A privacy-preserving and efficient byzantine consensus through multi-signature with ring

The consortium blockchain has three challenges in terms of performance, security, and privacy when adopting the Practical Byzantine Fault Tolerance (PBFT) protocol. The throughput and scalability of consortium blockchain are focused on meanwhile the privacy protection can hardly be ignored. This work proposes a privacy-preserving multi-signature and hierarchical Byzantine consensus protocol. Specifically, the signature combines a ring signature and a Schnorr one to provide three levels of privacy protection. The consensus protocol layers the network nodes into different clusters, which overcomes the shortcomings of PBFT and Schnorr signature. The theoretical analysis proves the security and privacy of the protocol and expounds the application scenarios, and the efficiency evaluation shows that the signature verification speed is 6.28 times faster than the Schnorr scheme, and the consensus in a 250-nodes network is 51.3% faster than the Schnorr-based PBFT consensus.