The Latest Developments and Applications of Blockchain Consensus Protocols

Blockchain technology, as a representative of decentralized distributed ledger technology, is fundamentally centered around consensus mechanisms. The consensus mechanism directly affects the scalability and security of blockchain systems. This article will explore the current development status of blockchain consensus protocols, with a focus on analyzing the latest advancements in the Asynchronous Byzantine Fault Tolerant State Machine Replication (BFT SMR) protocol.

Overview of Current Asynchronous Consensus Protocols

Currently, sMVBA is the fastest asynchronous MVBA protocol with an expected latency of 10δ. Although the 2-chain VABA has claimed to achieve an expected latency of 9.5δ, its actual performance is questioned due to various security vulnerabilities. These vulnerabilities include the lack of authentication checks, the use of promotion strategies hindering liveness, and consistency attacks caused by relaxing the leader authentication definition.

New Protocol Design

2PAC ( Phase 2 Asynchronous Consensus )

To address the issues of existing protocols, researchers have proposed the 2PAC protocol, which includes two variants:

1. 2PAClean:

   • Achieve +90% throughput and 9.5δ expected latency
   • The message complexity is O(n²)
   • Improve efficiency by optimizing processes

2. 2PACBIG:

   • The fastest blockchain consensus protocol in the current O(n³) message complexity
   • The single MVBA running time is only 4δ under no fault conditions.

Ultra-Fast Pipeline Blockchain

Researchers have proposed a new pipelined block design that significantly reduces the latency of pipelined blocks. This mechanism introduces a fast path, where under a fair scheduler, the decision time for pipelined blocks may even be less than that of non-pipelined blocks. This design ensures the latency of the fast path across all executions and is not affected by faulty processes.

Performance Evaluation

Theoretical analysis and practical testing have shown that:

• The expected delay for 2PAClean in the worst case is 9.5δ, and in the good case (no faults and semi-fair scheduler) is 6δ.
• 2PAClean's throughput is 80%-100% higher than that of chain-based sMVBA.
• The single MVBA runtime for 2PACBIG is 4δ, outperforming all existing protocols.
• s2PAClean and s2PACBIG implement 4δ and 3δ pipeline block decision times, respectively.

Future Research Directions

1. Protocol Optimization: Further simplify the structure, reducing unnecessary message passing and computational overhead.
2. Security Analysis: In-depth study of the performance of the new protocol under various attack scenarios.
3. Practical Application: Apply the new protocol to actual blockchain systems to verify performance in real network environments.

Conclusion

The design of the new generation consensus protocol significantly improves the throughput and latency performance of blockchain systems. These advancements lay the foundation for blockchain technology to play a greater role in the future digital economy. With in-depth research and technological optimization, we have reason to believe that blockchain will be more widely applied across various industries, driving the rapid development of the digital economy.