Description
In this thesis, we study two differentprimitives. Lossy trapdoor functions and zero-knwoledge proof systems.The lossy trapdoor functions (LTFs) arefunction families in which injective functionsand lossy ones are computationally indistin-guishable. Since their introduction, they havebeen found useful in constructing various cryp-tographic primitives. We give in this thesisefficient constructions of two different vari-ants of LTF: Lossy Algebraic Filter andR-LTF. With these two different variants, wecan improve the efficiency of the KDM-CCA(Key-Depended-Message Chosen-Ciphertext-Attack) encryption schemes, fuzzy extractoresand deterministic encryption.In the second part of this thesis, we in-vestigated on constructions of zero-knowledgeproof systems. We give the first logarithmic-size ring-signature with tight security usinga variant of Groth-KolhweizΣ-protocol in therandom oracle model. We also proposed onenew construction of lattice-based Designated-Verifier Non-Interactive Zero-Knowledge argu-ments (DVNIZK). Using this new construction, we build a lattice-based voting scheme in the standard model. lien: rien
Next sessions
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CryptoVerif: a computationally-sound security protocol verifier
Speaker : Bruno Blanchet - Inria
CryptoVerif is a security protocol verifier sound in the computational model of cryptography. It produces proofs by sequences of games, like those done manually by cryptographers. It has an automatic proof strategy and can also be guided by the user. It provides a generic method for specifying security assumptions on many cryptographic primitives, and can prove secrecy, authentication, and[…]-
Cryptography
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