PAMPC: Publicly Auditable Multi-Party Computation with Cheater Detection

Although the basic secure multi-party computation (MPC) protocol can detect the existence of cheaters, it cannot identify the actual identity of cheaters. In addition, most of the related works cannot provide public auditability, such as proving the correctness of the protocol process to the external third party. In this paper, a publicly auditable secure multi-party computation protocol PAMPC is constructed by using linear secret sharing with honest-majority. This protocol is designed based on the SPDZ scheme and is divided into two phases: offline and online. The public record is continuously updated by the parties during the operation of the protocol. Due to its publicly auditable nature, any external third party can verify the correctness of computation circuit computed by any party and the output obtained after reconstruction by calculating the public record, so that third party can reveal the real identity of the cheaters, and eventually expose the collection of cheaters to all parties. The security of the PAMPC protocol is proven in the universally composable framework.