LegoZK: A Dynamically Reconfigurable Accelerator for Zero-Knowledge Proof

Abstract

Zero-knowledge proof (ZKP) allows a prover to convince a verifier of the truth of a statement without revealing any secret information. This property is utilized in numerous privacy-preserving applications. However, the huge overhead of proof generation impedes the widespread adoption of ZKP. As a result, many ZKP accelerators have been developed to speed up proof generation. However, existing accelerators are designed at the granularity of core operators and exhibit low hardware resource utilization and limited adaptability. In this paper, we identify the commonality of all computation stages in proof generation at the level of basic finite field arithmetic operations. Based on this insight, we propose LegoZK, a dynamically reconfigurable hardware accelerator for ZKP. LegoZK employs finite field arithmetic units (FAUs) as its fundamental components and integrates these FAUs with a hierarchical on-chip network (NoC). By dynamically configuring the FAUs and the NoC, LegoZK can effectively accelerate the entire proof generation process, achieving higher overall performance. Additionally, for the most time-consuming MSM, this paper proposes a fast, fully pipelined bucket reduction algorithm based on lookup tables, which significantly reduces the latency of MSM. Experimental results demonstrate that LegoZK achieves on average speedup of $31.96 \times$ and $11.30 \times$ in proof generation compared to the state-of-the-art ZKP ASIC accelerator PipeZK and the GPU accelerator GZKP, respectively. And compared to PipeZK, LegoZK achieves $\mathbf{5 0. 1 \%}$ area reduction and $\mathbf{3 7. 7 \%}$ power consumption reduction.