WDIFF

draft-ietf-krb-wg-ocsp-for-pkinit-02.txt --> draft-ietf-krb-wg-ocsp-for-pkinit-03.txt

NETWORK WORKING GROUP L. Zhu
Internet-Draft K. Jaganathan
Expires: May 21, June 3, 2005 Microsoft Corporation
N. Williams
Sun Microsystems
November 20,
December 3, 2004

OCSP Support for PKINIT
draft-ietf-krb-wg-ocsp-for-pkinit-02
draft-ietf-krb-wg-ocsp-for-pkinit-03

Status of this Memo

This document is an Internet-Draft and is subject to all provisions
of section 3 of RFC 3667. By submitting this Internet-Draft, each
author represents that any applicable patent or other IPR claims of
which he or she is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with
RFC 3668.

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
http://www.ietf.org/shadow.html.

This Internet-Draft will expire on May 21, June 3, 2005.

Abstract

This document defines a mechanism to enable in-band transmission of
OCSP responses.
Online Certificate Status Protocol (OCSP) responses in the Kerberos
network authentication protocol. These responses are used to verify
the validity of the certificates used in PKINIT - the Kerberos
Version 5 extension that provides for the use of public key cryptography.

Zhu, et al. Expires May 21, June 3, 2005 [Page 1]

Internet-Draft OCSP Support for PKINIT November December 2004

cryptography.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4
3. Message Definition . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgement Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 . 9
7.1 Normative References . . . . . . . . . . . . . . . . . . . . 9
7.2 Informative References . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 8 . 9
Intellectual Property and Copyright Statements . . . . . . . 10 . 11

Zhu, et al. Expires May 21, June 3, 2005 [Page 2]

Internet-Draft OCSP Support for PKINIT November December 2004

1. Introduction

Online Certificate Status Protocol (OCSP) [RFC2560] enables
applications to obtain timely information regarding the revocation
status of a certificate. Because OCSP responses are well-bounded and
small in size, constrained clients may wish to use OCSP to check the
validity of KDC the certificates for Kerberos Key Distribution Center
(KDC) in order to avoid transmission of large Certificate Revocation
Lists (CRLs) and therefore save bandwidth on constrained networks
[OCSP-PROFILE].

This document defines a pre-authentication type [CLARIFICATIONS],
where the client and the KDC MAY piggyback OCSP responses for
certificates used in authentication exchanges, as defined in
[PKINIT].

By using this OPTIONAL extension, PKINIT clients and the KDC can
maximize the reuse of cached OCSP responses.

Zhu, et al. Expires May 21, June 3, 2005 [Page 3]

Internet-Draft OCSP Support for PKINIT November December 2004

2. Conventions Used in This Document

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].

Zhu, et al. Expires May 21, June 3, 2005 [Page 4]

Internet-Draft OCSP Support for PKINIT November December 2004

3. Message Definition

A pre-authentication type identifier is defined for this mechanism:

PA-PK-OCSP-RESPONSE 16

The corresponding pre-authentication padata-value field [CLARIFICATIONS] contains OCSP data as
follows:

PA-PK-OCSP-DATA the
DER [X60] encoding of the following ASN.1 type:

PKOcspData ::= SEQUENCE OF OcspResponse

OcspResponse ::= OCTET STRING
-- contains a complete OCSP response,
-- defined in [RFC2560]

The client MAY send OCSP responses for certificates used in
PA-PK-AS-REQ [PKINIT] via a PA-PK-OCSP-RESPONSE.

The KDC that receives a PA-PK-OCSP-RESPONSE the then SHOULD send a
PA-PK-OCSP-RESPONSE containing OCSP responses for certificates used
in response. the KDC's PA-PK-AS-REP. The client can request a
PA-PK-OCSP-RESPONSE by using a PKOcspData containing an empty sequence in its request.
sequence.

The KDC MAY send a PA-PK-OCSP-RESPONSE when it does not receive a
PA-PK-OCSP-RESPONSE from the client.

The PA-PK-OCSP-RESPONSE sent by the KDC contains OCSP responses for
certificates used in PA-PK-AS-REP [PKINIT].

