Complex protocol design by composition method

Aiming at the present methods,which have the following characters: Abstract,the narrow application range and complexity to design security protocol.A new approach is presented to design security protocol.Firstly,the concepts of the base case and the component are defined in the protocol.Secondly,the security attributes on the components are analyzed,and the single-step protocols which can implement the special security goals based on the components are designed.Finally,the composition rules which allow the combination of several single-step protocols part into a complicated protocol are defined.The security properties established by each independent part can’t be destroyed by the rules.Then the security protocol can be designed by the choice and composition of the single-step protocols which in specific application environment.The research results show that the specification of a complex protocol to be decomposed into the specifications of simpler single-step protocols can be permitted by the composition framework,and the design and verification of the protocol are easier to be handled.