draft-denhartog-pairing-curves-jose-cose.txt

Network Working Group                                 K. Den Hartog, Ed.
Internet-Draft                                                     Mattr
Intended status: Standards Track                            May 31, 2021
Expires: December 2, 2021


        Pairing Friendly Curves Representations in JOSE and COSE
              draft-denhartog-pairing-curves-jose-cose-00

Abstract

   This specification defines representations enabling the Standards for
   Pairing Frinedly Curves 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 December 2, 2021.

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.




Den Hartog              Expires December 2, 2021                [Page 1]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Notational Conventions  . . . . . . . . . . . . . . . . .   3
   2.  Barreto Naehrig (BN) Curves . . . . . . . . . . . . . . . . .   3
     2.1.  BN256 Curve . . . . . . . . . . . . . . . . . . . . . . .   3
       2.1.1.  Bn256G1 Curve JOSE Key Representation . . . . . . . .   3
       2.1.2.  Bn256G1 Curve COSE Key Representation . . . . . . . .   3
       2.1.3.  Bn256G2 Curve JOSE Key Representation . . . . . . . .   3
       2.1.4.  Bn256G2 Curve COSE Key Representation . . . . . . . .   4
     2.2.  BN462 Curve . . . . . . . . . . . . . . . . . . . . . . .   4
       2.2.1.  Bn462G1 Curve JOSE Key Representation . . . . . . . .   4
       2.2.2.  Bn462G1 Curve COSE Key Representation . . . . . . . .   4
       2.2.3.  Bn462G2 Curve JOSE Key Representation . . . . . . . .   4
       2.2.4.  Bn462G2 Curve COSE Key Representation . . . . . . . .   5
   3.  Barreto Lynn Scott (BLS) Curves . . . . . . . . . . . . . . .   5
     3.1.  BLS12-381 Curve . . . . . . . . . . . . . . . . . . . . .   5
       3.1.1.  Bls12381G1 Curve JOSE Key Representation  . . . . . .   5
       3.1.2.  Bls12381G1 Curve COSE Key Representation  . . . . . .   5
       3.1.3.  Bls12381G2 Curve JOSE Key Representation  . . . . . .   5
       3.1.4.  Bls12381G2 Curve COSE Key Representation  . . . . . .   6
     3.2.  BLS48-581 Curve . . . . . . . . . . . . . . . . . . . . .   6
       3.2.1.  Bls48581G1 Curve JOSE Key Representation  . . . . . .   6
       3.2.2.  Bls48581G1 Curve COSE Key Representation  . . . . . .   6
       3.2.3.  Bls48581G2 Curve JOSE Key Representation  . . . . . .   6
       3.2.4.  Bls48581G2 Curve COSE Key Representation  . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  JSON Web Key Elliptic Curve Registrations . . . . . . . .   7
     4.2.  COSE Elliptic Curve Registrations . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  10
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .  11
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   This specification defines algorithm encodings and representations
   enabling the Standard Pairing Frinedly Curves to be used for JSON
   Object Signing and Encryption (JOSE) [RFC7517] [RFC7517] and CBOR
   Object Signing and Encryption (COSE) [RFC8152] [RFC8152] messages.
   The elliptic curve and associated algorithm are registered in
   appropriate IANA JOSE and COSE registries.








Den Hartog              Expires December 2, 2021                [Page 2]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


1.1.  Notational 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 RFC 2119 [RFC2119] RFC 8174 [RFC8174] when, and only when, they
   appear in all capitals, as shown here.

2.  Barreto Naehrig (BN) Curves

2.1.  BN256 Curve

2.1.1.  Bn256G1 Curve JOSE Key Representation

   The pairing friendly elliptic curve "BN256" which uses the largest
   prime-order subgroup of E(GF(p)) is represented in a JSON Web Key
   (JWK) [RFC7517] [RFC7517] using these values: o "kty": "OKP" o "crv":
   "Bn256G1" plus "x" value to represent the curve point for the public
   key.  The "x" value MUST be encoded using [SEC1] [SEC1] format and
   MUST be base64url encoded without padding as defined in [RFC7515]
   [RFC7515] Appendix C.

2.1.2.  Bn256G1 Curve COSE Key Representation

   It is represented in a COSE_Key [RFC8152] [RFC8152] using these
   values:

   o "kty" (1): "OKP" (1)
   o "crv" (-1): "Bn256G1" (TBD - requested assignment 9)

   plus "x" (-2) values to represent the curve point for the key.  The
   "x" value MUST be encoded using [SEC1] [SEC1] point compression
   format.

