cover -- copyright page -- title page -- Contents -- Preface to the First Edition -- Preface to the Second Edition -- 1 Monoalphabetic Ciphers Using Additive Alphabets -- 1.1 The Caesar Cipher -- Exercises -- 1.2 Modular arithmetic -- Exercises -- 1.3 Additive alphabets -- Exercises -- 1.4 Solution of additive alphabets by completing the plain component -- Exercises -- 1.5 Solving additive alphabets by frequency considerations -- Exercises -- 1.6 Alphabets based on multiplications of the normal sequence -- Exercises -- 1.7 Solution of multiplicative alphabets -- Exercises -- 1.8 Affine ciphers -- Exercises -- 2 General Monoalphabetic Substitution -- 2.1 Mixed alphabets -- Exercises -- 2.2 Solution of mixed alphabet ciphers -- Exercises -- 2.3 Solution of monoalphabets in five letter groupings -- Exercises -- 2.4 Monoalphabets with symbols as cipher equivalents -- Exercises -- 3 Polyalphabetic Substitution -- 3.1 Polyalphabetic ciphers -- Exercises -- 3.2 Recognition of polyalphabetic ciphers -- Exercises -- 3.3 Determination of number of alphabets -- Exercises -- 3.4 Solution of individual alphabets, if additive -- Exercises -- 3.5 Polyalphabetic ciphers with a mixed plain sequence -- 3.6 Matching alphabets -- Exercises -- 3.7 Reduction of a polyalphabetic cipher to a monoalphabet -- 3.8 Polyalphabetic ciphers with mixed cipher sequences -- 3.9 General comments about polyalphabetic ciphers -- Exercises -- 4 Polygraphic Systems -- 4.1 Digraphic ciphers based on linear transformations-matrices -- Exercises -- 4.2 Multiplication of matrices-inverses -- Exercises -- 4.3 Involutory transformations -- Exercises -- 4.4 Recognition of digraphic ciphers -- 4.5 Solution of a linear transformation -- Exercises -- 4.6 How to make the Hill System more secure -- 5 Transposition -- 5.1 Columnar transposition -- Exercises.

5.2 Solution of transpositions with completely filled rectangles -- Exercises -- 5.3 Incompletely filled rectangles -- Exercises -- 5.4 Solution of incompletely filled rectangles-probable word method -- Exercises -- 5.5 Incompletely filled rectangles-general case -- Exercises -- 5.6 Repetitions between messages -- identical length messages -- Exercises -- 6 RSA Encryption -- 6.1 Public-key encryption -- 6.2 The RSA method -- 6.3 Creating the RSA keys -- Exercises -- 6.4 Why RSA works-Fermat's Little Theorem -- Exercises -- 6.5 Computational considerations -- Exercises -- 6.6 Maple and Mathematica for RSA -- Exercises -- 6.7 Breaking RSA and signatures -- Exercises -- 7 Perfect Security-One-time Pads -- 7.1 One-time pads -- Exercises -- 7.2 Pseudo-random number generators -- Exercises -- Appendix A: Tables -- Table of digraphic frequencies -- Log Weights -- Frequencies of the letters of the alphabet in a sample of 1000 letters, arranged alphabetically and by frequency. -- Frequencies of letters as initial letters of 16,410 words of newspaper text, arranged alphabetically and by frequency. -- Frequencies of letters as final letters of 16,410 words of newspaper text, arranged alphabetically and by frequency. -- Appendix B: ASCII Codes -- Appendix C: Binary Numbers -- Exercises -- Solutions to Exercises -- Chapter 1 -- Chapter 2 -- Chapter 3 -- Chapter 4 -- Chapter 5 -- Chapter 6 -- Chapter 7 -- Appendix C -- Further Readings -- Index -- About the Authors.