Cryptanalysis Of Several Block Ciphers And Hash Functions

With the rapid development of computer technology, the information security becomes an important issue, cryptography plays a significant role as foundation of information security. Block ciphers and hash functions have been widely used in the field of information security as the primitives, cryptanalysis of which is always the hotspot of international cryptography research. This dissertation focuses on the cryptanalysis of block ciphers Camellia and ARIA, and hash functions SM3 and BLAKE-256, with several meaningful results presented.Camellia is a block cipher designed by NTT and Mitsubishi of Japan in 2000. It has been selected for use by the ISO/IEC, the European Union’s NESSIE project and the Japanese CRYPTREC project. Hence, Camellia attracts a significant amount of attention of the cryptology researchers. In this dissertation, we propose the first 7-round impossible differentials of Camellia with two F L/F L-1layers, which contains one more F L/F L-1layer than before leading to less key guess. Then we achieve the first 11-round impossible differential attack on Camellia-128. The impossible differential attacks on 11/12-round Camellia-192 and 14-round Camellia-256 are also given.The block cipher ARIA was designed by Korean cryptographers in 2003. ARIA is based on SPN structure with the same design idea of AES. It was selected as a Korean standard in 2004. Combined with some e?cient techniques used in the meet-in-themiddle(MITM) attacks on AES by Dunkelman et al. in 2010 and Derbez et al. in 2013,such as the un-ordered Multiset structure and differential enumeration technique, we give some 4-round and 5-round significant distinguishing properties of ARIA. Based on these distinguishers, we present MITM attacks on 7-round ARIA-128 and 9-round ARIA-256,which are both the first results for ARIA in terms of meet-in-the-middle attack. The MITM attacks on 7-round ARIA-192 and 8-round ARIA-256 with lower complexities are also given.SM3 was designed by Xiaoyun Wang et al. and published as the Chinese cryptographic hash function standard in 2010. Utilizing the differential characteristics with high probabilities, we apply boomerang attack to the compression function of SM3. By message modification technique, the complexities of attacks are significantly improved.Boomerang attacks on 34/35-steps SM3 with practical complexities and 36/37/38-steps with theoretical complexities are proposed, and the corresponding boomerang quartets(for middle steps) are also given. These are the best results against round-reduced SM3.The hash function BLAKE is one of the five finalists of the NIST SHA-3 competition submitted by Aumasson et al. We launch the first valid boomerang attacks on up to 7-round and 8-round keyed permutation of BLAKE-256. The 7-round boomerang attack is practical, which is the best practical result for round-reduced BLAKE-256.