IPSEC Working Group                                          Will Price
INTERNET-DRAFT                                             PGP Security
draft-ietf-ipsec-openpgp-01.txt                           23 March 2001


                         OpenPGP Key Usage in IKE

Status of this Memo

   This document is a submission to the IETF IP Security Protocol
   (IPSEC) Working Group.  Comments are solicited and should be
   addressed to the working group mailing list (ipsec@lists.tislab.com)
   or to the editor.

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet- Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
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Copyright Notice

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

Abstract

   This document defines a profile for the usage of OpenPGP keys within
   the IKE [IKE] protocol.  The ISAKMP [ISAKMP] protocol on which IKE
   is based defines an identifier for the use of OpenPGP [OPENPGP]
   keys, but does not define how they should be used.

   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.




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Certificate Payload Key Format

   Whenever an OpenPGP key is sent as part of a Certificate payload,
   the format MUST be that of the raw binary OpenPGP key.  OpenPGP
   wrappings such as ASCII Armor MUST NOT be used.

   For RSA Signature authentication, the RSA master key is used for
   signing.  For DSS Signature authentication, the DSS master key
   is used for signing.  For Public Key Encryption modes, the
   current valid subkey is used for encryption.  If the key has no
   subkeys, but the master key is usable for encryption such as an
   RSA master key, the master key is used for encryption.

Use of Multiple Certificate Formats

   The Certificate Request payload SHOULD be used to aid in
   distinguishing between the types of certificate expected by the
   remote system.  Each side MAY request any type of certificate.
   There is no requirement that both sides must request the same
   type of certificate.  It is RECOMMENDED that implementations
   use the Certificate Request payload regularly when performing
   certificate-based authentication in order to aid in interoperability
   between implementations that may use multiple certificates in
   multiple formats.

   If a specific OpenPGP certificate authority is requested, the
   Certificate Authority field of the Certificate Request payload
   should contain the full OpenPGP fingerprint of the certificate
   authority.  Note that the use of the Certificate Request payload
   remains important regardless of whether a specific certificate
   authority is requested.  This allows the remote IKE implementation
   to know the preferred type of certificate.

Phase 1 Identification

   Identification payloads in IKE Phase 1 when using certificate
   authentication are required by the IPsec DOI [DOI] to use IDs
   which represent the certificate.

   Phase 1 identities when authenticating with an OpenPGP key MUST be
   of type ID_KEY_ID and contain the full OpenPGP fingerprint of the
   authenticating key represented as raw binary bytes of the size of
   the key's hash algorithm output.

Other Payloads

   Other payloads such as Signature, and the format of public key
   encryption remain identical to the formats defined in IKE.



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Infrastructure

   Methods for retrieving up to date key revocation information,
   establishing designated revokers, and otherwise establishing
   key validity through the PGP web of trust or through an OpenPGP
   meta-introducer hierarchy are already well-established.
   Implementations of this specification MUST NOT accept revoked
   or expired keys for authentication.


References

   [IKE]     D. Harkins, and D. Carrel, "The Internet Key Exchange
             (IKE)", RFC 2409, November 1998.

   [ISAKMP]  D. Maughan, M. Schertler, M. Schneider, J. Turner,
             "Internet Security Association and Key Management Protocol
             (ISAKMP)", RFC 2408, November 1998

   [DOI]     D. Piper, "The Internet IP Security Domain of
             Interpretation for ISAKMP", RFC 2407, November 1998

   [OpenPGP] J. Callas, L. Donnerhacke, H. Finney, R. Thayer,
             "OpenPGP Message Format", RFC 2440, November 1998.

Author

   Will Price <wprice@pgp.com>
   PGP Security, Inc.





















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