Using Curve25519 and Curve448 in PKIX
draft-josefsson-pkix-newcurves-01

Abstract

This document specify "named curve" object identifiers for the Curve25519 and Curve448 curves, for use in various X.509 PKIX structures.

Status of This Memo

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This Internet-Draft will expire on April 14, 2016.

Copyright Notice

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1. Introduction

In [I-D.irtf-cfrg-curves], the elliptic curves Curve25519 and Curve448 are described. They are designed with performance and security in mind. The curves may be used for Diffie-Hellman and Digital Signature operations.

This RFC define ASN.1 "named curve" object identifiers for Curve25519 and Curve448, for use in the Internet X.509 PKI [RFC5280].

Rather than defining a new subject public key format for these two curves, this document re-use the existing ECDSA/ECDH public-key contained (described in section 2.3.5 of [RFC3279]) and introduce two new "named curve" OIDs. This approach is the same as for the Brainpool curves [RFC5639].

2. Requirements 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].

3. Curve25519 and Curve448 Named Curve Identifier

Certificates conforming to [RFC5280] may convey a public key for any public key algorithm. The certificate indicates the algorithm through an algorithm identifier. This algorithm identifier is an OID and optionally associated parameters. Section 2.3.5 of [RFC3279] describe ECDSA/ECDH public keys, specifying the id-ecPublicKey OID. This OID has the associated EcpkParameters parameters structure, which contains the namedCurve CHOICE. Here we introduce two new OIDs for use in the namedCurve field.

	id-Curve25519   OBJECT IDENTIFIER ::= { 1.3.6.1.4.1.11591.15.1 }
	id-Curve448     OBJECT IDENTIFIER ::= { 1.3.6.1.4.1.11591.15.2 }
	id-Curve25519ph OBJECT IDENTIFIER ::= { 1.3.6.1.4.1.11591.15.3 }
	id-Curve448ph   OBJECT IDENTIFIER ::= { 1.3.6.1.4.1.11591.15.4 }
	

The OID id-Curve25519 refers to Curve25519. The OID id-Curve448 refers to Curve448. Both curves are described in [I-D.irtf-cfrg-curves]. The OIDs id-Curve25519ph and id-Curve448ph refers to Curve25519 and Curve448 when used with pre-hashing as Ed25519ph and Ed448ph described in [I-D.irtf-cfrg-eddsa].

The public key value encoded into the ECPoint value is the raw binary values described in [I-D.irtf-cfrg-curves].

4. Acknowledgements

Text and/or inspiration were drawn from [RFC5280], [RFC3279], [RFC5480], and [RFC5639].

Several people suggested the utility of specifying OIDs for encoding Curve25519/Curve448 public keys into PKIX certificates, the editor of this document cannot take credit for this idea.

5. IANA Considerations

None.

6. Security Considerations

The security considerations of [RFC3279], [RFC5280], [RFC5480] and [I-D.irtf-cfrg-curves] apply accordingly.

7. References

7.1. Normative References

7.2. Informative References

Author's Address

Table of Contents

• 1. Introduction
• 2. Requirements Terminology
• 3. Curve25519 and Curve448 Named Curve Identifier
• 4. Acknowledgements
• 5. IANA Considerations
• 6. Security Considerations
• 7. References
• 7.1. Normative References
• 7.2. Informative References
• Author's Address