Technical Summary
This document describes protocol extensions (hereafter called PKINIT)
to the Kerberos protocol specification. These extensions provide a
method for integrating public key cryptography into the initial
authentication exchange, by using asymmetric-key signature and/or
encryption algorithms in pre-authentication data fields. A
companion document describes the use of OCSP with this protocol.
Working Group Summary
This document is the result of work begun nearly 10 years ago in
the CAT working group. In that time the two working groups have
focused much of their energy on this work, resulting in quite a lot
of discussion, some heated debate, and a few compromises. Due to
timing constraints, one significant stakeholder was forced to adopt
and deploy an early version of this specification, rather than
waiting for the final product. While we regret being unable to
meet their timeline, much of the intervening time was well-spent,
and we think the protocol is significantly improved as a result.
This document represents the consensus of the Kerberos Working
Group.
Protocol Quality
Several major Kerberos implementors have indicated an intent to
implement this protocol; some have done so already. While the
current version has not yet been widely deployed, significant
experience has been gained by wide deployment of earlier versions
of this protocol. This protocol was reviewed by Jeffrey Hutzelman
and Sam Hartman.
Note to RFC Editor
Please make the following changes in draft-ietf-cat-kerberos-pk-init:
In section 1:
OLD: The corner-stone of Kerberos V5 is the Ticket and the Authenticator.
NEW: The corner-stones of Kerberos V5 are the Ticket and the Authenticator.
In section 3.1.3:
OLD:
All structures defined in or imported into this document MUST be
encoded using Distinguished Encoding Rules (DER) [X680] [X690]
(unless otherwise noted). All data structures carried in OCTET
STRINGs must be encoded according to the rules specified in
corresponding specifications.
NEW:
All structures defined in or imported into this document MUST be
encoded using Distinguished Encoding Rules (DER) [X680] [X690]
(unless otherwise noted). All data structures carried in OCTET
STRINGs MUST be encoded according to the rules specified in the
specifications defining each data structure; a reference to the
appropriate specification is provided for each data structure.
In section 4:
OLD: In addition, if any CA is trusted to issue KDC certificates can
NEW: In addition, if any CA that is trusted to issue KDC certificates can
Add at the end of section 4:
NEW:
The key usage number 6 used by the asChecksum field is also used
for the authenticator checksum (cksum field of AP-REQ) contained
in the PA-TGS-REQ preauthentication data contained in a TGS-REQ
[RFC4120]. This conflict is present for historical reasons; the
reuse of key usage numbers is strongly discouraged.