BitPacker: Enabling High Arithmetic Efficiency in Fully Homomorphic Encryption Accelerators
Name
3620665.3640397.pdf
Size
1.09 MB
Format
Adobe PDF
Checksum (MD5)
f7fe026b29c4af898861ac70e07f031f
Author(s)
Samardzic, Nikola
Sanchez, Daniel
Date Issued
April 27, 2024
Publisher
ACM
Citation
Samardzic, Nikola and Sanchez, Daniel. 2024. "BitPacker: Enabling High Arithmetic Efficiency in Fully Homomorphic Encryption Accelerators."
Version
Final published version
Abstract
Fully Homomorphic Encryption (FHE) enables computing directly on encrypted data. Though FHE is slow on a CPU, recent hardware accelerators compensate most of FHE's overheads, enabling real-time performance in complex programs like deep neural networks. However, the state-of-the-art FHE scheme, CKKS, is inefficient on accelerators. CKKS represents encrypted data using integers of widely different sizes (typically 30 to 60 bits). This leaves many bits unused in registers and arithmetic datapaths. This overhead is minor in CPUs, but accelerators are dominated by multiplications, so poor utilization causes large area and energy overheads.
We present BitPacker, a new implementation of CKKS that keeps encrypted data packed in fixed-size words, enabling near-full arithmetic efficiency in accelerators. BitPacker is the first redesign of an FHE scheme that targets accelerators. On a state-of-the-art accelerator, BitPacker improves performance by gmean 59% and by up to 3×, and reduces energy by gmean 59%. BitPacker does not reduce precision and can be applied to all prior accelerators without hardware changes.
Description
ASPLOS '24: Proceedings of the 29th ACM International Conference on Architectural Support for Programming Languages and Operating Systems April 27-May 1, 2024, La Jolla, CA, USA
MIT Department
Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
Terms of Use
Creative Commons Attribution-Noncommercial-ShareAlike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1145/3620665.3640397
