Cryptology ePrint Archive: Report 2018/589

Implementation and Performance Evaluation of RNS Variants of the BFV Homomorphic Encryption Scheme

Ahmad Al Badawi and Yuriy Polyakov and Khin Mi Mi Aung and Bharadwaj Veeravalli and Kurt Rohloff

Abstract: Homomorphic encryption is an emerging form of encryption that provides the ability to compute on encrypted data without ever decrypting them. Potential applications include aggregating sensitive encrypted data on a cloud environment and computing on the data in the cloud without compromising data privacy. There have been several recent advances resulting in new homomorphic encryption schemes and optimized variants. We implement and evaluate the performance of two optimized variants, namely Bajard-Eynard-Hasan-Zucca (BEHZ) and Halevi-Polyakov-Shoup (HPS), of the most promising homomorphic encryption scheme in CPU and GPU. The most interesting (and also unexpected) result of our performance evaluation is that the HPS variant in practice scales significantly better (typically by 15%-30%) with increase in multiplicative depth of the computation circuit than BEHZ, implying that the HPS variant will always outperform BEHZ for most practical applications. For the multiplicative depth of 98, our fastest GPU implementation performs homomorphic multiplication in 51 ms for 128-bit security settings, which is faster by two orders of magnitude than prior results and already practical for cloud environments supporting GPU computations. Large multiplicative depths supported by our implementations are required for applications involving deep neural networks, logistic regression learning, and other important machine learning problems.

Category / Keywords: implementation / Lattice-Based Cryptography, Homomorphic Encryption, Scale-Invariant Scheme, Residue Number Systems, Software Implementation

Original Publication (with minor differences): IEEE Transactions on Emerging Topics in Computing

Date: received 7 Jun 2018, last revised 5 Mar 2019

Contact author: polyakov at njit edu

Available format(s): PDF | BibTeX Citation

Version: 20190306:034305 (All versions of this report)

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