Re: [jose] CFRG ECC in JOSE

On 2015-11-11 02:22, Justin Richer wrote:
> I would lean toward using a new “kty” value for these as the syntax is different from existing ones. This will help parsers and existing implementations add this in without adding special processing rules: code is already set up to branch on “kty” so let’s keep that behavior. Note you can still reuse parts of the key definition (like “d” is found in both RSA and EC keypairs) without having to overload a new syntax since the kty defines a new namespace, effectively. I suggest a value of “ED” since they’re all “edwards” curves from my quick read.

It would IMO be great if this issue is coordinated with the integration of these curves in PKI(X).

Anders

>
>   — Justin
>
>> On Nov 10, 2015, at 5:58 PM, Manger, James <James.H.Manger@team.telstra.com> wrote:
>>
>> How do you calculate a JWK thumbprint [RFC7638] of these keys?
>>
>> A thumbprint is supposed to cover the "required" members. draft-liusvaara-jose-cfrg-curves implies the thumbprint would cover {alg, crv, kty, x}. That is different from other "kty":"EC" keys, where the thumbprint covers {crv, kty, x, y}. It is different from all other keys that exclude "alg".
>>
>> Theoretically we can probably have per-curve thumbprint rules, though so far the thumbprint rules have been per-type (per kty value).
>>
>> Two options could be:
>> 1. Reuse "kty":"EC" but have per-curve thumbprint rules
>> 2. Define a new key type, say, "kty":"EC2" for elliptic curve keys with these thumbprint rules
>>
>> Either way, draft-liusvaara-jose-cfrg-curves should explicitly state the members covered by a RFC7638 thumbprint.
>>
>> --
>> James Manger
>>
>>
>> -----Original Message-----
>> From: jose [mailto:jose-bounces@ietf.org] On Behalf Of Ilari Liusvaara
>> Sent: Wednesday, 11 November 2015 4:56 AM
>> To: jose@ietf.org
>> Subject: [jose] CFRG ECC in JOSE
>>
>> I cooked up a pre-draft (already circulated privately) about using CFRG
>> ECC work in JOSE. Encompasses both ECDH and signatures.
>>
>>
>> Comments (before I attempt to submit this as an I-D)?
>>
>>
>> -----------------------------------------------------------------------
>> Network Working Group                                       I. Liusvaara
>> Internet-Draft                                               Independent
>> Intended status: Standards Track                        October 17, 2015
>> Expires: April 19, 2016
>>
>>
>>                    CFRG curves and signatures in JOSE
>>                     draft-liusvaara-jose-cfrg-curves
>>
>> Abstract
>>
>>    This document defines how to use curves and algorithms from IRTF CFRG
>>    elliptic curves work (Diffie-Hellman and signatures) in JOSE.
>>
>> 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 http://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 April 19, 2016.
>>
>> Copyright Notice
>>
>>    Copyright (c) 2015 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
>>    (http://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.
>>
>>
>>
>>
>>
>>
>> Liusvaara                Expires April 19, 2016                 [Page 1]
>>
>>
>> Internet-Draft     CFRG curves and signatures in JOSE       October 2015
>>
>>
>> Table of Contents
>>
>>    1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
>>      1.1.  Requirements Terminology  . . . . . . . . . . . . . . . .   2
>>      1.2.  Notation  . . . . . . . . . . . . . . . . . . . . . . . .   2
>>    2.  Algorithms  . . . . . . . . . . . . . . . . . . . . . . . . .   2
>>      2.1.  Signatures  . . . . . . . . . . . . . . . . . . . . . . .   3
>>        2.1.1.  Curves  . . . . . . . . . . . . . . . . . . . . . . .   3
>>        2.1.2.  Algorithms  . . . . . . . . . . . . . . . . . . . . .   3
>>        2.1.3.  Signing . . . . . . . . . . . . . . . . . . . . . . .   4
>>        2.1.4.  Verification  . . . . . . . . . . . . . . . . . . . .   4
>>      2.2.  ECDH-ES . . . . . . . . . . . . . . . . . . . . . . . . .   4
>>        2.2.1.  Parameters  . . . . . . . . . . . . . . . . . . . . .   4
>>        2.2.2.  Performing the ECDH operation . . . . . . . . . . . .   5
>>    3.  Security considerations . . . . . . . . . . . . . . . . . . .   5
>>    4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
>>    5.  IANA considerations . . . . . . . . . . . . . . . . . . . . .   6
>>    6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
>>      6.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
>>      6.2.  Informative References  . . . . . . . . . . . . . . . . .   8
>>    Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   9
>>
>> 1.  Introduction
>>
>>    Internet Research Task Force (IRTF) Crypto Forum Research Group
>>    (CFRG) selected new elliptic curves and signature algorithms for
>>    asymmetric key cryptography.  This document defines how those curves
>>    and algorithms are to be used in JOSE in interoperable manner.
