Process Algebraic Modeling of Authentication Protocols for Analysis of Parallel Multi-Session Executions

Many security protocols have the aim of authenticating one agent acting as initiator to another agent acting as responder and vice versa. Sometimes, the authentication fails because of executing several parallel sessions of a protocol, and that an agent may play both the initiator and responder role in parallel sessions. We take advantage of the notion of transition systems to specify authentication for parallel multiple sessions execution. To model the authentication, two main notions called 1. agent's scope and 2.agent's recognizability are introduced which consider the difference of ability of agents due to their different roles in the protocol and different access to keys and secrets.