SOCI^+: An Enhanced Toolkit for Secure OutsourcedComputation on Integers

TL;DR

SOCI+ is an improved toolkit for secure outsourced integer computation that enhances performance and reduces overhead using a novel cryptosystem and optimized protocols, making secure cloud computing more practical.

Contribution

SOCI+ introduces a new (2, 2)-threshold Paillier cryptosystem and efficient protocols, significantly outperforming the original SOCI scheme in computation and communication efficiency.

Findings

Up to 5.4 times faster computation

40% reduction in communication overhead

Supports secure multiplication, comparison, sign bit, and division protocols

Abstract

Secure outsourced computation is critical for cloud computing to safeguard data confidentiality and ensure data usability. Recently, secure outsourced computation schemes following a twin-server architecture based on partially homomorphic cryptosystems have received increasing attention. The Secure Outsourced Computation on Integers (SOCI) [1] toolkit is the state-of-the-art among these schemes which can perform secure computation on integers without requiring the costly bootstrapping operation as in fully homomorphic encryption; however, SOCI suffers from relatively large computation and communication overhead. In this paper, we propose SOCI+ which significantly improves the performance of SOCI. Specifically, SOCI+ employs a novel (2, 2)-threshold Paillier cryptosystem with fast encryption and decryption as its cryptographic primitive, and supports a suite of efficient secure arithmetic computation on integers protocols, including a secure multiplication protocol (SMUL), a secure comparison protocol (SCMP), a secure sign bit-acquisition protocol (SSBA), and a secure division protocol (SDIV), all based on the (2, 2)-threshold Paillier cryptosystem with fast encryption and decryption. In addition, SOCI+ incorporates an offline and online computation mechanism to further optimize its performance. We perform rigorous theoretical analysis to prove the correctness and security of SOCI+. Compared with SOCI, our experimental evaluation shows that SOCI+ is up to 5.4 times more efficient in computation and 40% less in communication overhead.