol. For example, they might be - added in extension fields of other protocols, bundled into an HTTP - header, or just transmitted as files. This flexibility is - intentional to allow broader adoption. This flexibility is possible - because EAT's are self-secured with signing (and possibly - additionally with encryption and anti-replay). The transmission - protocol is not required to fulfill any additional security - requirements. + EATs may be transmitted by any protocol the same as CWTs and JWTs. + For example, they might be added in extension fields of other + protocols, bundled into an HTTP header, or just transmitted as files. + This flexibility is intentional to allow broader adoption. This + flexibility is possible because EAT's are self-secured with signing + (and possibly additionally with encryption and anti-replay). The + transmission protocol is not required to fulfill any additional + security requirements. For certain devices, a direct connection may not exist between the EAT-producing device and the Relying Party. In such cases, the EAT - should be protected against malicious access. The use of COSE allows - for signing and encryption of the EAT. Therefore even if the EAT is - conveyed through intermediaries between the device and Relying Party, - such intermediaries cannot easily modify the EAT payload or alter the - signature. + should be protected against malicious access. The use of COSE and + JOSE allows for signing and encryption of the EAT. Therefore, even + if the EAT is conveyed through intermediaries between the device and + Relying Party, such intermediaries cannot easily modify the EAT + payload or alter the signature. 1.4.2. Signing Scheme The term "signing scheme" is used to refer to the system that includes end-end process of establishing signing attestation key material in the entity, signing the EAT, and verifying it. This might involve key IDs and X.509 certificate chains or something similar but different. The term "signing algorithm" refers just to the algorithm ID in the COSE signing structure. No particular signing algorithm or signing scheme is required by this standard. @@ -296,556 +289,684 @@ There are three main implementation issues driving this. First, secure non-volatile storage space in the entity for the attestation key material may be highly limited, perhaps to only a few hundred bits, on some small IoT chips. Second, the factory cost of provisioning key material in each chip or device may be high, with even millisecond delays adding to the cost of a chip. Third, privacy-preserving signing schemes like ECDAA (Elliptic Curve Direct Anonymous Attestation) are complex and not suitable for all use cases. - Eventually some form of standardization of the signing scheme may be - required. This might come in the form of another standard that adds - to this document, or when there is clear convergence on a small - number of signing schemes this standard can be updated. + Over time to faciliate interoperability, some signing schemes may be + defined in EAT profiles or other documents either in the IETF or + outside. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. This document reuses terminology from JWT [RFC7519], COSE [RFC8152], and CWT [RFC8392]. - StringOrURI. The "StringOrURI" term in this specification has the - same meaning and processing rules as the JWT "StringOrURI" term - defined in Section 2 of [RFC7519], except that it is represented - as a CBOR text string instead of a JSON text string. - - NumericDate. The "NumericDate" term in this specification has the - same meaning and processing rules as the JWT "NumericDate" term - defined in Section 2 of [RFC7519], except that it is represented - as a CBOR numeric date (from Section 2.4.1 of [RFC7049]) instead - of a JSON number. The encoding is modified so that the leading - tag 1 (epoch-based date/time) MUST be omitted. - Claim Name. The human-readable name used to identify a claim. - Claim Key. The CBOR map key used to identify a claim. - - Claim Value. The CBOR map value representing the value of the claim. + Claim Key. The CBOR map key or JSON name used to identify a claim. - CWT Claims Set. The CBOR map that contains the claims conveyed by - the CWT. + Claim Value. The CBOR map or JSON object value representing the + value of the claim. - FloatOrNumber. The "FloatOrNumber" term in this specification is the - type of a claim that is either a CBOR positive integer, negative - integer or floating point number. + CWT Claims Set. The CBOR map or JSON object that contains the claims + conveyed by the CWT or JWT. Attestation Key Material (AKM). The key material used to sign the EAT token. If it is done symmetrically with HMAC, then this is a simple symmetric key. If it is done with ECC, such as an IEEE DevID [IDevID], then this is the private part of the EC key pair. If ECDAA is used, (e.g., as used by Enhanced Privacy ID, i.e. EPID) then it is the key material needed for ECDAA. -3. The Claims +3. The Claims Information Model -3.1. Universal Entity ID (UEID) Claim + This section describes new claims defined for attestation. It also + mentions several claims defined by CWT and JWT are particularly + important for 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 + [IANA.JWT.Claims] claims registries. * All claims are optional * No + claims are mandatory * All claims that are not understood by + implementations MUST be ignored + + CDDL along with text descriptions is used to define the information + model. Each claim is defined as a CDDL group (the group is a general + aggregation and type definition feature of CDDL). In the data model, + described in the Section 4, the CDDL groups turn into CBOR map + entries and JSON name/value pairs. + +3.1. Nonce Claim (cti and jti) + + All EATs should have a nonce to prevent replay attacks. The nonce is + generated by the relying party, sent to the entity by any protocol, + and included in the token. Note that intrinsically by the nature of + a nonce no security is needed for its transport. + + CWT defines the "cti" claim. JWT defines the "jti" claim. These + carry the nonce in an EAT. + + TODO: what about the JWT claim "nonce"? + +3.2. Timestamp claim (iat) + + The "iat" claim defined in CWT and JWT is used to indicate the date- + of-creation of the token. + +3.3. Universal Entity ID Claim (ueid) UEID's identify individual manufactured entities / devices such as a mobile phone, a water meter, a Bluetooth speaker or a networked security camera. It may identify the entire device or a submodule or subsystem. It does not identify types, models or classes of devices. It is akin to a serial number, though it does not have to be sequential. - It is identified by Claim Key X (X is TBD). - UEID's must be universally and globally unique across manufacturers and countries. UEIDs must also be unique across protocols and systems, as tokens are intended to be embedded in many different protocols and systems. No two products anywhere, even in completely different industries made by two different manufacturers in two - different countries. should have the same UEID (if they are not - global and universal in this way then relying parties receiving them - will have to track other characteristics of the device to keep - devices distinct between manufacturers). + different countries should have the same UEID (if they are not global + and universal in this way, then relying parties receiving them will + have to track other characteristics of the device to keep devices + distinct between manufacturers). + + There are privacy considerations for UEID's. See Section 6.1. The UEID should be permanent. It should never change for a given device / entity. In addition, it should not be reprogrammable. - - UEID's are binary byte-strings (resulting in a smaller size than text - strings). When handled in text-based protocols, they should be - base-64 encoded. - - UEID's are variable length with a maximum size of 33 bytes (1 type - byte and 256 bits). A receivers of a token with UEIDs may reject the - token if a UEID is larger than 33 bytes. - - 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. - - A UEID is a byte string. From the consumer's view (the rely party) - it is opaque with no bytes having any special meaning. + UEID's are variable length. The recommended maximum is 33 bytes (1 + type byte and 256 bits). The recommended minimum is 17 bytes (1 type + and 128 bits) because fewer bytes endanger the universal uniqueness. 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 accommodate different industries and different manufacturing processes and to give options to avoid paying fees for certain types of manufacturer registrations. + Creation of new types requires a Standards Action [RFC8126]. + +------+--------+---------------------------------------------------+ | Type | Type | Specification | | Byte | Name | | +------+--------+---------------------------------------------------+ - | 0x01 | GUID | This is a 128 to 256 bit random number generated | - | | | once and stored in the device. The GUID may be | - | | | constructed from various identifiers on the | - | | | device using a hash function or it may be just | - | | | the raw random number. | + | 0x01 | RAND | This is a 128- to 256-bit random number generated | + | | | once and stored in the device. This may be | + | | | constructed by concatenating enough identifiers | + | | | to be universally unique and then feeding the | + | | | concatenation through a cryptographic hash | + | | | function. It may also be a cryptographic quality | + | | | random number generate once at the beginning of | + | | | the life of the device and stored. | | 0x02 | IEEE | This makes use of the IEEE company identification | | | EUI | registry. An EUI is made up of an OUI and OUI-36 | | | | or a CID, different registered company | | | | identifiers, and some unique per-device | | | | identifier. EUIs are often the same as or similar | | | | to MAC addresses. (Note that while devices with | | | | multiple network interfaces may have multiple MAC | | | | addresses, there is only one UEID for a device) | | | | TODO: normative references to IEEE. | - | 0x03 | IMEI | This is a 14-digit identifier consisting of an 8 | - | | | digit Type Allocation Code and a six digit serial | + | 0x03 | IMEI | This is a 14-digit identifier consisting of an | + | | | 8-digit Type Allocation Code and a 6-digit serial | | | | number allocated by the manufacturer, which SHALL | | | | be encoded as a binary integer over 48 bits. The | | | | IMEI value encoded SHALL NOT include Luhn | | | | checksum or SVN information. | | 0x04 | EUI-48 | This is a 48-bit identifier formed by | | | | concatenating the 24-bit OUI with a 24-bit | | | | identifier assigned by the organisation that | | | | purchased the OUI. | | 0x05 | EUI-60 | This is a 60-bit identifier formed by | | | | concatenating the 24-bit OUI with a 36-bit | | | | identifier assigned by the organisation that | | | | purchased the OUI. | | 0x06 | EUI-64 | This is a 64-bit identifier formed by | | | | concatenating the 24-bit OUI with a 40-bit | | | | identifier assigned by the organisation that | | | | purchased the OUI. | +------+--------+---------------------------------------------------+ Table 1: UEID Composition Types - The consumer (the Relying Party) of a UEID should treat a UEID as a + 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 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 - 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 they should use the OUI claim that is defined elsewhere. The reasons for this are: o UEIDs types may vary freely from one manufacturer to the next. - o New types of UEIDs may be created. For example a type 0x04 UEID + o New types of UEIDs may be created. For example, a type 0x07 UEID may be created based on some other manufacturer registration scheme. 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 0x02 or vice versa. The main requirement on the manufacturer is that UEIDs be universally unique. -3.2. Origination (origination) Claims + ### CDDL + + ueid_claim = ( + ueid: bstr ) + +3.4. Origination Claim (origination) 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 manufacturer. The following table gives some examples: +-------------------+-----------------------------------------------+ | Name | Description | +-------------------+-----------------------------------------------+ | Acme-TEE | The EATs are generated in the TEE authored | | | and configured by "Acme" | | Acme-TPM | The EATs are generated in a TPM manufactured | | | by "Acme" | | Acme-Linux-Kernel | The EATs are generated in a Linux kernel | | | configured and shipped by "Acme" | | Acme-TA | The EATs are generated in a Trusted | | | Application (TA) authored by "Acme" | +-------------------+-----------------------------------------------+ - The claim is represented by Claim Key X+1. It is type StringOrURI. - TODO: consider a more structure approach where the name and the URI and other are in separate fields. TODO: This needs refinement. It is somewhat parallel to issuer claim in CWT in that it describes the authority that created the token. -3.3. OEM identification by IEEE OUI +3.4.1. CDDL + + origination_claim = ( + origination: string_or_uri ) + +3.5. OEM identification by IEEE OUI (oemid) This claim identifies a device OEM by the IEEE OUI. Reference TBD. It is a byte string representing the OUI in binary form in network byte order (TODO: confirm details). Companies that have more than one IEEE OUI registered with IEEE should pick one and prefer that for all their devices. Note that the OUI is in common use as a part of MAC Address. This claim is only the first bits of the MAC address that identify the manufacturer. The IEEE maintains a registry for these in which many - companies participate. This claim is represented by Claim Key TBD. + companies participate. -3.4. Security Level (seclevel) Claim +3.5.1. CDDL + + oemid_claim = ( + oemid: bstr ) + +3.6. The Security Level Claim (security_level) EATs have a claim that roughly characterizes the device / entities ability to defend against attacks aimed at capturing the signing key, forging claims and at forging EATs. This is done by roughly defining four security levels as described below. This is similar to the - security levels defined in the Metadata Service definied by the Fast + security levels defined in the Metadata Service defined by the Fast Identity Online (FIDO) Alliance (TODO: reference). These claims describe security environment and countermeasures available on the end-entity / client device where the attestation key reside and the claims originate. - This claim is identified by Claim Key X+2. The value is an integer - between 1 and 4 as defined below. - 1 - Unrestricted There is some expectation that implementor will protect the attestation signing keys at this level. Otherwise the EAT provides no meaningful security assurances. 