  Cryptographic Protocols (CP) are distributed algorithms intended for secure
communication in an insecure environment. They are used, for example, in
electronic payments, electronic voting procedures, systems of confidential data
processing, etc. Errors in CPs can bring to great financial and social damage,
therefore it is necessary to use mathematical methods to substantiate the
correctness and safety of CPs. In this paper, a distributed process model of
CPs is presented, which allows one to formally describe CPs and their
properties. It is shown how to solve the problems of verification of CPs on the
base of this model.
