An improved Cache trace attack on AES and CLEFIA was proposed by considering Cache miss trace informa-tion and S-box misalignment.Current trace driven attacks all assume that the S-box is perfectly aligned in Cache

and it’s impossible to recover the whole first round key of AES and CLEFIA under limited key searching space.However

the re-search demonstrates that the S-box is misaligned in Cache at most cases

by utilizing the Cache miss trace information of the cipher encryption

200 samples first round analysis and 50 samples last round analysis can reduce 128bit AES master key searching space to 216 and 1 respectively

80 samples first round analysis can reduce 128bit CLEFIA first round key searching space to 216

220 samples first three rounds analysis can reduce 128bit CLEFIA master key searching space to 216

all of the attacks above can be finished within 1 second.