ML-KEM (CRYSTALS-Kyber) on FPGA using the residue number system

The NIST standardisation process for Post-Quantum Cryptography (PQC) has nominated the CRYSTALS-Kyber Key-Encapsulation Mechanism (KEM) scheme as the primary key establishment method. The algorithm was renamed as the Module-Lattice-Based Key-Encapsulation Mechanism (ML-KEM). This work proposes an efficient design for ML-KEM on FPGA with built-in side-channel attack (SCA) protection. The design is based on combining two methodologies: the Residue Number System (RNS) arithmetic and the look-up tables implementation. At the arithmetic level in the number-theoretic transform (NTT) computation of the polynomial multiplication, the operations are spread across the RNS channels, and these computations are implemented using look-up tables. The use of look-up tables resulted in low-latency RNS implementation and higher performance. The proposed design, implemented on Xilinx Artix-7 FPGA, shows higher performance with a reasonable increase in area, whilst the experimental TVLA results demonstrate the design’s SCA protection advantages.