Using Curve25519 and Curve448 Public Keys in PKIX
draft-josefsson-pkix-newcurves-00

Abstract

This document specify "named curve" object identifiers for Curve25519 and Curve448, for use as subject public keys in X.509 PKIX Certificates.

Status of This Memo

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This Internet-Draft will expire on December 31, 2015.

Copyright Notice

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1. Introduction

In [I-D.irtf-cfrg-curves], Curve25519 and Curve448 are described. They are Elliptic Curve Diffie-Hellman (ECDH) functions, designed with performance and security in mind.

This RFC define ASN.1 "named curve" object identifiers for Curve25519 and Curve448 (aka Goldilocks) public keys, 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 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 Public Keys

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 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 ::= { 1.3.6.1.4.1.11591.7 }
	  id-Curve447 OBJECT IDENTIFIER ::= { 1.3.6.1.4.1.11591.8 }
	

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 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 Public Keys
• 4. Acknowledgements
• 5. IANA Considerations
• 6. Security Considerations
• 7. References
• 7.1. Normative References
• 7.2. Informative References
• Author's Address