Attack On Reduced-Round Crypton Cipher

The modern symmetry cipher algorithm can be divided into two main algorithms; the block cipher algorithm and the stream cipher algorithm. Currently, the block cipher is used more frequently than the stream cipher algorithm. The American Data Encryption Standard DES was proposed in 1976 and used thru the end of the 20th century. During this time, the DES algorithm and its transmutations dominated the research and development of the block cipher algorithm. But with the advancement of computer technology and the level of cryptanalysis, these two algorithms have proven difficult to adapt to the new security requirements. In 1997, the US National Institute for Security Technologies (NIST) initiated to organize the process of collecting the new encryption standard algorithm (AES) worldwide. One of the 15 submissions of block ciphers attracted by the NIST process about AES, Crypton was designed by Chae Hoon Lim in 1998. The reason why this algorithm failed to be selected by the NIST was not a problem with its security, but another issue.In this paper an attack on a reduced round version of Crypton is presented. The attack is based on the dedicated Square attack. An explanation of how the attack works on Crypton is presented and proofs given that the user key for 6 rounds of Crypton can be recovered with time complexity 2⁵⁰.In the first chapter this paper introduces detailed information on Crypton. This information includes some conceptions in cryptography and the development of the block cipher algorithm. Crypton is a 128-bit block cipher algorithm created by iterating a fully parallel round function 12 times. The cipher's design was greatly influenced by Square,...