Horst Feistel

Horst Feistel (January 30, 1915 – November 14, 1990) was a German-American cryptographer who worked on the design of ciphers at IBM, initiating research that culminated in the development of the Data Encryption Standard (DES) in the 1970s. The structure used in DES, called a Feistel network, is commonly used in many block ciphers.