Improved Lightweight Encryption Algorithm Based on Optimized S-Box

Hui and Wang proposed a lightweight security encryption algorithm-LEA. And by increasing the bit selection logic traps, the S-box design is optimized. However, we show that there is something wrong in their design. Firstly, the initial key is too short. Secondly, the elements selection method of the LEA S-box is not as they claimed as more secure than the S-box of DES. On the contrary, because of the increased logical operations, it reduces the implementation efficiency. In this paper, we improve the key generation algorithm of PRESENT instead of the key generation algorithm of LEA, thus greatly improving the security of the algorithm. And we use the evolution method for generating better evolutionary S-box to replace the S-box in the LEA. This is not only to meet the requirements of lightweight encryption algorithm, but also to meet the security needs in the practical application of this method.