Rc4 Stream Cipher and Its Variants

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.

Goutam Paul is an assistant professor in the Department of Computer Science and Engineering at Jadavpur University. Dr. Paul has published articles in numerous refereed journals, including Discrete Applied Mathematics, Journal of Mathematical Cryptology, and Designs, Codes and Cryptography. His research interests include cryptography, security, steganography, and combinatorial algorithms.
Subhamoy Maitra is a professor at the Indian Statistical Institute. Dr. Maitra has contributed extensively to many peer-reviewed journals, such as IEEE Transactions on Information Theory, Discrete Mathematics, and Designs, Codes and Cryptography. He is also on the editorial board of Cryptography and Communications: Discrete Structures, Boolean Functions and Sequences. His research interests include cryptographically significant Boolean functions, design and cryptanalysis of stream ciphers, analysis of RSA and factorization, and cryptanalysis of digital watermarking schemes.

Introduction to CryptographyEtymology and Some Historical Facts Primary Goals of CryptographyBasic TerminologyCryptographic Attack ModelsCryptographic SecurityPrivate and Public Key Cryptosystems

Stream Ciphers and RC4Introduction to Stream CiphersAttack Models for Stream Cipher CryptanalysisHardware Stream CiphersSoftware Stream CiphersOn Randomness and Pseudo-Randomness

Analysis of Key SchedulingBias of Permutation toward Secret KeyNon-Randomness of PermutationMovement Frequency of Permutation ValuesKey Collisions

Key Recovery from State InformationReversibility of RC4 PRGARecovery through Solving Simultaneous EquationsImprovement by Difference EquationsGroup of Key Bytes ApproachByte by Byte RecoveryBit by Bit RecoveryBidirectional Key Search

Analysis of Keystream GenerationFinney Cycles Glimpse Theorem Biased Permutation Index Selection for the First Keystream ByteCharacterization of PRGA EvolutionSome Biases in First Keystream Byte toward Secret KeyMore Biases in Many Keystream Bytes toward Secret KeyExhaustive Enumeration of All Biases State Recovery from Keystream

Distinguishing AttacksA Theoretical Framework of Distinguishing Attacks Distinguishers Based on Initial Keystream BytesDistinguishers Based on Any Stage of PRGA

WEP and WPA AttacksRC4 in WEP and the Attack PrincipleFMS AttackMantin’s AttackKlein’s AttackPTW and VX Attacks RC4 in WPA and Related Attacks

Fault AttacksHoch and Shamir’s Attack Impossible and Differential Fault Attacks Fault Attack Based on Fork Model Fault Attack with Pseudo-Random Index Stuck

Variants of RC4Byte-Oriented VariantsWord-Oriented VariantsRC4-Based HashRC4+

Stream Cipher HC-128 Description of HC-128 Linear Approximation of Feedback Functions Distinguishing Attacks on HC-128 Collisions in h1, h2 and State Leakage in Keystream Constructing Full-State Given Only Half-State Information Design Modification with Respect to Known Observations

ConclusionSafe Use of RC4

Appendix A: A Sample C Implementation of RC4 Appendix B: Verified Test Vectors of RC4
Bibliography
Index
Research Problems are presented at the end of chapters 3-10.