The International Journals of Engineering & Sciences (IJENS)
Most of cryptographic protocols are subjects to very subtle attacks. Therefore, many researchers have developed tools to model and analyze protocols to guarantee their security properties. The spi calculus has proved to be useful for analyzing and reasoning on cryptographic protocols. However, current works assumed that the spi calculus dealt with transferring a single unstructured message for sending each message in a single action, which is mostly needed in implementing real protocols with an open environment, such case cause a problem in proving the freshness of generated keys for each output action.