HeW: a Hash Function based on lightweight Block cipher FeW

A new hash function HeW: A hash function based on light weight block cipher FeW is proposed in this paper. The compression function of HeW is based on block cipher FeW. It is believed that key expansion algorithm of block cipher slows down the performance of the overlying hash function. Thereby, block ciphers become a less favourable choice to design a compression function. As a countermeasure, we cut down the key size of FeW from 80-bit to 64-bit and provide a secure and efficient key expansion algorithm for the modified key size. FeW based compression function plays a vital role to enhance the efficiency of HeW. We test the hash output for randomness using the NIST statistical test suite and test the avalanche effect, bit variance and near collision resistance. We also give the security estimates of HeW against differential cryptanalysis, length extension attack, slide attack and rotational distinguisher.