GENWiki

Independent Submission N. Mavrogiannopoulos Request for Comments: 8479 Red Hat Category: Informational September 2018 ISSN: 2070-1721

              Storing Validation Parameters in PKCS#8

Abstract

 This memo describes a method of storing parameters needed for
 private-key validation in the Private-Key Information Syntax
 Specification as defined in PKCS#8 format (RFC 5208).  It is equally
 applicable to the alternative implementation of the Private-Key
 Information Syntax Specification as defined in RFC 5958.

 The approach described in this document encodes the parameters under
 a private enterprise extension and does not form part of a formal
 standard.

Status of This Memo

 This document is not an Internet Standards Track specification; it is
 published for informational purposes.

 This is a contribution to the RFC Series, independently of any other
 RFC stream.  The RFC Editor has chosen to publish this document at
 its discretion and makes no statement about its value for
 implementation or deployment.  Documents approved for publication by
 the RFC Editor are not candidates for any level of Internet Standard;
 see 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/rfc8479.

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.

Mavrogiannopoulos Informational [Page 1] RFC 8479 Storing Validation Parameters in PKCS#8 September 2018

Table of Contents

 1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
 2.  ValidationParams Attribute  . . . . . . . . . . . . . . . . .   3
 3.  Example Structure . . . . . . . . . . . . . . . . . . . . . .   4
 4.  Compatibility Notes . . . . . . . . . . . . . . . . . . . . .   4
 5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
 6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
 7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
   7.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
   7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
 Appendix A.  ASN.1 Module . . . . . . . . . . . . . . . . . . . .   7
 Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   8
 Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

Mavrogiannopoulos Informational [Page 2] RFC 8479 Storing Validation Parameters in PKCS#8 September 2018

1. Introduction

 RSA or DSA private keys generated using the Shawe-Taylor prime
 generation algorithm described in [FIPS186-4] allow for parameter
 validation, i.e., they verify whether the primes are actually prime
 and were correctly generated.  That is done by generating the
 parameters from a known seed and a selected hash algorithm.

 Storing these parameters in a private-key format such as the RSA
 Private-Key Syntax from PKCS#1 [RFC8017] or common representations
 for DSA private keys does not allow information needed for validation
 to be attached to the parameters.  The purpose of this document is to
 describe such a method using the Private-Key Information Syntax
 Specification as defined in [RFC5208] and the alternative
 specification described in [RFC5958].

 The approach described in this document encodes the parameters under
 a private enterprise extension and does not form part of a formal
 standard.  The encoding can be used as is or as the basis for a
 standard at a later time.

2. ValidationParams Attribute

 The information related to the validation parameters is stored as an
 attribute in the PrivateKeyInfo structure.  The attribute is
 identified by the id-attr-validation-parameters object identifier and
 contains as AttributeValue a single ValidationParams structure.

   id-attr-validation-parameters OBJECT IDENTIFIER ::=
                                            {1 3 6 1 4 1 2312 18 8 1}

   ValidationParams ::= SEQUENCE {
       hashAlgo OBJECT IDENTIFIER,
       seed OCTET STRING
   }

 The algorithm identifier in ValidationParams should be a hash
 algorithm identifier for the methods described in [FIPS186-4].  The
 ValidationParams sequence must be DER encoded [ITU-T-X690].

Mavrogiannopoulos Informational [Page 3] RFC 8479 Storing Validation Parameters in PKCS#8 September 2018

3. Example Structure

 The following structure contains an RSA key generated using the
 algorithm from Section B.3.3 of [FIPS186-4], with SHA2-384 hash.  The
 seed used is
 8af4328c87bebcec31e303b8f5537effcb6a91d947084d99a369823b36f01462 (hex
 encoded).

