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Internet X.509 Public Key Infrastructure: Additional Algorithm Identifiers for RSASSA-PSS and ECDSA using SHAKEs as Hash Functions
draft-ietf-lamps-pkix-shake-02

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This is an older version of an Internet-Draft that was ultimately published as RFC 8692.
Authors Panos Kampanakis , Quynh Dang
Last updated 2018-06-30 (Latest revision 2018-02-16)
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draft-ietf-lamps-pkix-shake-02
LAMPS WG                                                   P. Kampanakis
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                                 Q. Dang
Expires: December 31, 2018                                          NIST
                                                           June 29, 2018

     Internet X.509 Public Key Infrastructure: Additional Algorithm
  Identifiers for RSASSA-PSS and ECDSA using SHAKEs as Hash Functions
                     draft-ietf-lamps-pkix-shake-02

Abstract

   Digital signatures are used to sign messages, X.509 certificates and
   CRLs (Certificate Revocation Lists).  This document describes the
   conventions for using the SHAKE family of hash functions in the
   Internet X.509 as one-way hash functions with the RSA Probabilistic
   Signature Scheme and ECDSA signature algorithms.  The conventions for
   the associated subject public keys are also described.

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 31, 2018.

Copyright Notice

   Copyright (c) 2018 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

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   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.  Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Identifiers . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Use in PKIX . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Signatures  . . . . . . . . . . . . . . . . . . . . . . .   4
       4.1.1.  RSASSA-PSS Signatures . . . . . . . . . . . . . . . .   5
       4.1.2.  ECDSA Signatures  . . . . . . . . . . . . . . . . . .   5
     4.2.  Public Keys . . . . . . . . . . . . . . . . . . . . . . .   6
       4.2.1.  RSASSA-PSS Public Keys  . . . . . . . . . . . . . . .   6
       4.2.2.  ECDSA Public Keys . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Appendix A.  ASN.1 module . . . . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Change Log

   [ EDNOTE: Remove this section before publication. ]

   o  draft-ietf-lamps-pkix-shake-02:

      *  Significant reorganization of the sections to simplify the
         introduction, the new OIDs and their use in PKIX.

      *  Added new OIDs for RSASSA-PSS that hardcode hash, salt and MFG,
         according the WG consensus.

      *  Updated Public Key section to use the new RSASSA-PSS OIDs and
         clarify the algorithm identifier usage.

      *  Removed the no longer used SHAKE OIDs from section 3.1.

      *  Consolidated subsection for message digest algorithms.

      *  Text fixes.

   o  draft-ietf-lamps-pkix-shake-01:

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      *  Changed titles and section names.

      *  Removed DSA after WG discussions.

      *  Updated shake OID names and parameters, added MGF1 section.

      *  Updated RSASSA-PSS section.

      *  Added Public key algorithm OIDs.

      *  Populated Introduction and IANA sections.

   o  draft-ietf-lamps-pkix-shake-00:

      *  Initial version

2.  Introduction

   This document describes several cryptographic algorithm identifiers
   for several cryptographic algorithms which use variable length output
   SHAKE functions introduced in [SHA3] which can be used with the
   Internet X.509 Certificate and CRL profile [RFC5280].

   The SHA-3 family of one-way hash functions is specified in [SHA3].
   In the SHA-3 family, two extendable-output functions, called SHAKE128
   and SHAKE256 are defined.  Four hash functions, SHA3-224, SHA3-256,
   SHA3-384, and SHA3-512 are also defined but are out of scope for this
   document.  A SHAKE is a variable length hash function.  The output
   lengths, in bits, of the SHAKE hash functions are defined by the d
   parameter.  The corresponding collision and preimage resistance
   security levels for SHAKE128 and SHAKE256 are respectively
   min(d/2,128) and min(d,128) and min(d/2,256) and min(d,256) bits.

   SHAKEs can be used as the message digest function (to hash the
   message to be signed) and as the hash function in the mask generating
   functions in RSASSA-PSS and ECDSA.  In this document, we define four
   new OIDs for RSASSA-PSS and ECDSA when SHAKE128 and SHAKE256 are used
   as hash functions.  The same algorithm identifiers are used for
   identifying a public key, and identifying a signature.

