Kerberos: An Authentication Service for Open Network Systems

In an open network computing environment, a workstation cannot be trusted to identify its users correctly to network services. Kerberos provides an alternative approach whereby a trusted third-party authentication service is used to verify users’ identities. This paper gives an overview of the Kerberos authentication model as implemented for MIT’s Project Athena. It describes the protocols used by clients, servers, and Kerberos to achieve authentication. It also describes the management and replication of the database required. The views of Kerberos as seen by the user, programmer, and administrator are described. Finally, the role of Kerberos in the larger Athena picture is given, along with a list of applications that presently use Kerberos for user authentication. We describe the addition of Kerberos authentication to the Sun Network File System as a case study for integrating Kerberos with an existing application.