Wikipedia:Today's featured article/July 22, 2006

Cryptography is a discipline of mathematics and computer science concerned with information security and related issues, particularly encryption and authentication. Prior to the early 20th century, cryptography was chiefly concerned with linguistic patterns. Since then, the emphasis has shifted, and cryptography now makes extensive use of areas of mathematics such as of information theory, computational complexity, statistics, combinatorics, and especially number theory. Cryptography is also a branch of engineering, but an unusual one, as it deals with active, intelligent and malevolent opposition. There is also active research examining the relationship between cryptographic problems and quantum physics. Cryptography is central to the techniques used in computer and network security for such purposes as access control and information confidentiality. Cryptography is used in many applications that touch everyday life; the security of ATM cards, computer passwords, and electronic commerce all depend on cryptography. (More...)