High Efficiency Secure Channels for a Secure Multiparty Computation Protocol Based on Signal
Yunqi Yang, Rui Zhang · Security and Communication Networks · 2023
Secure multiparty computation (MPC) requires the messages transmitted in secure channels which can provide encryption and authorization to the messages. To implement a secure channel for MPC protocols, researchers have tried some communication protocols, such as TLS and Noise. However, these methods have some limitations. These protocols need a trusted certification authority to provide identity authorization which is difficult for an MPC protocol, and how participants manage the key of each party and how to use the key to establish communication is also a problem. A Signal protocol is an end-to-end encryption communication protocol, which is known as the most secure communication protocol in the world. Based on the Signal protocol, we implemented a signal-based secure multiparty computation protocol, which can run the MPC protocol and transmit messages through a signal-based secure channel. Compared with previous research on the MPC protocol over Signal secure channels, the new MPC client adds group communication of the Signal protocol to transmit messages, which significantly improves the communication efficiency of broadcast messages of MPC protocols. To test the communication efficiency of the new MPC client, we implemented a concrete BLS threshold signature protocol on the new client, comparing the elapsed time of key generation and signing on the new client to that on the client only using Signal end-to-end communication. According to our experiment result, we found that the new client run at least 37.48% faster than the old client on the BLS threshold signature whose number of parties ranges from 3 to 5, if the parties have sent Signal group messages to each other. The more parties in the MPC protocol, the higher the proportion of broadcast messages and the more obvious the performance improvement of the new client. Our work improves the performance of MPC secure channels based on the Signal protocol, especially for complex MPC protocols with many participants.