2- Restricted Entities at this level should not be general-purpose operating environments that host features such as app download systems, web browsers and complex productivity applications. It is akin to the Secure Restricted level (see below) without the - security orientation. Examples include a WiFi subsystem, an IoT + security orientation. Examples include a Wi-Fi subsystem, an IoT camera, or sensor device. - 3 - Secure Restricted Entities at this level must meet the critera + 3 - Secure Restricted Entities at this level must meet the criteria defined by FIDO Allowed Restricted Operating Environments (TODO: reference). Examples include TEE's and schemes using virtualization-based security. Like the FIDO security goal, security at this level is aimed at defending well against large- scale network / remote attacks against the device. 4 - Hardware Entities at this level must include substantial defense against physical or electrical attacks against the device itself. It is assumed any potential attacker has captured the device and can disassemble it. Example include TPMs and Secure Elements. This claim is not intended as a replacement for a proper end-device security certification schemes such as those based on FIPS (TODO: reference) or those based on Common Criteria (TODO: reference). The claim made here is solely a self-claim made by the Entity Originator. -3.5. Nonce (nonce) Claim +3.6.1. CDDL - The "nonce" (Nonce) claim represents a random value that can be used - to avoid replay attacks. This would be ideally generated by the CWT - consumer. This value is intended to be a CWT companion claim to the - existing JWT claim **_IANAJWT_ (TODO: fix this reference). The nonce - claim is identified by Claim Key X+3. + security_level_type = ( + unrestricted: 1, + restricted: 2, + secure_restricted: 3, + hardware: 4 + ) -3.6. Secure Boot and Debug Enable State Claims + security_level_claim = ( + security_level: security_level_type ) -3.6.1. Secure Boot Enabled (secbootenabled) Claim +3.7. Secure Boot and Debug Enable State Claims (boot_state) - The "secbootenabled" (Secure Boot Enabled) claim represents a boolean - value that indicates whether secure boot is enabled either for an - entire device or an individual submodule. If it appears at the - device level, then this means that secure boot is enabled for all + This claim is an array of five Boolean values indicating the boot and + debug state of the entity. + +3.7.1. Secure Boot Enabled + + This indicates whether secure boot is enabled either for an entire + device or an individual submodule. If it appears at the device + level, then this means that secure boot is enabled for all submodules. Secure boot enablement allows a secure boot loader to authenticate software running either in a device or a submodule prior - allowing execution. This claim is identified by Claim Key X+4. + allowing execution. -3.6.2. Debug Disabled (debugdisabled) Claim +3.7.2. Debug Disabled - The "debugdisabled" (Debug Disabled) claim represents a boolean value - that indicates whether debug capabilities are disabled for an entity + This indicates whether debug capabilities are disabled for an entity (i.e. value of 'true'). Debug disablement is considered a - prerequisite before an entity is considered operational. This claim - is identified by Claim Key X+5. - -3.6.3. Debug Disabled Since Boot (debugdisabledsincebboot) Claim + prerequisite before an entity is considered operational. - The "debugdisabledsinceboot" (Debug Disabled Since Boot) claim - represents a boolean value that indicates whether debug capabilities - for the entity were not disabled in any way since boot (i.e. value of - 'true'). This claim is identified by Claim Key X+6. +3.7.3. Debug Disabled Since Boot -3.6.4. Debug Permanent Disable (debugpermanentdisable) Claim + This claim indicates whether debug capabilities for the entity were + not disabled in any way since boot (i.e. value of 'true'). - The "debugpermanentdisable" (Debug Permanent Disable) claim - represents a boolean value that indicates whether debug capabilities - for the entity are permanently disabled (i.e. value of 'true'). This - value can be set to 'true' also if only the manufacturer is allowed - to enabled debug, but the end user is not. This claim is identified - by Claim Key X+7. +3.7.4. Debug Permanent Disable -3.6.5. Debug Full Permanent Disable (debugfullpermanentdisable) Claim + This claim indicates whether debug capabilities for the entity are + permanently disabled (i.e. value of 'true'). This value can be set + to 'true' also if only the manufacturer is allowed to enabled debug, + but the end user is not. - The "debugfullpermanentdisable" (Debug Full Permanent Disable) claim - represents a boolean value that indicates whether debug capabilities - for the entity are permanently disabled (i.e. value of 'true'). This - value can only be set to 'true' if no party can enable debug - capabilities