Overview: VBFT combines PoS, Verifiable Number Function (VNF) and BFT to ensure high degrees of randomness, fairness, and state finality quickly. VBFT improves on regular BFT by introducing verifiable randomness. VBFT separates consensus into two syncing tiers. In VBFT, proposal nodes are selected to propose blocks. Then, verification nodes are selected (through VNF) to verify blocks proposed and vote on their priority. The two parts sync with one another seamlessly to verify transactions. 

Strengths: Proponents of VBFT claim that it allows for superior chain scalability through the way it selects consensus nodes with Verifiable Number Function. Through VNF, it has high degrees of resilience against attacks. And because Byzantine Fault-Tolerant coins are not forkable, VBFT also has state finality (once nodes verify transactions, you can’t mine previous blocks). 

Criticisms: VBFT is still under development, and its source code is not yet open on GitHub. As it stands, it’s difficult to vet the claims that it makes. Because the nature of combining several consensus mechanisms and steps into one, the attack vector broadens.

List of Coins: Ontology (ONT)