Stream Ciphers


Author: Andreas Klein
Publisher: Springer Science & Business Media
ISBN: 1447150791
Category: Computers
Page: 399
View: 5927
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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.

Stream Ciphers and Number Theory


Author: Thomas W. Cusick,Cunsheng Ding,Ari R. Renvall
Publisher: Gulf Professional Publishing
ISBN: 9780444516312
Category: Mathematics
Page: 474
View: 9764
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This is the unique book on cross-fertilisations between stream ciphers and number theory. It systematically and comprehensively covers known connections between the two areas that are available only in research papers. Some parts of this book consist of new research results that are not available elsewhere. In addition to exercises, over thirty research problems are presented in this book. In this revised edition almost every chapter was updated, and some chapters were completely rewritten. It is useful as a textbook for a graduate course on the subject, as well as a reference book for researchers in related fields. · Unique book on interactions of stream ciphers and number theory. · Research monograph with many results not available elsewhere. · A revised edition with the most recent advances in this subject. · Over thirty research problems for stimulating interactions between the two areas. · Written by leading researchers in stream ciphers and number theory.

Stream Ciphers and Number Theory


Author: T.W. Cusick,C. Ding,Ari R. Renvall
Publisher: Elsevier
ISBN: 0080541844
Category: Mathematics
Page: 430
View: 7493
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This book is almost entirely concerned with stream ciphers, concentrating on a particular mathematical model for such ciphers which are called additive natural stream ciphers. These ciphers use a natural sequence generator to produce a periodic keystream. Full definitions of these concepts are given in Chapter 2. This book focuses on keystream sequences which can be analysed using number theory. It turns out that a great deal of information can be deducted about the cryptographic properties of many classes of sequences by applying the terminology and theorems of number theory. These connections can be explicitly made by describing three kinds of bridges between stream ciphering problems and number theory problems. A detailed summary of these ideas is given in the introductory Chapter 1. Many results in the book are new, and over seventy percent of these results described in this book are based on recent research results.

The Stability Theory of Stream Ciphers


Author: Cunsheng Ding,Guozhen Xiao,Weijuan Shan
Publisher: Springer Science & Business Media
ISBN: 9783540549734
Category: Computers
Page: 187
View: 342
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Secure message transmission is of extreme importance in today's information-based society. Stream encryption is a practically important means to this end. This monograph is devoted to a new aspect of stream ciphers, namely the stability theory of stream ciphers, with the purpose of developing bounds on complexity which can form part of the basis for a general theory of data security and of stabilizing stream-cipher systems. The approach adopted in this monograph is new. The topic is treated by introducing measure indexes on the security of stream ciphers, developing lower bounds on these indexes, and establishing connections among them. The treatment involves the stability of boolean functions, the stability of linear complexity of key streams, the period stability of key streams, and the stability of source codes. Misleading ideas about stream ciphers are exposed and new viewpoints presented. The numerous measure indexes and bounds on them that are introduced here, the approach based on spectrum techniques, andthe ten open problems presented will all be useful to the reader concerned with analyzing and designing stream ciphers for securing data.

New Stream Cipher Designs

The ESTREAM Finalists
Author: Matthew Robshaw,Olivier Billet
Publisher: Springer Science & Business Media
ISBN: 354068350X
Category: Computers
Page: 293
View: 3883
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Thequestion“Streamciphers:deadoralive?”wasposedbyAdiShamir.Intended to provokedebate,the questioncouldnot havebeen better, ormorestarkly,put. However,itwasnotShamir'sintentiontosuggestthatstreamciphersthemselves were obsolete; rather he was questioning whether stream ciphers of a dedicated designwererelevantnowthattheAESispervasivelydeployedandcanbeusedas a perfectly acceptablestreamcipher. To explore this question the eSTREAM Project was launched in 2004, part of the EU-sponsored ECRYPT Framework VI Network of Excellence. The goal of the project was to encourage academia and industry to consider the “dead stream cipher” and to explore what could be achieved with a dedicated design. Now, after several years of hard work, the project has come to a close and the 16 ciphers in the ?nal phase of eSTREAM are the subject of this book. The designers of all the ?nalist ciphers are to be congratulated. Regardless of whether a particular algorithm appears in the ?nal portfolio, in reaching the third phase of eSTREAM all the algorithms constitute a signi?cant milestone in the development of stream ciphers. However, in addition to thanking all designers, implementers, and crypt- alysts who participated in eSTREAM, this is a ?tting place to o?er thanks to some speci?c individuals.

