Compositional Analysis of Contract Signing Protocols

Michael Backes (1) , Anupam Datta (2) , Ante Derek (2) , John C. Mitchell (2) , Mathieu Turuani (3)

1 IBM Zurich Research Laboratory
2 Computer Science Department [Stanford]
3 CASSIS - Combination of approaches to the security of infinite states systems

We develop a general method for reasoning about contract-signing protocols using a specialized protocol logic. The method is applied to prove properties of the Asokan-Shoup-Waidner and the Garay-Jacobson-MacKenzie protocols. Our method offers certain advantages over previous analysis techniques. First, it is compositional: the security guarantees are proved by combining the independent proofs for the three subprotocols of which each protocol is comprised. Second, the formal proofs are carried out in a ``template'' form, which gives us a reusable proof that may be instantiated for the ASW and GJM protocols, as well as for other protocols with the same arrangement of messages. Third, the proofs follow the design intuition. In particular, in proving game-theoretic properties like \emph{fairness}, we demonstrate that the specific strategy that the protocol designer had in mind works, instead of showing that one exists. Finally, our results hold even when an unbounded number of sessions are executed in parallel.

Domaines: Cryptographie et sécurité [cs.CR]

Michael Backes, Anupam Datta, Ante Derek, John C. Mitchell, Mathieu Turuani. Compositional Analysis of Contract Signing Protocols. 18th IEEE Computer Security Foundations Workshop - CSFW 2005, Jun 2005, Aix-en-Provence/France, pp.94-110. ⟨inria-00103647⟩