A scalable block cipher design using filter banks over finite fields

Abstract

A scalable block cipher based on a filter bank structure over GF(28) is proposed. The filter bank structure is used to introduce the diffusion during the circular convolution process between the filters coefficients (which are generated from the key) and the plaintext. The confusion is achieved by the mixing between the analysis filter bank and a novel addition mod 2n and XOR scheme. The proposed cipher is scalable in both block and key lengths. The cipher is shown to be secure against differential and linear cryptanalysis and of lesser complexity than the AES. The proposed cipher structure enables security versus complexity versus performance trade-offs to be made, an increasingly important aspect of security in communications systems.