for the entity. Often this is implemented by blowing a - fuse on a chip as fuses cannot be restored once blown. This claim is - identified by Claim Key X+8. +3.7.5. Debug Full Permanent Disable -3.7. Location (loc) Claim + This claim indicates whether debug capabilities for the entity are + permanently disabled (i.e. value of 'true'). This value can only be + set to 'true' if no party can enable debug capabilities for the + entity. Often this is implemented by blowing a fuse on a chip as + fuses cannot be restored once blown. - The "loc" (location) claim is a CBOR-formatted object that describes - the location of the device entity from which the attestation - originates. It is identified by Claim Key X+10. It is comprised of - an array of additional subclaims that represent the actual location - coordinates (latitude, longitude and altitude). The location - coordinate claims are consistent with the WGS84 coordinate system - [WGS84]. In addition, a subclaim providing the estimated accuracy of - the location measurement is defined. +3.7.6. CDDL -3.7.1. lat (latitude) claim + boot_state_type = [ + secure_boot_enabled=> bool, + debug_disabled=> bool, + debug_disabled_since_boot=> bool, + debug_permanent_disable=> bool, + debug_full_permanent_disable=> bool + ] - The "lat" (latitude) claim contains the value of the device location - corresponding to its latitude coordinate. It is of data type - FloatOrNumber and identified by Claim Key X+11. + boot_state_claim = ( + boot_state: boot_state_type + ) -3.7.2. long (longitude) claim +3.8. The Location Claim (location) - The "long" (longitude) claim contains the value of the device - location corresponding to its longitude coordinate. It is of data - type FloatOrNumber and identified by Claim Key X+12. + The location claim is a CBOR-formatted object that describes the + location of the device entity from which the attestation originates. + It is comprised of a map of additional sub claims that represent the + actual location coordinates (latitude, longitude and altitude). The + location coordinate claims are consistent with the WGS84 coordinate + system [WGS84]. In addition, a sub claim providing the estimated + accuracy of the location measurement is defined. -3.7.3. alt (altitude) claim +3.8.1. CDDL - The "alt" (altitude) claim contains the value of the device location - corresponding to its altitude coordinate (if available). It is of - data type FloatOrNumber and identified by Claim Key X+13. + location_type = { + latitude => number, + longitude => number, + altitude => number, + accuracy => number, + altitude_accuracy => number, + heading_claim => number, + speed_claim => number + } -3.7.4. acc (accuracy) claim + location_claim = ( + location: location_type ) - The "acc" (accuracy) claim contains a value that describes the - location accuracy. It is non-negative and expressed in meters. It - is of data type FloatOrNumber and identified by Claim Key X+14. +3.9. The Age Claim (age) -3.7.5. altacc (altitude accuracy) claim + The "age" claim contains a value that represents the number of + seconds that have elapsed since the token was created, measurement + was made, or location was obtained. Typical attestable values are + sent as soon as they are obtained. However, in the case that such a + value is buffered and sent at a later time and a sufficiently + accurate time reference is unavailable for creation of a timestamp, + then the age claim is provided. - The "altacc" (altitude accuracy) claim contains a value that - describes the altitude accuracy. It is non-negative and expressed in - meters. It is of data type FloatOrNumber and identified by Claim Key - X+15. + age_claim = ( + age: uint) -3.7.6. heading claim +3.10. The Uptime Claim (uptime) - The "heading" claim contains a value that describes direction of - motion for the entity. Its value is specified in degrees, between 0 - and 360. It is of data type FloatOrNumber and identified by Claim - Key X+16. + The "uptime" claim contains a value that represents the number of + seconds that have elapsed since the entity or submod was last booted. -3.7.7. speed claim +3.10.1. CDDL - The "speed" claim contains a value that describes the velocity of the - entity in the horizontal direction. Its value is specified in - meters/second and must be non-negative. It is of data type - FloatOrNumber and identified by Claim Key X+17. + uptime_claim = ( + uptime: uint ) -3.8. ts (timestamp) claim +3.11. Nested EATs, the EAT Claim (nested_eat) - The "ts" (timestamp) claim contains a timestamp derived using the - same time reference as is used to generate an "iat" claim (see - Section 3.1.6 of [RFC8392]). It is of the same type as "iat" - (integer or floating-point), and is identified by Claim Key X+18. It - is meant to designate the time at which a measurement was taken, when - a location was obtained, or when a token was actually transmitted. - The timestamp would be included as a subclaim under the "submod" or - "loc" claims (in addition to the existing respective subclaims), or - at the device level. + It is allowed for one EAT to be embedded in another. This is for + complex devices that have more than one subsystem capable of + generating an EAT. Typically, one will be the device-wide EAT that + is low to medium security and another from a Secure Element or + similar that is high security. -3.9. age claim + The contents of the "eat" claim must be a fully signed, optionally + encrypted, EAT token. - The "age" claim contains a value that represents the number of - seconds that have elapsed since the token was created, measurement - was made, or location was obtained. Typical attestable values are - sent as soon as they are obtained. However in the case that such a - value is buffered and sent at a later time and a sufficiently - accurate time reference is unavailable for creation of a timestamp, - then the age claim is provided. It is identified by Claim Key X+19. +3.11.1. CDDL -3.10. uptime claim + nested_eat_claim = ( + nested_eat: nested_eat_type) - The "uptime" claim contains a value that represents the number of - seconds that have elapsed since the entity or submod was last booted. - It is identified by Claim Key X+20. + A nested_eat_type is defined in words rather than CDDL. It is either + a full CWT or JWT including the COSE or JOSE signing. -3.11. The submods Claim +3.12. The Submods Claim (submods) Some devices are complex, having many subsystems or submodules. A mobile phone is a good example. It may have several connectivity - submodules for communications (e.g., WiFi and cellular). It may have - sub systems for low-power audio and video playback. It may have one - or more security-oriented subsystems like a TEE or a Secure Element. + submodules for communications (e.g., Wi-Fi and cellular). It may + have subsystems for low-power audio and video playback. It may have + one or more security-oriented subsystems like a TEE or a Secure + Element. The claims for each these can be grouped together in a submodule. Specifically, the "submods" claim is an array. Each item in the array is a CBOR map containing all the claims for a particular - submodule. It is identified by Claim Key X+22. + submodule. The security level of the submod is assumed to be at the same level as the main entity unless there is a security level claim in that submodule indicating otherwise. The security level of a submodule can never be higher (more secure) than the security level of the EAT it is a part of. -3.11.1. The submod_name Claim +3.12.1. The submod_name Claim Each submodule should have a submod_name claim that is descriptive name. This name should be the CBOR txt type. -3.11.2. Nested EATs, the eat Claim +3.12.2. CDDL - It is allowed for one EAT to be embedded in another. This is for - complex devices that have more than one subsystem capable of - generating an EAT. Typically one will be the device-wide EAT that is - low to medium security and another from a Secure Element or similar - that is high security. + In the following a generic_claim_type is any CBOR map entry or JSON + name/value pair. - The contents of the "eat" claim must be a fully signed, optionally - encrypted, EAT token. It is identified by Claim Key X+23. + submod_name_type = ( + submod_name: tstr ) -4. CBOR Interoperability + submods_type = [ * submod_claims ] - EAT is a one-way protocol. It only defines a single message that - goes from the entity to the server. The entity implementation will - often be in a contained environment with little RAM and the server - will usually not be. The following requirements for interoperability - take that into account. The entity can generally use whatever - encoding it wants. The server is required to support just about - every encoding. + submod_claims = { + submod_name_type, + * generic_claim_type + } - Canonical CBOR encoding is explicitly NOT required as it would place - an unnecessary burden on the entity implementation. + submods_claim = ( + submods: submod_type ) -4.1. Integer Encoding (major type 0 and 1) +4. Data Model - The entity may use any integer encoding allowed by CBOR. The server - MUST accept all integer encodings allowed by CBOR. + This makes use of the types defined in CDDL Appendix D, Standard + Prelude. -4.2. String Encoding (major type 2 and 3) +4.1. Common CDDL Types - 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. +string_or_uri = #6.32(tstr) / tstr; See JSON section below for JSON encoding of string_or_uri - Major type 2, bstr, SHOULD be have tag 21, 22 or 23 to indicate - conversion to base64 or such when converting to JSON. +4.2. CDDL for CWT-defined Claims -4.3. Map and Array Encoding (major type 4 and 5) + This section provides CDDL for the claims defined in CWT. It is non- + normative as [RFC8392] is the authoritative definition of these + claims. - 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. + cwt_claim = ( + issuer_claim // + subject_claim // + audience_claim // + expiration_claim // + not_before_claim // + issued_at_calim // + cwt_id_claim + ) -4.4. Date and Time + issuer_claim = ( + issuer: string_or_uri ) - The entity should send dates as tag 1 encoded as 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. + subject_claim = ( + subject: string_or_uri ) - The entity may send tag 0 dates, however tag 1 is preferred. The - server must support tag 0 UTC dates. + audience_claim = ( + audience: string_or_uri ) -4.5. URIs + expiration_claim = ( + expiration: time ) - URIs should be encoded as text strings and marked with tag 32. + not_before_claim = ( + not_before: time ) -4.6. Floating Point + issued_at_calim = ( + issued_at: time ) - Encoding data in floating point is to be used only if necessary. - Location coordinates are always in floating point. The server must - support decoding of all types of floating point. + cwt_id_claim = ( + cwt_id: bstr ) -4.7. Other types + issuer = 1 + subject = 2 + audience = 3 + expiration = 4 + not_before = 5 + issued_at = 6 + cwt_id = 7 - Use of Other types like bignums, regular expressions and so SHOULD - NOT be used. The server MAY support them, but is not required to. - Use of these tags is +4.3. JSON + +4.3.1. JSON Labels + ueid = "ueid" + origination = "origination" + oemid = "oemid" + security_level = "security_level" + boot_state = "boot_state" + location = "location" + age = "age" + uptime = "uptime" + nested_eat = "nested_eat" + submods = "submods" + +4.3.2. JSON Interoperability + + JSON should be encoded per RFC 8610 Appendix E. In addition, the + following CDDL types are encoded in JSON as follows: + + o bstr - must be base64url encoded + + o time - must be encoded as NumericDate as described section 2 of + [RFC7519]. + + o string_or_uri - must be encoded as StringOrURI as described + section 2 of [RFC7519]. + +4.4. CBOR + +4.4.1. Labels + + ueid = 8 + origination = 9 + oemid = 10 + security_level = 11 + boot_state = 12 + location = 13 + age = 14 + uptime = 15 + nested_eat = 16 + submods = 17 + submod_name = 18 + + latitude 1 + longitude 2 + altitude 3 + accuracy 4 + altitude_accuracy 5 + heading_claim 6 + speed_claim 7 + +4.4.2. 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. + + o 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. + + o 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. + + o Major type 2, bstr, SHOULD be have tag 21 to indicate conversion + to base64url in case that conversion is performed. + + o 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. + + o Date and Time - The entity should send dates as tag 1 encoded as + 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. + + o URIs - URIs should be encoded as text strings and marked with tag + 32. + + o Floating Point - The entity may use any floating-point encoding. + The relying party must support decoding of all types of floating- + point. + + o Other types - Use of Other types like bignums, regular expressions + and such, SHOULD NOT be used. The server MAY support them but is + not required to so interoperability is not guaranteed. + +4.5. Collected CDDL + + A generic_claim is any CBOR map entry or JSON name/value pair. + +eat_claims = { ; the top-level payload that is signed using COSE or JOSE + * claim +} + +claim = ( + ueid_claim // + origination_claim // + oemid_claim // + security_level_claim // + boot_state_claim // + location_claim // + age_claim // + uptime_claim // + nested_eat_claim // + cwt_claim // + generic_claim_type // + ) + + TODO: copy the rest of the CDDL here (wait until the CDDL is more + settled so as to avoid copying multiple times) 5. IANA Considerations 5.1. Reuse of CBOR Web Token (CWT) Claims Registry Claims defined for EAT are compatible with those of CWT so the CWT - Claims Registry is re used. New new IANA registry is created. All - EAT claims should be registered in the CWT Claims Registry. + Claims Registry is re used. No new IANA registry is created. All + EAT claims should be registered in the CWT and JWT Claims Registries. 5.1.1. Claims Registered by This Document o Claim Name: UEID o Claim Description: The Universal Entity ID o JWT Claim Name: N/A - o Claim Key: X + o Claim Key: 8 o Claim Value Type(s): byte string o Change Controller: IESG o Specification Document(s): *this document* TODO: add the rest of the claims in here -5.2. EAT CBOR Tag Registration - - How an EAT consumer determines whether received CBOR-formatted data - actually represents a valid EAT is application-dependent, much like a - CWT. For instance, a specific MIME type associated with the EAT such - as "application/eat" could be sufficient for identification of the - EAT. Note however that EAT's can include other EAT's (e.g. a device - EAT comprised of several submodule EAT's). In this case, a CBOR tag - dedicated to the EAT will be required at least for the submodule - EAT's and the tag must be a valid CBOR tag. In other words - the EAT - CBOR tag can optionally prefix a device-level EAT, but a EAT CBOR tag - must always prefix a submodule EAT. The proposed EAT CBOR tag is 71. - -5.2.1. Tag Registered by This Document - - o CBOR Tag: 71 - - o Data Item: Entity Attestation Token (EAT) - - o Semantics: Entity Attestation Token (CWT), as defined in - *this_doc* - - o Reference: *this_doc* - - o Point of Contact: Giridhar Mandyam, mandyam@qti.qualcomm.com - 6. Privacy Considerations 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. Examples would include suppression of location claims for EAT's provided to unauthenticated consumers. 