What is Communicating Sequential Processes (CSP)

The purpose of this chapter is to introduce the reader to the research area of formal analysis of authentication protocols. It briefly introduces the basic notions of cryptography and its use in authentication protocols. The chapter looks at the Needham-Schroeder (1978) protocol as an example of an authentication protocol, and examines the history of the protocol as a stimulus to the formal analysis of such protocols. We then introduce the process algebra CSP (Hoare, 1985) to model authentication protocols and present Schneider’s (1998) rank function approach to analysing such protocols. The chapter concludes by describing related ongoing work in this area of research and highlight some of the challenges posed by the problem of analysing and designing protocols.