—-BEGIN PRIVATE KEY—–

MIIE/gIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQCpPwXwfhDsWA3q

 jN2BWg1xfDjvZDVNfgTV/b95g304Aty3z13xPXAhHZ3ROW3pgPxTj9fiq7ZMy4Ua
 gMpPK81v3pHX1uokC2KcGXbgbAq2Q8ClxSXgEJllRwDENufjEdV10gArt8NlIP0N
 lota1kQUuI1DMsqc5DTIa35Nq4j1GW+KmLtP0kCrGq9fMGwjDbPEpSp9DTquEMHJ
 o7kyJIjB+93ikLvBUTgbxr+jcnTLXuhA8rC8r+KXre4NPPNPRyefRcALLt/URvfA
 rTvFOQfi3vIjNhBZL5FdC+FVAr5QnF3r2+cuDPbnczr4/rr81kzFGWrwyAgF5FWu
 pFtB5IYDAgMBAAECggEAHZ88vGNsNdmRkfhWupGW4cKCuo+Y7re8Q/H2Jd/4Nin2
 FKvUPuloaztiSGDbVm+vejama/Nu5FEIumNJRYMeoVJcx2DDuUxO1ZB1aIEwfMct
 /DWd0/JDzuCXB0Cu5GTWLhlz0zMGHXihIdQ0DtGKt++3Ncg5gy1D+cIqqJB515/z
 jYdZmb0Wqmz7H3DisuxvnhiCAOuNrjcDau80hpMA9TQlb+XKNGHIBgKpJe6lnB0P
 MsS/AjDiDoEpP9GG9mv9+96rAga4Nos6avYlwWwbC6d+hHIWvWEWsmrDfcJlm2gN
 tjvG8omj00t5dAt7qGhfOoNDGr5tvJVo/g96O/0I8QKBgQDdzytVRulo9aKVdAYW
 /Nj04thtnRaqsTyFH+7ibEVwNIUuld/Bp6NnuGrY+K1siX8+zA9f8mKxuXXV9KK4
 O89Ypw9js2BxM7VYO9Gmp6e1RY3Rrd8w7pG7/KqoPWXkuixTay9eybrJMWu3TT36
 q7NheNmBHqcFmSQQuUwEmvp3MQKBgQDDVaisMJkc/sIyQh3XrlfzmMLK+GlPDucD
 w5e50fHl8Q5PmTcP20zVLhTevffCqeItSyeAno94Xdzc9vZ/rt69410kJEHyBO9L
 CmhtYz94wvSdRhbqf4VzAl2WU184sIYiIZDGsnGScgIYvo6v6mITjRhc8AMdYoPR
 rL6xp6frcwKBgFi1+avCj6mFzD+fxqu89nyCmXLFiAI+nmjTy7PM/7yPlNB76qDG
 Dil2bW1Xj+y/1R9ld6S1CVnxRbqLe+TZLuVS82m5nRHJT3b5fbD8jquGJOE+e+xT
 DgA0XoCpBa6D8yRt0uVDIyxCUsVd5DL0JusN7VehzcUEaZMyuL+CyDeRAoGBAImB
 qH6mq3Kc6Komnwlw4ttJ436sxr1vuTKOIyYdZBNB0Zg5PGi+MWU0zl5LDroLi3vl
 FwbVGBxcvxkSBU63FHhKMQw7Ne0gii+iQQcYQdtKKpb4ezNS1+exd55WTIcExTgL
 tvYZMhgsh8tRgfLWpXor7kWmdBrgeflFiOxZIL1/AoGAeBP7sdE+gzsh8jqFnVRj
 7nOg+YllJAlWsf7cTH4pLIy2Eo9D+cNjhL9LK6RaAd7PSZ1adm8HfaROA2cfCm84
 RI4c7Ue0G+N6LZiFvC0Bfi5SaPVAExXOty8UqjOCoZavSaXBPuNcTXZuzswcgbxI
 G5/kaJNHoEcdlVsPsYWKRNKgPzA9BgorBgEEAZIIEggBMS8wLQYJYIZIAWUDBAIC
 BCCK9DKMh7687DHjA7j1U37/y2qR2UcITZmjaYI7NvAUYg==
 -----END PRIVATE KEY-----

4. Compatibility Notes

 For compatibility, it is recommended that implementations following
 this document support generation and validation using the SHA2-384
 hash algorithm.

