Paper 2022/1118

PentaGOD: Stepping beyond Traditional GOD with Five Parties

Nishat Koti, Indian Institute of Science Bangalore
Varsha Bhat Kukkala, Indian Institute of Science Bangalore
Arpita Patra, Indian Institute of Science Bangalore
Bhavish Raj Gopal, Indian Institute of Science Bangalore

Secure multiparty computation (MPC) is increasingly being used to address privacy issues in various applications. The recent work of Alon et al. (CRYPTO'20) identified the shortcomings of traditional MPC and defined a Friends-and-Foes (FaF) security notion to address the same. We showcase the need for FaF security in real-world applications such as dark pools. This subsequently necessitates designing concretely efficient FaF-secure protocols. Towards this, keeping efficiency at the center stage, we design ring-based FaF-secure MPC protocols in the small-party honest-majority setting. Specifically, we provide (1,1)-FaF secure 5 party computation protocols (5PC) that consider one malicious and one semi-honest corruption and constitutes the optimal setting for attaining honest-majority. At the heart of it lies the multiplication protocol that requires a single round of communication with 8 ring elements (amortized). To facilitate having FaF-secure variants for several applications, we design a variety of building blocks optimized for our FaF setting. The practicality of the designed (1,1)-FaF secure 5PC framework is showcased by benchmarking dark pools. In the process, we also improve the efficiency and security of the dark pool protocols over the existing traditionally secure ones. This improvement is witnessed as a gain of up to $62\times$ in throughput compared to the existing ones. Finally, to demonstrate the versatility of our framework, we also benchmark popular deep neural networks.

Note: This paper is the full version of the paper to appear in the ACM Conference on Computer and Communications Security (CCS) 2022.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. ACM CCS 2022
multi-party computation friends-and-foes (FaF) security honest majority dark pools PPML
Contact author(s)
kotis @ iisc ac in
varshak @ iisc ac in
arpita @ iisc ac in
gbhavish @ gmail com
2022-08-29: approved
2022-08-29: received
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      author = {Nishat Koti and Varsha Bhat Kukkala and Arpita Patra and Bhavish Raj Gopal},
      title = {PentaGOD: Stepping beyond Traditional GOD with Five Parties},
      howpublished = {Cryptology ePrint Archive, Paper 2022/1118},
      year = {2022},
      doi = {10.1145/3548606.3559369},
      note = {\url{}},
      url = {}
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