URESC, Unbalanced Rotor Enhanced Symmetric Cipher

URESC is a new cryptosystem, stands for unbalanced rotor enhancing symmetric cipher. It uses main cryptographic terms of substitution and permutation, and key dependency back-to-back with unbalanced rotor to achieve the requested goals of the design like perfect statistics and large period. Each wheel of unbalanced rotor contains different number of elements, which are pre-selected of prime number greater than 256 and less than 512. Rotor wheels are implemented using modulo 2⁷² operations. URESC has 64 bits basic block; substitutions are performed on each single basic block at a time. The resulted block of rotor called expanded basic block, of 72 bits. Two types of permutations are used, horizontal and vertical. Finally a key dependency operation is applied. The key of each round is generated using a small rotor called key-rotor. URESC achieves memory-less, normalized ciphertext statistics, and small processing speed trend.