LECipher: a low energy lightweight block cipher for intelligent environment monitoring system

Abstract Significant energy challenges are faced in real-time secure data monitoring in intelligent environmental monitoring systems. A lightweight block cipher LECipher is proposed to provide security for intelligent environmental monitoring systems with low energy. Firstly, a generalized Feistel variant structure (GFS) is proposed, which has good diffusivity. Secondly, an 8-bit S-box generation scheme is constructed based on Boolean functions. The hardware area of the S-box only requires 25.32 Gate Equivalents (GE). Its hardware area has significant advantages compared with the currently published 8-bit S-boxes. Then, using XOR and cyclic shift operations combined with the recursive depth-first search (DFS) strategy in the linear layer. Two 8th-order binary involution circulant matrices are constructed. A 16th-order binary involution circulant matrix is constructed to further improve the security of the LECipher on this basis. The design idea of dynamic adjustment is adopted in the key schedule algorithm. More specially, the different key schedule operations are performed alternately every three rounds to improve the randomization of the round key. Encryption and decryption of LECipher require only 1542 GE and 6.50 μ J/bit on the UMC 0.18 μ m, according to a detailed hardware performance evaluation. The energy is reduced by 61% and 29% compared with the SKINNY and Midori ciphers, respectively. Furthermore, comprehensive security analyses show that LECipher maintains sufficient security boundaries. Finally, an experimental platform for encrypted transmission of intelligent environmental monitoring systems based on LECipher is established, which further verifies the feasibility of its application in internet of things (IoT) devices.