Zero-knowledge virtual machines (zkVMs) are a key technology for driving the large-scale adoption of zero-knowledge proofs (ZKP), but their performance bottlenecks severely limit their practicality. While current hardware acceleration research has exclusively focused on backend proving, we identify that the frontend execution and trace generation phase is rapidly emerging as the new system bottleneck. To address this challenge, we propose ZK-Tracer, the first hardware accelerator architecture specifically designed for the zkVM frontend. ZK-Tracer features a novel heterogeneous design comprising a Main Trace Unit and parallel Permutation Trace Units. It exposes a fine-grained interface to the host software through a lightweight instruction set extension, enabling efficient task offloading. Our ASIC implementation results demonstrate that ZK-Tracer achieves up to 1829x speedup in trace generation over a high-performance multi-core CPU. When integrated with existing backend proving accelerators, it delivers a remarkable 963x end-to-end performance improvement for the entire ZKP system.

翻译：零知识虚拟机（zkVM）是推动零知识证明（ZKP）大规模应用的关键技术，但其性能瓶颈严重限制了实际可用性。当前硬件加速研究主要集中在后端证明阶段，而本文发现前端执行与迹生成阶段正迅速成为新的系统瓶颈。为应对这一挑战，我们提出ZK-Tracer——首款专为zkVM前端设计的硬件加速器架构。ZK-Tracer采用创新的异构设计，包含主迹单元与并行排列迹单元。通过轻量级指令集扩展，该架构向主机软件暴露细粒度接口，实现高效任务卸载。ASIC实现结果表明，ZK-Tracer在迹生成任务上相较高性能多核CPU可实现高达1829倍的加速。当与现有后端证明加速器集成时，能为整个ZKP系统带来惊人的963倍端到端性能提升。