Feistel cipher

In cryptography, a Feistel cipher (or feistel network, Luby-Rackoff block cipher) is a symmetric structure used by block ciphers. Named after Horst Feistel.

Feistel ciphers are used in DES, GOST (aka Magma), Blowfish, Twofish, Lucifer, Camellia, FEAL, RC2, RC6, Skipjack, and many others.

https://en.wikipedia.org/wiki/Feistel_cipher

---