Bart Preneel

Bio: Bart Preneel is an academic researcher from Katholieke Universiteit Leuven. The author has contributed to research in topics: Hash function & Cryptography. The author has an hindex of 82, co-authored 844 publications receiving 25572 citations. Previous affiliations of Bart Preneel include Bulgarian Academy of Sciences & Electronics and Telecommunications Research Institute.

Towards measuring anonymity

Abstract: This paper introduces an information theoretic model that allows to quantify the degree of anonymity provided by schemes for anonymous connections. It considers attackers that obtain probabilistic information about users. The degree is based on the probabilities an attacker, after observing the system, assigns to the different users of the system as being the originators of a message. As a proof of concept, the model is applied to some existing systems. The model is shown to be very useful for evaluating the level of privacy a system provides under various attack scenarios, for measuring the amount of information an attacker gets with a particular attack and for comparing different systems amongst each other.

Mutual Information Analysis

Abstract: We propose a generic information-theoretic distinguisher for differential side-channel analysis. Our model of side-channel leakage is a refinement of the one given by Standaert et al.An embedded device containing a secret key is modeled as a black box with a leakage function whose output is captured by an adversary through the noisy measurement of a physical observable. Although quite general, the model and the distinguisher are practical and allow us to develop a new differential side-channel attack. More precisely, we build a distinguisher that uses the value of the Mutual Information between the observed measurements and a hypothetical leakage to rank key guesses. The attack is effective without any knowledge about the particular dependencies between measurements and leakage as well as between leakage and processed data, which makes it a universal tool. Our approach is confirmed by results of power analysis experiments. We demonstrate that the model and the attack work effectively in an attack scenario against DPA-resistant logic.

RIPEMD-160: A Strengthened Version of RIPEMD

Abstract: Cryptographic hash functions are an important tool in cryptography for applications such as digital fingerprinting of messages, message authentication, and key derivation. During the last five years, several fast software hash functions have been proposed; most of them are based on the design principles of Ron Rivest's MD4. One such proposal was RIPEMD, which was developed in the framework of the EU project RIPE (Race Integrity Primitives Evaluation). Because of recent progress in the cryptanalysis of these hash functions, we propose a new version of RIPEMD with a 160-bit result, as well as a plug-in substitute for RIPEMD with a 128-bit result. We also compare the software performance of several MD4-based algorithms, which is of independent interest.

Hash Functions Based on Block Ciphers: A Synthetic Approach

Abstract: Constructions for hash functions based on a block cipher are studied where the size of the hashcode is equal to the block length of the block cipher and where the key size is approximately equal to the block length. A general model is presented, and it is shown that this model covers 9 schemes that have appeared in the literature. Within this general model 64 possible schemes exist, and it is shown that 12 of these are secure; they can be reduced to 2 classes based on linear transformations of variables. The properties of these 12 schemes with respect to weaknesses of the underlying block cipher are studied. The same approach can be extended to study keyed hash functions (MAC's) based on block ciphers and hash functions based on modular arithmetic. Finally a new attack is presented on a scheme suggested by R. Merkle.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Handbook of Applied Cryptography

Abstract: From the Publisher: A valuable reference for the novice as well as for the expert who needs a wider scope of coverage within the area of cryptography, this book provides easy and rapid access of information and includes more than 200 algorithms and protocols; more than 200 tables and figures; more than 1,000 numbered definitions, facts, examples, notes, and remarks; and over 1,250 significant references, including brief comments on each paper.

Random graphs

Abstract: We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.