wdiff draft-ietf-sidr-rpki-algs-02.txt draft-ietf-sidr-rpki-algs-03.txt

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
draft-ietf-sidr-rpki-algs-02.txt
draft-ietf-sidr-rpki-algs-03.txt

Abstract

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.

Status of this Memo

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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
algorithm
[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
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 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.

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 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
[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 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
document.

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
Cooper.

7. Sean Turner has provided additional review input to this
document.

9. Normative References

[I-D.ietf-sidr-arch]

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

[I-D.ietf-sidr-cp]
Seo, K., Watro, R., September 2010.

[ID.ietf-sidr-cp]
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.

[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),
February May 2008.

[RFC3447] Jonsson, J.

[ID.ietf-sidr-signed-object]
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
APNIC

Email: gih@apnic.net