{"ID":2900913,"CreatedAt":"2026-06-01T05:51:17.9442275Z","UpdatedAt":"2026-06-01T06:23:29.641557848Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2605.31004","arxiv_id":"2605.31004","title":"HE^2: A Communication-Light Heterogeneous Architecture for Efficient Fully Homomorphic Encryption","abstract":"CKKS, an emerging fully homomorphic encryption (FHE) scheme, has been promising in privacy-preserving applications by enabling SIMD fixed-point computations on ciphertexts. Despite its strong security guarantees, CKKS involves both compute-intensive operators (ComOps) with high computational cost and memory-intensive operators (MemOps) with large memory footprints, making existing ASIC-based or NMP-based acceleration approaches suffer from high hardware overhead and limited efficiency. This observation motivates the integration of the architectural advantages of both paradigms into a heterogeneous xPU (ASIC)-xMU (NMP) architecture. However, in such a design, frequent and long-latency heterogeneous communication caused by the dominant keyswitch operator remains a key performance bottleneck. In this paper, we propose $HE^2$, a communication-light xPU-xMU heterogeneous FHE accelerator with dataflow graph (DFG) optimization and architecture co-design. First, we observe that the majority of communication arises at the interface between ModUp/ModDown and neighboring MemOps. To address this, we propose a DFG-level optimization framework to fully exploit the ModUp/ModDown reduction potential of the hoisting algorithm by identifying parallel keyswitch blocks and fusing them for reduced communication frequency. Second, we design an efficient heterogeneous architecture that adopts a group-level pipelined execution to effectively hide communication latency by leveraging the inherent parallelism across decomposed groups. End-to-end evaluation results show that $HE^2$ achieves 1.66$\\times$ speedup and 9.23$\\times$ lower EDAP (Energy-Delay-Area Product) compared to the state-of-the-art accelerator, with communication stalls accounting for only 6.67% of the total latency.","short_abstract":"CKKS, an emerging fully homomorphic encryption (FHE) scheme, has been promising in privacy-preserving applications by enabling SIMD fixed-point computations on ciphertexts. Despite its strong security guarantees, CKKS involves both compute-intensive operators (ComOps) with high computational cost and memory-intensive o...","url_abs":"https://arxiv.org/abs/2605.31004","url_pdf":"https://arxiv.org/pdf/2605.31004v1","authors":"[\"Shangyi Shi\",\"Husheng Han\",\"Zhaoxuan Kan\",\"Yinghao Yang\",\"Jianan Mu\",\"Tenghui Hua\",\"Ge Yu\",\"Xinyao Zheng\",\"Ling Liang\",\"Zidong Du\",\"Xing Hu\"]","published":"2026-05-29T08:38:53Z","proceeding":"cs.AR","tasks":"[\"cs.AR\",\"cs.CR\"]","methods":"[]","has_code":false}