Formal Security Analysis on dBFT Protocol of NEO
Qin Wang, Rujia Li, Shiping Chen, Yang Xiang · Distributed Ledger Technologies Research and Practice · 2022
NEO is one of the top public chains worldwide. It adopts a new consensus algorithm calleddelegated Byzantine Fault Tolerance(dBFT). In this article, we formalize dBFT via the state machine replication model and point out its potential issues. Our theoretical analysis indicates that dBFT could guarantee neitherlivenessnorsafety, even if the number of Byzantine nodes is no more than the threshold, which has contradicted the established security claim. Then, we identify two attacks and successfully simulate them. Finally, we provide recommendations. Notably, NEO official team has accepted our suggested fixes.