Analysing the security of a non-repudiation communication protocol with mandatory proof of receipt

Non-repudiation is a security service concerned with preventing a denial by one of the principals involved in a communication of having participated in all or part of the communication. Principals exchange evidence information, which proves their participation in the communication. The evidence is digitally signed, making it non-forgeable and undeniable. In this paper, a non-repudiation communication protocol with mandatory proof of receipt is formally analysed. The verification technique used in the analysis applies a modal logic of knowledge and belief to prove the correctness of the protocol. This involves a process of deductive reasoning, where the desired protocol goals are deduced by applying a set of axioms, theorems and inference rules to the assumptions and message exchanges of the protocol. If the protocol is shown to fulfil its goals it can be deemed to be correct and secure.