Collision-Integral Attack of Reduced-Round FOX
Wenling Wu · Dianzi xuebao · 2005
FOX are a family of block ciphers presented recently,which are based upon some results on proven security and have high performances on various platforms.In this paper,we construct some distinguishers between 3-round FOX and a random permutation of the blocks space.By using collision-searching techniques and integral attack,the distinguishers are used to attack on 4,5,6 and 7 rounds of FOX64.The four subkeys of 4-round FOX64 can be recovered with 2 9 chosen plaintexts and 2 45.4 encryptions.The five subkeys of 5-round FOX64 can be recovered with 2 9 chosen plaintexts and 2 109.4 encryptions.The six subkeys of 6-round FOX64 can be recovered with 2 9 chosen plaintexts and 2 173.4 encryptions.The seven subkeys of 7-round FOX64 can be recovered with 2 9 chosen plaintexts and 2 237.4 encryptions.Therefore,4-round FOX64/64,5-round FOX64/128,6-round FOX64/192 and 7-round FOX64/256 are not immune to Collision-Integral attack.