A Type System for Privacy Properties

Véronique Cortier (1, 2) , Niklas Grimm (3) , Joseph Lallemand (2, 1) , Matteo Maffei (3)

1 LORIA - Laboratoire Lorrain de Recherche en Informatique et ses Applications
2 PESTO - Proof techniques for security protocols
3 TU Wien - Vienna University of Technology = Technische Universität Wien

Mature push button tools have emerged for checking trace properties (e.g. secrecy or authentication) of security protocols. The case of indistinguishability-based privacy properties (e.g. ballot privacy or anonymity) is more complex and constitutes an active research topic with several recent propositions of techniques and tools. We explore a novel approach based on type systems and provide a (sound) type system for proving equivalence of protocols, for a bounded or an unbounded number of sessions. The resulting prototype implementation has been tested on various protocols of the literature. It provides a significant speed-up (by orders of magnitude) compared to tools for a bounded number of sessions and complements in terms of expressiveness other state-of-the-art tools, such as ProVerif and Tamarin: e.g., we show that our analysis technique is the first one to handle a faithful encoding of the Helios e-voting protocol in the context of an untrusted ballot box.

Mots clés: Protocols; privacy; symbolic models; type systems

Domaines: Cryptographie et sécurité [cs.CR]

Véronique Cortier, Niklas Grimm, Joseph Lallemand, Matteo Maffei. A Type System for Privacy Properties. CCS'17 - 24th ACM Conference on Computer and Communications Security, Oct 2017, Dallas, United States. pp.409 - 423. ⟨hal-01626109⟩