6.1. 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 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 governmental privacy regulation. In other usage situations UEID will not be allowed for certain products like browsers that give privacy for the end user. it will often be the case that tokens will not have a UEID for these reasons. There are several strategies that can be used to still be able to put UEID's in tokens: @@ -875,118 +996,158 @@ 7. Security Considerations TODO: Perhaps this can be the same as CWT / COSE, but not sure yet because it involves so much entity / device security that those do not. 8. References 8.1. Normative References + [IANA.CWT.Claims] + IANA, "CBOR Web Token (CWT) Claims", n.d., + . + + [IANA.JWT.Claims] + IANA, "JSON Web Token (JWT) Claims", n.d., + . + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, October 2013, . [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, . + [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for + Writing an IANA Considerations Section in RFCs", BCP 26, + RFC 8126, DOI 10.17487/RFC8126, June 2017, + . + [RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)", RFC 8152, DOI 10.17487/RFC8152, July 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig, "CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392, May 2018, . + [RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data + Definition Language (CDDL): A Notational Convention to + Express Concise Binary Object Representation (CBOR) and + JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, + June 2019, . + [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, . [WGS84] National Imagery and Mapping Agency, "National Imagery and Mapping Agency Technical Report 8350.2, Third Edition", 2000, . 8.2. 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. + [ECMAScript] + "Ecma International, "ECMAScript Language Specification, + 5.1 Edition", ECMA Standard 262", June 2011, + . + [IDevID] "IEEE Standard, "IEEE 802.1AR Secure Device Identifier"", December 2009, . [Webauthn] Worldwide Web Consortium, "Web Authentication: A Web API for accessing scoped credentials", 2016. Appendix A. Examples A.1. Very Simple EAT This is shown in CBOR diagnostic form. Only the payload signed by COSE is shown. { - / nonce / 11:h'948f8860d13a463e8e', + / nonce (cti) / 7:h'948f8860d13a463e8e', / UEID / 8:h'0198f50a4ff6c05861c8860d13a638ea4fe2f', - / secbootenabled / 13:true, - / debugpermanentdisable / 15:true, - / ts / 21:1526542894, + / boot_state / 12:{true, true, true, true, false} + / time stamp (iat) / 6:1526542894, } A.2. Example with Submodules, Nesting and Security Levels { - / nonce / 11:h'948f8860d13a463e8e', + / nonce / 7:h'948f8860d13a463e8e', / UEID / 8:h'0198f50a4ff6c05861c8860d13a638ea4fe2f', - / secbootenabled / 13:true, - / debugpermanentdisable / 15:true, - / ts / 21:1526542894, - / seclevel / 10:3, / secure restriced OS / + / boot_state / 12:{true, true, true, true, false} + / time stamp (iat) / 6:1526542894, + / seclevel / 11:3, / secure restricted OS / - / submods / 30: + / submods / 17: [ / 1st submod, an Android Application / { - / submod_name / 30:'Android App "Foo"', - / seclevel / 10:1, / unrestricted / + / submod_name / 18:'Android App "Foo"', + / seclevel / 11:1, / unrestricted / / app data / -70000:'text string' }, / 2nd submod, A nested EAT from a secure element / { - / submod_name / 30:'Secure Element EAT', - / eat / 31:71( 18( + / submod_name / 18:'Secure Element EAT', + / eat / 16:61( 18( / an embedded EAT / [ /...COSE_Sign1 bytes with payload.../ ] )) } / 3rd submod, information about Linux Android / { - / submod_name/ 30:'Linux Android', - / seclevel / 10:1, / unrestricted / + / submod_name/ 18:'Linux Android', + / seclevel / 11:1, / unrestricted / / custom - release / -80000:'8.0.0', / custom - version / -80001:'4.9.51+' } ] } +Appendix B. Changes from 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 + the significant differences. + +B.1. From draft-mandyam-rats-eat-00 + + This is a fairly large change in the orientation of the document, but + not new claims have been added. + + o Separate information and data model using CDDL. + + o Say an EAT is a CWT or JWT + + o Use a map to structure the boot_state and location claims + Authors' Addresses Giridhar Mandyam Qualcomm Technologies Inc. 5775 Morehouse Drive San Diego, California USA Phone: +1 858 651 7200 EMail: mandyam@qti.qualcomm.com