Communication Protocols

Abstract

Recent advances in communication have made the use of dynamic and reconfigurable network topologies a mandatory requirement in scenarios where the participants must actively collaborate to each other to achieve a common, specific goal. A particular case of those scenarios are the Peer-to-Peer (P2P) systems. The wide applicability of P2P-based applications and its pervasive presence in corporate applications are two important factors that suggest a careful study of the communication protocols underlying these systems. Surprisingly, little effort has been invested in giving formal foundations that support both protocols and its security properties. This paper is intended to be a step towards such a research strand, using a process calculus as main resource to build such foundations. In particular, we focus on the reconfiguration problem in P2P-based applications. We propose two protocols for modeling this problem: while the first one is inspired on an existing protocol (known as the Friends Troubleshooting Network or FTN), the second constitutes an original proposal based on a multi-layered encryption system. We show how SPL (the process calculi in which both models are given) is well-suited to model and to proof certain security properties of the protocols.