Idea Algorithm And Its Variants

With the rapid development of information and communication technology, people attach more importance to the information & correspondence security, especially to network security. The dissertation research mainly IDEA and realize of its mutation. The approach has theoretical significance, and has better practical values for information, communication and network security. Cryptography technology is the core of information security, and block cipher is one of most important research in cryptography, its security, which protects data storage and transmission, can't be replaced by other types of ciphers. The born of AES and the launching of NESSIE project, bring a new climax of block cipher research all over the world. So, the thesis studies and discusses the subject deeply at this research background. In the parameters of block cipher, block length n is an important parameter that must be considered. To make block cipher security, block length n must be long enough to prevent it from being statistical analysis. Longer block length has advantage at realizing efficiency, plain text of IDEA is 64bits, at present, its security is enough, but consider the development trend of computer science in the future, it has positive meanings for the development of block cipher to construct an involution permutation with 128 bits long and to utilize it design a secret-key block cipher with 128 bits long. It is development trends in the future. First, the thesis introduces summarily the status quo of block cipher, and analyzes its development trend. Second, it approaches the main theory and technology of block cipher, and analyzes some important block ciphers. And then, it based on the above discussion, discard the dross and select the essential, the thesis approached the main theory and technology of IDEA; presented two schemes of using IDEA grouping cipher arithmetic to build hashing function and with double key system to achieve identity authentication and digital signature; constructed an involution permutation with 128 bits long by use of the MA-structure in IDEA, simply analyses its properties and presents a new secret-key block cipher basing the involution permutation.