- Secure: an eavesdropper should not be able to impersonate users
- Reliable: many services depend on Kerberos for access control, must be highly reliable and support a distributed architecture where one system can back up another
- Transparent: each user should enter a single password to obtain network services and should be unaware of underlying protocols. (these days referred to as single sign-on)
- Scalable: system should scale to support large numbers of users and servers; this suggests a modular, distributed architecture