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 Huston & Michaelson Expires April 18, 2016 [Page 1] Internet-Draft RPKI Algorithm Profile October 2015 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 Huston & Michaelson Expires April 18, 2016 [Page 2] Internet-Draft RPKI Algorithm Profile October 2015 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]. Huston & Michaelson Expires April 18, 2016 [Page 3] Internet-Draft RPKI Algorithm Profile October 2015 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. Huston & Michaelson Expires April 18, 2016 [Page 4] Internet-Draft RPKI Algorithm Profile October 2015 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. Huston & Michaelson Expires April 18, 2016 [Page 5] Internet-Draft RPKI Algorithm Profile October 2015 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. Huston & Michaelson Expires April 18, 2016 [Page 6] Internet-Draft RPKI Algorithm Profile October 2015 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, . [RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification Request Syntax Specification Version 1.7", RFC 2986, DOI 10.17487/RFC2986, November 2000, . [RFC3370] Housley, R., "Cryptographic Message Syntax (CMS) Algorithms", RFC 3370, DOI 10.17487/RFC3370, August 2002, . [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, . [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, . Huston & Michaelson Expires April 18, 2016 [Page 7] Internet-Draft RPKI Algorithm Profile October 2015 [RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure Certificate Request Message Format (CRMF)", RFC 4211, DOI 10.17487/RFC4211, 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, DOI 10.17487/RFC5280, May 2008, . [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, RFC 5652, DOI 10.17487/RFC5652, September 2009, . [RFC5754] Turner, S., "Using SHA2 Algorithms with Cryptographic Message Syntax", RFC 5754, DOI 10.17487/RFC5754, January 2010, . [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480, 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, DOI 10.17487/RFC6484, February 2012, . [RFC6487] Huston, G., Michaelson, G., and R. Loomans, "A Profile for X.509 PKIX Resource Certificates", RFC 6487, DOI 10.17487/ RFC6487, February 2012, . [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, . [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, . Huston & Michaelson Expires April 18, 2016 [Page 8] Internet-Draft RPKI Algorithm Profile October 2015 [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, . [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, . [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, . Authors' Addresses Geoff Huston APNIC Email: gih@apnic.net George Michaelson (editor) APNIC Email: ggm@apnic.net Huston & Michaelson Expires April 18, 2016 [Page 9]