>>
>>    This extends [RFC7517] and [RFC7518]
>>
>> 1.1.  Requirements Terminology
>>
>>    The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
>>    "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
>>    document are to be interpreted as described in [RFC2119].
>>
>> 1.2.  Notation
>>
>>    All inputs to and outputs from the the ECDH and signature functions
>>    are defined to be octet strings, with the exception of output of
>>    verfication function, which is a boolean.
>>
>> 2.  Algorithms
>>
>>
>>
>>
>>
>>
>>
>> Liusvaara                Expires April 19, 2016                 [Page 2]
>>
>>
>> Internet-Draft     CFRG curves and signatures in JOSE       October 2015
>>
>>
>> 2.1.  Signatures
>>
>> 2.1.1.  Curves
>>
>>    The following curves are defined for the algorithms are defined here
>>    (to be applied as values of "crv" parameter):
>>
>>       crv value:            The curve:
>>       E255                  Edwards25519
>>       E448                  Edwards448
>>
>>    For each of these curves:
>>
>>    1.  The parameter "kty" MUST be "EC".
>>
>>    2.  The parameter "crv" MUST be set to appropriate value.
>>
>>    3.  The parameter "alg" MUST be set to appropriate value.
>>
>>    4.  The parameter "x" is the base64url [RFC4648] encoded public key
>>        octet string (note: this is not the same as sec1 encoding).  This
>>        MUST be present for both public and private keys.
>>
>>    5.  The parameter "y" MUST NOT be present.  These curves only have
>>        one public key component.
>>
>>    6.  The parameter "d" is the base64url encoded private key octet
>>        string.  This MUST be present for private keys, and MUST NOT be
>>        present for public keys.
>>
>>    7.  These curves MUST NOT be used for ECDH-ES.
>>
>>    8.  If key is private key, and thus both "x" and "d" are present,
>>        then "x" MUST be the public key corresponding to private key "d".
>>
>> 2.1.2.  Algorithms
>>
>>    The following signature algorithms are defined here (to be applied as
>>    values of "alg" parameter):
>>
>>      alg value:     crv:    The algorithm:
>>      Ed25519        E255    Ed25519
>>      Ed25519ph      E255    Ed25519ph
>>      Ed448          E448    Ed448
>>      Ed448ph        E448    Ed448ph
>>
>>
>>
>>
>>
>>
>> Liusvaara                Expires April 19, 2016                 [Page 3]
>>
>>
>> Internet-Draft     CFRG curves and signatures in JOSE       October 2015
>>
>>
>>    The key type for these algorithms MUST be "EC", "alg" parameter MUST
>>    be present and "crv" parameter MUST match the indicated one for each
>>    algorithm.
>>
>> 2.1.3.  Signing
>>
>>    Signing for these is preformed by applying the signing algorithm
>>    defined in [I-D.irtf-cfrg-eddsa] to the private key (as private key),
>>    public key (as public key) and the JWS Signing Input (as message).
>>    The resulting signature is the JWS Signature value.  All inputs and
>>    outputs are octet strings.
>>
>> 2.1.4.  Verification
>>
>>    Verification is performed by applying the verification algorithm
>>    defined in [I-D.irtf-cfrg-eddsa] to the public key (as public key),
>>    the JWS Signing Input (as message) and the JWS Signature value (as
>>    signature).  All inputs are octet strings.  If the algorithm accepts,
>>    the signature is valid, otherwise it is invalid.
>>
>> 2.2.  ECDH-ES
>>
>>    The following curves are defined for the algorithms are defined here
>>    (to be applied as values of "crv" parameter):
>>
>>       crv value:          The curve:
>>       X255                X25519
>>       X448                X448
>>
>>    The key type used with these keys is "EC".
>>
>>    These curves MUST NOT be used for signatures.
