i have a calenderserver version -2.4 from apple running on a linux squeeze box and
i want to encrypt password, on my caldav.plist i have the above config for authentication(basic enabled), but if i disable basic auth and enable kerberos or digest then i got an error: unable to connect.
so what to do?

To answer this question it is essential to know how you store user credentials.

To authenticate with a secure authentication mechanism (digest) the server needs

From your description (or lack of) of your problem it seems that you store user

credentials in a way that gives the server no access to the clear text pass phrases.