Horst Feistel (January 30, 1915 – November 14, 1990) was a German-borncryptographer who worked on the design of ciphers at IBM, initiating researchthat culminated in the development of the Data Encryption Standard (DES) in the1970s.

Life and work.

Feistel was born in Berlin, Germany in 1915, and moved to the United Statesin 1934.

Feistel obtained a bachelor's degree at MIT, and his master's atHarvard, both in physics. Despite this, his true calling was cryptography.

Unfortunately, his German background aroused suspicion, and he washarassed by the NSA, who were jealously protected the domain of crypto.

During World War II, he was placed under house arrest, butnevertheless gained U.S.citizenship on 31 January 1944.

He worked on crypto systems for the US Air Force (IdentificationFriend or Foe (IFF) devices) and Mitre Corp, both of whom were pressured tohalt his research.

He was subsequently employed at MIT's Lincoln Laboratory, then theMITRE corporation.

Finally, he moved to IBM, where he received an award for hiscryptographic work. His research at IBM led to the development of the Luciferand Data Encryption Standard (DES) ciphers. Feistel was one of the earliestnon-government researchers to study the design and theory of block ciphers.

Feistel lent his name to the Feistel network construction, a commonmethod for constructing block ciphers (for example DES).

He married Leona (Gage) in 1945, with whom he had a daughter, Peggy.

Feistel结构的优点在于：由于它是对称的密码结构，所以对信息的加密和解密的过程就极为相似，甚至完全一样。这就使得在实施的过程中，对编码量和线路传输的要求就减少了几乎一半。