\
None                                                           S. Turner
Internet-Draft                                                     sn3rd
Intended status: Standards Track                           P. Kampanakis
Expires: 8 September 2022                                     J. Massimo
                                                                     AWS
                                                           B. Westerbaan
                                                              Cloudflare
                                                            7 March 2022


Algorithm Identifiers for NIST's PQC Algorithms for Use in the Internet
                    X.509 Public Key Infrastructure
          draft-turner-lamps-nist-pqc-kem-certificates-01

Abstract

   This document specifies algorithm identifiers and ASN.1 encoding
   format for the US NIST's PQC KEM (United States National Institute of
   Standards and Technology's Post Quantum Cryptography Key
   Encapsulation Mechanism) algorithms.  The algorithms covered are
   Candidate TBD1.  The encoding for public key and private key is also
   provided.

   [EDNOTE: This draft is not expected to be finalized before the NIST
   PQC Project has standardized PQ algorithms.  After NIST has
   standardized its first algorithms, this document will replace TBD,
   with the appropriate algorithms and parameters before proceeding to
   ratification.  The algorithm Candidate TBD1 has been added as an
   example in this draft, to provide a more detailed illustration of the
   content - it by no means indicates its inclusion in the final
   version.  This specification will use object identifiers for the new
   algorithms that are assigned by NIST, and will use placeholders until
   these are released.]

About This Document

   This note is to be removed before publishing as an RFC.

   Status information for this document may be found at
   https://datatracker.ietf.org/doc/draft-turner-lamps-nist-pqc-kem-
   certificates/.

   Discussion of this document takes place on the Limited Additional
   Mechanisms for PKIX and SMIME (lamps) Working Group mailing list
   (mailto:spasm@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/spasm/.





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   Source for this draft and an issue tracker can be found at
   https://github.com/ seanturner/draft-turner-lamps-nist-pqc-kem-
   certificates.

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 8 September 2022.

Copyright Notice

   Copyright (c) 2022 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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
   3.  Algorithm Identifiers . . . . . . . . . . . . . . . . . . . .   3
   4.  Candidate TBD1  . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Subject Public Key Fields . . . . . . . . . . . . . . . . . .   4
   6.  Key Usage Bits  . . . . . . . . . . . . . . . . . . . . . . .   5
   7.  Private Key Format  . . . . . . . . . . . . . . . . . . . . .   5
   8.  ASN.1 Module  . . . . . . . . . . . . . . . . . . . . . . . .   6
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7



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     11.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     11.2.  Informative References . . . . . . . . . . . . . . . . .   7
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   The US NIST PQC Project has selected the Candidate TBD1 algorithms as
   winners of their PQC Project [PQCProj].  These algorithms are KEM
   algorithms.  NIST has also defined object identifiers for these
   algorithms (TODO insert reference).

   This document specifies the use of the Candidate TBD1 algorithms in
   X.509 public key certifiates, see [RFC5280].  It also specifies
   private key encoding.  An ASN.1 module is included for reference
   purposes.

   These certificates could be used as Issuers in CMS where the public
   key is used to encapsulate a shared secret used to derive a symmetric
   key used to encrypt content in CMS [EDNOTE: Add reference draft-
   perret-prat-lamps-cms-pq-kem].  To be used in TLS, these certificates
   could only be used as end-entity identity certificates and would
   require significant updates to the protocol [EDNOTE: Add reference
   draft-celi-wiggers-tls-authkem].

2.  Conventions and Definitions

   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.

3.  Algorithm Identifiers

   Certificates conforming to [RFC5280] can convey a public key for any
   public key algorithm.  The certificate indicates the algorithm
   through an algorithm identifier.  An algorithm identifier consists of
   an object identifier and optional parameters.

   The AlgorithmIdentifier type, which is included herein for
   convenience, is defined as follows:

      AlgorithmIdentifier  ::=  SEQUENCE  {
          algorithm   OBJECT IDENTIFIER,
          parameters  ANY DEFINED BY algorithm OPTIONAL
      }




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      |  NOTE: The above syntax is from [RFC5280] and matches the
      |  version used therein, i.e., the 1988 ASN.1 syntax.  See
      |  [RFC5912] for ASN.1 copmatible with the 2015 ASN.1 syntax.

   The fields in AlgorithmIdentifier have the following meanings:

   *  algorithm identifies the cryptographic algorithm with an object
      identifier.  XXX such OIDs are defined in Sections Section 4.

   *  parameters, which are optional, are the associated parameters for
      the algorithm identifier in the algorithm field.

   In this document, TODO (specify number) new OIDs for identifying the
   different algorithm and parameter pairs.  For all of the object
   identifiers, the parameters MUST be absent.

   It is possible to find systems that require the parameters to be
   present.  This can be due to either a defect in the original 1997
   syntax or a programming error where developers never got input where
   this was not true.  The optimal solution is to fix these systems;
   where this is not possible, the problem needs to be restricted to
   that subsystem and not propagated to the Internet.