3.  Identifiers

   The new identifiers for RSASSA-PSS signatures using SHAKEs are below.

     id-RSASSA-PSS-SHAKE128  OBJECT IDENTIFIER  ::=  { TBD }

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     id-RSASSA-PSS-SHAKE256  OBJECT IDENTIFIER  ::=  { TBD }

     [ EDNOTE: "TBD" will be specified by NIST later. ]

   The new algorithm identifiers of ECDSA signatures using SHAKEs are
   below.

  id-ecdsa-with-shake128 OBJECT IDENTIFIER  ::=  { joint-iso-ccitt(2)
                        country(16) us(840) organization(1) gov(101) csor(3) algorithms(4)
                        id-ecdsa-with-shake(3) TBD }

  id-ecdsa-with-shake256 OBJECT IDENTIFIER  ::=  { joint-iso-ccitt(2)
                        country(16) us(840) organization(1) gov(101) csor(3) algorithms(4)
                        id-ecdsa-with-shake(3) TBD }

  [ EDNOTE: "TBD" will be specified by NIST later. ]

   The parameters for these four identifiers above MUST be absent.  That
   is, the identifier SHALL be a SEQUENCE of one component, the OID.

4.  Use in PKIX

4.1.  Signatures

   Signatures can be placed in a number of different ASN.1 structures.
   The top level structure for an X.509 certificate, to illustrate how
   signatures are frequently encoded with an algorithm identifier and a
   location for the signature, is

      Certificate  ::=  SEQUENCE  {
         tbsCertificate       TBSCertificate,
         signatureAlgorithm   AlgorithmIdentifier,
         signatureValue       BIT STRING  }

   The identifiers defined in Section 3 can be used as the
   AlgorithmIdentifier in the signatureAlgorithm field in the sequence
   Certificate and the signature field in the sequence tbsCertificate in
   X.509 [RFC3280].

   Conforming CA implementations MUST specify the algorithms explicitly
   by using the OIDs specified in Section 3 when encoding RSASSA-PSS and
   ECDSA with SHAKE signatures, and public keys in certificates and
   CRLs.  Encoding rules for RSASSA-PSS and ECDSA signature values are
   specified in [RFC4055] and [RFC5480] respectively.

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   Conforming client implementations that process RSASSA-PSS and ECDSA
   with SHAKE signatures when processing certificates and CRLs MUST
   recognize the corresponding OIDs.

4.1.1.  RSASSA-PSS Signatures

   The RSASSA-PSS algorithm is defined in [RFC8017].  When id-RSASSA-
   PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256 specified in Section 3 is
   used, the encoding MUST omit the parameters field.  That is, the
   AlgorithmIdentifier SHALL be a SEQUENCE of one component, id-RSASSA-
   PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256.

   The hash algorithm to hash a message being signed and the hash
   algorithm in the maskGenAlgorithm used in RSASSA-PSS MUST be the
   same, SHAKE128 or SHAKE256 respectively.  The output-length of the
   hash algorithm which hashes the message SHALL be 32 or 64 bytes
   respectively.

   The maskGenAlgorithm is the MGF1 specified in Section B.2.1 of
   [RFC8017].  The output length for SHAKE128 or SHAKE256 being used as
   the hash function in MGF1 is (n - 264)/8 or (n - 520)/8 bytes
   respectively, where n is the RSA modulus in bits.  For example, when
   RSA modulus n is 2048, the output length of SHAKE128 or SHAKE256 in
   the MGF1 will be 223 or 191 when id-RSASSA-PSS-SHAKE128 or id-RSASSA-
   PSS-SHAKE256 is used respectively.

   The RSASSA-PSS saltLength MUST be 32 or 64 bytes respectively.
   Finally, the trailerField MUST be 1, which represents the trailer
   field with hexadecimal value 0xBC [RFC8017].

4.1.2.  ECDSA Signatures

   The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined in
   [X9.62].  When the id-ecdsa-with-SHAKE128 or id-ecdsa-with-SHAKE256
   (specified in Section 3) algorithm identifier appears, the respective
   SHAKE function (SHAKE128 or SHAKE256) is used as the hash.  The
   encoding MUST omit the parameters field.  That is, the
   AlgorithmIdentifier SHALL be a SEQUENCE of one component, the OID id-
   ecdsa-with-SHAKE128 or id-ecdsa-with-SHAKE256.

