9.4. Symmetric Cryptography
You've learned the basic concepts underlying symmetric key cryptography, asymmetric key cryptography, and hashing functions. In the following sections, we'll take an in-depth look at several common symmetric cryptosystems: the Data Encryption Standard (DES), Triple DES (3DES), International Data Encryption Algorithm (IDEA), Blowfish, Skipjack, and the Advanced Encryption Standard (AES).
9.4.1. Data Encryption Standard
The U.S. government published the Data Encryption Standard in 1977 as a proposed standard cryptosystem for all government communications. Indeed, many government entities continue to use DES for cryptographic applications today, despite that it was superseded by the Advanced Encryption Standard in December ...