Messages format

Jeffrey Hutzelman jhutz at
Tue Jun 10 22:37:01 EDT 2008

--On Tuesday, June 03, 2008 03:41:15 PM +0200 
mohamed.chaari at wrote:

> I want to add some fonctionnalities to kerberos, I would like to know
> where are defined the format of the messages (AP-REQ, AP-REP, TGS-REQ,
> TGS-REP...)

As Ken pointed out, the formats and semantics of core Kerberos messages are 
defined in RFC4120, available from <>. 
The Kerberos cryptographic framework is described in RFC3961.  There are 
also a number of other documents which describe various extensions to the 
Kerberos protocol, including the AES enctypes (RFC3962), PKINIT (RFC4556, 
RFC4557), enctype negotiation (RFC4537), and others.  There are also a 
number of additional extensions and changes currently being worked on by 
the IETF's Kerberos Working Group; a list of these is available at 

If you are interested in helping to extend the Kerberos protocol, I 
encourage you to subscribe to the Kerberos Working Group mailing list at 
<> and to become active 
in the working group.  However, bear in mind that the purpose of krb-wg is 
to define and standardize the Kerberos protocol, so questions about the 
details of MIT's implementation are more appropiate here.

-- Jeffrey T. Hutzelman (N3NHS) <jhutz+ at>
   Co-chair, IETF Kerberos Working Group
   Carnegie Mellon University - Pittsburgh, PA

More information about the krbdev mailing list