Probabilistic Model Checking of Security Protocols without Perfect Cryptography Assumption

This paper presents the description of a new, probabilistic approach to model checking of security protocols. The protocol, beyond traditional verification, goes through a phase in which we resign from a perfect cryptography assumption. We assume a certain minimal, but measurable probability of breaking/gaining the cryptographic key, and explore how it affects the execution of the protocol. As part of this work we have implemented a tool, that helps to analyze the probability of interception of sensitive information by the Intruder, depending on the preset parameters (number of communication participants, keys, nonces, the probability of breaking a cipher, etc.). Due to the huge size of the constructed computational spaces, we use parallel computing to search for states that contain the considered properties.