SIDR                                                           G. Huston
Internet-Draft                                                     APNIC
Intended status: Standards Track                         October 8, 2010
Expires: April 11, 2011

 A Profile for Algorithms and Key Sizes for use in the Resource Public
                           Key Infrastructure


   This document defines a profile for specifies the algorithm and algorithms, algorithms' parameters,
   asymmetric key formats, asymmetric key size to be
   used and signature format for
   the Resource Public Key Infrastructure subscribers that generate
   digital signatures applied to on certificates, Certificate Revocation Lists, and
   signed objects in the context of as well as for the Resource Public Key
   Infrastructure. Relying Parties (RPs) that verify
   these digital signatures.

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1.  Introduction

   This document defines a profile for specifies:

      *  the digital signature algorithm and parameters;
      *  the hash algorithm and parameters;
      *  the public and private key size to be formats; and,
      *  the signature format
   used for by Resource Public Key Infrastructure (RPKI) subscribers when
   they apply digital signatures applied to certificates, Certificate Revocation
   Lists (CRLs), and signed objects in the context of the Resource
   Public Key Infrastructure (RPKI) [I-D.ietf-sidr-arch]. (e.g., Route Origin Authorizations
   (ROAs) and manifests).  Relying Parties (RPs) also use this document
   when verify RPKI subscribers' digital signatures [ID.ietf-sidr-arch].

   This section of the profile document is specified in a distinct profile
   document, referenced by other RPKI profiles and
   specifications, including the RPKI Certificate Policy (CP)
   [I-D.ietf-sidr-cp] and
   [ID.ietf-sidr-cp], the RPKI Certificate Profile
   [I-D.ietf-sidr-res-certs], in order to allow for a degree of
   [ID.ietf-sidr-res-certs], the SIDR architecture [ID.ietf-sidr-arch],
   and key agility in the RPKI, while permitting some longer
   term stability in signed object template for the CP and Certificate Profile specifications. RPKI
   [ID.ietf-sidr-signed-object].  Familiarity with these documents is

1.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119. RFC2119.

2.  Algorithm and Key Size

   This profile specifies the use of RSASSA-PKCS1-v1_5 [RFC3447] with  Algorithms

   Two cryptographic algorithms are used in the SHA-256 hash 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 compute the signature as "RSASSA-PKCS1-v1_5") from
         Section 5 of [RFC4055].

      *  The hashing algorithm used in certificates, CRLs, and signed
         objects is SHA-256 [SHS].  Hash algorithms are not identified
         by themselves in certificates and CRLs instead they are
         combined with the context of digital signature algorithm (see below).
         When used in the RPKI.  Accordingly, Cryptographic Message Syntax (CMS) SignedData,
         the OID value in hash algorithm (in this case, the RPKI hash algorithm is
         sometimes called a message digest algorithm) is identified by
         itself.  For CMS SignedData, the object identifier and
         parameters for such SHA-256 in [RFC5754] MUST be used when
         populating the digestAlgorithms and digestAlgorithm fields.

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

   When used to generate and verify digital signatures the hash and
   digital signature algorithms are referred 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
   1.2.840.113549.1.1.11 (sha256WithRSAEncryption). used.

   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]; and,- In CMS
      SignedData, the OID appears in each SignerInfo signatureAlgoithm
      field [RFC3370] using the OID from above.

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.

   In order to facilitate a potential need to transition to stronger
   cryptographic algorithms

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 future, Certification Authorities
   (CAs) structures and Relying Parties (RPs) SHOULD their sub-structures follow:

   algorithm (which is an AlgorithmIdentifier type):
      The object identifier for RSA PKCS#1 v1.5 with SHA-256 MUST be able to generate and verify
   RSASSA-PKCS1-v1_5 signatures using
      used in the SHA-512 hash algorithm and RSA 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.

      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 sizes format.

4.  Signature Format

   The structure for the certificate's signature field is as specified
   in Section 1.2 of 3072 and 4096 bits.

3.  Future Upates [RFC4055].  The structure for the Cryptographic
   Message Syntax (CMS) SignedData's signature field is as specified in

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 updated 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 accomodate 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


   In anticipation of a potential need to transition to stronger
   cryptographic algorithms in the future, CAs and RPs SHOULD be able to
   generate and verify RSASSA-PKCS1-v1_5 signatures using the SHA-512
   hash algorithm and RSA key sizes of 3072 and 4096 bits.

6.  Security Considerations

   The Security Considerations of [RFC3779], [RFC4055], [RFC5280], and [RFC4055]
   [ID.ietf-sidr-res-certs] a apply to signatures certificate and CRLs.  The
   Security Considerations of [RFC5754] apply to signed objects.  No new
   security are introduced as defined by a result of this profile, and their use.

5. specification.

7.  IANA Considerations

   [There are no IANA considerations in this document.]


8.  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
   thanks.  The constraint on key size noted in this profile is the
   outcome of comments from Stephen Kent and review comments from David

7.  Sean Turner has provided additional review input to this

9.  Normative References


              Lepinski, M. and S. Kent, "An Infrastructure to Support
              Secure Internet Routing", draft-ietf-sidr-arch (work in
              progress), July 2009.

              Seo, K., Watro, R., September 2010.

              Kent, S., Kong, D., Seo, K., and S. Kent, R. Watro, "Certificate
              Policy (CP) for the Resource PKI (RPKI)",
              draft-ietf-sidr-cp (work in progress), July 2009.

   [I-D.ietf-sidr-res-certs] September 2010.

              Husotn, G., Michaelson, G., and R. Loomans, "A Profile for
              X.509 PKIX Resource Certificates",
              draft-ietf-sidr-res-certs (work in progress),
              February May 2008.

   [RFC3447]  Jonsson, J.

              Lepinski, M., Chi, A., and B. Kaliski, "Public-Key Cryptography
              Standards (PKCS) #1: RSA Cryptography Specifications
              Version 2.1", RFC 3447, February 2003.

   [RFC3779]  Lynn, C., S. Kent, S., and K. Seo, "X.509 Extensions "Signed Object
              Template for IP
              Addresses and AS Identifiers", the Resource Public Key Infrastructure",
              draft-ietf-sidr-signed-object-01.txt (work in progress),
              October 2010.

   [RFC3370]  Housley, R., "Cryptographic Message Syntax (CMS)
              Algorithms", RFC 3779, June 2004. 3370, August 2002.

   [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.

   [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.

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

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

Author's Address

   Geoff Huston