Improving Privacy in Blockchain by Combining Group Signature and Groth-Sahai Certification System

Background: Blockchain as a decentralized technology distributed on a peer-to-peer network has received a lot of attention recently. It implements a link block structure for data validation and storage, and implements a reliable consensus mechanism for synchronizing data changes, making it possible to create a tamper-proof digital platform for data storage and sharing. Questions/Purposes: There are some privacy challenges that may prevent the widespread use of Blockchain. The privacy plan is a double-edged sword. It must also fully protect the privacy of legal users. But if it is not fully controlled, illegal and criminal acts such as money laundering and extortion will be ignored. The aim of this study is to strike a balance between privacy protection and monitoring. Methods: This paper presents a design, based on the group signature and the Groth-Sahai certification system. Results: Reconfigure user anonymous and traceable technology in Blockchain by Groth-Sahai method, including initial stage; user registration; message sending; message verification; user tracking. Conclusions: This article proposes a scheme that can ensure the anonymity and traceability of the sender and receiver at the same time.