Olivier Pereira

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In March 2009, the Université catholique de Louvain elected its President using a custom deployment of the Helios web-based open-audit voting system. Out of 25,000 potential voters, 5000 registered, and almost 4000 voted in each round of the election. The precision of the voting system turned out to be crucial: in the first round, the leader came short of(More)
Relay attacks are one of the most challenging threats RFID will have to face in the close future. They consist in making the verifier believe that the prover is in its close vicinity by surreptitiously forwarding the signal between the verifier and an out-of-field prover. Distance bounding protocols represent a promising way to thwart relay attacks, by(More)
The Fiat-Shamir transformation is the most efficient construction of non-interactive zero-knowledge proofs. This paper is concerned with two variants of the transformation that appear but have not been clearly delineated in existing literature. Both variants start with the prover making a commitment. The strong variant then hashes both the commitment and(More)
Energy is a central concern in the deployment of wireless sensor networks. In this paper, we investigate the energy cost of cryptographic protocols, both from a communication and a computation point of view, based on practical measurements on the MICAz and TelosB sensors. We focus on the cost of two key agreement protocols: Kerberos and the elliptic curve(More)
Susan Bell, Office of the Travis County Clerk Josh Benaloh, Microsoft Research Michael D. Byrne, Rice University Dana DeBeauvoir, Office of the Travis County Clerk Bryce Eakin, independent researcher Gail Fisher, Office of the Travis County Clerk Philip Kortum, Rice University Neal McBurnett, ElectionAudits Julian Montoya, Office of the Travis County Clerk(More)
In this report, we are concerned with models to analyze the security of cryptographic algorithms against side-channel attacks. Our objectives are threefold. In a first part of the paper, we aim to survey a number of well known intuitions related to physical security and to connect them with more formal results in this area. For this purpose, we study the(More)
We study the security of a block cipher-based pseudorandom number generator (PRNG), both in the black box world and in the physical world, separately. We first show that the construction is a secure PRNG in the ideal cipher model. Then, we demonstrate its security against a Bayesian side-channel key recovery adversary. As a main result, we show that our(More)
Wepresent a symbolic framework for refinement and composition of security protocols. The framework uses the notion of ideal functionalities. These are abstract systems which are secure by construction and which can be combined into larger systems. They can be separately refined in order to obtain concrete protocols implementing them. Our work builds on(More)