Automated analysis of security protocols with global state

Article type: Research Article

Authors: Kremer, Steve^a | Künnemann, Robert^{b; *}

Affiliations: [a] Inria Nancy – Grand Est and LORIA, France | [b] CISPA and Saarland University, Germany

Correspondence: [*] Corresponding author. E-mail: [email protected].

Abstract: Security APIs, key servers and protocols that need to keep the status of transactions, require to maintain a global, non-monotonic state, e.g., in the form of a database or register. However, most existing automated verification tools do not support the analysis of such stateful security protocols – sometimes because of fundamental reasons, such as the encoding of the protocol as Horn clauses, which are inherently monotonic. A notable exception is the recent tamarin prover which allows specifying protocols as multiset rewrite (msr) rules, a formalism expressive enough to encode state. As multiset rewriting is a “low-level” specification language with no direct support for concurrent message passing, encoding protocols correctly is a difficult and error-prone process. We propose a process calculus which is a variant of the applied pi calculus with constructs for manipulation of a global state by processes running in parallel. We show that this language can be translated to msr rules whilst preserving all security properties expressible in a dedicated first-order logic for security properties. The translation has been implemented in a prototype tool which uses the tamarin prover as a backend. We apply the tool to several case studies among which a simplified fragment of PKCS#11, the Yubikey security token, and an optimistic contract signing protocol.

Keywords: Automated verification, stateful security protocols, security APIs

DOI: 10.3233/JCS-160556

Journal: Journal of Computer Security, vol. 24, no. 5, pp. 583-616, 2016