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The Profile for Algorithms and Key Sizes for use in the Resource Public Key Infrastructure
draft-ietf-sidr-rfc6485bis-04

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 7935.
Authors Geoff Huston , George G. Michaelson
Last updated 2015-12-07 (Latest revision 2015-10-15)
RFC stream Internet Engineering Task Force (IETF)
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Stream WG state WG Document
Revised I-D Needed - Issue raised by IESG
Document shepherd Sandra L. Murphy
Shepherd write-up Show Last changed 2015-10-16
IESG IESG state Became RFC 7935 (Proposed Standard)
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Responsible AD Alvaro Retana
Send notices to aretana@cisco.com
IANA IANA review state IANA OK - No Actions Needed
draft-ietf-sidr-rfc6485bis-04
SIDR                                                           G. Huston
Internet-Draft                                        G. Michaelson, Ed.
Obsoletes: 6485 (if approved)                                      APNIC
Intended status: Standards Track                        October 16, 2015
Expires: April 18, 2016

The Profile for Algorithms and Key Sizes for use in the Resource Public
                           Key Infrastructure
                   draft-ietf-sidr-rfc6485bis-04.txt

Abstract

   This document specifies the algorithms, algorithms' parameters,
   asymmetric key formats, asymmetric key size, and signature format for
   the Resource Public Key Infrastructure (RPKI) subscribers that
   generate digital signatures on certificates, Certificate Revocation
   Lists (CRLs), Cryptographic Message Syntax (CMS) signed objects and
   certification requests as well as for the relying parties (RPs) that
   verify these digital signatures.

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 18, 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

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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Algorithms  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Asymmetric Key Pair Formats . . . . . . . . . . . . . . . . . . 4
     3.1.  Public Key Format . . . . . . . . . . . . . . . . . . . . . 4
     3.2.  Private Key Format  . . . . . . . . . . . . . . . . . . . . 5
   4.  Signature Format  . . . . . . . . . . . . . . . . . . . . . . . 5
   5.  Additional Requirements . . . . . . . . . . . . . . . . . . . . 5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   8.  Changes Aplied to RFC6485 . . . . . . . . . . . . . . . . . . . 6
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     10.1. Normative References  . . . . . . . . . . . . . . . . . . . 7
     10.2. Informative References  . . . . . . . . . . . . . . . . . . 8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 9

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1.  Introduction

   This document specifies:

      *  the digital signature algorithm and parameters;
      *  the hash algorithm and parameters;
      *  the public and private key formats; and,
      *  the signature format
   used by Resource Public Key Infrastructure (RPKI) [RFC6480]
   subscribers when they apply digital signatures to certificates and
   Certificate Revocation Lists (CRLs) [RFC5280], Cryptographic Message
   Syntax (CMS) signed objects [RFC5652] (e.g., Route Origin
   Authorizations (ROAs) [RFC6482] and manifests [RFC6486]), and
   certification requests [RFC2986][RFC4211].  Relying parties (RPs)
   also use the algorithms defined in this document to verify RPKI
   subscribers' digital signatures [RFC6480].

   This document is referenced by other RPKI profiles and
   specifications, including the RPKI Certificate Policy (CP) [RFC6484],
   the RPKI Certificate Profile [RFC6487], the RPKI Architecture
   [RFC6480], and the Signed Object Template for the RPKI [RFC6488].
   Familiarity with these documents is assumed.

1.1.  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].

2.  Algorithms

   Two cryptographic algorithms are used in the RPKI:

      *  The signature algorithm used in certificates, CRLs, CMS signed
         objects, and certification requests is RSA Public-Key
         Cryptography Standards (PKCS) #1 Version 1.5 (sometimes
         referred to as "RSASSA-PKCS1-v1_5") from Section 8.2 of
         [RFC3447].

      *  The hashing algorithm used in certificates, CRLs, CMS signed
         objects and certification requests is SHA-256 [SHS] (see note
         below).

         NOTE: The exception is the use of SHA-1 [SHS] when CAs generate
         authority and subject key identifiers [RFC6487].

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   In certificates, CRLs, and certification requests the hashing and
   digital signature algorithms are identified together, i.e., "RSA
   PKCS#1 v1.5 with SHA-256" or more simply "RSA with SHA-256".  The
   Object Identifier (OID) sha256WithRSAEncryption from [RFC4055] MUST
   be used in these products.

   The OID is in the following locations:

      In the certificate, the OID appears in the signature and
      signatureAlgorithm fields [RFC4055];

      In the CRL, the OID appears in the signatureAlgorithm field
      [RFC4055]; and

      In a certification request, the OID appears in the PKCS #10
      signatureAlgorithm field [RFC2986], or in the Certificate Request
      Message Format (CRMF) POPOSigningKey algorithmIdentifier field
      [RFC4211].

