Horst Feistel

German-American cryptographer

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July 20, 2026

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Horst Feistel was a German-American cryptographer who played a pivotal role in the development of modern encryption. He devised the Lucifer algorithm, which was later modified and adopted by the U.S. National Bureau of Standards as the Data Encryption Standard (DES) in 1977.1

DES was a significant advancement in data security, used for unclassified government applications and financial transactions. It employed a product cipher structure, combining substitution and transposition operations in multiple rounds, a design now known as a Feistel cipher. While revolutionary at the time, DES was eventually superseded by the more secure Advanced Encryption Standard (AES) due to increasing computational power.12

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Data Encryption Standard
…one of the company’s researchers, Horst Feistel, a few years earlier. The Lucifer algorithm was evaluated in secret consultations between the NBS and the U.S. National Security Agency (NSA). After some modifications to the internal functions and a shortening of the code key size from 112 bits to 56 bits,…
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…one of the company’s researchers, Horst Feistel, a few years earlier. The Lucifer algorithm was evaluated in secret consultations between the NBS and the U.S. National Security Agency (NSA). After some modifications to the internal functions and a shortening of the code key size from 112 bits to 56 bits,…
Read More