Cryptology

FR BRX XQFHUVWCQG WKLV? If you can't decipher this coded message you must read this book! How can messages be transmitted secretly? How can one guarantee that the message arrives safely in the right hands exactly as it was transmitted? Cryptology—the art and science of 'secret writing' — provides ideal methods to solve these problems of data security. Technological advances have stimulated interest in the study of cryptology. Of course, computers can break cryptosystems more efficiently than humans can. Computers allow complex and sophisticated mathematical techniques which achieve a degree of security undreamt of by previous generations. Today the applications of cryptology range from the encryption of television programs sent via satellite, to user authentication of computers, to new forms of electronic payment systems using smart cards. The first half of the book studies and analyzes classical cryptosystems. Here we find Caesar's cipher, the Spartan scytale, the Vigenére cipher, and more. The theory of cipher systems is presented, including a description of the best possible cipher, the one-time pad. An introduction to linear shift registers, which serve as building blocks for most presently used ciphers, is also given. The second half of the book looks at the exciting new directions of public-key cryptology, which since its invention in 1976, has revolutionized data security. The author also looks at the famous RSA-algorithm, algorithms based on 'discrete logarithms,' the so-called zero-knowledge algorithms, and the smart cards that bring cryptographic services to the man-on-the-street. Although the mathematics covered is nontrivial, the book is fun to read, and the author presents the material clearly and simply. Many exercises and references accompany each chapter. The book will appeal to a wide audience including teachers, students, and the interested layman. Cryptology was originally published in German by Vieweg. This edition has been extensively revised.