Note the lack of integrity protection for the empty or missing OCSP
response; lack of an expected OCSP response from the KDC for the
KDC's certificates SHOULD be treated as an error by the client,
unless it is configured otherwise.

When using OCSP, the response is signed by the OCSP server, which is
trusted by the receiver. Depending on local policy, further
verification of the validity of the OCSP servers MAY need to may be done. needed

The client and the KDC SHOULD ignore invalid OCSP responses received
via this mechanism, and they MAY implement CRL processing logic as a
fall-back position, if the OCSP responses received via this mechanism
alone are not sufficient for the verification of certificate
validity. The client and/or the KDC MAY ignore a valid OCSP response
and perform their own revocation status verification independently.

Zhu, et al. Expires May 21, June 3, 2005 [Page 5]

Internet-Draft OCSP Support for PKINIT November December 2004

4. Security Considerations

The pre-authentication data in this document do not actually
authenticate any principals, and MUST it is designed to be used in
conjunction with PKINIT.

There is a downgrade attack against clients which want OCSP responses
from the KDC for the KDC's certificates. The clients, however, can
treat the absence of valid OCSP responses as an error, based on their
local configuration.

Zhu, et al. Expires May 21, June 3, 2005 [Page 6]

Internet-Draft OCSP Support for PKINIT November December 2004

5. IANA Considerations

This document defines a new pre-authentication type for use with
PKINIT to encode OCSP responses. The official value

No IANA actions are required for this padata
identifier need to be acquired from IANA. document.

Zhu, et al. Expires May 21, June 3, 2005 [Page 7]

Internet-Draft OCSP Support for PKINIT November December 2004

6. Acknowledgements

This document was based on conversations among the authors, Jeffrey
Altman, Sam Hartman, Martin Rex and other members of the Kerberos
working group.

Zhu, et al. Expires June 3, 2005 [Page 8]

Internet-Draft OCSP Support for PKINIT December 2004

7. References

7.1 Normative References

[CLARIFICATIONS]
Neuman, B., Yu, Y., Hartman, S. and K. Raeburn, "The
Kerberos Network Authentication Service (V5)",
draft-ietf-krb-wg-kerberos-clarifications, Work in
progress.

[OCSP-PROFILE]
Deacon, A. and R. Hurst, "Lightweight OCSP Profile for
High Volume Environments",
draft-ietf-pkix-lightweight-ocsp-profile, Work work in
progress.

[PKINIT] Tung, B., Neuman, B. and S. Medvinsky, "Public Key
Cryptography for Initial Authentication in Kerberos",
draft-ietf-cat-kerberos-pk-init, Work work in progress.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC2560] Myers, M., Ankney, R., Malpani, A., Galperin, S. and C.
Adams, "X.509 Internet Public Key Infrastructure Online
Certificate Status Protocol - OCSP", RFC 2560, June 1999.

[X690] ASN.1 encoding rules: Specification of Basic Encoding
Rules (BER), Canonical Encoding Rules (CER) and
Distinguished Encoding Rules (DER), ITU-T Recommendation
X.690 (1997) | ISO/IEC International Standard 8825-1:1998.

7.2 Informative References

[OCSP-PROFILE]
Deacon, A. and R. Hurst, "Lightweight OCSP Profile for
High Volume Environments", August 2004.

Authors' Addresses

Larry Zhu
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052
US

EMail: lzhu@microsoft.com

Karthik Jaganathan
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052
US

EMail: karthikj@microsoft.com

Zhu, et al. Expires May 21, June 3, 2005 [Page 8] 9]

Internet-Draft OCSP Support for PKINIT November December 2004

Nicolas Williams
Sun Microsystems
5300 Riata Trace Ct
Austin, TX 78727
US

EMail: Nicolas.Williams@sun.com

Zhu, et al. Expires May 21, June 3, 2005 [Page 9] 10]

Internet-Draft OCSP Support for PKINIT November December 2004

Intellectual Property Statement

The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.

Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.

The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.

Disclaimer of Validity

This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.

Acknowledgment

Funding for the RFC Editor function is currently provided by the
Internet Society.

Zhu, et al. Expires May 21, June 3, 2005 [Page 10] 11]

----