LTE: Lightweight and Time-Efficient Hardware Encoder for Post-Quantum Scheme HQC

Post-quantum cryptography (PQC) has gained increasing attention across the hardware research community, especially after the National Institute of Standards and Technology (NIST) started the PQC standardization process. There are, however, very few hardware implementations reported for the Hamming Quasi-Cyclic (HQC), which is one of the NIST fourth-round PQC candidates. As encoding is an important step in code-based public key encryption scheme, this paper presents a Lightweight and Time-Efficient (LTE) hardware encoder for HQC. Our proposed design features a streamlined data flow setup to manage the iterative computations between the Reed-Solomon encoder and the Reed-Muller encoder, and a detailed analysis to obtain an optimized Galois field multiplier. The proposed LTE encoder is also implemented on an FPGA platform to demonstrate its area-time efficiency. Our evaluation shows that the proposed hardware implementation of HQC encoder outperforms the most recently reported state-of-the-art hardware implementation with 34.5%, 26.7%, and 35.2% reduction in area-delay product (ADP) for hqc-128, hqc-192, and hqc-256, respectively.