Cryptology, for millennia a "secret science", is rapidly gaining in practical importance for the protection of communication channels, databases, and software. Beside its role in computerized information systems, cryptology is finding more and more applications inside computer systems and networks, extending to access rights and source file protection.
The first part of this book treats secret codes and their uses - cryptography - before moving on to the process of covertly decrypting a secret code - cryptanalysis.
Spiced with a wealth of exciting, amusing, and occasionally personal stories from the history of cryptology, and presupposing only elementary mathematical knowledge, this book will also stimulate general readers.

1 Introductory Synopsis.- 2 Aims and Methods of Cryptography.- 3 Encryption Steps: Simple Substitution.- 4 Encryption Steps: Polygraphic Substitution and Coding.- 5 Encryption Steps: Linear Substitution.- 6 Encryption Steps: Transposition.- 7 Polyalphabetic Encryption: Families of Alphabets.- 8 Polyalphabetic Encryption: Keys.- 9 Composition of Classes of Methods.- 10 Open Encryption Key Systems.- 11 Encryption Security.- 12 Exhausting Combinatorial Complexity.- 13 Anatomy of Language: Patterns.- 14 Polyalphabetic Case: Probable Words.- 15 Anatomy of Language: Frequencies.- 16 Kappa and Chi.- 17 Periodicity Examination.- 18 Alignment of Accompanying Alphabets.- 19 Compromises.- 20 Linear Basis Analysis.- 21 Anagramming.- 22 Concluding Remarks.- Appendix: Axiomatic Information Theory.- Photo Credits.