Flexible structures of lightweight block ciphers PRESENT, SIMON and LED

Security and privacy of the Internet of Things (IoT) systems are critical challenges in many data-sensitive applications. The IoT systems are constrained in terms of execution time, flexibility and computational resources. In recent years, many encryption algorithms have been proposed to provide the security of IoT communication. In this study, flexible and high-throughput hardware structures of the PRESENT, SIMON, and LED lightweight block ciphers are presented for IoT applications. The proposed flexible structures can perform various configurations of these block ciphers to support variable key sizes. For example, the PRESENT, SIMON, and LED ciphers support key sizes (80, 128 bits), (96, 144, 128, 192, and 256 bits), and (64, 128 bits), respectively. Therefore, these architectures provide versatile implementations that enable adaptive security level using a variable key size. In the proposed structures, sub-blocks of the ciphers are implemented based on optimised circuits. In the PRESENT and LED ciphers, the S-boxes are implemented based on area-optimised logic circuits. The implementation results of proposed flexible architectures are achieved in 180 nm CMOS technology. Area, throughput and throughput/area of the proposed structures have improved compared to other related works.