>>
>> 2.2.1.  Parameters
>>
>>    For each of these curves:
>>
>>    1.  The "x" parameter is base64url encoding of point octet string
>>        (note: This is not SEC1 encoding).  This parameter MUST be
>>        present in both public and private keys.
>>
>>    2.  The "y" parameter MUST NOT be present.  These functions only have
>>        one public key component.
>>
>>    3.  The "d" parameter is base64url encoding of scalar octet string.
>>        This parameter MUST be present in private keys, and it MUST NOT
>>        be present in public keys.
>>
>>
>>
>>
>> Liusvaara                Expires April 19, 2016                 [Page 4]
>>
>>
>> Internet-Draft     CFRG curves and signatures in JOSE       October 2015
>>
>>
>>    4.  If key is private key, and thus both "x" and "d" are present,
>>        then "x" MUST be the output of applying ECDH function to the
>>        value of "d" (as scalar input) and the standard basepoint (as
>>        u-coordinate input).
>>
>> 2.2.2.  Performing the ECDH operation
>>
>>    The "x" parameter of "epk" field is set as follows:
>>
>>    Apply the appropriate ECDH function to the ephemeral private key (as
>>    scalar input) and the standard basepoint (as u-coordinate input).
>>    The output is the value for "x" parameter of "epk" field.  All inputs
>>    and outputs are octet strings.
>>
>>    The Z value (raw key agreement output) for key agreement is
>>    determined as follows:
>>
>>    Apply the appropriate ECDH function to the ephemeral private key (as
>>    scalar input) and receiver public key (as u-coordinate input).  The
>>    output is the Z value.  All inputs and outputs are octet strings.
>>
>> 3.  Security considerations
>>
>>    Security considerations from [I-D.irtf-cfrg-curves] and
>>    [I-D.irtf-cfrg-eddsa] apply here.
>>
>>    The same key MUST NOT be used with multiple algorithms, since some of
>>    the algorithms defined here interact in bad ways.  For this reason
>>    "alg" parameters for signature keys are REQUIRED.
>>
>>    Do not assume that signature also binds the key used for signing, it
>>    does not (there are also other widespread signature algorithms where
>>    this binding fails, as such binding is not part of the definition of
>>    secure signature primitive).  As an example of such failure, the
>>    Ed25519ph signature of X under key (Ed25519ph,Y) is identical to
>>    Ed25519 signature of SHA512(X) under key (Ed25519,Y).  And often it
>>    takes only setting a few bits of message (easy to do by brute force)
>>    to make the message valid enough to be processed in some very
>>    surprising way.
>>
>>    If key generation or batch signature verification is performed, a
>>    well-seed cryptographical random number generator is REQUIRED.
>>    Signing and non-batch signature verification are deterministic
>>    operations do not need random numbers of any kind.
>>
>>
>>
>>
>>
>>
>>
>> Liusvaara                Expires April 19, 2016                 [Page 5]
>>
>>
>> Internet-Draft     CFRG curves and signatures in JOSE       October 2015
>>
>>
>> 4.  Acknowledgements
>>
>>    Mike Jones for comments on initial pre-draft.
