FeW: A Lightweight Block Cipher

Abstract

In this paper, we propose a new lightweight block cipher FeW which encrypts plaintext in the blocksof 64-bit using 80/128 bits key to produce 64-bit ciphertext. We also propose a new structure namely FeistelM structure by admixture of Feistel and 4-branch generalised Feistel structures. This new structure significantlycontributes to enhance the security margins of our design against the basic cryptanalytic attacks like differential,linear and impossible differential attacks. Security analysis signifies that FeW has enough security margins againstthese cryptanalytic attacks and it can resist any key recovery attack beyond 17 rounds with the complexity betterthan 264.