Gotta Hash Ém All! Speeding Up Hash Functions for Zero-Knowledge Proof Applications

Collision-resistant cryptographic hash functions (CRHs) are crucial for security in modern systems but are optimized for standard CPUs. While heavily used in zero-knowledge proof (ZKP) applications, traditional CRHs are inefficient in the ZK domain. ZK-friendly hashes have been developed but struggle on consumer hardware due to a lack of specialized ZK-specific hardware. To address this, we present HashEmAll, a novel collection of FPGA-based realizations of three ZK-friendly hash functions: Griffin, Rescue-Prime, and Reinforced Concrete. Each hash offers different optimization focuses, allowing users to choose based on the constraints of their applications. Through our ZK-optimized arithmetic functions on reconfigurable hardware, HashEmAll outperforms CPU implementations by up to $23\times$ with lower power consumption and compatibility with accessible FPGAs.