Cédric Lauradoux

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Sosemanuk is a new synchronous software-oriented stream cipher, corresponding to Profile 1 of the ECRYPT call for stream cipher primitives. Its key length is variable between 128 and 256 bits. It accommodates a 128-bit initial value. Any key length is claimed to achieve 128-bit security. The Sosemanuk cipher uses both some basic design principles from the(More)
Many distance bounding protocols appropriate for the RFID technology have been proposed recently. Unfortunately, they are commonly designed without any formal approach, which leads to inaccurate analyzes and unfair comparisons. Motivated by this need, we introduce a unified framework that aims to improve analysis and design of distance bounding protocols.(More)
The F-FCSR family of algorithms have been presented about one year ago with [2] and [1]. While some flaws where found in the initial propositions (on the IV-setup procedure, and a TMD tradeoff attack), there are yet no known weaknesses of the core of these algorithms. We sum up here some of the properties of the automaton that are better understood now, and(More)
Terrorist fraud is a relay attack against distance bounding protocols where the prover conspires with an adversary to misrepresent the distance between himself and the verifier. In ideal situations, the adversary does not gain any knowledge about the prover's long-term secret. This makes designing a distance bounding protocol resistant to a such fraud(More)
—With the wide adoption of handheld devices (e.g., smartphones, tablets), a large number of location-based services (also called LBSs) have flourished providing mobile users with real-time and contextual information on the move. Accounting for the amount of location information they are given by users, these services are able to track users wherever they go(More)
— In this note we reconsider the code-based pseudo-random generator proposed by Fischer and Stern. This generator is proven as secure as the syndrome decoding problem but has two main drawbacks: it is slow (3000 bits/s) and a large size of memory is needed (88 kiloBytes). We propose a variation on the scheme which avoid them: the use of regular words speeds(More)
Decim is a new stream cipher designed for hardware applications with restricted resources. The design of the cipher is based on both a nonlinear filter LFSR and an irregular decimation mechanism recently introduced and called the ABSG. Apart from the security aspects, the design goal is to produce a stream cipher with a compact hardware implementation and(More)
Many distance bounding protocols appropriate for RFID technology have been proposed recently. However, the design and the analysis of these protocols are not based on a formal perspective. Motivated by this need, a formal framework is presented that helps the future attempts to cryptanalyze and design new distance bounding protocols. We first formalize the(More)