Feistel Network

What Does Feistel Network Mean?

A Feistel network is a cryptographic technique used in the construction of block cipher-based algorithms and mechanisms. Designed by IBM employees Horst Feistel and Don Coppersmith, the first use of the Feistel network was in Lucifer block cipher.


A Feistel network is also known as a Feistel cipher.

Techopedia Explains Feistel Network

A Feistel network implements a series of iterative ciphers on a block of data and is generally designed for block ciphers that encrypt large quantities of data. A Feistel network works by splitting the data block into two equal pieces and applying encryption in multiple rounds. Each round implements permutation and combinations derived from the primary function or key. The number of rounds varies for each cipher that implements a Feistel network.

Moreover, as a reversible algorithm, a Feistel network produces the same output until the input is the same.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.