SIDR G. Huston
Internet-Draft APNIC
Intended status: Standards Track April 13, 2011
Expires: October 15, 2011
The Profile for Algorithms and Key Sizes for use in the Resource Public
Key Infrastructure
draft-ietf-sidr-rpki-algs-05.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
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on October 15, 2011.
Copyright Notice
Copyright (c) 2011 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
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carefully, as they describe your rights and restrictions with respect
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include Simplified BSD License text as described in Section 4.e of
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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 [ID.ietf-sidr-arch].
This document is referenced by other RPKI profiles and
specifications, including the RPKI Certificate Policy (CP)
[ID.ietf-sidr-cp], the RPKI Certificate Profile
[ID.ietf-sidr-res-certs], the SIDR architecture [ID.ietf-sidr-arch],
and the signed object template for the RPKI
[ID.ietf-sidr-signed-object]. 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]. Hash algorithms are not identified
by themselves in certificates and CRLs instead they are
combined with the digital signature algorithm (see below).
When used in the Cryptographic Message Syntax (CMS) SignedData,
the hash algorithm (in this case, the hash algorithm is
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sometimes called a message digest algorithm) is identified by
itself. For CMS SignedData, the object identifier and
parameters for 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 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];
In CMS SignedData, the OID appears in each SignerInfo
signatureAlgoithm field [RFC3370] using the OID from above; 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.
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 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
[RFC3370].
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.
6. Security Considerations
The Security Considerations of [RFC4055], [RFC5280], and
[ID.ietf-sidr-res-certs] 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
[There are no IANA considerations in this document.]
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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
Cooper. Sean Turner has provided additional review input to this
document.
9. Normative References
[ID.ietf-sidr-arch]
Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", draft-ietf-sidr-arch (work in
progress), September 2010.
[ID.ietf-sidr-cp]
Kent, S., Kong, D., Seo, K., and R. Watro, "Certificate
Policy (CP) for the Resource PKI (RPKI)",
draft-ietf-sidr-cp (work in progress), September 2010.
[ID.ietf-sidr-res-certs]
Husotn, G., Michaelson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates",
draft-ietf-sidr-res-certs (work in progress), May 2008.
[ID.ietf-sidr-signed-object]
Lepinski, M., Chi, A., and S. Kent, "Signed Object
Template for the Resource Public Key Infrastructure",
draft-ietf-sidr-signed-object-01.txt (work in progress),
October 2010.
[RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification
Request Syntax Specification Version 1.7", RFC 2986,
November 2000.
[RFC3370] Housley, R., "Cryptographic Message Syntax (CMS)
Algorithms", RFC 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.
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[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.
[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
APNIC
Email: gih@apnic.net
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