# Feistel cipher

> English word · Noun

## Definitions
1. A symmetric structure used in the construction of block ciphers. It is an iterated cipher with an internal function called a round function.

## Etymology
Named after the German-born physicist and cryptographer Horst Feistel.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/feistel-cipher