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
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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.
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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.
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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"
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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:
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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:
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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))
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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
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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
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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:
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8. Normative References
[DPFC09] IRTF CFRG, "Pairing-Friendly Curves", November 2020,
.
[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, .
[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, .
[SEC1] Standards for Efficient Cryptography Group (SECG), "SEC 1:
Elliptic Curve Cryptography", 2009,
.
Author's Address
Kyle Den Hartog (editor)
Mattr
Email: kyle.denhartog@mattr.global
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