





Internet Engineering Task Force (IETF)                        R. Housley
Request for Comments: 8619                                Vigil Security
Category: Standards Track                                      June 2019
ISSN: 2070-1721


                     Algorithm Identifiers for the
      HMAC-based Extract-and-Expand Key Derivation Function (HKDF)

Abstract

   RFC 5869 specifies the HMAC-based Extract-and-Expand Key Derivation
   Function (HKDF) algorithm.  This document assigns algorithm
   identifiers to the HKDF algorithm when used with three common one-way
   hash functions.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8619.

Copyright Notice

   Copyright (c) 2019 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
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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.







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RFC 8619                        HKDF OIDs                      June 2019


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  ASN.1 . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  HKDF Algorithm Identifiers  . . . . . . . . . . . . . . . . .   2
   3.  ASN.1 Module  . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   The HKDF algorithm [RFC5869] is a key derivation function based on
   the Hashed Message Authentication Code (HMAC).  This document assigns
   algorithm identifiers to the HKDF algorithm when used with three
   common one-way hash functions.  These algorithm identifiers are
   needed to make use of the HKDF in some security protocols, such as
   the Cryptographic Message Syntax (CMS) [RFC5652].

1.1.  Terminology

   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.

1.2.  ASN.1

   In this specification, values are generated using ASN.1 [X.680] using
   the Basic Encoding Rules (BER) and the Distinguished Encoding Rules
   (DER) [X.690].

2.  HKDF Algorithm Identifiers

   This section assigns three algorithm identifiers to HKDF [RFC5869]
   used with three common one-way hash functions that are specified in
   [SHS]: SHA-256, SHA-384, and SHA-512.  When any of these three object
   identifiers appear within the ASN.1 type AlgorithmIdentifier, the
   parameters component of that type SHALL be absent.

   The specification of AlgorithmIdentifier is available in [RFC5911],
   which evolved from the original definition in X.509 [X.509-88].




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RFC 8619                        HKDF OIDs                      June 2019


   The assigned object identifiers are:

   id-alg-hkdf-with-sha256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 28 }

   id-alg-hkdf-with-sha384 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 29 }

   id-alg-hkdf-with-sha512 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 30 }

3.  ASN.1 Module

   This section contains the ASN.1 module for the HKDF algorithm
   identifiers.  This module imports types from other ASN.1 modules that
   are defined in [RFC5912].

   HKDF-OID-2019
     { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
       smime(16) modules(0) id-mod-hkdf-oid-2019(68) }

   DEFINITIONS IMPLICIT TAGS ::=
   BEGIN

   -- EXPORTS All

   IMPORTS

   AlgorithmIdentifier{}, KEY-DERIVATION
     FROM AlgorithmInformation-2009  -- [RFC5912]
       { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7) id-mod(0)
         id-mod-algorithmInformation-02(58) } ;

   --
   -- Object Identifiers
   --

   id-alg-hkdf-with-sha256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 28 }

   id-alg-hkdf-with-sha384 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 29 }

   id-alg-hkdf-with-sha512 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 30 }





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RFC 8619                        HKDF OIDs                      June 2019


   --
   -- Key Derivation Algorithm Identifiers
   --

   KeyDevAlgs KEY-DERIVATION ::= {
     kda-hkdf-with-sha256 |
     kda-hkdf-with-sha384 |
     kda-hkdf-with-sha512,
     ... }

   kda-hkdf-with-sha256 KEY-DERIVATION ::= {
       IDENTIFIER id-alg-hkdf-with-sha256
       PARAMS ARE absent
       SMIME-CAPS { IDENTIFIED BY id-alg-hkdf-with-sha256 } }

   kda-hkdf-with-sha384 KEY-DERIVATION ::= {
       IDENTIFIER id-alg-hkdf-with-sha384
       PARAMS ARE absent
       SMIME-CAPS { IDENTIFIED BY id-alg-hkdf-with-sha384 } }

   kda-hkdf-with-sha512 KEY-DERIVATION ::= {
       IDENTIFIER id-alg-hkdf-with-sha512
       PARAMS ARE absent
       SMIME-CAPS { IDENTIFIED BY id-alg-hkdf-with-sha512 } }

