Smart Contract Based Multi-Party Computation with Privacy Preserving and Settlement Addressed

While the multiple party computation (MPC) has been suggested for over two decades, we still have not witnessed implementations that make MPC or its derivates deployed in a palpable reality. Difficulties stem from serial security and trust issues, typically expressed in data leakage, lazy calculation, and deny of payment etc. Many solutions rely on a third party to organize parties co-working, however, this requires each participant to totally trust the third party and delegate the source data and payment to it. In this paper, we suggest a protocol under blockchain structure to achieve efficient MPC without a trusted third party. The cooperation and schedule tasks are executed by a zero-knowledge coordinator, while the smart contracts is used to handle user request and safe payment. Cryptography techniques are adopted to ensure confidentiality, privacy-preserving and verifiability. All the data are transferred and calculated in the cipher state, and only the payed user can decrypt for the calculation result.