Paper 2010/201

Impossible Differential Cryptanalysis on E2

Yuechuan Wei and Ruilin Li and Ping Li and Chao Li

Abstract

E2 is a 128-bit block cipher which employs Feistel structure and 2-round SPN in round function. It is an AES candidate and was designed by NTT. In the former publications, E2 is supposed no more than 5-round impossible differential. In this paper, we describe some 6-round impossible differentials of E2. By using the 6-round impossible differential, we first present an attack on 9-round reduced version of E2-256 without IT Function(the initial transformation) and FT-Function(the Final transformation) function.