   In CMS SignedData, the hashing (message digest) and digital signature
   algorithms are identified separately.  The object identifier and
   parameters for SHA-256 (as defined in [RFC5754]) MUST be used for the
   SignedData digestAlgorithms field and the SignerInfo digestAlgorithm
   field.  The object identifier and parameters for rsaEncryption
   [RFC3370] MUST be used for the SignerInfo signatureAlgorithm field
   when generating CMS SignedData objects.  RPKI implementations MUST
   accept either rsaEncryption or sha256WithRSAEncryption for the
   SignerInfo signatureAlgorithm field when verifying CMS SignedData
   objects (for compatibility with objects produced by implementations
   conforming to [RFC6485]).

3.  Asymmetric Key Pair Formats

   The RSA key pairs used to compute the signatures MUST have a 2048-bit
   modulus and a public exponent (e) of 65,537.

3.1.  Public Key Format

   The subject's public key is included in subjectPublicKeyInfo
   [RFC5280].  It has two sub-fields: algorithm and subjectPublicKey.
   The values for the structures and their sub-structures follow:

   algorithm (which is an AlgorithmIdentifier type):
      The object identifier for RSA PKCS#1 v1.5 with SHA-256 MUST be
      used in the algorithm field, as specified in Section 5 of
      [RFC4055].  The value for the associated parameters from that
      clause MUST also be used for the parameters field.

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   subjectPublicKey:
      RSAPublicKey MUST be used to encode the certificate's
      subjectPublicKey field, as specified in [RFC4055].

3.2.  Private Key Format

   Local policy determines the private key format.

4.  Signature Format

   The structure for the certificate's signature field is as specified
   in Section 1.2 of [RFC4055].  The structure for the CMS SignedData's
   signature field is as specified in [RFC5652].

5.  Additional Requirements

   It is anticipated that the RPKI will require the adoption of updated
   key sizes and a different set of signature and hash algorithms over
   time, in order to maintain an acceptable level of cryptographic
   security to protect the integrity of signed products in the RPKI.
   This profile should be replaced to specify such future requirements,
   as and when appropriate.

   Certification Authorities (CAs) and RPs SHOULD be capable of
   supporting a transition to allow for the phased introduction of
   additional encryption algorithms and key specifications, and also
   accommodate the orderly deprecation of previously specified
   algorithms and keys.  Accordingly, CAs and RPs SHOULD be capable of
   supporting multiple RPKI algorithm and key profiles simultaneously
   within the scope of such anticipated transitions.  The recommended
   procedures to implement such a transition of key sizes and algorithms
   is specified in [RFC6916]

6.  Security Considerations

   The Security Considerations of [RFC4055], [RFC5280], and [RFC6487]
   apply to certificate and CRLs.  The Security Considerations of
   [RFC2986], [RFC4211], and [RFC6487] apply to certification />
   requests.  The Security Considerations of [RFC5754] apply to CMS
   signed objects.  No new security threats are introduced as a result
   of this specification.

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7.  IANA Considerations

   [Remove before publication.  There are no IANA considerations in this
   document.]

8.  Changes Aplied to RFC6485

   This update includes a slight technical change to [RFC6485] that is
   considered to be outside the limited scope of an erratum.  The
   document update process has included other errata and also corrected
   a number of nits.

   Section 2 of [RFC6485] specified sha256WithRSAEncryption as the OID
   to use for the SignerInfo signatureAlgorithm field in CMS
   SignedObjects.  However, existing implementations use the
   rsaEncryption OID for this field.  (Support for rsaEncryption in 3rd
   party cryptographic libraries is better than sha256WithRSAEncryption,
   perhaps because [RFC3370] says that support for rsaEncryption is
   required while support for OIDs that specify both RSA and a digest
   algorithm is optional.)

   Rather than force existing implementations to switch to
   sha256WithRSAEncryption, this document was changed to follow existing
   practice.  This does not represent a cryptographic algorithm change,
   just an identifier change.  (Unlike certificates, CRLs, and
   certification requests, CMS signed objects have a separate algorithm
   identifier field for the hash (digest) algorithm, and that field is
   already required to contain the id-sha256 OID per Section 2.)

   To avoid compatibility problems, RPs are still required to accept
   sha256WithRSAEncryption if encountered.

   Other changes include:

      *  Minor wording and typo fixes.
      *  Some incorrect references were fixed ([RFC5652] instead of
         [RFC3370], [RFC3447] instead of [RFC4055]).
      *  Additional citations were added to the Introduction.
      *  Section 2 now references the correct CRMF POPOSigningKey field
         (algorithmIdentifier instead of signature).
      *  Certification requests are now mentioned along with
         certificates, CRLs, and CMS signed objects.
      *  Section 5 now cites [RFC6916] (algorithm agility).
      *  "Signed object" is now "CMS signed object" everywhere.

