Kerberized Credential Translation: A Solution to Web Access Control

Abstract

Kerberos, a widely used network authentication mechanism, is integrated into numerous applications, UNIX and Windows 2000 login, AFS, Telnet, and SSH to name a few. Yet, Web applications rely on SSL to achieve authenticated and secure connections. SSL provides strong authentication by using certificates and public key challenge response authentication. The expansion of the Internet requires each system to leverage the strength of the other, which suggests the necessity of interoperability between them. This paper describes the design, implementation and performance of a system that provides controlled access to Kerberized services through a browser. This system provides a single sign-on through Kerberos, which produces both Kerberos and public key credentials. The Web server uses a plugin that translates user's public key credentials to Kerberos credentials. The Web server's subsequent authenticated actions taken on a user's behalf are limited in time and scope. Performance measurements show how the overhead introduced by credentialed translation is amortized over the login session.