摘要：In recent two years, zero correlation linear cryptanalysis has shown its great potential in cryptanalysis and it has proven to be effective against massive ciphers. LEA is a block cipher proposed by Deukjo Hong, who is the designer of an ISO standard block cipher - HIGHT. This paper evaluates the security level on LEA family ciphers against zero correlation linear cryptanalysis. Firstly, we identify some 9-round zero correlation linear hulls for LEA. Accordingly, we propose a distinguishing attack on all variants of 9-round LEA family ciphers. Then we propose the first zero correlation linear cryptanalysis on 13-round LEA-192 and 14-round LEA-256. For 13-round LEA-192, we propose a key recovery attack with time complexity of 2~(131.30) 13-round LEA encryptions, data complexity of 2~(128) plaintext-ciphertext pairs and memory complexity of 2~(60.58) bytes. For 14-round LEA-256, we propose a key recovery attack with time complexity of 2~(250.19) 14-round LEA encryptions, data complexity of 2~(128) plaintext-ciphertext pairs and memory complexity of 2~(142.35) bytes. As far as we know, these are the best results on LEA using zero correlation linear cryptanalysis so far.
关键词：Cryptography;cryptanalysis;zero correlation linear cryptanalysis;LEA family ciphers;ARX ciphers
