A Hybrid Analysis for Security Protocols with StateJuly 2014
Topics: Network Protocols, Cybersecurity, Network Security, Computer Security, Data Encryption
Cryptographic protocols rely on message-passing to coordinate activity among principals. Many richly developed tools, based on well-understood foundations, are available for the design and analysis of pure message-passing protocols. However, in many protocols, a principal uses non-local, mutable state to coordinate its local sessions. Cross-session state poses difficulties for protocol analysis tools. We provide a framework for modeling stateful protocols, and a hybrid analysis method. We leverage theorem-proving—specifically, PVS—for reasoning about computations over state. An "enrich-by-need" approach—embodied by CPSA—focuses on the message-passing part. The Envelope Protocol, due to Mark Ryan furnishes a case study.