4.  Candidate TBD1

   TODO insert object-identifiers

5.  Subject Public Key Fields

   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
     }

      |  NOTE: The above syntax is from [RFC5280] and matches the
      |  version used therein, i.e., the 1988 ASN.1 syntax.  See
      |  [RFC5912] for ASN.1 copmatible with the 2015 ASN.1 syntax.

   The fields in SubjectPublicKeyInfo have the following meanings:

   *  algorithm is the algorithm identifier and parameters for the
      public key (see above).






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   *  subjectPublicKey contains the byte stream of the public key.  The
      algorithms defined in this document always encode the public key
      as TODO pick format e.g., exact multiple of 8 bits?.

   The following is an example of a TBD public key encoded using the
   textual encoding defined in [RFC7468].

     -----BEGIN PUBLIC KEY-----
     TODO insert example public key
     -----END PUBLIC KEY-------

6.  Key Usage Bits

   The intended application for the key is indicated in the keyUsage
   certificate extension; see Section 4.2.1.3 of [RFC5280].

   If the keyUsage extension is present in a certificate that indicates
   Candidate TBD1 in SubjectPublicKeyInfo, then the following MUST be
   present:

     keyEncipherment;

7.  Private Key Format

   "Asymmetric Key Packages" [RFC5958] describes how to encode a private
   key in a structure that both identifies what algorithm the private
   key is for and allows for the public key and additional attributes
   about the key to be included as well.  For illustration, the ASN.1
   structure OneAsymmetricKey is replicated below.  The algorithm-
   specific details of how a private key is encoded are left for the
   document describing the algorithm itself.

     OneAsymmetricKey ::= SEQUENCE {
         version                  Version,
         privateKeyAlgorithm      PrivateKeyAlgorithmIdentifier,
         privateKey               PrivateKey,
         attributes           [0] IMPLICIT Attributes OPTIONAL,
         ...,
         [[2: publicKey       [1] IMPLICIT PublicKey OPTIONAL ]],
         ...
     }

     PrivateKey ::= OCTET STRING

     PublicKey ::= BIT STRING






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      |  NOTE: The above syntax is from [RFC5958] and matches the
      |  version used therein, i.e., the 2002 ASN.1 syntax.  The syntax
      |  used therein is compatible with the 2015 ASN.1 syntax.

   For the keys defined in this document, the private key is always an
   opaque byte sequence.  The ASN.1 type PqckemPrivateKey is defined in
   this document to hold the byte sequence.  Thus, when encoding a
   OneAsymmetricKey object, the private key is wrapped in a
   PqckemPrivateKey object and wrapped by the OCTET STRING of the
   "privateKey" field.

     PqckemPrivateKey ::= OCTET STRING

   The following is an example of a TBD private key encoded using the
   textual encoding defined in [RFC7468].

     -----BEGIN PRIVATE KEY-----
     TODO iser example private key
     -----END PRIVATE KEY-------

   The following example, in addition to encoding the TBD private key,
   has an attribute included as well as the public key.  As with the
   prior example, the textual encoding defined in [RFC7468] is used.

     -----BEGIN PRIVATE KEY-----
     TODO insert example private key with attribute
     -----END PRIVATE KEY-------

      |  NOTE: There exist some private key import functions that have
      |  not implemented the new ASN.1 structure OneAsymmetricKey that
      |  is defined in [RFC5958].  This means that they will not accept
      |  a private key structure that contains the public key field.
      |  This means a balancing act needs to be done between being able
      |  to do a consistency check on the key pair and widest ability to
      |  import the key.

8.  ASN.1 Module

   TODO ASN.1 Module

9.  Security Considerations

   The Security Considerations section of [RFC5280] applies to this
   specification as well.

   [EDNOTE: Discuss side-channels for Candidate TBD1.]





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10.  IANA Considerations

   This document will have some IANA actions.

11.  References

11.1.  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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [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>.

   [RFC5912]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
              Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
              DOI 10.17487/RFC5912, June 2010,
              <https://www.rfc-editor.org/info/rfc5912>.

   [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958,
              DOI 10.17487/RFC5958, August 2010,
              <https://www.rfc-editor.org/info/rfc5958>.

   [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>.

11.2.  Informative References

   [PQCProj]  National Insititue of Standards and Technology, "Post-
              Quantum Cryptography Project", 20 December 2016,
              <https://csrc.nist.gov/projects/post-quantum-
              cryptography>.

   [RFC7468]  Josefsson, S. and S. Leonard, "Textual Encodings of PKIX,
              PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468,
              April 2015, <https://www.rfc-editor.org/info/rfc7468>.

Acknowledgments

   TODO acknowledge.





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Authors' Addresses

   Sean Turner
   sn3rd

   Email: sean@sn3rd.com


   Panos Kampanakis
   AWS

   Email: kpanos@amazon.com


   Jake Massimo
   AWS

   Email: jakemas@amazon.com


   Bas Westerbaan
   Cloudflare

   Email: bas@westerbaan.name



























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