Security: Theoretical attacks better than exhaustive key search Serpent 9 23 32 Twofish 6 10 16 M ars 115 16 without 16 mixing rounds Rijndael 310 RC6 15 520 05 101520253035 of rounds in the attack/total of rounds13 Security: Theoretical attacks better than exhaustive key search 0 5 10 15 20 25 30 35 Twofish Serpent Rijndael RC6 Mars without 16 mixing rounds # of rounds in the attack/total # of rounds 6 16 9 32 7 10 15 20 11 16 23 10 5 3 5