2.1.3.  Bn256G2 Curve JOSE Key Representation

   The pairing friendly elliptic curve "BN256" which uses an r-order
   subgroup of E'(GF(p^2)) is represented in a JSON Web Key (JWK)
   [RFC7517] [RFC7517] using these values:

   o "kty": "OKP"
   o "crv": "Bn256G2"

   plus "x" value to represent the curve point for the public key.  The
   "x" value MUST be encoded using [SEC1] [SEC1] and MUST be base64url
   encoded without padding as defined in [RFC7515] [RFC7515] Appendix C.





Den Hartog              Expires December 2, 2021                [Page 3]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


2.1.4.  Bn256G2 Curve COSE Key Representation

   It is represented in a COSE_Key [RFC8152] [RFC8152] using these
   values:

   o "kty" (1): "OKP" (1)
   o "crv" (-1): "Bn256G2" (TBD - requested assignment 10)

   plus "x" (-2) values to represent the curve point for the key.  The
   "x" value MUST be encoded using [SEC1] [SEC1] point compression
   format.

2.2.  BN462 Curve

2.2.1.  Bn462G1 Curve JOSE Key Representation

   The pairing friendly elliptic curve "BN462" which uses the largest
   prime-order subgroup of E(GF(p)) is represented in a JSON Web Key
   (JWK) [RFC7517] [RFC7517] using these values:

   o "kty": "OKP"
   o "crv": "Bn462G1"

   plus "x" value to represent the curve point for the public key.  The
   "x" value MUST be encoded using [SEC1] [SEC1] and MUST be base64url
   encoded without padding as defined in [RFC7515] [RFC7515] Appendix C.

2.2.2.  Bn462G1 Curve COSE Key Representation

   It is represented in a COSE_Key [RFC8152] [RFC8152] using these
   values:

   o "kty" (1): "OKP" (1)
   o "crv" (-1): "Bn462G1" (TBD - requested assignment 11)

   plus "x" (-2) values to represent the curve point for the key.

2.2.3.  Bn462G2 Curve JOSE Key Representation

   The pairing friendly elliptic curve "BN462" which uses an r-order
   subgroup of E'(GF(p^2)) is represented in a JSON Web Key (JWK)
   [RFC7517] [RFC7517] using these values:

   o "kty": "OKP"
   o "crv": "Bn462G2"






Den Hartog              Expires December 2, 2021                [Page 4]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


   plus "x" value to represent the curve point for the public key.  The
   "x" value MUST be encoded using [SEC1] [SEC1] and MUST be base64url
   encoded without padding as defined in [RFC7515] [RFC7515] Appendix C.

2.2.4.  Bn462G2 Curve COSE Key Representation

   It is represented in a COSE_Key [RFC8152] [RFC8152] using these
   values:

   o "kty" (1): "OKP" (1)
   o "crv" (-1): "Bn462G2" (TBD - requested assignment 12)

   plus "x" (-2) values to represent the curve point for the key.

3.  Barreto Lynn Scott (BLS) Curves

3.1.  BLS12-381 Curve

3.1.1.  Bls12381G1 Curve JOSE Key Representation

   The pairing friendly elliptic curve "BLS12-381" which uses the
   largest prime-order subgroup of E(GF(p)) is represented in a JSON Web
   Key (JWK) [RFC7517] [RFC7517] using these values:

   o "kty": "OKP"
   o "crv": "Bls12381G1"

   plus "x" value to represent the curve point for the public key.  The
   "x" value MUST be encoded using the Z-Cash serialization defined in
   [DPFC09] [DPFC09] and MUST be base64url encoded without padding as
   defined in [RFC7515] [RFC7515] Appendix C.

3.1.2.  Bls12381G1 Curve COSE Key Representation

   It is represented in a COSE_Key [RFC8152] [RFC8152] using these
   values:

   o "kty" (1): "OKP" (1)
   o "crv" (-1): "Bls12381G1" (TBD - requested assignment 13)

   plus "x" (-2) values to represent the curve point for the key.

3.1.3.  Bls12381G2 Curve JOSE Key Representation

   The pairing friendly elliptic curve "BLS12-381" which uses an r-order
   subgroup of E'(GF(p^2)) is represented in a JSON Web Key (JWK)
   [RFC7517] [RFC7517] using these values:




Den Hartog              Expires December 2, 2021                [Page 5]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


   o "kty": "OKP"
   o "crv": "Bls12381G2"

   plus "x" value to represent the curve point for the public key.  The
   "x" value MUST be encoded using the Z-Cash serialization defined in
   [DPFC09] [DPFC09] and MUST be base64url encoded without padding as
   defined in [RFC7515] [RFC7515] Appendix C.

3.1.4.  Bls12381G2 Curve COSE Key Representation

   It is represented in a COSE_Key [RFC8152] [RFC8152] using these
   values:

   o "kty" (1): "OKP" (1)
   o "crv" (-1): "Bls12381G2" (TBD - requested assignment 14)

   plus "x" (-2) values to represent the curve point for the key.

