Rache: Radix-additive caching for homomorphic encryption

TL;DR

Rache is a caching optimization technique that significantly accelerates homomorphic encryption operations by caching ciphertexts, expanding plaintexts into radix-based sums, and using only addition, thus improving performance for cloud data privacy.

Contribution

Rache introduces a novel caching and radix-expansion approach that enhances the efficiency of homomorphic encryption schemes in practical applications.

Findings

Rache outperforms Paillier encryption by orders of magnitude.

It exhibits almost linear scalability with data volume.

The method effectively reduces computational overhead in homomorphic encryption.

Abstract

One of the biggest concerns for many applications in cloud computing lies in data privacy. A potential solution to this problem is homomorphic encryption (HE), which supports certain operations directly over the ciphertexts. Conventional HE schemes, however, exhibit significant performance overhead and are hardly applicable to real-world applications. This paper presents Rache, a caching optimization for accelerating the performance of HE schemes. The key insights of Rache include (i) caching some homomorphic ciphertexts before encrypting the large volume of plaintexts; (ii) expanding the plaintexts into a summation of powers of radixes; and (iii) constructing the ciphertexts with only homomorphic addition. The extensive evaluation shows that Rache exhibits almost linear scalability and outperforms Paillier by orders of magnitude.