Formal Testing & Algebraic Modelling Techniques for Verifying Cryptographic Protocols

Before trusting a communications security protocol with potentially critical or sensitive information, it is necessary to have some degree of assurance that the protocol fulfils its intended objectives. To provide this assurance it is necessary to use formal verification techniques, as intuitive reasoning does not satisfactorily guarantee complete freedom from protocol errors. In this paper, a number of recently published formal techniques for verifying cryptographic protocols, are described. The techniques are categorised as being based on algebraic modelling, or based on some form of testing. A comparative overview of the verification techniques available is presented, indicating their benefits, limitations and scope of application.