Section: New Results

Formal study of cryptography

Participants : Gilles Barthe [IMDEA Software Institute] , François Dupressoir [IMDEA Software Institute] , Benjamin Grégoire [correspondant] , César Kunz [IMDEA Software Institute] , Yassine Lakhnech [Univ. Grenoble 1] , Benedikt Schmid [IMDEA Software Institute] , Pierre-Yves Strub [IMDEA Software Institute] , Santiago Zanella Béguelin [MSR] .

The goal of this work is to provide a friendly tool easily usable by cryptographers without knowledge of formal proof assistants. The idea is to use the techniques formally proved in Certycrypt and to call SMT-provers. We provide two differents tools:

• Easycrypt (see http://www.easycrypt.info/ ) is a toolset for reasoning about relational properties of probabilistic computations with adversarial code. Its main application is the construction and verification of game-based cryptographic proofs. This year, Easycrypt has been fully reimplemented, allowing more modularity in proofs and an interactive prover has been integrated.

• ZooCrypt (see http://www.easycrypt.info/zoocrypt/ ) is an automated tool for analyzing the security of padding-based public-key encryption schemes (i.e. schemes built from trapdoor permutations and hash functions). ZooCrypt includes an experimental mechanism to generate EasyCrypt proofs of security of analyzed schemes.

This year we published papers concerning formal proofs for properties of elliptic curves, differential privacy, padding-based encryption, and probabilistic relational verification.