LiCryptor: High-Speed and Compact Multi-Grained Reconfigurable Accelerator for Lightweight Cryptography

Emerging modern internet-of-things (IoT) systems require hardware development to support multiple 8/32/64-bit lightweight cryptographic (LWC) algorithms with high speed and energy efficiency to ensure diverse security requirements. Accordingly, a coarse-grained reconfigurable array (CGRA) is considered the most effective architecture for achieving high speed, low power, and high flexibility for implementing LWC algorithms. However, existing CGRA designs for cryptography focus only on improvements to outdated 8/32-bit algorithms, suffer from large area requirements, and have long compilation times. To address these issues, this paper proposes a new CGRA-based accelerator named LiCryptor to support various 8/32/64-bit LWC algorithms with high speed and small area. Three innovative ideas are proposed to enable LiCryptor to achieve these goals: a compact multi-grained processing element array (M-PEA), a shared 8/32/64-bit arithmetic logic unit (ALU), and an assembly-like inline directive (AID) mapping method. The LiCryptor has been successfully implemented and verified on the Xilinx ZCU102 FPGA. Real-time performance evaluation across various LWC algorithms on FPGA shows that LiCryptor is 1.33 to 4 times better in execution time and 3.4 to 153 times better in power-delay products (PDP) compared to today's most powerful CPUs. Notably, evaluation of AID mapping on the ARM Cortex-A53 CPU of the ZCU102 FPGA shows that its compilation time is less than 1.5 ms for most LWC algorithms, at least 2,333 times faster than CFG mapping in current CGRAs. Moreover, experimental results on 45nm ASIC technology show that the LiCryptor significantly outperforms existing CGRAs and other reconfigurable designs in terms of throughput and area efficiency.