Improved Attacks on Full GOST

GOST is a well known block cipher which was developed in the Soviet Union during the 1970’s as an alternative to the US-developed DES. In spite of considerable cryptanalytic effort, until very recently there were no published single key attacks against its full 32-round version which were faster than the 2256 time complexity of exhaustive search. In February 2011, Isobe used in a novel way the previously discovered reflection property in order to develop the first such attack, which requires 232 data, 264 memory and 2224 time. Shortly afterwards, Courtois and Misztal used a different technique to attack the full GOST using 264 data, 264 memory and 2226 time. In this paper we introduce a new fixed point property and a better way to attack 8-round GOST in order to find improved attacks on full GOST: Given 232 data we can reduce the memory complexity from an impractical 264 to a practical 236 without changing the 2224 time complexity, and given 264 data we can simultaneously reduc...

• Type: Journal
• Year: 2011
• Where: IACR
• Authors: Itai Dinur, Orr Dunkelman, Adi Shamir
• Keywords: Block Cipher, Exhaustive Search, IACR 2011, Time Complexity