HAWK: Fully Homomorphic Encryption Accelerator with Fixed-Word Key Decomposition Switching

Fully Homomorphic Encryption (FHE) allows for direct computation on encrypted data, preserving privacy while enabling outsourced processing.Despite its compelling advantages, FHE schemes come with a significant performance penalty.Although recent cryptographic advances have introduced promising optimization technologies to mitigate computational burden, FHE accelerator designs face significant challenges in deploying these algorithmic optimizations.These challenges stem primarily from divergent computational precision requirements and escalating onchip memory demands, leading to mismatches between algorithm and hardware constraints.We propose HAWK, an FHE acceleration solution based on algorithm-hardware co-design.We begin with an in-depth analysis of the original key decomposition switching approach (KDS), identifying the main limitations of applying it to mainstream FHE accelerators.To address these issues, we propose the fixed-word key decomposition switching method (FW-KDS), significantly reducing computational overhead and memory requirements by up to 58%.We demonstrate how to effectively integrate this method into fixed-word accelerator designs and introduce several further * Mingzhe Zhang and Shoumeng Yan are corresponding authors.