Cryptology, 2nd Edition

Chapter 11

The Advanced Encryption Standard

As we have noted, in practice, known public-key ciphers are in general much slower than known non-public-key ciphers when all are implemented properly. Because of this, non-public-key ciphers continue to play a practical role in modern society. Of course, as we have also noted, the progress in technology that our society achieved over the last several decades has made the types of ciphers we considered before Chapter 9 obsolete, at least from a security perspective. However, non-public-key ciphers do exist that are useful in modern society. Such ciphers are typically called symmetric-key ciphers, since users must usually agree upon encryption and decryption keys that are clearly related, often identical, ...