CSHER: A System for Compact Storage with HE-Retrieval


Adi Akavia and Neta Oren, University of Haifa; Boaz Sapir and Margarita Vald, Intuit Israel Inc.


Homomorphic encryption (HE) is a promising technology for protecting data in use, with considerable progress in recent years towards attaining practical runtime performance. However, the high storage overhead associated with HE remains an obstacle to its large-scale adoption. In this work we propose a new storage solution in the two-server model resolving the high storage overhead associated with HE, while preserving rigorous data confidentiality. We empirically evaluated our solution in a proof-of-concept system running on AWS EC2 instances with AWS S3 storage, demonstrating storage size with zero overhead over storing AES ciphertexts, and 10ยตs amortized end-to-end runtime. In addition, we performed experiments on multiple clouds, i.e., where each server resides on a different cloud, exhibiting similar results. As a central tool we introduce the first perfect secret sharing scheme with fast homomorphic reconstruction over the reals; this may be of independent interest.

Open Access Media

USENIX is committed to Open Access to the research presented at our events. Papers and proceedings are freely available to everyone once the event begins. Any video, audio, and/or slides that are posted after the event are also free and open to everyone. Support USENIX and our commitment to Open Access.

@inproceedings {287154,
author = {Adi Akavia and Neta Oren and Boaz Sapir and Margarita Vald},
title = {{CSHER}: A System for Compact Storage with {HE-Retrieval}},
booktitle = {32nd USENIX Security Symposium (USENIX Security 23)},
year = {2023},
isbn = {978-1-939133-37-3},
address = {Anaheim, CA},
pages = {4751--4768},
url = {https://www.usenix.org/conference/usenixsecurity23/presentation/akavia},
publisher = {USENIX Association},
month = aug

Presentation Video