Applied Cryptanalysis

MARK STAMP, PHD, is Professor of Computer Science at San Jose State University. In addition to his experience working in private industry and academia, Dr. Stamp spent seven years as a cryptanalyst for the U.S. National Security Agency. He is the author of Information Security: Principles and Practice. RICHARD M. LOW, PHD, is Lecturer in the Department of Mathematics at San Jose State University. His research interests include cryptography, combinatorics, and group theory.

"…a very good book for students and people who want to learn some real cryptanalysis…" (Computing Reviews.com, October 1, 2007) "…this is not a book to be merely read or studied, but a field manual to be followed." (Computing Reviews.com, August 14, 2007)

• Preface. About The Authors . Acknowledgments. 1. Classic Ciphers. 1.1 Introduction . 1.2 Good Guys and Bad Guys. 1.3 Terminology . 1.4 Selected Classic Crypto Topics. 1.4.1 Transposition Ciphers . 1.4.2 Substitution Ciphers. 1.4.3 One-Time Pad . 1.4.4 Codebook Ciphers . 1.5 Summary. 1.6 Problems . 2. World War II Ciphers. 2.1 Introduction . 2.2 Enigma . 2.2.1 Enigma Cipher Machine . 2.2.2 Enigma Keyspace . 2.2.3 Rotors . 2.2.4 Enigma Attack . 2.2.5 More Secure Enigma. 2.3 Purple. 2.3.1 Purple Cipher Machine . 2.3.2 Purple Keyspace . 2.3.3 Purple Diagnosis . 2.3.4 Decrypting Purple. 2.3.5 Purple versus Enigma . 2.4 Sigaba . 2.4.1 Sigaba Cipher Machine. 2.4.2 Sigaba Keyspace . 2.4.3 Sigaba Attack . 2.4.4 Sigaba Conclusion . 2.5 Summary . 2.6 Problems . 3. Stream Ciphers. 3.1 Introduction . 3.2 Shift Registers . 3.2.1 Berlekamp-Massey Algorithm . 3.2.2 Cryptographically Strong Sequences . 3.2.3 Shift Register-Based Stream Ciphers. 3.2.4 Correlation Attack. 3.3 ORYX . 3.3.1 ORYX Cipher. 3.3.2 ORYX Attack. 3.3.3 Secure ORYX. 3.4 RC4. 3.4.1 RC4 Algorithm . 3.4.2 RC4 Attack . 3.4.3 Preventing the RC4 Attack. 3.5 PKZIP. 3.5.1 PKZIP Cipher. 3.5.2 PKZIP Attack. 3.5.3 Improved PKZIP. 3.6 Summary. 3.7 Problems. 4. Block Ciphers. 4.1 Introduction . 4.2 Block Cipher Modes . 4.3 Feistel Cipher. 4.4 Hellman’s Time-Memory Trade-Off. 4.4.1 Cryptanalytic TMTO. 4.4.2 Bad Chains. 4.4.3 Success Probability. 4.4.4 Distributed TMTO. 4.4.5 TMTO Conclusions. 4.5 CMEA. 4.5.1 CMEA Cipher. 4.5.2 SCMEA Cipher. 4.5.3 SCMEA Chosen Plaintext Attack. 4.5.4 CMEA Chosen Plaintext Attack. 4.5.5 SCMEA Known Plaintext Attack. 4.5.6 CMEA Known Plaintext Attack. 4.5.7 More Secure CMEA. 4.6 Akelarre . 4.6.1 Akelarre Cipher. 4.6.2 Akelarre Attack. 4.6.3 Improved Akelarre? 4.7 FEAL . 4.7.1 FEAL-4 Cipher. 4.7.2 FEAL-4 Differential Attack. 4.7.3 FEAL-4 Linear Attack. 4.7.4 Confusion and Diffusion. 4.8 Summary. 4.9 Problems. 5. Hash Functions. 5.1 Introduction . 5.2 Birthdays and Hashing. 5.2.1 The Birthday Problem. 5.2.2 Birthday Attacks on Hash Functions. 5.2.3 Digital Signature Birthday Attack. 5.2.4 Nostradamus Attack. 5.3 MD4. 5.3.1 MD4 Algorithm. 5.3.2 MD4 Attack. 5.3.3 A Meaningful Collision . 5.4 MD5 . 5.4.1 MD5 Algorithm. 5.4.2 A Precise Differential. 5.4.3 Outline of Wang?s Attack. 5.4.4 Wang’s MD5 Differentials. 5.4.5 Reverse Engineering Wang’s Attack. 5.4.6 Stevens’ Attack. 5.4.7 A Practical Attack. 5.5 Summary. 5.6 Problems. 6. Public Key Systems. 6.1 Introduction . 6.2 Merkle-Hellman Knapsack. 6.2.1 Lattice-Reduction Attack . 6.2.2 Knapsack Conclusion. 6.3 Diffie-Hellman Key Exchange . 6.3.1 Man-in-the-Middle Attack . 6.3.2 Diffie-Hellman Conclusion . 6.4 Arithmetica Key Exchange . 6.4.1 Hughes-Tannenbaum Length Attack . 6.4.2 Arithmetica Conclusion . 6.5 RSA . 6.5.1 Mathematical Issues . 6.5.2 RSA Conclusion . 6.6 Rabin Cipher . 6.6.1 Chosen Ciphertext Attack. 6.6.2 Rabin Cryptosystem Conclusion . 6.7 NTRU Cipher . 6.7.1 Meet-in-the-Middle Attack. 6.7.2 Multiple Transmission Attack. 6.7.3 Chosen Ciphertext Attack. 6.7.4 NTRU Conclusion . 6.8 ElGamal Signature Scheme . 6.8.1 Mathematical Issues. 6.8.2 ElGamal Signature Conclusion . 6.9 Summary . 6.10 Problems. 7. Public Key Attacks. 7.1 Introduction . 7.2 Factoring Algorithms . 7.2.1 Trial Division . 7.2.2 Dixon’s Algorithm . 7.2.3 Quadratic Sieve. 7.2.4 Factoring Conclusions. 7.3 Discrete Log Algorithms. 7.3.1 Trial Multiplication . 7.3.2 Baby-Step Giant-Step. 7.3.3 Index Calculus. 7.3.4 Discrete Log Conclusions. 7.4 RSA Implementation Attacks. 7.4.1 Timing Attacks . 7.4.2 Glitching Attack. 7.4.3 Implementation Attacks Conclusions . 7.5 Summary . 7.6 Problems. Appendix . A-1 MD5 Tables . A-2 Math . A-2.1 Number Theory . A-2.2 Group Theory . A-2.3 Ring Theory . A-2.4 Linear Algebra. Annotated Bibliography. Index.