 The extension defined in this document is applicable both to the
 Private-Key Information Syntax Specification (PKCS#8) [RFC5208] and
 to Asymmetric Key Packages [RFC5958].

Mavrogiannopoulos Informational [Page 4] RFC 8479 Storing Validation Parameters in PKCS#8 September 2018

5. Security Considerations

 All the considerations in [RFC5208] and [RFC5958] apply.

6. IANA Considerations

 This document has no IANA actions.

7. References

7.1. Normative References

 [FIPS186-4]
            National Institute of Standards and Technology, "Digital
            Signature Standard (DSS)", FIPS PUB 186-4,
            DOI 10.6028/NIST.FIPS.186-4, July 2013.

 [ITU-T-X680]
            International Telecommunication Union, "Abstract Syntax
            Notation One (ASN.1): Specification of basic notation",
            ITU-T Recommendation X.680, July 2002,
            <https://www.itu.int/ITU-T/studygroups/com17/languages/
            X.680-0207.pdf>.

 [ITU-T-X690]
            International Telecommunication Union, "ASN.1 encoding
            rules: Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished Encoding
            Rules (DER)", ITU-T Recommendation X.690, July 2002,
            <https://www.itu.int/ITU-T/studygroups/com17/languages/
            X.690-0207.pdf>.

 [RFC5208]  Kaliski, B., "Public-Key Cryptography Standards (PKCS) #8:
            Private-Key Information Syntax Specification Version 1.2",
            RFC 5208, DOI 10.17487/RFC5208, May 2008,
            <https://www.rfc-editor.org/info/rfc5208>.

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

Mavrogiannopoulos Informational [Page 5] RFC 8479 Storing Validation Parameters in PKCS#8 September 2018

7.2. Informative References

 [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>.

 [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>.

Mavrogiannopoulos Informational [Page 6] RFC 8479 Storing Validation Parameters in PKCS#8 September 2018

Appendix A. ASN.1 Module

 This appendix provides non-normative ASN.1 definitions for the
 structures described in this specification using ASN.1 as defined in
 [ITU-T-X680] and [RFC5912].

    PrivateKeyValidationAttrV1
      { iso(1) identified-organization(3) dod(6) internet(1)
        private(4) enterprise(1) 2312 18 1 1 }

    DEFINITIONS IMPLICIT TAGS ::=

    BEGIN

- EXPORTS ALL

    IMPORTS

    ATTRIBUTE
     FROM PKIX-CommonTypes-2009  --  [RFC5912]
       { iso(1) identified-organization(3) dod(6) internet(1)
         security(5) mechanisms(5) pkix(7) id-mod(0)
         id-mod-pkixCommon-02(57) } ;

- PrivateKeyInfo is defined in [RFC5208].
- This definition adds the validation parameters attribute
- to the set of allowed attributes.

    PrivateKeyInfo ATTRIBUTE ::= {
      at-validation-parameters, ... }

    at-validation-parameters ATTRIBUTE ::= {
      TYPE ValidationParams
      IDENTIFIED BY id-attr-validation-parameters }

    id-attr-validation-parameters OBJECT IDENTIFIER ::=
      { 1 3 6 1 4 1 2312 18 8 1 }

    ValidationParams ::= SEQUENCE {
      hashAlg OBJECT IDENTIFIER,
      seed OCTET STRING }

END

Mavrogiannopoulos Informational [Page 7] RFC 8479 Storing Validation Parameters in PKCS#8 September 2018

Acknowledgements

 The author would like to thank Russ Housley for his comments and the
 ASN.1 module appendix.

Author's Address

 Nikos Mavrogiannopoulos
 Red Hat, Inc.
 Brno
 Czech Republic

 Email: nmav@redhat.com

Mavrogiannopoulos Informational [Page 8]