"Cryptography is a key technology in electronic security systems. It is used to keep data secret, digitally sign documents, access control, and so forth. Users therefore should not only know how its techniques work but they must also be able to estimate their efficiency and security. Based on courses fought by the author, this book explains the basic methods of modern cryptography. It is written for readers with only basic mathematical knowledge who are interested in modern cryptographic algorithms and their mathematical foundation."--BOOK JACKET.