Editing Feistel cipher (section)

{{short description|Cryptography construction}}
{{Use dmy dates|date=February 2025}}
[[File:Feistel cipher diagram en.svg|right|300px]]
In [[cryptography]], a '''Feistel cipher''' (also known as '''Luby–Rackoff block cipher''') is a [[Symmetric-key algorithm|symmetric structure]] used in the construction of [[block cipher]]s, named after the [[Germany|German]]-born [[physicist]] and cryptographer [[Horst Feistel]], who did pioneering research while working for [[IBM]]; it is also commonly known as a '''Feistel network'''. A large number of [[block cipher]]s use the scheme, including the US [[Data Encryption Standard]], the Soviet/Russian [[GOST (block cipher)|GOST]] and the more recent [[Blowfish (cipher)|Blowfish]] and [[Twofish]] ciphers. In a Feistel cipher, encryption and decryption are very similar operations, and both consist of iteratively running a function called a "[[Round (cryptography)|round function]]" a fixed number of times.