Security analysis of pure DDP-based cipher proper for multimedia and ubiquitous device

Abstract

DDP-64, based on various controlled operations, is a 64-bit Feistel-like block cipher consisting of 10 rounds with a 128-bit key. It was designed to attempt to have a high security level and a high speed performance in hardware on ubiquitous computing systems and multimedia. In this paper, however, we show that DDP-64 doesn't have a high security level, more precisely, we show that it is vulnerable to related-key differential attack. This attack, which is much faster than the key exhaustive search, requires about 2(54) data and 2(54) time complexities. This work is the first known cryptanalytic result on DDP-64 so far.