The Profile for Algorithms and Key Sizes for use in the Resource Public Key Infrastructure
draft-ietf-sidr-rfc6485bis-00

SIDR                                                           G. Huston
Internet-Draft                                        G. Michaelson, Ed.
Obsoletes: 6485 (if approved)                                      APNIC
Intended status: Standards Track                           March 7, 2014
Expires: September 8, 2014

The Profile for Algorithms and Key Sizes for use in the Resource Public
                           Key Infrastructure
                   draft-ietf-sidr-rfc6485bis-00.txt

Abstract

   This document specifies the algorithms, algorithms' parameters,
   asymmetric key formats, asymmetric key size and signature format for
   the Resource Public Key Infrastructure subscribers that generate
   digital signatures on certificates, Certificate Revocation Lists, and
   signed objects 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
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   This Internet-Draft will expire on September 8, 2014.

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   document authors.  All rights reserved.

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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.

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) subscribers when
   they apply digital signatures to certificates, Certificate Revocation
   Lists (CRLs), and signed objects (e.g., Route Origin Authorizations
   (ROAs) and manifests).  Relying Parties (RPs) also use this document
   when 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 SIDR Architecture
   [RFC6480], and the Signed Object Template for the RPKI [RFC2119].
   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, and signed
         objects is RSA Public-Key Cryptography Standards (PKCS) #1
         Version 1.5 (sometimes referred to as "RSASSA-PKCS1-v1_5") from
         Section 5 of [RFC4055].

      *  The hashing algorithm used in certificates, CRLs, and signed
         objects is SHA-256 [SHS] (see note below).  Hashing algorithms
         are not identified individually in certificates and CRLs, as
         the identity of the hashing algorithm is combined with the
         identity of the digital signature algorithm.

         When used in the context of the Cryptographic Message Syntax

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         (CMS) SignedData, the hashing algorithm is identified
         individually (in this case the hashing algorithm is sometimes
         called a message digest algorithm).

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

   For generating and verifying certificates, and CRLs the hashing and
   digital signature algorithms are referred to 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 this case.

   For CMS SignedData, the object identifier and parameters for SHA-256
   in [RFC5754] MUST be used for the SignedData digestAlgorithms field
   and the SignerInfo digestAlgorithm field when generating and
   verifying CMS SignedData objects.  The object identifier and
   parameters for rsaEncryption MUST be used for the SignerInfo
   signatureAlgorithm field when generating CMS SignedData objects.
   RPKI implementations MUST accept CMS SignedData objects that use the
   object identifier and parameters for either rsaEncryption or
   sha256WithRSAEncryption for the SignerInfo signatureAlgorithm field
   when verifying CMS SignedData objects.

   Locations for this OID are as follows:

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

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

      In CMS SignedData, the OID appears in each SignerInfo
      signatureAlgorithm field, the SignerInfo digestAlgorithm field,
      and in the SignedData digestAlgorithms [RFC5652]; and,

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

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.

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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.

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

3.2.  Private Key Format

   Local Policy determines 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 Cryptographic
   Message Syntax (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 relaced to specify such future requirements,
   as and when appropriate.

   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 not specified in this
   document.

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6.  Security Considerations

   The Security Considerations of [RFC4055], [RFC5280], and [RFC6487] a
   apply to certificate and CRLs.  The Security Considerations of
   [RFC5754] apply to signed objects.  No new security are introduced as
   a result of this specification.

7.  IANA Considerations

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

8.  IESG Considerations

   [Remove before publication.

   Dear IESG, This is a slight technical change to RFC6485, and the
   advice to the WG from a Routing AD was that this is outside the
   limited scope of an erratum.

   RFC 6485 defines The Profile for Algorithms and Key Sizes for Use in
   the Resource Public Key Infrastructure (RPKI).  Section 2 specifies a
   single signature algorithm (SHA-256) and a single CMS OID,
   sha256withRSAEncryption, to be used for the SignerInfo field of the
   CMS object.

   A closer reading of RFC 4055 and RFC 5754 identified that the CMS
   SignerInfo field must support use of the rsaEncryption OID for full
   conformance with the CMS specifications, and the normative references
   in RFC 6485 inherits the requirement.  This change is applied to
   Section 2 of RFC6485, as set forth in this document.  By conforming
   to the CMS specifications as per this updateed specification, RPKI
   CMS objects are less likely to be rejected as non-conformant with the
   standards.  No change is made to the cryptographic status of the CMS
   objects produced.  This change reflects the behaviour of deployed
   interoperating code.  No other changes have been made to this
   specification.]

9.  Acknowledgments

   The author acknowledges the re-use in this draft of material
   originally contained in working drafts the RPKI Certificate Policy
   and Resource Certificate profile 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

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   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.  George Michaelson
   edited the update to this document.

10.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
              Request Syntax Specification Version 1.7", RFC 2986,
              November 2000.

   [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,
              June 2005.

   [RFC4211]  Schaad, J., "Internet X.509 Public Key Infrastructure
              Certificate Request Message Format (CRMF)", RFC 4211,
              September 2005.

   [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, May 2008.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)",
              RFC 5652, September 2009.

   [RFC5754]  Turner, S., "Using SHA2 Algorithms with Cryptographic
              Message Syntax", RFC 5754, January 2010.

   [RFC6480]  Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", RFC 6480, February 2012.

   [RFC6484]  Kent, S., Kong, D., Seo, K., and R. Watro, "Certificate
              Policy (CP) for the Resource Public Key Infrastructure
              (RPKI)", BCP 173, RFC 6484, February 2012.

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   [RFC6487]  Huston, G., Michaelson, G., and R. Loomans, "A Profile for
              X.509 PKIX Resource Certificates", RFC 6487,
              February 2012.

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

Authors' Addresses

   Geoff Huston
   APNIC

   Email: gih@apnic.net

   George Michaelson (editor)
   APNIC

   Email: ggm@apnic.net

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