Area-Efficient Matrix-Vector Polynomial Multiplication Architecture for ML-KEM Using Interleaving and Folding Transformation

The ML-KEM post-quantum cryptography (PQC) scheme requires matrix-vector polynomial multiplication and polynomial arithmetic operations in the number theoretic transform (NTT) domain. Prior optimization approach KyberMat leverages the transposed-form fast filtering structure and sub-structure sharing technique, reducing the computational complexity. In this paper, a novel and area-efficient design builds upon the KyberMat framework, using the hierarchical interleaved folding algorithm to reduce hardware resources. Two design strategies are utilized in the proposed design. The proposed design initially scales down the NTT/inverse NTT processors via folding transformation, while utilizing a fixed number of DSPs and LUTs across different security levels of ML-KEM. This work further introduces a recursive summing unit along with the interleaving method to ensure continuous data processing and ultimately improve hardware utilization and throughput. The experimental result shows that our proposed area-efficient design achieves an average reduction of 71.55% in DSPs and 63.89% in LUTs among three different security levels, compared to the KyberMat framework.