Modeling and Verification of the Nervos CKB Block Synchronization Protocol in UPPAAL

Qi Zhang, Yuteng Lu, Meng Sun

Abstract: The Nervos CKB (Common Knowledge Base) is a public permission-less blockchain designed for a peer-to-peer crypto- economy network. The CKB block synchronization protocol is an important part of the Nervos CKB, which provides a set of rules that participating nodes must obey while synchronizing their blocks. The protocol contains three stages: Connecting Header, Downloading Block and Accepting Block. In this paper, we develop the formal model of the CKB block synchronization protocol and verify some important properties of the protocol using the UPPAAL model checker. Based on the formal model, the reliability of CKB can be guaranteed.