A simple framework for real-time cryptographic protocol analysis with compositional proof rules

Abstract

A real-time process algebra, enhanced with specific constructs for handling cryptographic primitives, is proposed to model cryptographic protocols in a simple way. We show that some security properties, such as authentication and secrecy, can be re-formulated in this timed setting. Moreover, we show that they can be seen as suitable instances of a general information flow-like scheme, called timed generalized non-deducibility on compositions ( tGNDC), parametric w.r.t. the observational semantics of interest. We show that, when considering timed trace semantics, there exists a most powerful hostile environment (or enemy) that can try to compromise the protocol. Moreover, we present a couple of compositionality results for tGNDC, one of which is time dependent, and show their usefulness by means of a case study.