SOCI+: An enhanced toolkit for Secure Outsourced Computation on Integers

• Main Authors: ZHAO, Bowen, DENG, Weiquan, LI, Xiaoguo, LIU, Ximeng, PEI, Qingqi, DENG, Robert H.
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 2024
• Subjects: Computer architecture; Costs; Cryptography; Homomorphic encryption; Paillier cryptosystem; Protocols; secure computing; Secure outsourced computation; Servers; Threat modeling; threshold cryptosystem; Information Security
• Online Access: https://ink.library.smu.edu.sg/sis_research/8815; https://ink.library.smu.edu.sg/context/sis_research/article/9818/viewcontent/SOCI_av_cc_by.pdf
• Institution: Singapore Management University

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 5.3 times more efficient in online runtime and 40% less in communication overheads.