Host mobility is becoming an increasingly important feature with the recent arrival of laptop and palmtop computers, the development of wireless network interfaces and the implementation of global networks. Unfortunately, this mobile environment is also much more vulnerable to penetration by intruders. A possible means of protection can be authentication. This guarantees the identity of a communication peer.

This thesis studies the constraints imposed on the mobile environment with respect to authentication. It compares the two prevailing authentication mechanisms, Kerberos and SPX, and tries to make suggestions of how a mechanism can be adapted to the mobile environment.