时 间: 2011年6月23日（周四）下午2:30

地 点: 清华大学高等研究院 科学馆322报告厅

题 目: ARX-based Cryptography

报 告 人: Dr. Nicky Mouha

Institute for Advanced Study, Tsinghua University, China;

Katholieke Universiteit Leuven, Belgium;

Institute for BroadBand Technology (IBBT), Belgium

Abstract:Due to their fast performance in software, an increasing number of cryptographic primitives are constructed using the operations addition modulo 2^n, bit rotation and XOR (ARX). Examples include two out of the five finalists of NIST's ongoing SHA-3 competition, namely Skein and BLAKE. However, the security properties of ARX-based cryptographic primitives are not well understood. In particular, there are currently no bounds for the resistance of ARX-based ciphers against linear and differential cryptanalysis, two of the most commonly used techniques in the cryptanalysis of symmetric-key primitives. The goal of this lecture is to give an introduction to the field of ARX-based cryptography, no specific background knowledge is required. This talk is based on the invited lecture given at the ECRYPT II Summer School held in Albena, Bulgaria.

Biography:Nicky Mouha obtained a BSc in Electrical Engineering (Magna Cum Laude) in 2006, and an MSc in Electrical Engineering (Summa Cum Laude) in 2008, both at Katholieke Universiteit Leuven, Belgium. He is now a PhD student at the same university on the topic of "Cryptanalysis and Design of Hash functions", under the supervision of Prof. Bart Preneel. His main research interest is symmetric-key cryptography, with a focus on cryptanalyis and cryptographic design, as well as implementation issues in both hardware and software. He has published several results on the topic of ARX-based cryptography, including "The Differential Analysis of S-Functions" at SAC 2010, "Meet-in-the-Middle Attacks on Reduced-Round XTEA" at CT-RSA 2011 and "The Additive Differential Probability of ARX" at FSE 2011. He is now a visiting PhD student at the Institute for Advanced Study of Tsinghua University, under the supervision of Prof. Xiaoyun Wang.