Paper 2006/219

Cryptographically Sound Security Proofs for Basic and Public-Key Kerberos

Michael Backes and Iliano Cervesato and Aaron D. Jaggard and Andre Scedrov and Joe-Kai Tsay

Abstract

We present a computational analysis of basic Kerberos with and without its public-key extension PKINIT in which we consider authentication and key secrecy properties. Our proofs rely on the Dolev--Yao-style model of Backes, Pfitzmann, and Waidner, which allows for mapping results obtained symbolically within this model to cryptographically sound proofs if certain assumptions are met. This work was the first verification at the computational level of such a complex fragment of an industrial protocol. By considering a recently fixed version of PKINIT, we extend symbolic correctness results we previously attained in the Dolev--Yao model to cryptographically sound results in the computational model.

Note: Revised full version. This updates the formalization of the certificates binding keys to principals.