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Lecture Notes in Computer Science 2355 Edited by G Lecture Notes in Computer Science 2355 Edited by G. Goos, J. Hartmanis, and J. van Leeuwen 3 Berlin Heidelberg New York Barcelona Hong Kong London Milan Paris Tokyo Mitsuru Matsui (Ed.) Fast Software Encryption 8th International Workshop, FSE 2001 Yokohama, Japan, April 2-4, 2001 Revised Papers 13 Series Editors Gerhard Goos, Karlsruhe University, Germany Juris Hartmanis, Cornell University, NY, USA Jan van Leeuwen, Utrecht University, The Netherlands Volume Editor Mitsuru Matsui Mitsubishi Electric Corporation 5-1-1 Ofuna Kamakura Kanagawa, 247-8501, Japan E-mail: [email protected] Cataloging-in-Publication Data applied for Die Deutsche Bibliothek - CIP-Einheitsaufnahme Fast software encryption : 8th international workshop ; proceedings / FSE 2001, Yokohama, Japan, April2-4,2001. Mitsuru Matsui (ed.). - Berlin ; Heidelberg ; New York ; Barcelona ; Hong Kong ; London ; Milan ; Paris ; Tokyo : Springer, 2002 (Lecture notes in computer science ; Vol. 2355) ISBN 3-540-43869-6 CR Subject Classification (1998): E.3, F.2.1, E.4, G.4 ISSN 0302-9743 ISBN 3-540-43869-6 Springer-Verlag Berlin Heidelberg New York This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. Springer-Verlag Berlin Heidelberg New York a member of BertelsmannSpringer Science+Business Media GmbH http://www.springer.de © Springer-Verlag Berlin Heidelberg 2002 Printed in Germany Typesetting: Camera-ready by author, data conversion by PTP Berlin, Stefan Sossna e. K. Printed on acid-free paper SPIN 10870083 06/3142 543210 Preface Fast Software Encryption is an eight-year-old workshop on symmetric crypto- graphy, including the design and cryptanalysis of block and stream ciphers, as well as hash functions. The first Fast Software Encryption Workshop was held in Cambridge in 1993, followed by Leuven in 1994, Cambridge in 1996, Haifa in 1997, Paris in 1998, Rome in 1999, and New York in 2000. This Fast Software Encryption Workshop, FSE 2001, was held from 2-4 April 2001 in Yokohama, Japan, in cooperation with the Institute of Industrial Science, of the University of Tokyo. This year a total of 46 papers were submitted to FSE 2001. After a two- month review process, 27 papers were accepted for presentation at the workshop. In addition, we were fortunate to be able to organize a special talk by Bart Preneel on the NESSIE project, a European initiative to evaluate cryptographic algorithms. The committee of this workshop was: General Chair Hideki Imai (The University of Tokyo) Program Committee Ross Anderson (Cambridge Univ.) Eli Biham (Technion) Cunsheng Ding (Singapore) Henri Gilbert (France Telecom) Dieter Gollman (Microsoft) Thomas Johansson (Lund Univ.) Lars Knudsen (Bergen Univ.) James Massey (Denmark) Mitsuru Matsui (Mitsubishi Electric, Chair) Kaisa Nyberg (Nokia) Bart Preneel (Katholieke Univ. Leuven) Bruce Schneier (Counterpane) We would like to thank all submitting authors and the committee members for their hard work. We are also appreciative of the financial support provided by Mitsubishi Electric Corporation. Special thanks are due to Toshio Tokita, Junko Nakajima, Yasuyuki Sakai, Seiichi Amada, Toshio Hasegawa, Katsuyuki Takashima, and Toru Sorimachi for their efforts in making the local arrangements for this workshop. We were very pleased and honored to host the first FSE workshop held in Asia. Finally, we are also happy to announce that the next FSE will be the first FSE workshop sponsored by International Association for Cryptologic Research (IACR). May 2002 Mitsuru Matsui Table of Contents Cryptanalysis of Block Ciphers I The Saturation Attack – A Bait for Twofish ........................... 1 Stefan Lucks Linear Cryptanalysis of Reduced Round Serpent ....................... 16 Eli Biham, Orr Dunkelman, Nathan Keller Cryptanalysis of the Mercy Block Cipher ............................. 28 Scott R. Fluhrer Hash Functions and Boolean Functions Producing Collisions for PANAMA ................................... 37 Vincent Rijmen, Bart Van Rompay, Bart Preneel, Joos Vandewalle The RIPEMDL and RIPEMDR Improved Variants of MD4 Are Not Collision Free ...................................................... 52 Christophe Debaert, Henri Gilbert New Constructions of Resilient Boolean Functions with Maximal Nonlinearity ....................................................... 66 Yuriy Tarannikov Modes of Operations Optimized Self-Synchronizing Mode of Operation ...................... 