Impossible differential attack on 13-round Camellia-192

In this paper, we study the security of the block ciphers Camellia-192 and Camellia-256 in the impossible differential context. In particular, we present the first attack on 13 rounds of Camellia-192 with FL / FL - 1 layers. An attack on 14 rounds of Camellia-256 requiring less complexity than the previous impossible differential attacks is also described. We analyze the security of Camellia in the impossible differential context.We improve the complexity of the impossible differential attacks on 12 rounds of Camellia-192 and 14 rounds of Camellia-256.We present the first attack on 13 rounds of Camellia-192.