This site reflects work in progress.
Read the specification (a precursor to an Internet Draft)
DEPRECATION: This specification will probably not be continued:
- As discussed under related work, the unpredictable number of exchanges for GSS-API is not a good match with TLS, and it might be better if such exchanges are implemented in a protocol of their own;
- A protocol as general as GSS-API is difficult, perhaps even impossible, to bind cryptographically with TLS;
- Separation of TLS-DH with TLS-KRB5 can only integrate the two at the expense of restructured TLS code bases;
- Dedicated integration enables a very fast and very secure implementation that makes the solution highly practical.
About this specification
The specification for TLS-KRB5 introduces a few concepts into TLS:
- An extension option to indicate one or more acceptable realms, much like the ServerNameIndication extension which mentions the DNS-name being addressed;
- A use of the ServerKeyExhange to pose a random challenge to a client;
- A use of the ClientKeyExchange to present a Kerberos5 ticket to the server, and in addition resolve the server's random challenge.
This can be placed in the usual tick-tock handshaking exchange of a TLS session being built up.