The Machines Take Over: Computer Cryptography

Modern cryptology rests on the shoulders of three men of rare talents. William Friedman, Lester Hill, and Claude Shannon moved cryptology from an esoteric, mystical, strictly linguistic realm into the world of mathematics and statistics. Once Friedman, Hill, and Shannon placed cryptology on firm mathematical ground, other mathematicians and computer scientists developed the new algorithms to do digital encryption in the computer age. Despite some controversial flaws, the 1976 U.S. Federal Data Encryption Standard (DESData Encryption Standard (DES)) was the most widely used computer encryption algorithm in the twentieth century. In 2001 a much stronger algorithm, the Advanced Encryption Standard (AESAdvanced Encryption Standard (AES)) that was vetted by a new burgeoning public cryptologic community, replaced it. This chapter introduces Hill and Shannon and explores the details of the DES and the AES.