WebAuthn Working Group F. Dang Internet-Draft Tsinghua University Intended status: Informational 6 November 2021 Expires: 10 May 2022 Using SM2 with JOSE and COSE draft-dang-webauthn-sm2-00 Abstract This specification defines algorithm encodings and representations enabling the ISO/IEC 14888-3:2018 elliptic curve "SM2" to be used for JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE) messages. 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 10 May 2022. Copyright Notice Copyright (c) 2021 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. Dang Expires 10 May 2022 [Page 1] Internet-Draft Using SM2 with JOSE and COSE November 2021 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Notation and Conventions . . . . . . . . . . 2 2. JOSE and COSE SM2 Curve Key Representations . . . . . . . . . 2 3. ECDSA Signature with SM2 Curve . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 4.1. JSON Web Key Elliptic Curve Registration . . . . . . . . 3 4.2. JOSE Algorithm Registration . . . . . . . . . . . . . . . 3 4.3. COSE Elliptic Curves Registration . . . . . . . . . . . . 4 4.4. COSE Algorithm Registration . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.1. Normative References . . . . . . . . . . . . . . . . . . 4 6.2. Informative References . . . . . . . . . . . . . . . . . 5 Appendix A. Document History . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction This specification defines algorithm encodings and representations enabling the ISO/IEC 14888-3:2018 elliptic curve "SM2" [ISO14888-3] to be used for JSON Object Signing and Encryption (JOSE) [RFC7515] and CBOR Object Signing and Encryption (COSE) [RFC8152] messages. The elliptic curve and associated algorithm are registered in appropriate IANA JOSE and COSE registries. 1.1. Requirements Notation and Conventions 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. 2. JOSE and COSE SM2 Curve Key Representations The ISO/IEC 14888-3:2018 elliptic curve "SM2" [ISO14888-3] is represented in a JSON Web Key (JWK) [RFC7517] using these values: * kty: EC * crv: SM2 plus x and y values to represent the curve point for the key. Other optional values such as alg MAY also be present. It is represented in a COSE_Key [RFC8152] using these values: Dang Expires 10 May 2022 [Page 2] Internet-Draft Using SM2 with JOSE and COSE November 2021 * kty (1): EC2 (2) * crv (-1): SM2 (TBD - requested assignment 9) plus x (-2) and y (-3) values to represent the curve point for the key. Other optional values such as alg (3) MAY also be present. 3. ECDSA Signature with SM2 Curve The ECDSA signature algorithm is defined in [ISO14888-3]. Implementations need to check that the key type is EC for JOSE or EC2 (2) for COSE when creating or verifying a signature. The ECDSA algorithm specified in this document is: +===============+================================+=============+ | JOSE Alg Name | COSE Alg Value | Description | +===============+================================+=============+ | SM2 | TBD (requested assignment -48) | ECDSA w/ | | | | SM2 Curve | +---------------+--------------------------------+-------------+ Table 1: ECDSA Algorithm Values 4. IANA Considerations 4.1. JSON Web Key Elliptic Curve Registration This section registers the following value in the IANA "JSON Web Key Elliptic Curve" registry [IANA.JOSE.Curves]. * Curve Name: curveSM2 * Curve Description: SM2 Curve * JOSE Implementation Requirements: Optional * Change Controller: IESG * Specification Document(s): Section 2 of [[ this specification ]] 4.2. JOSE Algorithm Registration This section registers the following value in the IANA "JSON Web Signature and Encryption Algorithms" registry [IANA.JOSE.Algorithms]. * Algorithm Name: SM2 * Algorithm Description: ECDSA w/ SM2 Curve * Algorithm Usage Locations: alg * JOSE Implementation Requirements: Optional * Change Controller: IESG * Reference: Section 3 of [[ this specification ]] * Algorithm Analysis Document(s): [ISO14888-3] Dang Expires 10 May 2022 [Page 3] Internet-Draft Using SM2 with JOSE and COSE November 2021 4.3. COSE Elliptic Curves Registration This section registers the following value in the IANA "COSE Elliptic Curves" registry [IANA.COSE.Curves]. * Name: curveSM2 * Value: TBD (requested assignment 9) * Key Type: EC2 * Description: SM2 Curve * Change Controller: IESG * Reference: Section 2 of [[ this specification ]] * Recommended: Yes 4.4. COSE Algorithm Registration This section registers the following value in the IANA "COSE Algorithms" registry [IANA.COSE.Algorithms]. * Name: SM2 * Value: TBD (requested assignment -48) * Description: ECDSA w/ SM2 Curve * Reference: Section 3 of this document * Recommended: Yes 5. Security Considerations The procedures and security considerations described in the [ISO14888-3] specifications apply to implementations of this specification. 6. References 6.1. Normative References [ISO14888-3] International Organization for Standardization, "IT Security techniques - Digital signatures with appendix - Part 3: Discrete logarithm based mechanisms", November 2018. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May 2015, . Dang Expires 10 May 2022 [Page 4] Internet-Draft Using SM2 with JOSE and COSE November 2021 [RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517, DOI 10.17487/RFC7517, May 2015, . [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, . 6.2. Informative References [IANA.COSE.Algorithms] IANA, "COSE Algorithms", . [IANA.COSE.Curves] IANA, "COSE Elliptic Curves", . [IANA.JOSE.Algorithms] IANA, "JSON Web Signature and Encryption Algorithms", . [IANA.JOSE.Curves] IANA, "JSON Web Key Elliptic Curve", . Appendix A. Document History [[ to be removed by the RFC Editor before publication as an RFC ]] -00 * Initial version. Author's Address Dang Expires 10 May 2022 [Page 5] Internet-Draft Using SM2 with JOSE and COSE November 2021 Fan Dang Tsinghua University Beijing 100084 China Email: dangfan@tsinghua.edu.cn Dang Expires 10 May 2022 [Page 6]