>>
>> 5.  IANA considerations
>>
>>    The following is added to JSON Web Signature and Encryption
>>    Algorithms Registry:
>>
>>    o  Algorithm Name: "Ed25519"
>>
>>    o  Algorithm Description: Ed25519 signature algorithm
>>
>>    o  Algorithm Usage Location(s): "alg"
>>
>>    o  JOSE Implementation Requirements: Optional
>>
>>    o  Change Controller: IESG
>>
>>    o  Specification Document(s): Section 2.1 of [RFC-THIS]
>>
>>    o  Algorithm Analysis Documents(s): n/a
>>
>>
>>    o  Algorithm Name: "Ed25519ph"
>>
>>    o  Algorithm Description: Ed25519 signature algorithm with prehash
>>
>>    o  Algorithm Usage Location(s): "alg"
>>
>>    o  JOSE Implementation Requirements: Optional
>>
>>    o  Change Controller: IESG
>>
>>    o  Specification Document(s): Section 2.1 of [RFC-THIS]
>>
>>    o  Algorithm Analysis Documents(s): n/a
>>
>>
>>    o  Algorithm Name: "Ed448"
>>
>>    o  Algorithm Description: Ed448 signature algorithm
>>
>>    o  Algorithm Usage Location(s): "alg"
>>
>>    o  JOSE Implementation Requirements: Optional
>>
>>    o  Change Controller: IESG
>>
>>
>>
>> Liusvaara                Expires April 19, 2016                 [Page 6]
>>
>>
>> Internet-Draft     CFRG curves and signatures in JOSE       October 2015
>>
>>
>>    o  Specification Document(s): Section 2.1 of [RFC-THIS]
>>
>>    o  Algorithm Analysis Documents(s): n/a
>>
>>
>>    o  Algorithm Name: "Ed448ph"
>>
>>    o  Algorithm Description: Ed448 signature algorithm with prehash
>>
>>    o  Algorithm Usage Location(s): "alg"
>>
>>    o  JOSE Implementation Requirements: Optional
>>
>>    o  Change Controller: IESG
>>
>>    o  Specification Document(s): Section 2.1 of [RFC-THIS]
>>
>>    o  Algorithm Analysis Documents(s): n/a
>>
>>
>>    The following is added to JSON Web Key Elliptic Curve Registry:
>>
>>    o  Curve Name: "X25519"
>>
>>    o  Curve Description: The X25519 function
>>
>>    o  JOSE Implementation Requirements: Optional
>>
>>    o  Change Controller: IESG
>>
>>    o  Specification Document(s): Section 2.2 of [RFC-THIS]
>>
>>
>>    o  Curve Name: "X448"
>>
>>    o  Curve Description: The X448 function
>>
>>    o  JOSE Implementation Requirements: Optional
>>
>>    o  Change Controller: IESG
>>
>>    o  Specification Document(s): Section 2.2 of [RFC-THIS]
>>
>>
>>    o  Curve Name: "Ed25519"
>>
>>    o  Curve Description: The Edwards25519 curve
>>
>>
>>
>>
>> Liusvaara                Expires April 19, 2016                 [Page 7]
>>
>>
>> Internet-Draft     CFRG curves and signatures in JOSE       October 2015
>>
>>
>>    o  JOSE Implementation Requirements: Optional
>>
>>    o  Change Controller: IESG
>>
>>    o  Specification Document(s): Section 2.1 of [RFC-THIS]
>>
>>
>>    o  Curve Name: "Ed448"
>>
>>    o  Curve Description: The Edwards448 curve
>>
>>    o  JOSE Implementation Requirements: Optional
>>
>>    o  Change Controller: IESG
>>
>>    o  Specification Document(s): Section 2.2 of [RFC-THIS]
>>
>>
>> 6.  References
>>
>> 6.1.  Normative References
>>
>>    [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
>>               Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
>>               RFC2119, March 1997,
>>               <http://www.rfc-editor.org/info/rfc2119>.
>>
>>    [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
>>               Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
>>               <http://www.rfc-editor.org/info/rfc4648>.
>>
>>    [I-D.irtf-cfrg-curves]
>>               Langley, A. and M. Hamburg, "Elliptic Curves for
>>               Security", draft-irtf-cfrg-curves-09 (work in progress),
>>               September 2015.
>>
>>    [I-D.irtf-cfrg-eddsa]
>>               Josefsson, S. and I. Liusvaara, "Edwards-curve Digital
>>               Signature Algorithm (EdDSA)", draft-irtf-cfrg-eddsa-00
>>               (work in progress), October 2015.
>>
>> 6.2.  Informative References
>>
>>    [RFC7517]  Jones, M., "JSON Web Key (JWK)", RFC 7517, DOI 10.17487/
>>               RFC7517, May 2015,
>>               <http://www.rfc-editor.org/info/rfc7517>.
>>
>>
>>
>>
>>
>> Liusvaara                Expires April 19, 2016                 [Page 8]
>>
>>
>> Internet-Draft     CFRG curves and signatures in JOSE       October 2015
>>
>>
>>    [RFC7518]  Jones, M., "JSON Web Algorithms (JWA)", RFC 7518, DOI
>>               10.17487/RFC7518, May 2015,
>>               <http://www.rfc-editor.org/info/rfc7518>.
>>
>> Author's Address
>>
>>    Ilari Liusvaara
>>    Independent
>>
>>    Email: ilariliusvaara@welho.com
>>
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>> Liusvaara                Expires April 19, 2016                 [Page 9]
>>
>> -----------------------------------------------------------------------
>>
>>
>> -Ilari
>>
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Re: [jose] CFRG ECC in JOSE - thumbprint