International Association
for Cryptologic Research

In this paper, we propose a new lightweight block cipher called FeW which encrypts 64-bit plaintext using key size 80/128 bits and produces 64-bit ciphertext. FeW is a software oriented design with the aim of achieving high efficiency in software based environments. We use a mix of Feistel and generalised Feistel structures (referred as Feistel-M structure hereinafter) to enhance the security of our design against basic cryptanalytic attacks like differential, linear, impossible differential and zero correlation attacks. Security analysis of this scheme proves its strength against present day cryptanalytic attacks.