programming help (encryption etc.)

[shyguy]

as a project i am adding security to a chat room application all in java...

i already have the basic chat server and client, but i need to create a seperate java application to integrate with it to add security.

so i basically need to set it up so that all communications are encrypted, so outside eavesdroppers cant understand them. i have to implement authentication so that only verified users can access the chat service. the method used was going to be a based on a simplified version of the Kerberos protocol. was going to omit the Kerberos ticket server from this for the time being.

any help here would be muchly appreciated... source code of a working example would be great...