A pure hardware implementation of CRYSTALS-KYBER PQC algorithm through resource reuse

This paper presents a pure hardware implementation of CRYSTALS-KYBER algorithm on Xilinx FPGAs. CRYSTALS-KYBER is one of 26 candidate algorithms in Round 2 of NIST Post-Quantum Cryptography (PQC) standardization process. The proposed design focuses on maximizing resource utilization by reusing most of the functional modules in the encapsulation and decapsulation processes of the algorithm. For instance, the hash module integrates several different hash functions in one module. Efficient parallel and pipelined computations are applied in the NTT module. Through the analysis of simulation and synthesis results, it is found that the proposed work has the advantages of higher frequencies and lower execution times. The scheme operates at 155 MHz and 192 MHz frequencies on Xilinx Artix-7 and Virtex-7 FPGAs, respectively. Compared with the performance of an embedded Cortex-M4 processor, the hardware implementation can achieve a maximum speedup of 129 times for encryption/decryption.