   For simplicity and compliance with the ECDSA standard specification,
   the output size of the hash function must be explicitly determined.
   The output size, d, for SHAKE128 or SHAKE256 used in ECDSA MUST be
   256 or 512 bits respectively.

   Conforming CA implementations that generate ECDSA with SHAKE
   signatures in certificates or CRLs MUST generate such signatures in
   accordance with all the requirements specified in Sections 7.2 and

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   7.3 of [X9.62] or with all the requirements specified in
   Section 4.1.3 of [SEC1].  They MAY also generate such signatures in
   accordance with all the recommendations in [X9.62] or [SEC1] if they
   have a stated policy that requires conformance to these standards.
   These standards may have not specified SHAKE128 and SHAKE256 as hash
   algorithm options.  However, SHAKE128 and SHAKE256 with output length
   being 32 and 64 octets respectively are subtitutions for 256 and
   512-bit output hash algorithms such as SHA256 and SHA512 used in the
   standards.

4.2.  Public Keys

   Certificates conforming to [RFC5280] can convey a public key for any
   public key algorithm.  The certificate indicates the algorithm
   through an algorithm identifier.  This algorithm identifier is an OID
   and optionally associated parameters.

   In the X.509 certificate, the subjectPublicKeyInfo field has the
   SubjectPublicKeyInfo type, which has the following ASN.1 syntax:

     SubjectPublicKeyInfo  ::=  SEQUENCE  {
          algorithm         AlgorithmIdentifier,
          subjectPublicKey  BIT STRING
     }

   The fields in SubjectPublicKeyInfo have the following meanings:

   o  algorithm is the algorithm identifier and parameters for the
      public key.

   o  subjectPublicKey contains the byte stream of the public key.  The
      algorithms defined in this document always encode the public key
      as an exact multiple of 8-bits.

   The conventions for RSASSA-PSS and ECDSA public keys algorithm
   identifiers are as specified in [RFC3279], [RFC4055] and [RFC5480] ,
   but we include them below for convenience.

4.2.1.  RSASSA-PSS Public Keys

   [RFC3279] defines the following OID for RSA AlgorithmIdentifier in
   the SubjectPublicKeyInfo with NULL parameters.

     rsaEncryption OBJECT IDENTIFIER ::=  { pkcs-1 1}

   Additionally, when the RSA private key owner wishes to limit the use
   of the public key exclusively to RSASSA-PSS, the AlgorithmIdentifiers
   for RSASSA-PSS defined in Section 3 can be used as the algorithm

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   field in the SubjectPublicKeyInfo sequence [RFC3280].  The identifier
   parameters, as explained in section Section 3, MUST be absent.

   Regardless of what public key algorithm identifier is used, the RSA
   public key, which is composed of a modulus and a public exponent,
   MUST be encoded using the RSAPublicKey type [RFC4055].  The output of
   this encoding is carried in the certificate subjectPublicKey.

     RSAPublicKey ::= SEQUENCE {
           modulus INTEGER, -- n
           publicExponent INTEGER  -- e
     }

4.2.2.  ECDSA Public Keys

   For ECDSA, when id-ecdsa-with-shake128 or id-ecdsa-with-shake256 is
   used as the AlgorithmIdentifier in the algorithm field of
   SubjectPublicKeyInfo, the parameters, as explained in section
   Section 3, MUST be absent.

   Additionally, the mandatory EC SubjectPublicKey is defined in
   Section 2.1.1 and its syntax is in Section 2.2 of [RFC5480].  We also
   include them here for convenience:

     id-ecPublicKey OBJECT IDENTIFIER ::= {
          iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 }

   The id-ecPublicKey parameters MUST be present and are defined as

     ECParameters ::= CHOICE {
         namedCurve         OBJECT IDENTIFIER
         -- implicitCurve   NULL
         -- specifiedCurve  SpecifiedECDomain
      }

   The ECParameters associated with the ECDSA public key in the signer's
   certificate SHALL apply to the verification of the signature.

