Zero-Correlation Linear Cryptanalysis of Reduced Round ARIA with Partial-sum and FFT

Abstract

Block cipher ARIA was first proposed by some South Korean experts in 2003, and later, it was established as a Korean Standard block cipher algorithm by Korean Agency for Technology and Standards. In this paper, we focus on the security evaluation of ARIA block cipher against the recent zero-correlation linear cryptanalysis. In addition, Partial-sum technique and FFT (Fast Fourier Transform) technique are used to speed up the cryptanalysis, respectively. We first introduce some 4-round linear approximations of ARIA with zero-correlation, and then present some key-recovery attacks on 6/7-round ARIA-128/256 with Partial-sum technique and FFT technique.The key-recovery attack with Partial-sum technique on 6-round ARIA-128 needs 2^{123.6}known plaintexts (KPs), 2^{121} encryptions and 2^{90.3} bytes memory, and the attack with FFT technique requires 2^{124.1} KPs, 2^{121.5} encryptions and 2^{90.3}bytes memory. Moreover, applying Partial-sum technique, we can attack 7-round ARIA-256 with 2^{124.6} KPs, 2^{203.5} encryptions and 2^{152} bytes and 7-round ARIA-256 employing FFT technique, requires 2^{124.7} KPs, 2^{209.5} encryptions and 2^{152} bytes. Our results are the first zero-correlation linear cryptanalysis results on ARIA.