78 Ammar Alkassar, Alexander Geraldy, Birgit Pfitzmann, Ahmad-Reza Sadeghi Fast Encryption and Authentication: XCBC Encryption and XECB Authentication Modes .............................................. 92 Virgil D. Gligor, Pompiliu Donescu Incremental Unforgeable Encryption ..................................9 Enrico Buonanno, Jonathan Katz, Moti Yung Cryptanalysis of Stream Ciphers I ZIP Attacks with Reduced Known Plaintext ...........................125 Michael Stay Cryptanalysis of the SEAL 3.0 Pseudorandom Function Family ..........135 Scott R. Fluhrer VIII Table of Contents Cryptanalysis of SBLH .............................................144 Goce Jakimovski, Ljupˇco Kocarev A Practical Attack on Broadcast RC4 ................................152 Itsik Mantin, Adi Shamir Cryptanalysis of Block Ciphers II Improved Square Attacks against Reduced-Round Hierocrypt ........165 Paulo S.L.M. Barreto, Vincent Rijmen, Jorge Nakahara, Bart Preneel, Joos Vandewalle, Hae Y. Kim Differential Cryptanalysis of Q .......................................174 Eli Biham, Vladimir Furman, Michal Misztal, Vincent Rijmen Differential Cryptanalysis of Nimbus .................................187 Vladimir Furman Cryptanalysis of Stream Ciphers II Fast Correlation Attack Algorithm with List Decoding and an Application .......................................................196 Miodrag J. Mihaljevi´c, Marc P.C. Fossorier, Hideki Imai Bias in the LEVIATHAN Stream Cipher ..............................211 Paul Crowley, Stefan Lucks Analysis of SSC2...................................................219 Daniel Bleichenbacher, Willi Meier Pseudo-Randomness Round Security and Super-Pseudorandomness of MISTY Type Structure ....................................................233 Tetsu Iwata, Tomonobu Yoshino, Tomohiro Yuasa, Kaoru Kurosawa New Results on the Pseudorandomness of Some Blockcipher Constructions .....................................................248 Henri Gilbert, Marine Minier FSE2001 Special Talk NESSIE: A European Approach to Evaluate Cryptographic Algorithms ...267 Bart Preneel Cryptanalysis of Block Ciphers III Related Key Attacks on Reduced Round KASUMI .....................277 Mark Blunden, Adrian Escott Table of Contents IX Security of Camellia against Truncated Differential Cryptanalysis ........286 Masayuki Kanda, Tsutomu Matsumoto Impossible Differential Cryptanalysis of Zodiac ........................300 Deukjo Hong, Jaechul Sung, Shiho Moriai, Sangjin Lee, Jongin Lim Design and Evaluation The Block Cipher SC00 ...........................................312 Takeshi Shimoyama, Hitoshi Yanami, Kazuhiro Yokoyama, Masahiko Takenaka, Kouichi Itoh, Jun Yajima, Naoya Torii, Hidema Tanaka Flaws in Differential Cryptanalysis of Skipjack .........................328 Louis Granboulan Efficient Algorithms for Computing Differential Properties of Addition ..........................................................336 Helger Lipmaa, Shiho Moriai Author Index .................................................351 The Saturation Attack – A Bait for Twofish Stefan Lucks Theoretische Informatik University of Mannheim, 68131 Mannheim, Germany [email protected] Abstract. This paper introduces the notion of a “saturation attack”. Consider a permutation p over w-bit words. If p is applied to all 2w dis- joint words, the set of outputs is exactly the same as the set of inputs. A saturation attack exploits this fact. The current paper applies saturation attacks on reduced-round variants of the Twofish block cipher with up to seven rounds with full whitening or eight rounds without whitening at the end (i.e., half of the cipher). The attacks take up to 2127 chosen plaintexts (half of the codebook) and are 2–4 times faster than exhaustive search. The attacks are based on key-independent distinguishers for up to six rounds of Twofish, making extensive use of saturation properties. 1 Introduction Modern b-bit block ciphers often use permutations p : {0, 1}w →{0, 1}w with w<bas building blocks. E.g., p may be an S-box, a round function, or a group operation where one of the operands is constant. The constant may be unknown to the cryptanalyst, e.g. as a part of the (round) key. We regard the input for p as a data channel. For the cryptanalyst, p may be known or unknown, and the cryptanalysts may be unable to determine the input for p.A“saturation attack” is based on the idea of choosing a set of k ∗ 2w plaintexts such that each of the 2w inputs for p occurs exactly k times. In this case, we say that the data channel into p is “saturated”. A saturation attack exploits the fact that if
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