Meet-in-the-Middle Attacks on Reduced-Round XTEA

Impossible Differential Cryptanalysis of the Lightweight Block Ciphers TEA, XTEA and HIGHT

TEA, XTEA and HIGHT are lightweight block ciphers with 64-bit block sizes and 128-bit keys. The round functions of the three ciphers are based on the simple operations XOR, modular addition and shift/rotation. TEA and XTEA are Feistel ciphers with 64 rounds designed by Needham and Wheeler, where XTEA is a successor of TEA, which was proposed by the same authors as an enhanced version of TEA. HI...

Three-Subset Meet-in-the-Middle Attack on Reduced XTEA

Improved Meet-in-the-Middle Attacks on Reduced-Round DES

The Data Encryption Standard (DES) is a 64-bit block cipher. Despite its short key size of 56 bits, DES continues to be used to protect financial transactions valued at billions of Euros. In this paper, we investigate the strength of DES against attacks that use a limited number of plaintexts and ciphertexts. By mounting meet-in-the-middle attacks on reduced-round DES, we find that up to 6-roun...

New Fixed Point Attacks on GOST2 Block Cipher

GOST block cipher designed in the 1970s and published in 1989 as the Soviet and Russian standard GOST 28147-89. In order to enhance the security of GOST block cipher after proposing various attacks on it, designers published a modified version of GOST, namely GOST2, in 2015 which has a new key schedule and explicit choice for S-boxes. In this paper, by using three exactly identical portions of ...

Meet-in-the-Middle Attacks on Reduced-Round Hierocrypt-3

Hierocrypt-3 is an SPN-based block cipher designed by Toshiba Corporation. It operates on 128-bit state using either 128, 192 or 256bit key. In this paper, we present two meet-in-the-middle attacks in the single-key setting on the 4-round reduced Hierocrypt-3 with 256-bit key. The first attack is based on the differential enumeration approach where we propose a truncated differential characteri...