Publications de Serge Vaudenay

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Due to the rapidly growing number of devices that need to communicate securely, there is still significant interest in the development of efficient encryption schemes. It is important to maintain a portfolio of different constructions in order to enable a ...

Although linear perfect diffusion primitives, i.e. MDS matrices, are widely used in block ciphers, e.g. AES, very little systematic work has been done on how to find ``efficient'' ones. In this paper we attempt to do so by considering software implementations on various platforms. These considerations lead to interesting combinatorial problems: how to maximize the number of occurrences of 1 in those matrices, and how to minimize the number of pairwise different entries. We investigate these problems and con

Combining several primitives together to offer greater security is an old idea in cryptography. Recently, this concept has resurfaced as it could be used to improve trust in new Post-Quantum (PQ) schemes and smooth the transition to PQ cryptography. In par ...

We design a suite of protocols so that a small tamper-resistant device can be used as a biometric identity document which can be scanned by authorized terminals. We target both strongly secure identification and strong privacy. Unlike biometric passports, ...

Current proposals of extractable witness encryption are based on multilinear maps. In this paper, we propose a new construction without. We propose the notion of hidden group with hashing and make an extractable witness encryption from it. We show that the ...

Many wearable devices identify themselves in a pervasive way. But at the same time, people want to remain anonymous. Modeling anonymity and unlinkability in identification protocols is a delicate issue. In this paper, we revisit the privacy model from Asiacrypt 2007. We show how to achieve forward-privacy (in the V07 sense) using an IND-CCA secure cryptosystem with the PKC protocol. We review the impossibility result of strong privacy and the model extension from CANS~2012 to reach strong privacy (in the OV

We derive bounds on the expected loss for authenti-cation protocols in channels which are constrained due to noisyconditions and communication costs. This is motivated by anumber of authentication protocols, where at least some partof the authentication is ...

At EuroCrypt ’08, Gilbert, Robshaw and Seurin proposed HB# to improve on HB+ in terms of transmission cost and security against man-in-the-middle attacks. Although the security of HB# is formally proven against a certain class of man- in-the-middle adversa ...

The Data Encryption Standard (DES) is a cryptographic algorithm, designed by IBM, that was selected to be the national standard in 1977 by the National Bureau of Standards. The algorithm itself was entirely published but the design criteria were kept secre ...

This article presents optimization results on the MOVA undeniable signature scheme presented last year by Monnerat and Vaudenay at PKC'04 as well as its generalization proposed at Asiacrypt'04 which is based on a secret group homomorphism. The original MOV ...

In contrast with traditional cryptographic protocols in which parties can have access to common third parties, and where at least one of them is assumed to be honest, we propose here a new model which is relevant for networks of communication devices with security modules. We then focus on the problem of fair exchange in this model. We propose a probabilistic protocol which provides arbitrarily low unfairness (involving a complexity cost).

We propose a way to establish peer-to-peer authenticated communications over an insecure channel by using an extra channel which can authenticate very short strings, e.g. 15 bits. We call this SAS-based authentication as for authentication based on short a ...

We propose HELEN, a new code-based public-key cryptosystem whose security is based on the hardness of the Learning from Parity with Noise problem~(LPN) and the decisional minimum distance problem. We show that the resulting cryptosystem achieves indistingu ...

In this article we focus on constructing an algorithm that automatizes the generation of LPN solving algorithms from the considered parameters. When searching for an algorithm to solve an LPN instance, we make use of the existing techniques and optimize th ...

RFID systems makes it possible for a server to identify known tags in wireless settings. As they become more and more pervasive, people privacy is more and more threatened. In this talk, we list a few models for privacy in RFID and compare them. We review ...

At the Asiacrypt'96 Conference, Lenstra presented a DSA variant which offers some workload advantage for the signer. In this paper, we show some instances of it are not secure unless special care is taken.

Several generalizations of linear cryptanalysis have been proposed in the past, as well as very similar attacks in a statistical point of view. In this paper, we define a rigorous general statistical framework which allows to interpret most of these attacks in a simple and unified way. Then, we explicitely construct optimal distinguishers, we evaluate their performance, and we prove that a block cipher immune to classical linear cryptanalysis possesses some resistance to a wide class of generalized versions

Constructing a block cipher requires us to define a random permutation, which is usually performed by the Feistel scheme and its variants. In this paper we investigate the Lai-Massey scheme which was used in IDEA. We show that we cannot use it Â as isÂ in order to obtain results like the Luby-Rackoff theorem. This can however be done by introducing a simple function which has an orthomorphism property. We also show that this design offers nice decorrelation properties, and we propose a block cipher family

Passports are documents that help immigration officers to identify people. In order to strongly authenticate their data and to automatically identify people, they are now equipped with RFID chips. These contain private information, biometrics, and a digita ...

In this paper, we study an E0-like combiner with memory as the keystream generator. First, we formulate a systematic and simple method to compute correlations of the FSM output sequences (up to certain bits). An upper bound of the correlations is given, wh ...

Serge Vaudenay

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Towards Efficient LPN-Based Symmetric Encryption

Perfect diffusion primitives for block ciphers - building efficient MDS matrices

FO-like Combiners and Hybrid Post-Quantum Cryptography

BioID: a Privacy-Friendly Identity Document

Towards Witness Encryption Without Multilinear Maps

On Privacy for RFID

Expected loss bounds for authentication in constrained channels

On the Security of HB# against a Man-in-the-Middle Attack

DES S-box generator

Optimization of the MOVA Undeniable Signature Scheme

Cryptography with Guardian Angels: Bringing civilization to pirates - Abstract

Secure communications over insecure channels based on short authenticated strings

HELEN: a Public-key Cryptosystem Based on the LPN Problem (Extended Abstract)

Optimization of LPN Solving Algorithms

RFID Privacy based on Public-Key Cryptography

On the Security of Lenstra's DSA Variant

How Far Can We Go Beyond Linear Cryptanalysis?

On the Lai-Massey scheme

About Machine-Readable Travel Documents

Cryptanalysis of an E0-like Combiner with Memory