Enhanced IDEA Algorithm For Strong Encryption Based On Efficient Strong Rotor Banks

Information security becomes an important issue of the communication networks. In this paper we propose a new symmetric cryptosystem based on IDEA system. The plaintext block is divided into basic sub-blocks each of thirty-two bits in length. The new Proposal can encrypt blocks of plaintext of length 512 bits into blocks of the same length. The key length is 1024 bits. The total number of rounds is 17. It uses modulo 2 32 addition and thirty-two bits XORING are used followed by modulo 2 32 - 5 multiplication which is prime number to increase the field in multiplication operation. It uses a new efficient and strong rotor bank which provides best resistance against linear and differential cryptanalysis, also provides better resistance against algebraic attack because it is implemented using Kasami Exponent function one of APN (Almost Perfect Nonlinear) function. The rotor banks rotate by irregular step and we use it to generate the subkeys which give us high diffusion and confusion. In this system, we try to get the minimum correlation between plaintext and ciphertext, highly avalanche effect and defeat the frequency analysis and most well-known attacks. The new algorithm is compared with IDEA and gives excellent results from the viewpoint of the security characteristics and the statistics of the ciphertext. Also, we apply the randomness test to the proposed algorithm and the results shown that the new design passes all tests which proven its security.