Codes and ciphers : Julius Caesar, the ENIGMA, and the Internet /

In today's age of the Internet, most people have at least a passing acquaintance with the need for data encryption, whether because of e-mail, e-banking, e-commerce, or just because of general uneasiness about who is aware of what is sent over the Net. Churchhouse (emer., Cardiff Univ., Wales) offers a history and explanation of codes, ciphers, cryptography, and cryptanalysis from Julius Caesar and WW II code-breaking activities to the present day, including the world of the Internet. It makes for a most interesting read. Although Churchhouse's aim is to introduce general readers to the world of codes and ciphers, he does demand at least a certain amount of good will on the part of the reader in entertaining ideas of logic and mathematics. While the more sophisticated mathematical explanations are left for an appendix, even an introduction to the subject of codes and ciphers, as this book presents, demands some tolerance for details. Chapter titles include, e.g., "Polyalphabetic Systems," "Jigsaw Ciphers," "Ciphers for Spies," "Producing Random Numbers and Letters," and "Encipherment and the Internet." An excellent resource to support introductory courses in cryptography or cryptanalysis. General readers; lower-division undergraduate and graduate students; two-year technical program students. C. Koch Oberlin College