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9.  Acknowledgments

   The authors acknowledge the reuse in this document of material
   originally contained in working drafts the RPKI Certificate Policy
   [RFC6484] and resource certificate profile [RFC6487] documents.  The
   co-authors of these two documents, namely Stephen Kent, Derrick Kong,
   Karen Seo, Ronald Watro, George Michaelson and Robert Loomans, are
   acknowledged, with thanks.  The constraint on key size noted in this
   profile is the outcome of comments from Stephen Kent and review
   comments from David Cooper.  Sean Turner has provided additional
   review input to this document.

   Andrew Chi and David Mandelberg discovered the issue addressed in
   this update to [RFC6485], and the changes in this updated
   specification reflect the outcome of a discussion between Rob Austein
   and Matt Lepinski on the SIDR Working group mailing list.  Richard
   Hansen edited this update to the document.

10.  References

10.1.  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>.

   [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
              Request Syntax Specification Version 1.7", RFC 2986,
              DOI 10.17487/RFC2986, November 2000,
              <http://www.rfc-editor.org/info/rfc2986>.

   [RFC3370]  Housley, R., "Cryptographic Message Syntax (CMS)
              Algorithms", RFC 3370, DOI 10.17487/RFC3370, August 2002,
              <http://www.rfc-editor.org/info/rfc3370>.

   [RFC3447]  Jonsson, J. and B. Kaliski, "Public-Key Cryptography
              Standards (PKCS) #1: RSA Cryptography Specifications
              Version 2.1", RFC 3447, DOI 10.17487/RFC3447,
              February 2003, <http://www.rfc-editor.org/info/rfc3447>.

   [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,
              <http://www.rfc-editor.org/info/rfc4055>.

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   [RFC4211]  Schaad, J., "Internet X.509 Public Key Infrastructure
              Certificate Request Message Format (CRMF)", RFC 4211,
              DOI 10.17487/RFC4211, September 2005,
              <http://www.rfc-editor.org/info/rfc4211>.

   [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,
              <http://www.rfc-editor.org/info/rfc5280>.

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

   [RFC5754]  Turner, S., "Using SHA2 Algorithms with Cryptographic
              Message Syntax", RFC 5754, DOI 10.17487/RFC5754,
              January 2010, <http://www.rfc-editor.org/info/rfc5754>.

   [RFC6480]  Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
              February 2012, <http://www.rfc-editor.org/info/rfc6480>.

   [RFC6484]  Kent, S., Kong, D., Seo, K., and R. Watro, "Certificate
              Policy (CP) for the Resource Public Key Infrastructure
              (RPKI)", BCP 173, RFC 6484, DOI 10.17487/RFC6484,
              February 2012, <http://www.rfc-editor.org/info/rfc6484>.

   [RFC6487]  Huston, G., Michaelson, G., and R. Loomans, "A Profile for
              X.509 PKIX Resource Certificates", RFC 6487, DOI 10.17487/
              RFC6487, February 2012,
              <http://www.rfc-editor.org/info/rfc6487>.

   [RFC6488]  Lepinski, M., Chi, A., and S. Kent, "Signed Object
              Template for the Resource Public Key Infrastructure
              (RPKI)", RFC 6488, DOI 10.17487/RFC6488, February 2012,
              <http://www.rfc-editor.org/info/rfc6488>.

   [SHS]      National Institute of Standards and Technology (NIST),
              "FIPS Publication 180-3: Secure Hash Standard", FIPS
              Publication 180-3, October 2008.

10.2.  Informative References

   [RFC6482]  Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
              Origin Authorizations (ROAs)", RFC 6482, DOI 10.17487/
              RFC6482, February 2012,
              <http://www.rfc-editor.org/info/rfc6482>.

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   [RFC6485]  Huston, G., "The Profile for Algorithms and Key Sizes for
              Use in the Resource Public Key Infrastructure (RPKI)",
              RFC 6485, DOI 10.17487/RFC6485, February 2012,
              <http://www.rfc-editor.org/info/rfc6485>.

   [RFC6486]  Austein, R., Huston, G., Kent, S., and M. Lepinski,
              "Manifests for the Resource Public Key Infrastructure
              (RPKI)", RFC 6486, DOI 10.17487/RFC6486, February 2012,
              <http://www.rfc-editor.org/info/rfc6486>.

   [RFC6916]  Gagliano, R., Kent, S., and S. Turner, "Algorithm Agility
              Procedure for the Resource Public Key Infrastructure
              (RPKI)", BCP 182, RFC 6916, DOI 10.17487/RFC6916,
              April 2013, <http://www.rfc-editor.org/info/rfc6916>.

Authors' Addresses

   Geoff Huston
   APNIC

   Email: gih@apnic.net

   George Michaelson (editor)
   APNIC

   Email: ggm@apnic.net

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