Elements: Portable Library for Homomorphic Encrypted Machine Learning on FPGA Accelerated Cloud Cyberinfrastructure

利用同态加密（HE）直接对加密数据进行计算的隐私保护计算（PPC）近年来受到广泛关注。基于HE的机器学习（HE ML）推理可以在各种应用领域保护隐私，包括医疗保健、金融交易、边缘网络物理系统等。依赖于公共云或数据中心处理的隐私敏感应用程序可以使用HE ML推理来保护隐私。虽然HE ML推理提供了强大的隐私保证，但加密数据上的计算比未加密的计算要慢几个数量级，并且需要大量的硬件资源才能使它们对最终用户具有吸引力。新兴的数据中心和云平台被现场可编程门阵列（fpga）所增强。利用fpga的细粒度可编程架构，这些平台非常适合加速高智能机器学习。这项工作将利用fpga上的新算法、架构和内存优化，开发一个可移植和可配置的库，为端到端隐私敏感的机器学习推理提供安全、有弹性和值得信赖的网络基础设施。该库将为HE内核（L1库）提供FPGA加速知识产权（IP）内核，以及用于推断广泛研究的HE ML模型（L2库）的FPGA应用特定处理器（ASP）。该库将支持各种HE方案、安全级别、机器学习模型和FPGA平台。它将包括几个软件和硬件创新，以及各种HE特定的优化，如有效的数据布局，内存高效调度和可扩展的互连，以最大限度地提高内存利用率，并通过片上存储器提高数据重用。使用L1库中的IP核，本项目将组成一个FPGA ASP，具有特定领域的指令集架构（ISA）和编译器。FPGA加速器可以通过软件编程实现实时的HE - ML计算。该库将发布给计算机与信息科学与工程（CISE）社区，包括机器学习、软件和数据科学社区，以加速采用同态加密来保护隐私计算。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Privacy Preserving Computations (PPC) that utilize Homomorphic Encryption (HE) to perform computations on encrypted data directly have become attractive recently. HE based Machine Learning (HE ML) inference enables preservation of privacy in a wide variety of application domains that range from healthcare, financial transactions, edge cyber physical systems, etc. Privacy sensitive applications that rely on processing in a public cloud or data center can use HE ML inference to preserve privacy. While HE ML inference offers strong privacy guarantees, computations on encrypted data are orders of magnitude slower than unencrypted computations and require significant hardware resources to make them attractive for end users. Emerging data centers and cloud platforms are augmented with Field Programmable Gate Arrays (FPGAs). With the fine grained programmable architecture of FPGAs, these platforms are well suited for accelerating HE ML.This work will leverage novel algorithmic, architectural and memory optimizations on FPGAs to develop a portable and configurable library to enable secure, resilient, and trustworthy cyberinfrastructure for end-to-end privacy sensitive ML inference. The library will provide FPGA accelerated Intellectual Property (IP) cores for HE kernels (L1 Library) as well as a FPGA Application Specific Processor (ASP) for inference of widely studied HE ML models (L2 Library). The library will support various HE schemes, security levels, machine learning models and FPGA platforms. It will include several software and hardware innovations along with various HE specific optimizations such as efficient data layout, memory efficient scheduling and scalable interconnect to maximize memory utilization and to improve data reuse using on-chip memory. Using the IP cores in the L1 Library, this project will compose a FPGA ASP with a domain-specific Instruction Set Architecture (ISA) and a compiler. The FPGA accelerator can be programmed in software to realize real-time HE ML computations. The library will be released to the Computer & Information Science & Engineering (CISE) communities, including Machine Learning, Software, and Data Science communities, to accelerate the adoption of homomorphic encryption for privacy preserving computations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.