A Run-Time Configurable NTT Architecture for Homomorphic Encryption Based on 3D Algorithm

Homomorphic encryption (HE) allows computations on encrypted data without compromising data privacy, making it ideal for scenarios like privacy-preserving computing. The primary bottleneck within HE schemes is polynomial multiplication, which can be accelerated using the number theoretic transform (NTT). This paper proposes a run-time configurable (RTC) NTT/INTT accelerator supporting HE parameter sets based on the 3D NTT algorithm. A conflict-free memory access pattern is proposed to efficiently implement the 3D NTT algorithm without additional hardware units. Additionally, an on-the-fly twiddle factor generator (TFG) is proposed to optimize memory utilization for twiddle factors (TFs). The proposed design achieves significant improvements in performance and area efficiency compared to state-of-the-art FPGA implementations.