High-performance hybrid consensus

Short answer questions

What is a hybrid consensus mechanism? How is it different from a pure PoW or PoS mechanism?

Please explain the role of fast chains and slow chains in a hybrid consensus mechanism.

Why is Fruitchain more resistant to selfish mining attacks than Nakamoto chains?

Briefly describe the election process of the BFT committee.

Why is it necessary to establish a private communication network between BFT committee members in a hybrid consensus mechanism?

Describe a method for establishing a private communication network between BFT committee members in a hybrid consensus mechanism.

What is a "sticky timestamp"? What role does it play in decentralized exchanges?

Briefly describe the role of data sharding in a hybrid consensus mechanism.

How are smart contracts executed in a hybrid consensus mechanism?

Explain the gas fee mechanism in the hybrid consensus mechanism and how it differs from the Ethereum gas mechanism.

Answers

The hybrid consensus mechanism combines the advantages of both PoW and BFT consensus mechanisms. Unlike pure PoW or PoS mechanisms, the hybrid consensus mechanism uses BFT to achieve high throughput and fast confirmation, while using PoW to ensure decentralization and committee elections.

The fast chain is maintained by the BFT committee, which is responsible for processing transactions and generating blocks to achieve high throughput. The slow chain usually uses the PoW mechanism, which is responsible for electing BFT committee members and ensuring the security of the network.

Fruitchain requires a lower chain quality (>2/3) to ensure security, while the Nakamoto chain requires a higher chain quality (>3/4) to resist selfish mining attacks. This is because the fruits in the Fruitchain can be mined out of order, reducing the benefits of selfish mining.

First, the candidate nodes are screened according to the PoW contribution. Then, a part of the nodes are randomly selected from the candidate nodes using VRF to form a new BFT committee.

Private communication networks can improve the efficiency and security of communication between BFT committee members and avoid the delays and attack risks caused by relying on public networks.

One method is that each committee member encrypts his own IP address with the public key of other members and broadcasts it. Only committee members can decrypt and obtain the IP addresses of other members, thereby establishing a private communication network.

"Sticky timestamp" means that the physical timestamp is included in the transaction and the time order is enforced during the consensus process. It prevents malicious nodes from reordering transactions for profit and ensures the fairness of decentralized exchanges.

Data sharding distributes data and computing tasks to different shards for parallel processing, which can improve the throughput and scalability of hybrid consensus mechanisms.

Smart contracts in hybrid consensus mechanisms are usually executed on the fast chain, and BFT committee members run virtual machines to handle contract calls and state updates.

The gas fee mechanism in the hybrid consensus mechanism usually uses the gas futures market to reduce the volatility of gas prices through an averaging mechanism and encourage users to bid reasonably according to the network load.

Glossary

Term Definition Hybrid Consensus A consensus mechanism that combines two or more consensus mechanisms (such as PoW and BFT). PoW (Proof of Work) A consensus mechanism that requires nodes to perform computationally intensive tasks to solve puzzles in order to obtain the right to create new blocks. BFT (Byzantine Fault Tolerance) A property that allows a system to maintain consistency even when some nodes fail or behave maliciously. Fast Chain A blockchain maintained by a BFT committee that processes transactions and achieves high throughput. Slow chains are usually blockchains maintained by the PoW mechanism, responsible for electing BFT committee members and ensuring the security of the network. Fruitchain is an improved PoW blockchain that resists selfish mining attacks by introducing the concept of "fruit". The BFT committee consists of a group of nodes responsible for maintaining the fast chain and processing transactions. Sticky timestamps include physical timestamps in transactions and enforce time order during the consensus process to ensure the fairness of transactions. Data sharding distributes data and computing tasks to different shards for parallel processing to improve scalability. Gas fees are fees paid by users to execute smart contracts or transactions to compensate for the consumption of network resources. Gas futures market users can trade Gas prices in this market to hedge against Gas price volatility risks.