Verifiable Byzantine Fault Tolerance (VBFT) consensus

Verifiable Byzantine Fault Tolerance (VBFT) is a consensus mechanism introduced by the Ontology blockchain platform. It combines aspects of Byzantine Fault Tolerance (BFT) with verifiable random function (VRF) to achieve consensus among a group of selected nodes in a permissioned network setting. VBFT is designed to provide high throughput, low latency, and Byzantine fault tolerance while maintaining security and decentralization.?

?How VBFT works:

1. Consensus Node Selection:

• In VBFT, a fixed number of consensus nodes, also known as consensus participants or validators, are selected to participate in the consensus process.
• The selection of consensus nodes may be based on factors such as stake, reputation, or other criteria determined by the network.

2. Proposal and Verification:

• The consensus process begins when a designated consensus node proposes a new block of transactions.
• Other consensus nodes in the network receive the proposed block and independently verify its validity using cryptographic techniques.

3. Verifiable Random Function (VRF):

• VBFT incorporates verifiable random function (VRF) to select a subset of consensus nodes to participate in the block validation process.
• VRF ensures randomness and fairness in the selection of consensus nodes, preventing manipulation or bias in the consensus process.

4. Voting and Agreement:

• Once the proposed block is verified, consensus nodes cast their votes to either approve or reject the block.
• A predefined threshold of positive votes is required for the block to be considered confirmed and added to the blockchain.

Key Features of VBFT:

• High Throughput and Low Latency:

VBFT is designed to achieve high transaction throughput and low latency,

making it suitable for applications requiring fast confirmation times and

scalability.

• Byzantine Fault Tolerance:

VBFT provides resilience to Byzantine faults by requiring a threshold majority

of consensus nodes to agree on the validity of a block. This ensures

consistency and security even in the presence of malicious actors.

• Verifiable Random Function (VRF):

The use of VRF ensures randomness and fairness in the selection of

consensus nodes, enhancing the security and decentralization of the

consensus process.

• Finality and Immutability:

Once a block is confirmed by the consensus nodes, it is considered final and

immutable, providing certainty and finality to network participants about the

state of the blockchain.

• Adaptability and Governance:

VBFT consensus parameters, such as the threshold for block confirmation

and the selection of consensus nodes, can be customized based on the

specific requirements of the blockchain network.

Limitations of VBFT:

• Permissioned Nature: VBFT is primarily suitable for permissioned or consortium blockchain networks where consensus nodes are known and trusted entities. It may not be as suitable for fully decentralized public networks.
• Complexity: The integration of VRF adds complexity to the consensus mechanism, requiring careful implementation and validation to ensure security and correctness.

Overall, Verifiable Byzantine Fault Tolerance (VBFT) is a consensus mechanism designed to provide high throughput, low latency, and Byzantine fault tolerance for permissioned blockchain networks. It balances efficiency with security and decentralization, making it a compelling choice for enterprise and consortium blockchain applications.