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：零知识虚拟机是实现零知识证明大规模应用的关键技术，但其性能瓶颈严重制约了实际可用性。现有硬件加速研究主要聚焦于后端证明环节，而我们发现前端执行与迹线生成阶段正迅速成为新的系统瓶颈。针对这一挑战，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采用包含主迹线单元与并行排列迹线单元的新型异构设计，通过轻量级指令集扩展向主机软件提供细粒度接口，实现高效的任务卸载。ASIC实现结果表明，ZK-Tracer在迹线生成任务上相较于高性能多核CPU可实现最高1829倍加速。当与现有后端证明加速器集成时，其能为整个零知识证明系统带来高达963倍的端到端性能提升。