5.  IANA Considerations

   This document uses several new registries [ EDNOTE: Update here. ]

6.  Security Considerations

   The SHAKEs are deterministic functions.  Like any other deterministic
   functions, executing each function with the same input multiple times
   will produce the same output.  Therefore, users should not expect

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   unrelated outputs (with the same or different output lengths) from
   excuting a SHAKE function with the same input multiple times.

   Implementations must protect the signer's private key.  Compromise of
   the signer's private key permits masquerade.

   Implementations must randomly generate one-time values, such as the k
   value when generating a ECDSA signature.  In addition, the generation
   of public/private key pairs relies on random numbers.  The use of
   inadequate pseudo-random number generators (PRNGs) to generate such
   cryptographic values can result in little or no security.  The
   generation of quality random numbers is difficult.  [RFC4086] offers
   important guidance in this area, and [SP800-90A] series provide
   acceptable PRNGs.

   Implementers should be aware that cryptographic algorithms may become
   weaker with time.  As new cryptanalysis techniques are developed and
   computing power increases, the work factor or time required to break
   a particular cryptographic algorithm may decrease.  Therefore,
   cryptographic algorithm implementations should be modular allowing
   new algorithms to be readily inserted.  That is, implementers should
   be prepared to regularly update the set of algorithms in their
   implementations.

7.  Acknowledgements

   We would like to thank Sean Turner for his valuable contributions to
   this document.

8.  References

8.1.  Normative References

   [RFC3280]  Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
              X.509 Public Key Infrastructure Certificate and
              Certificate Revocation List (CRL) Profile", RFC 3280,
              DOI 10.17487/RFC3280, April 2002,
              <https://www.rfc-editor.org/info/rfc3280>.

   [RFC4055]  Schaad, J., Kaliski, B., and R. Housley, "Additional
              Algorithms and Identifiers for RSA Cryptography for use in
              the Internet X.509 Public Key Infrastructure Certificate
              and Certificate Revocation List (CRL) Profile", RFC 4055,
              DOI 10.17487/RFC4055, June 2005,
              <https://www.rfc-editor.org/info/rfc4055>.

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   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <https://www.rfc-editor.org/info/rfc5280>.

   [RFC5480]  Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
              "Elliptic Curve Cryptography Subject Public Key
              Information", RFC 5480, DOI 10.17487/RFC5480, March 2009,
              <https://www.rfc-editor.org/info/rfc5480>.

   [RFC8017]  Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
              "PKCS #1: RSA Cryptography Specifications Version 2.2",
              RFC 8017, DOI 10.17487/RFC8017, November 2016,
              <https://www.rfc-editor.org/info/rfc8017>.

   [SHA3]     National Institute of Standards and Technology, "SHA-3
              Standard - Permutation-Based Hash and Extendable-Output
              Functions FIPS PUB 202", August 2015,
              <https://www.nist.gov/publications/sha-3-standard-
              permutation-based-hash-and-extendable-output-functions>.

8.2.  Informative References

   [RFC3279]  Bassham, L., Polk, W., and R. Housley, "Algorithms and
              Identifiers for the Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 3279, DOI 10.17487/RFC3279, April
              2002, <https://www.rfc-editor.org/info/rfc3279>.

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security", BCP 106, RFC 4086,
              DOI 10.17487/RFC4086, June 2005,
              <https://www.rfc-editor.org/info/rfc4086>.

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

   [SP800-90A]
              National Institute of Standards and Technology,
              "Recommendation for Random Number Generation Using
              Deterministic Random Bit Generators. NIST SP 800-90A",
              June 2015,
              <http://nvlpubs.nist.gov/nistpubs/SpecialPublications/
              NIST.SP.800-90Ar1.pdf>.

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   [X9.62]    American National Standard for Financial Services (ANSI),
              "X9.62-2005 Public Key Cryptography for the Financial
              Services Industry: The Elliptic Curve Digital Signature
              Standard (ECDSA)", November 2005.

Appendix A.  ASN.1 module

   [ EDNOTE: More here. ]

Authors' Addresses

   Panos Kampanakis
   Cisco Systems

   Email: pkampana@cisco.com

   Quynh Dang
   NIST
   100 Bureau Drive, Stop 8930
   Gaithersburg, MD  20899-8930
   USA

   Email: quynh.dang@nist.gov

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