Generic Indifferentiability Proofs of Hash Designs
Résumé
—In this paper, we propose a formal analysis of domain extenders for hash functions in the indiffer-entiability framework. We define a general model for domain extenders and provide a unified proof of their security in the form of a generic reduction theorem. Our general model for domain exenders captures many iterated constructions such as domain extenders, modes of operation of symmetric cryptography such as CBC-MAC or blockciphers based on Feistel networks. Its proof has been carried out using the Computational Indistin-guishability Logic of Barthe et al.. The theorem can help designers of hash functions justifying the security of their constructions: they only need to bound the probability of well-defined events. Our model allows to consider many SHA-3 finalists and is instantiated on two well-known constructions, namely Chop-MD and Sponge. Finally, the indifferentiability bounds which we prove are convincing since they match previous proofs.
Domaines
Cryptographie et sécurité [cs.CR]Origine | Fichiers produits par l'(les) auteur(s) |
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