3.2.  BLS48-581 Curve

3.2.1.  Bls48581G1 Curve JOSE Key Representation

   The pairing friendly elliptic curve "BLS48-581" which uses the
   largest prime-order subgroup of E(GF(p)) is represented in a JSON Web
   Key (JWK) [RFC7517] [RFC7517] using these values:

   o "kty": "OKP"
   o "crv": "Bls48581G1"

   plus "x" value to represent the curve point for the public key.  The
   "x" value MUST be encoded using [SEC1] [SEC1] and MUST be base64url
   encoded without padding as defined in [RFC7515] [RFC7515] Appendix C.

3.2.2.  Bls48581G1 Curve COSE Key Representation

   It is represented in a COSE_Key [RFC8152] [RFC8152] using these
   values:

   o "kty" (1): "OKP" (1)
   o "crv" (-1): "Bls48581G1" (TBD - requested assignment 15)

   plus "x" (-2) values to represent the curve point for the key.

3.2.3.  Bls48581G2 Curve JOSE Key Representation

   The pairing friendly elliptic curve "BLS48-581" which uses the
   largest prime-order subgroup of E'(GF(p^8)) is represented in a JSON
   Web Key (JWK) [RFC7517] [RFC7517] using these values:



Den Hartog              Expires December 2, 2021                [Page 6]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


   o "kty": "OKP"
   o "crv": "Bls48581G2"

   plus "x" value to represent the curve point for the public key.  The
   "x" value MUST be encoded using [SEC1] [SEC1] and MUST be base64url
   encoded without padding as defined in [RFC7515] [RFC7515] Appendix C.

3.2.4.  Bls48581G2 Curve COSE Key Representation

   It is represented in a COSE_Key [RFC8152] [RFC8152] using these
   values:

   o "kty" (1): "OKP" (1)
   o "crv" (-1): "Bls48581G1" (TBD - requested assignment 16)

   plus "x" (-2) values to represent the curve point for the key.

4.  IANA Considerations

4.1.  JSON Web Key Elliptic Curve Registrations

   This section registers the following value in the IANA "JSON Web Key
   Elliptic Curve" registry [IANA.JOSE.Curves].

   o Curve Name: Bn256G1
   o Curve Description: 256 bit Barreto-Naehrig pairing friendly curve
   using the largest prime-order subgroup of E(GF(p))
   o JOSE Implementation Requirements: Prohibited
   o Change Controller: IESG
   o Specification Document(s): Section 2.1 of [[ this specification ]]

   o Curve Name: Bn256G2
   o Curve Description: 256 bit Barreto-Naehrig pairing friendly curve
   using an r-order subgroup of E'(GF(p^2))
   o JOSE Implementation Requirements: Prohibited
   o Change Controller: IESG
   o Specification Document(s): Section 2.3 of [[ this specification ]]

   o Curve Name: Bn462G1
   o Curve Description: 462 bit Barreto-Naehrig pairing friendly curve
   using the largest prime-order subgroup of E(GF(p))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 2.5 of [[ this specification ]]

   o Curve Name: Bn462G2
   o Curve Description: 462 bit Barreto-Naehrig pairing friendly curve
   using an r-order subgroup of E'(GF(p^2))



Den Hartog              Expires December 2, 2021                [Page 7]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 2.7 of [[ this specification ]]

   o Curve Name: Bls12381G1
   o Curve Description: 381 bit with an embedding degree of 12 Barreto-
   Lynn-Scott pairing friendly curve using an r-order subgroup of
   E(GF(p))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 3.1 of [[ this specification ]]

   o Curve Name: Bls12381G2
   o Curve Description: 381 bit with an embedding degree of 12 Barreto-
   Lynn-Scott pairing friendly curve using an r-order subgroup of
   E'(GF(p^2))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 3.3 of [[ this specification ]]

   o Curve Name: Bls48581G1
   o Curve Description: 581 bit with an embedding degree of 48 Barreto-
   Lynn-Scott pairing friendly curve using an r-order subgroup of
   E(GF(p))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 3.5 of [[ this specification ]]

   o Curve Name: Bls48581G1
   o Curve Description: 581 bit with an embedding degree of 48 Barreto-
   Lynn-Scott pairing friendly curve using an r-order subgroup of
   E'(GF(p^8))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 3.7 of [[ this specification ]]

4.2.  COSE Elliptic Curve Registrations

   This section registers the following value in the IANA "JSON Web Key
   Elliptic Curve" registry [IANA.JOSE.Curves].

