One Secure Block Cipher Based on Recursive Diffusion Layers and Four Rounds of AES

Security of the Advanced Encryption Standard (AES) block cipher is the main reason for using its components in the new designs. The diffusion layer is one of the main block ciphers components that effect the performance and security of them. Recursive diffusion layers that was defined formally in FSE 2012 by Sajadiyeh et al. are a class of the diffusion layers which using some words of output as inputs. In this paper, a new approach for designing a block cipher is defined. Using it, one can obtain a 256-block cipher based on the four rounds of AES and a recursive diffusion layer. The suggested algorithm is compared with Rijndael-256 and it is shown that it is more resistant against linear and differential cryptanalysis. Increasing this resistance, decreases the speed by one percent when compared by Rijndael-256, i.e. there is a tradeoff between the resistance and speed. Moreover, the suggested method has been generalized for designing the block ciphers with block sizes of 384 and 512 bit.