Development Status and New Design Discussion of Blockchain Consensus Protocol

Blockchain technology, as a representative of decentralized distributed ledgers, is fundamentally based on consensus mechanisms. This article delves into the latest advancements of the Asynchronous Byzantine Fault Tolerance State Machine Replication (BFT SMR) protocol and proposes two innovative protocol designs.

Overview of the Current Asynchronous Consensus Protocol

Currently, the sMVBA protocol has become the fastest asynchronous MVBA protocol with an expected delay of 10δ. Although the 2-chain VABA claimed to achieve an expected delay of 9.5δ, its actual performance fell short due to various security vulnerabilities.

New protocol design

1. 2PAC (2-phase asynchronous Consensus)

Based on an in-depth analysis of existing protocols, we propose the 2PAC protocol, which has several main variants including:

• 2PAClean: Achieved over 90% throughput improvement, expected latency is 9.5δ, message complexity is O(n²).
• 2PACBIG: The current message complexity is O(n³) for the fastest Blockchain Consensus protocol, with a single MVBA runtime of only 4δ under faultless conditions.

2. Ultra-fast pipeline block

This innovative design significantly reduces the latency of pipelined Blocks. Under the fair scheduler, the decision time of pipelined Blocks can even be lower than that of non-pipelined Blocks. This mechanism ensures low latency for fast paths during all execution processes, unaffected by faulty processes.

Performance Evaluation

Theoretical analysis and practical testing have shown that:

• The expected delay of 2PAClean in the worst case is 9.5δ, and in the good case is 6δ.
• The single MVBA runtime of 2PACBIG is 4δ, which is better than all existing protocols.
• The ultra-fast pipeline block design enables s2PAClean and s2PACBIG to achieve pipeline block decision times of 4δ and 3δ, respectively.

The calculation evaluation results show that 2PAClean and 2PACBIG perform excellently under various network conditions, especially in environments with high latency and high failure rates. 2PAClean achieves a good balance between message transmission delay and computational complexity, while 2PACBIG achieves lower latency through parallelization and optimization of the voting process.

Future Research Directions

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

With the continuous development of Blockchain technology, the asynchronous BFT Consensus protocol will play an increasingly important role in ensuring security and improving performance. The design of 2PAC and ultra-fast pipelined Blocks points the way for the future development of Blockchain consensus protocols: achieving higher throughput and lower latency by simplifying protocol structures and optimizing the consensus process.

These innovations have not only proven their superiority in theory but also demonstrated outstanding performance in practical tests, providing new ideas for achieving efficient and secure Blockchain Consensus protocols. With the deepening of research and optimization of technology, Blockchain is expected to play a more critical role in the future digital economy, and the new generation of Consensus protocols will lay a solid foundation for the development of this technology.