International Association
for Cryptologic Research

Zero-correlation linear attack is a new method for cryptanalysis of block ciphers. In this paper we adapt Matrix method to find zero-correlation approximations. Then we present several zero-correlation linear approximations for 14 rounds of Lblock. Finally, we describe a cryptanalysis for 22 rounds of the reduced Lblock. While the previous attacks on Lblock used chosen plaintexts, the new attack needs distinct known plaintexts which is a more realistic model. Also the time complexity is $2^8$ times faster than the previous attack.