Computational semantics for basic protocol logic a stochastic approach

This paper relates formal and computational models of cryptography in case of active adversaries when formal security analysis is done with first order logic. Instead of the way Datta et al. defined computational semantics to their Protocol Composition Logic, we introduce a new, fully probabilistic method to assign computational semantics to the syntax. We present this via considering a simple example of such a formal model, the Basic Protocol Logic by K. Hasebe and M. Okada [7] , but the technique is suitable for extensions to more complex situations such as PCL. We make use of the usual mathematical treatment of stochastic processes, hence are able to treat arbitrary probability distributions, non-negligible probability of collision, causal dependence or independence.