Making Computation on Encrypted Data Practical through Hardware Acceleration of Fully Homomorphic Encryption

Fully Homomorphic Encryption (FHE) enables offloading computation to untrusted servers with cryptographic privacy. Despite its attractive security, FHE is not yet widely adopted due to its prohibitive overheads, about 10,000× over unencrypted computation. Hardware acceleration is an attractive ap...

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Main Author: Samardzic, Nikola
Other Authors: Sanchez, Daniel
Format: Thesis
Published: Massachusetts Institute of Technology 2022
Online Access:https://hdl.handle.net/1721.1/144604
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author Samardzic, Nikola
author2 Sanchez, Daniel
author_facet Sanchez, Daniel
Samardzic, Nikola
author_sort Samardzic, Nikola
collection MIT
description Fully Homomorphic Encryption (FHE) enables offloading computation to untrusted servers with cryptographic privacy. Despite its attractive security, FHE is not yet widely adopted due to its prohibitive overheads, about 10,000× over unencrypted computation. Hardware acceleration is an attractive approach to bridge this performance gap, but it brings new challenges. These include operations on large vectors with complex dependencies that current vector processor architectures cannot handle, as well as extreme memory bandwidth demands. This thesis presents two FHE accelerators that address these challenges: F1 and CraterLake. F1 is the őrst programmable FHE accelerator, i.e., capable of executing full FHE programs. F1 is a wide-vector processor with novel functional units deeply specialized to FHE primitives. This organization provides so much compute throughput that data movement becomes the key bottleneck. Thus, F1 is primarily designed to minimize data movement. It speeds up shallow FHE computations (i.e., those of limited multiplicative depth) by gmean 5,400× over a 4-core CPU. Unfortunately, F1 becomes memory bandwidth bound on deeper computations (e.g., deep neural networks). This is because deep FHE programs require very large ciphertexts (tens of MBs each) and different algorithms that F1 does not support well. CraterLake addresses these shortcomings and is the őrst accelerator to effectively speed up arbitrarily large FHE programs. CraterLake introduces a new hardware architecture that efficiently scales to very large ciphertexts, novel functional units to accelerate key kernels, and new algorithms and compiler techniques to reduce data movement. These advances help CraterLake outperform a 32-core CPU by gmean 4,600× and deliver 11.2× the performance of F1 on deep benchmarks, even when we scale F1’s architecture to the size of CraterLake. These speedups enable new applications for FHE, such as real-time inference using deep neural networks.
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spelling mit-1721.1/1446042022-08-30T03:33:40Z Making Computation on Encrypted Data Practical through Hardware Acceleration of Fully Homomorphic Encryption Samardzic, Nikola Sanchez, Daniel Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Fully Homomorphic Encryption (FHE) enables offloading computation to untrusted servers with cryptographic privacy. Despite its attractive security, FHE is not yet widely adopted due to its prohibitive overheads, about 10,000× over unencrypted computation. Hardware acceleration is an attractive approach to bridge this performance gap, but it brings new challenges. These include operations on large vectors with complex dependencies that current vector processor architectures cannot handle, as well as extreme memory bandwidth demands. This thesis presents two FHE accelerators that address these challenges: F1 and CraterLake. F1 is the őrst programmable FHE accelerator, i.e., capable of executing full FHE programs. F1 is a wide-vector processor with novel functional units deeply specialized to FHE primitives. This organization provides so much compute throughput that data movement becomes the key bottleneck. Thus, F1 is primarily designed to minimize data movement. It speeds up shallow FHE computations (i.e., those of limited multiplicative depth) by gmean 5,400× over a 4-core CPU. Unfortunately, F1 becomes memory bandwidth bound on deeper computations (e.g., deep neural networks). This is because deep FHE programs require very large ciphertexts (tens of MBs each) and different algorithms that F1 does not support well. CraterLake addresses these shortcomings and is the őrst accelerator to effectively speed up arbitrarily large FHE programs. CraterLake introduces a new hardware architecture that efficiently scales to very large ciphertexts, novel functional units to accelerate key kernels, and new algorithms and compiler techniques to reduce data movement. These advances help CraterLake outperform a 32-core CPU by gmean 4,600× and deliver 11.2× the performance of F1 on deep benchmarks, even when we scale F1’s architecture to the size of CraterLake. These speedups enable new applications for FHE, such as real-time inference using deep neural networks. S.M. 2022-08-29T15:59:05Z 2022-08-29T15:59:05Z 2022-05 2022-06-21T19:25:41.370Z Thesis https://hdl.handle.net/1721.1/144604 In Copyright - Educational Use Permitted Copyright MIT http://rightsstatements.org/page/InC-EDU/1.0/ application/pdf Massachusetts Institute of Technology
spellingShingle Samardzic, Nikola
Making Computation on Encrypted Data Practical through Hardware Acceleration of Fully Homomorphic Encryption
title Making Computation on Encrypted Data Practical through Hardware Acceleration of Fully Homomorphic Encryption
title_full Making Computation on Encrypted Data Practical through Hardware Acceleration of Fully Homomorphic Encryption
title_fullStr Making Computation on Encrypted Data Practical through Hardware Acceleration of Fully Homomorphic Encryption
title_full_unstemmed Making Computation on Encrypted Data Practical through Hardware Acceleration of Fully Homomorphic Encryption
title_short Making Computation on Encrypted Data Practical through Hardware Acceleration of Fully Homomorphic Encryption
title_sort making computation on encrypted data practical through hardware acceleration of fully homomorphic encryption
url https://hdl.handle.net/1721.1/144604
work_keys_str_mv AT samardzicnikola makingcomputationonencrypteddatapracticalthroughhardwareaccelerationoffullyhomomorphicencryption