Sylvain Heraud

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We present an automated tool for elaborating security proofs of cryptographic systems from proof sketches—compact, formal representations of the essence of a proof as a sequence of games and hints. Proof sketches are checked automatically using off-the-shelf SMT solvers and automated theorem provers, and then compiled into verifiable proofs in the(More)
CertiCrypt [1] is a framework that assists the construction of machine-checked cryptographic proofs that can be automatically verified by third parties. To date, CertiCrypt has been used to prove formally the exact security of widely studied cryptographic systems, such as the OAEP padding scheme and the Full Domain Hash digital signature scheme. The purpose(More)
Zero-knowledge proofs have a vast applicability in the domain of cryptography, stemming from the fact that they can be used to force potentially malicious parties to abide by the rules of a protocol, without forcing them to reveal their secrets. Σ-protocols are a class of zero-knowledge proofs that can be implemented efficiently and that suffice(More)
Many cryptographic systems based on elliptic curves are proven secure in the Random Oracle Model, assuming there exist probabilistic functions that map elements in some domain (e.g. bitstrings) onto uniformly and independently distributed points in a curve. When implementing such systems, and in order for the proof to carry over to the implementation, those(More)
We present a deep embedding of Bellantoni and Cook’s syntactic characterization of polytime functions. We prove formally that it is correct and complete with respect to the original characterization by Cobham that required a bound to be proved manually. Compared to the paper proof by Bellantoni and Cook, we have been careful in making our proof fully(More)
Certificate translation is a method that transforms certificates of source programs into certificates of their compilation. It provides strong guarantees on low-level code, and is useful for eliminating trust in the compiler (for high assurance code) and in the code producer for mobile code security. The theory of certificate translation has been developed(More)
The goal of modern cryptography is to design efficient constructions that simultaneously achieve some desired functionality and provable security against resource-bounded adversaries. Over the years, the realm of cryptography has expanded from basic functionalities such as encryption, decryption and key agreement, to elaborate functionalities such as(More)
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