SAT and SMT-Based Verification of Security Protocols Including Time Aspects.

For many years various types of devices equipped with sensors have guaranteed proper work in a huge amount of machines and systems. For the proper operation of sensors, devices, and complex systems, we need secure communication. Security protocols (SP) in this case, guarantee the achievement of security goals. However, the design of SP is not an easy process. Sometimes SP cannot realise their security goals because of errors in their constructions and need to be investigated and verified in the case of their correctness. Now SP uses often time primitives due to the necessity of security dependence on the passing of time. In this work, we propose and investigate the SAT-and SMT-based formal verification methods of SP used in communication between devices equipped with sensors. For this, we use a formal model based on networks of communicating timed automata. Using this, we show how the security property of SP dedicated to the sensors world can be verified. In our work, we investigate such timed properties as delays in the network and lifetimes. The delay in the network is the lower time constraint related to sending the message. Lifetime is an upper constraint related to the validity of the timestamps generated for the transmitted messages.