DES encryption
The Data Encryption Standard (DES) was developed in the early 1970s by IBM. After consultation with the National Security Agency (NSA), it was strengthened against differential cryptoanalysis, but weakened against brute-force attacks. Controversies arose around the relatively short key length of 56-bits, and the involvement of the NSA, but it quickly spread as a worldwide standard. A strengthened version, called 3DES (tripple DES) was later developed that basically utilizes DES three times.
See also: Code-Breaking overview | Aes | Rc4 | Rsa