Internet Engineering Task Force (IETF) N. Mavrogiannopoulos
Request for Comments: 6091 KUL
Obsoletes: 5081 D. Gillmor
Category: Informational Independent
ISSN: 2070-1721 February 2011
Using OpenPGP Keys for Transport Layer Security (TLS) Authentication
Abstract
This memo defines Transport Layer Security (TLS) extensions and
associated semantics that allow clients and servers to negotiate the
use of OpenPGP certificates for a TLS session, and specifies how to
transport OpenPGP certificates via TLS. It also defines the registry
for non-X.509 certificate types.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6091.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Mavrogiannopoulos & Gillmor Informational [Page 1]
RFC 6091 Using OpenPGP Keys February 2011
Table of Contents
1. Introduction ....................................................2
2. Terminology .....................................................2
3. Changes to the Handshake Message Contents .......................3
3.1. Client Hello ...............................................3
3.2. Server Hello ...............................................4
3.3. Server Certificate .........................................4
3.4. Certificate Request ........................................6
3.5. Client Certificate .........................................6
3.6. Other Handshake Messages ...................................7
4. Security Considerations .........................................7
5. IANA Considerations .............................................7
6. Acknowledgements ................................................8
7. References ......................................................8
7.1. Normative References .......................................8
7.2. Informative References .....................................8
Appendix A. Changes from RFC 5081 .................................9
1. Introduction
The IETF has two sets of standards for public key certificates: one
set for the use of X.509 certificates [RFC5280], and one for OpenPGP
certificates [RFC4880]. At the time of this writing, TLS [RFC5246]
standards are defined to use X.509 certificates. This document
specifies a way to negotiate the use of OpenPGP certificates for a
TLS session, and specifies how to transport OpenPGP certificates via
TLS. The proposed extensions are backward-compatible with the
current TLS specification, so that existing client and server
implementations that make use of X.509 certificates are not affected.
These extensions are not backward-compatible with [RFC5081], and the
major differences are summarized in Appendix A. Although the OpenPGP
CertificateType value is being reused by this memo with the same
number as that specified in [RFC5081] but with different semantics,
we believe that this causes no interoperability issues because the
latter was not widely deployed.
2. Terminology
The term "OpenPGP key" is used in this document as in the OpenPGP
specification [RFC4880]. We use the term "OpenPGP certificate" to
refer to OpenPGP keys that are enabled for authentication.
This document uses the same notation and terminology used in the TLS
datatracker.ietf.org