   END

4.  Security Considerations

   Despite the simplicity of HKDF, there are many security
   considerations that have been taken into account in the design and
   analysis of this construction.  An exposition of all of these aspects
   is well beyond the scope of this document.  Please refer to [EPRINT]
   for detailed information, including rationale for the HKDF design.

5.  IANA Considerations

   One object identifier for the ASN.1 module in Section 3 was assigned
   in the "SMI Security for S/MIME Module Identifiers
   (1.2.840.113549.1.9.16.0)" registry [IANA-MOD]:

   id-mod-hkdf-oid-2019 OBJECT IDENTIFIER ::= {
      iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
      pkcs-9(9) smime(16) mod(0) 68 }







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RFC 8619                        HKDF OIDs                      June 2019


   Three object identifiers for the HKDF algorithm identifiers were
   assigned in the "SMI Security for S/MIME Algorithms
   (1.2.840.113549.1.9.16.3)" registry [IANA-ALG]:

   id-alg-hkdf-with-sha256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 28 }

   id-alg-hkdf-with-sha384 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 29 }

   id-alg-hkdf-with-sha512 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
       us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 30 }

6.  References

6.1.  Normative References

   [SHS]      National Institute of Standards and Technology (NIST),
              "Secure Hash Standard (SHS)", FIPS PUB 180-4,
              DOI 10.6028/NIST.FIPS.180-4, August 2015.

   [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>.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, DOI 10.17487/RFC5652, September 2009,
              <https://www.rfc-editor.org/info/rfc5652>.

   [RFC5869]  Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand
              Key Derivation Function (HKDF)", RFC 5869,
              DOI 10.17487/RFC5869, May 2010,
              <https://www.rfc-editor.org/info/rfc5869>.

   [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>.

   [X.680]    ITU-T, "Information technology -- Abstract Syntax Notation
              One (ASN.1): Specification of basic notation",
              ITU-T Recommendation X.680, ISO/IEC 8824-1:2015, August
              2015.








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RFC 8619                        HKDF OIDs                      June 2019


   [X.690]    ITU-T, "Information technology -- ASN.1 encoding rules:
              Specification of Basic Encoding Rules (BER), Canonical
              Encoding Rules (CER) and Distinguished Encoding Rules
              (DER)", ITU-T Recommendation X.690, ISO/IEC 8825-1:2015,
              August 2015.

6.2.  Informative References

   [EPRINT]   Krawczyk, H., "Cryptographic Extraction and Key
              Derivation: The HKDF Scheme", Proceedings of CRYPTO 2010,
              August 2010, <https://eprint.iacr.org/2010/264.pdf>.

   [IANA-ALG] IANA, "SMI Security for S/MIME Algorithms
              (1.2.840.113549.1.9.16.3)",
              <https://www.iana.org/assignments/smi-numbers/>.

   [IANA-MOD] IANA, "SMI Security for S/MIME Module Identifier
              (1.2.840.113549.1.9.16.0)",
              <https://www.iana.org/assignments/smi-numbers/>.

   [RFC5911]  Hoffman, P. and J. Schaad, "New ASN.1 Modules for
              Cryptographic Message Syntax (CMS) and S/MIME", RFC 5911,
              DOI 10.17487/RFC5911, June 2010,
              <https://www.rfc-editor.org/info/rfc5911>.

   [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>.

   [X.509-88] CCITT, "Recommendation X.509: The Directory -
              Authentication Framework", 1988.

Author's Address

   Russell Housley
   Vigil Security, LLC
   515 Dranesville Road
   Herndon, VA 20170
   United States of America

   Email: housley@vigilsec.com









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