A Lightweight and Efficient Encryption/Decryption Coprocessor for RLWE-Based Cryptography
Yushu Yang, Zihang Wang, Jianfei Wang, Jia Hou, Yang Su, Chen Yang · IEEE Transactions on Circuits & Systems II Express Briefs · 2024
Lattice-based cryptography has experienced significant advancements in recent years due to its versatility and simplicity. The ring learning with errors (RLWE) problem is widely adopted in lattice-based cryptography. However, the polynomial multiplication is the performance bottleneck of RLWE-based cryptography, which requires further examination. In this brief, a lightweight and efficient encryption/decryption coprocessor for RLWE-based cryptography is proposed. The time complexity of the Schoolbook polynomial multiplication (SPM) is reduced from${n}^{2}$to$ {n}^{ {2}} {/8}$by enhancing multiplication parallelism. Moreover, an optimized structure for the Compressed cumulative distribution table (CDT) Gaussian sampler is proposed, resulting in 22.2% reduction in storage resource. The proposed SPM structure demonstrates a$2.3\times $performance speedup and$2.7\times $hardware efficiency for the encryption core, compared with state-of-the-art SPM accelerators. Additionally, it achieves a$2.4\times $performance speedup and$3.2\times $improvements on hardware efficiency for the decryption core.