Meet-in-the-middle attack with Splice-and-Cut technique on the 19-round variant of block cipher HIGHT

Abstract

We show a meet-in-the-middle (MITM) attack with Splice-and-Cut technique (SCT) on the 19-round variant of the block cipher HIGHT. The original HIGHT having 32-round iteration was proposed by Hong et al. in 2006, which applies the 8-branch Type-2 generalized Feistel network (GFN) with 64- bit data block and 128-bit secret key. MITM attack was proposed by Diffie and Hellman in 1977 as a generic method to analyze symmetric-key cryptographic algorithms. SCT was proposed by Aoki and Sasaki to improve MITM attack in 2009. In this paper we show that 19-round HIGHT can be attacked with 28 bytes of memory, 28+2 pairs of chosen plain and cipher texts, and 2120.7 times of the encryption operation by using MITM attack with SCT.