09031 Abstracts Collection -- Symmetric Cryptography

From 11.01.09 to 16.01.09, the Seminar 09031 in ``Symmetric Cryptography \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Distinguishing attacks on block ciphers by differentials of two-block texts

Предложена модель наблюдений (случайные двублочные тексты, шифруемые на независимых случайных ключах), в которой разностные атаки различения полностью соответствуют общепринятым схемам их статистического расчёта. В этой модели получены нижние границы и асимптотические оценки объёма материала мультиразностных атак различения. Показано, что материала объёма O (1/pmax ) недостаточно для успешной атаки при малых значениях pmax — максимальной вероятности перехода разностей. Проведены вычислительные и статистические эксперименты для марковских моделей шифрсистемы SmallPresent c длиной блока до 28 бит

A Salad of Block Ciphers

This book is a survey on the state of the art in block cipher design and analysis. It is work in progress, and it has been for the good part of the last three years -- sadly, for various reasons no significant change has been made during the last twelve months. However, it is also in a self-contained, useable, and relatively polished state, and for this reason I have decided to release this \textit{snapshot} onto the public as a service to the cryptographic community, both in order to obtain feedback, and also as a means to give something back to the community from which I have learned much. At some point I will produce a final version -- whatever being a ``final version\u27\u27 means in the constantly evolving field of block cipher design -- and I will publish it. In the meantime I hope the material contained here will be useful to other people

Understanding sit-to-stand through experimentation and constraint-based modelling

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Advanced methods of Linear Cryptanalysis

In the present work we study advanced methods of linear cryptanalysis. At the beginning, we describe the principle of Matsui's linear cryptanalysis, the two basic algorithms - Algorithm 1 and Algorithm 2, against DES cipher. Further it is described a generalization of linear cryptanalysis and consequently partitioning and statistical cryptanalysis. Then it is followed by a look on the linear approximations over the correlation matrices. Furthermore, we study an improvement of Matsui's Algorithm 2 using Fast Fourier transform, based on circulant matrices theory. Finally we deal multidimensional linear cryptanalysis that uses multiple linear approximations and in the very end we propose an own design of improvement of multidimensional extension of Algorithm 2 by using Fast Fourier transform

Advanced methods of Linear Cryptanalysis

In the present work we study advanced methods of linear cryptanalysis. At the beginning, we describe the principle of Matsui's linear cryptanalysis, the two basic algorithms - Algorithm 1 and Algorithm 2, against DES cipher. Further it is described a generalization of linear cryptanalysis and consequently partitioning and statistical cryptanalysis. Then it is followed by a look on the linear approximations over the correlation matrices. Furthermore, we study an improvement of Matsui's Algorithm 2 using Fast Fourier transform, based on circulant matrices theory. Finally we deal multidimensional linear cryptanalysis that uses multiple linear approximations and in the very end we propose an own design of improvement of multidimensional extension of Algorithm 2 by using Fast Fourier transform