RC4 Stream Cipher and Its Variants


Author: Goutam Paul,Subhamoy Maitra
Publisher: CRC Press
ISBN: 1439831378
Category: Computers
Page: 311
View: 2244
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RC4 Stream Cipher and Its Variants is the first book to fully cover the popular software stream cipher RC4. With extensive expertise in stream cipher cryptanalysis and RC4 research, the authors focus on the analysis and design issues of RC4. They also explore variants of RC4 and the eSTREAM finalist HC-128. After an introduction to the vast field of cryptology, the book reviews hardware and software stream ciphers and describes RC4. It presents a theoretical analysis of RC4 KSA, discussing biases of the permutation bytes toward secret key bytes and absolute values. The text explains how to reconstruct the secret key from known state information and analyzes the RC4 PRGA in detail, including a sketch of state recovery attacks. The book then describes three popular attacks on RC4: distinguishing attacks, Wired Equivalent Privacy (WEP) protocol attacks, and fault attacks. The authors also compare the advantages and disadvantages of several variants of RC4 and examine stream cipher HC-128, which is the next level of evolution after RC4 in the software stream cipher paradigm. The final chapter emphasizes the safe use of RC4. With open research problems in each chapter, this book offers a complete account of the most current research on RC4.

Analysis and Design of Stream Ciphers


Author: Rainer A. Rueppel
Publisher: Springer Science & Business Media
ISBN: 3642828655
Category: Technology & Engineering
Page: 244
View: 8306
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It is now a decade since the appearance of W. Diffie and M. E. Hellmann's startling paper, "New Directions in Cryptography". This paper not only established the new field of public-key cryptography but also awakened scientific interest in secret-key cryptography, a field that had been the almost exclusive domain of secret agencies and mathematical hobbyist. A number of ex cellent books on the science of cryptography have appeared since 1976. In the main, these books thoroughly treat both public-key systems and block ciphers (i. e. secret-key ciphers with no memo ry in the enciphering transformation) but give short shrift to stream ciphers (i. e. , secret-key ciphers wi th memory in the enciphering transformation). Yet, stream ciphers, such as those . implemented by rotor machines, have played a dominant role in past cryptographic practice, and, as far as I can determine, re main still the workhorses of commercial, military and diplomatic secrecy systems. My own research interest in stream ciphers found a natural re sonance in one of my doctoral students at the Swiss Federal Institute of Technology in Zurich, Rainer A. Rueppe1. As Rainer was completing his dissertation in late 1984, the question arose as to where he should publish the many new results on stream ciphers that had sprung from his research.

Advanced Linear Cryptanalysis of Block and Stream Ciphers


Author: Pascal Junod,Anne Canteaut,IOS Press
Publisher: IOS Press
ISBN: 1607508443
Category: Computers
Page: 144
View: 2101
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The origins of linear cryptanalysis can be traced back to a number of seminal works of the early 1990s. Since its invention, several theoretical and practical aspects of the technique have been studied, understood and generalized, resulting in more elaborated attacks against certain ciphers, but also in some negative results regarding the potential of various attempts at generalization. This book gives an overview of the current state of the discipline and it takes a look at potential future developments, and is divided into five parts. The first part deals with basic assumptions in linear cryptanalysis and their consequences for the design of modern block ciphers; part two explores a theory of multi-dimensional linear attacks on block ciphers; and, the third part covers how linear attacks can be applied to stream ciphers and gives an overview of the development of linear attacks as well as a theoretical explanation of their current use.Part four details interesting and useful links between linear cryptanalysis and coding theory and the fifth and final part discusses how correlation analysis can be conducted at the level of elements of GF (2n) without the need to deal with field representation issues. This book will be of interest to anybody who wishes to explore this fascinating yet complex part of symmetrical cryptanalysis.

IPSec

The New Security Standard for the Internet, Intranets, and Virtual Private Networks
Author: Naganand Doraswamy,Dan Harkins
Publisher: Prentice Hall Professional
ISBN: 9780130461896
Category: Computers
Page: 262
View: 3537
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IPSec, Second Edition is the most authoritative, comprehensive, accessible, and up-to-date guide to IPSec technology. Two leading authorities cover all facets of IPSec architecture, implementation, and deployment; review important technical advances since IPSec was first standardized; and present new case studies demonstrating end-to-end IPSec security. New coverage also includes in-depth guidance on policies, updates on IPSec enhancements for large-scale enterprise environments, and much more.