Séminaire de Cryptographie

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Maria Isabel Gonzalez Vasco

Constructing group based provably secure encryption schemes: anon-abelian version of Cramer-Shoup's framework

Cryptographic primitives arising from group theory have in the last few years attracted a lot of attention. Unfortunately, up to date most of the existing proposals are still far away from practical applications, not only due to unlucky computational assumptions which later turned out to be invalid. In this talk we address the impact of modern security analysis in the sense of provable security to cryptographic proposals building on group theory, providing examples of security deficiencies in some of the proposed schemes. Motivated by this, we give a theoretical framework for the design of provably secure public key encryption schemes taking non-abelian groups as a base. Our construction is inspired by Cramer and Shoup's general framework and is conceived as a guiding tool towards the construction of provable secure schemes in the standard model (without any idealization assumptions).