[...]... Cryptographic Techniques 360 AII.4 Confusion 360 AII.5 Diffusion 361 AII.6 Compression 361 Recommended Reading 365 Index 367 CHAPTER 1 A History of Cryptography This chapter provides an overview of some of the classical methods of cryptography and some idea of how they evolved None of the methods described here is used today, because they are considered either insecure or impractical We begin with. .. SUBSTITUTION CIPHERS Mapping single letters to single letters is far too vulnerable to be useful Thus, cryptographers eventually came up with the idea of mapping entire blocks of plaintext letters to blocks of ciphertext letters The ciphertext blocks didn’t necessarily have the same length as the plaintext blocks For example, suppose we wish to map 8 letter blocks to 8 letter blocks In general, we could... Because cryptography often involves manipulating very large numbers, there are examples in the text that incorporate them These examples are also stored on the book’s Web site Click on the Sample Data Files link to view them By copying these files and pasting the large numbers into a math computation engine, you can verify the results claimed in the book Instructor’s Manual and Resources Instructors of... 10 with, since E is more likely to appear than any other letter in plaintext However, we have even more information: The most common triple in English is THE, and in this example it probably corresponds with the triple LJV Even with this short amount of text, we can try a few possibilities The one that works is shown in Table 1.12 Thus, we derive the keyword SCRAM 14 Chapter 1 A History of Cryptography. .. such is the case with the auto-key Vigenere This type of cipher begins with a priming key of length n, say k0, k1, , knϪ1 Encryption for the first n characters is done the same way (using the key) as for the simple shift Vigenere, but after that, to encipher the ith character of the plaintext, we add to it (with wrap-around) the (i Ϫ n)th letter of the plaintext This is easily seen with an example... alternative to the auto-key Vigenere is called a running key Vigenere It makes use of a very long key in the form of meaningful text, as in a book, of which both the sender and intended receiver have a copy EXAMPLE Suppose we are working with the ordinary alphabet Again, we show the ordinary letter/number associations, in Table 1.16, for quick reference To encrypt the message TORA TORA TORA we use... you use the many applets provided for you online If you are a student, this goes double for you, and if you are a teacher, quadruple Without the applets, this book is just another crypto book, but with them, IT’S AN ADVENTURE! HAVE FUN! Contents Chapter 1: A History of Cryptography 1 1.1 Codes 2 1.2 Monoalphabetic Substitution Ciphers 3 1.3 Frequency Analysis on Caesar Ciphers 4 1.4 Frequency Analysis... Miller’s Test 215 11.2 The Rabin–Miller Test 217 Exercises 219 Chapter 12: Factorization Techniques 221 12.1 Fermat Factorization 221 12.2 Monte Carlo Factorization 226 12.3 The Pollard p–1 Method of Factorization Exercises 234 230 Chapter 13: Exponential Congruences 235 13.1 Order of an Integer 236 13.2 Generators 237 13.3 Generator Selection 239 13.4 Calculating Discrete Logarithms 243 Exercises 256 Chapter... have access to a manual that provides solutions to the more difficult exercises in the text There are also programs written just for instructors that can be used to generate additional exercises Permission must be obtained to use this portion of the site Please contact your publisher’s representative at 1-800-832-0034 for your username and password Preface xi A Word of Thanks I would like to extend... ciphertext to the left by 17, though, we get the beautiful expression: FORMI SATIO AREES WITHO NOSEN EARNO FTHOU OIGNO HCAUS ETHER DRANC OUGHT SEXAC NPERC SENTI UTLOS SATIO SETON GHTNO RANCE EOFAN EISNO EOFMI RIGHT TLYEM EPTIO ALLYE SWITH NPERC GUEBO SEEIN NOOLD GUISH THING NDNOH HEREI PTINE NMENT MPTYN OUTGA EPTIO DYMIN GANDS AGEAN CESSA TOATT INDRA SNIRV SSEMP ALREA OTBOR INTHE NMENT DNOCO OONTO DDEAT . Data Bishop, David 1963- Introduction to cryptography with Java applets / David Bishop. p. cm. Includes index. ISBN 0-7637-2207-3 1. Computer security. 2. Cryptography. 3. Java (Computer program. y0 w0 h0" alt="" INTRODUCTION TO CRYPTOGRAPHY WITH JAVA ™ APPLETS DAVID BISHOP Grinnell College Copyright © 2003 by Jones and Bartlett Publishers, Inc. Cover image © Mark Tomalty / Masterfile. understanding of cryptography. A working knowledge of Java is assumed. You should have little trouble programming cryptographic algorithms in Java once the mathematics is understood. We begin the cryptographic