Theorem Proving based Framework for Verification of Group Key Protocols

The correctness of group key protocols in communication systems remains a great challenge because of dynamic characteristics of group key construction as we deal with open number of group members. In this paper, we present a combination of three different theorem-proving methods to verify security properties for group oriented protocols. In the first method, rank theorems for forward properties are established based on a set of generic formal specification requirements for group key management and distribution protocols. Rank theorems imply the validity of the security property to be proved, and are deduced from a set of rank functions we define over the protocol. In the second, we provide a sound and complete inference system to detect attacks in group key management protocols. The inference system provides an elegant and natural proof strategy for such protocols compared to existing approaches. Finally, in the third method, we use an event-B first-order proving system to provide invariant checking for group key secrecy property. In our framework, we applied each method on a different group protocol from the literature illustrating the features of each method.