We propose a practical flexible (or arbitrary) length small domain block cipher,
encryption scheme. FNR denotes
eingold. It can cipher small domain data formats like IPv4, Port numbers, MAC Addresses, Credit card numbers, any random short strings while preserving their input length. In addition to the classic Feistel networks, Naor and Reingold propose usage of Pair-wise independent permutation (PwIP) functions based on Galois Field GF(2
). Instead we propose usage of random
Invertible matrices in GF(2).