   o Curve Name: Bn256G1
   o Value: TBD (requested assignment 9)
   o Key Type: OKP
   o Curve Description: 256 bit Barreto-Naehrig pairing friendly curve
   using the largest prime-order subgroup of E(GF(p))
   o JOSE Implementation Requirements: Prohibited
   o Change Controller: IESG



Den Hartog              Expires December 2, 2021                [Page 8]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


   o Specification Document(s): Section 2.2 of [[ this specification ]]
   o Recommended: No (Prohibited)

   o Curve Name: Bn256G2
   o Value: TBD (requested assignment 10)
   o Key Type: OKP
   o Curve Description: 256 bit Barreto-Naehrig pairing friendly curve
   using an r-order subgroup of E'(GF(p^2))
   o JOSE Implementation Requirements: Prohibited
   o Change Controller: IESG
   o Specification Document(s): Section 2.4 of [[ this specification ]]
   o Recommended: No (Prohibited)

   o Curve Name: Bn462G1
   o Value: TBD (requested assignment 11)
   o Key Type: OKP
   o Curve Description: 462 bit Barreto-Naehrig pairing friendly curve
   using the largest prime-order subgroup of E(GF(p))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 2.6 of [[ this specification ]]
   o Recommended: No

   o Curve Name: Bn462G2
   o Value: TBD (requested assignment 12)
   o Key Type: OKP
   o Curve Description: 462 bit Barreto-Naehrig pairing friendly curve
   using an r-order subgroup of E'(GF(p^2))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 2.8 of [[ this specification ]]
   o Recommended: No

   o Curve Name: Bls12381G1
   o Value: TBD (requested assignment 13)
   o Key Type: OKP
   o Curve Description: 381 bit with an embedding degree of 12 Barreto-
   Lynn-Scott pairing friendly curve using an r-order subgroup of
   E(GF(p))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 3.2 of [[ this specification ]]
   o Recommended: Yes

   o Curve Name: Bls12381G2
   o Value: TBD (requested assignment 14)
   o Key Type: OKP




Den Hartog              Expires December 2, 2021                [Page 9]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


   o Curve Description: 381 bit with an embedding degree of 12 Barreto-
   Lynn-Scott pairing friendly curve using an r-order subgroup of
   E'(GF(p^2))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 3.4 of [[ this specification ]]
   o Recommended: Yes

   o Curve Name: Bls48581G1
   o Value: TBD (requested assignment 15)
   o Key Type: OKP
   o Curve Description: 581 bit with an embedding degree of 48 Barreto-
   Lynn-Scott pairing friendly curve using an r-order subgroup of
   E(GF(p))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 3.6 of [[ this specification ]]
   o Recommended: No

   o Curve Name: Bls48581G1
   o Value: TBD (requested assignment 16)
   o Key Type: OKP
   o Curve Description: 581 bit with an embedding degree of 48 Barreto-
   Lynn-Scott pairing friendly curve using an r-order subgroup of
   E'(GF(p^8))
   o JOSE Implementation Requirements: Optional
   o Change Controller: IESG
   o Specification Document(s): Section 3.8 of [[ this specification ]]
   o Recommended: No

5.  Security Considerations

   See [DPFC09] [DPFC09] for additional details about security
   considerations of the curves used.  Implementers should also consider
   section 9 of [RFC7517] [RFC7517] when implementing this work.

6.  Privacy Considerations

   To be added.

7.  Acknowledgements

   The authors of this draft would like to acknowledge the following
   individuals for the significant contribution of ideas and time spent
   reviewing this document:






Den Hartog              Expires December 2, 2021               [Page 10]

Internet-Draft  draft-denhartog-pairing-curves-jose-cose        May 2021


8.  Normative References

   [DPFC09]   IRTF CFRG, "Pairing-Friendly Curves", November 2020,
              <https://tools.ietf.org/html/draft-irtf-cfrg-pairing-
              friendly-curves-09>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC7515]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web
              Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
              2015, <https://www.rfc-editor.org/info/rfc7515>.

   [RFC7517]  Jones, M., "JSON Web Key (JWK)", RFC 7517,
              DOI 10.17487/RFC7517, May 2015,
              <https://www.rfc-editor.org/info/rfc7517>.

   [RFC8152]  Schaad, J., "CBOR Object Signing and Encryption (COSE)",
              RFC 8152, DOI 10.17487/RFC8152, July 2017,
              <https://www.rfc-editor.org/info/rfc8152>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [SEC1]     Standards for Efficient Cryptography Group (SECG), "SEC 1:
              Elliptic Curve Cryptography", 2009,
              <https://www.secg.org/sec1-v2.pdf>.

Author's Address

   Kyle Den Hartog (editor)
   Mattr

   Email: kyle.denhartog@mattr.global














Den Hartog              Expires December 2, 2021               [Page 11]