A framework for probabilistic model checking of security protocols using coloured stochastic activity networks and PDETool

One of the main concerns in today electronic technologies is how to ensure the security of these systems. Security protocols have a significant role in maintaining security in computer and communication systems. Therefore, these protocols need to be designed and developed based on rigorous engineering methodologies. Formal methods are among the mostly applied methods for verification of a wide range of systems. In this paper, a framework for probabilistic model checking of security protocols is presented. In the proposed framework, in the first step, a security protocols and some possible attack processes are specified using the security protocol language (SPL). Then, in the second step, the specification is transformed into a coloured stochastic activity network (CSAN) model, which is a high-level extension of stochastic Petri nets. For construction of CSAN model, PDETool can be used. In the third step, using this tool, the state space of the model is generated. In the fourth step, the obtained state space is transformed into the input language of PRISM, which is a tool for probabilistic model checking. In the final step, the security protocol is checked using PRISM and the probability of successful attack to the protocol is evaluated. As a case study, we have modeled and verified the Needham-Schroeder and TMN protocols using the proposed framework.