Stream Ciphers

• Andreas Klein
Book

1. Front Matter
Pages I-XIX
2. Andreas Klein
Pages 1-13
3. Shift Register-Based Stream Ciphers

1. Front Matter
Pages 15-15
2. Andreas Klein
Pages 17-58
3. Andreas Klein
Pages 59-89
4. Andreas Klein
Pages 91-115
5. Andreas Klein
Pages 117-130
6. Andreas Klein
Pages 131-154
7. Andreas Klein
Pages 155-165
4. Some Special Ciphers

1. Front Matter
Pages 167-167
2. Andreas Klein
Pages 169-181
3. Andreas Klein
Pages 183-228
4. Andreas Klein
Pages 229-239
5. Andreas Klein
Pages 241-257
5. Mathematical Background

1. Front Matter
Pages 259-259
2. Andreas Klein
Pages 261-292
3. Andreas Klein
Pages 293-303
4. Andreas Klein
Pages 305-310
5. Andreas Klein
Pages 311-327
6. Andreas Klein
Pages 329-335

Introduction

In cryptography, ciphers is the technical term for encryption and decryption algorithms. They are an important sub-family that features high speed and easy implementation and are an essential part of wireless internet and mobile phones.

Unlike block ciphers, stream ciphers work on single bits or single words and need to maintain an internal state to change the cipher at each step. Typically stream ciphers can reach higher speeds than block ciphers but they can be more vulnerable to attack. Here, mathematics comes into play. Number theory, algebra and statistics are the key to a better understanding of stream ciphers and essential for an informed decision on their safety.

Since the theory is less developed, stream ciphers are often skipped in books on cryptography. This book fills this gap. It covers the mathematics of stream ciphers and its history, and also discusses many modern examples and their robustness against attacks.

Part I covers linear feedback shift registers, non-linear combinations of LFSRs, algebraic attacks and irregular clocked shift registers. Part II studies some special ciphers including the security of mobile phones, RC4 and related ciphers, the eStream project and the blum-blum-shub generator and related ciphers.

Stream Ciphers requires basic knowledge of algebra and linear algebra, combinatorics and probability theory and programming. Appendices in Part III help the reader with the more complicated subjects and provides the mathematical background needed. It covers, for example, complexity, number theory, finite fields, statistics, combinatorics. Stream Ciphers concludes with exercises and solutions and is directed towards advanced undergraduate and graduate students in mathematics and computer science.

Keywords

Cryptographic ciphers RC4 Stream ciphers

Authors and affiliations

• Andreas Klein
• 1
1. 1.Dept. of Pure Mathem. & Computer AlgebraState University of GhentGhentBelgium

Bibliographic information

• DOI https://doi.org/10.1007/978-1-4471-5079-4
• Copyright Information Springer-Verlag London 2013
• Publisher Name Springer, London
• eBook Packages Mathematics and Statistics
• Print ISBN 978-1-4471-5078-7
• Online ISBN 978-1-4471-5079-4