[KCC 2023] Survey on Asynchronous BFT consensus Algorithms for Scalable and Robust Blockchain

Author:

Donghyeon Ryu, Chanik Park in POSTECH

 

Journal/Conference:

KCC '23

 

Paper:

(eng)

Survey on Asynchronous BFT consensus Algorithms for Scalable and Robust Blockchain.pdf

0.33MB

(kor)

강건하고 확장가능한 블록체인을 위한 비동기 BFT 합의 알고리즘 동향 조사.pdf

0.37MB

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Abstract

Blockchain technology is being applied to various areas such as non-fungible tokens (NFTs), decentralized finance (DeFi), security tokens (STs), central bank digital currencies (CBDCs), and decentralized identity (DID) based on its decentralization, transparency, and high reliability. However, the consensus process in blockchain requires all nodes to participate, which poses scalability limitations. To address scalability issues, synchronous BFT consensus algorithms, primarily from the PBFT family, have been applied. However, synchronous BFT algorithms are vulnerable to Byzantine faults and suffer from a concentration of load on leader nodes. As a result, more robust asynchronous BFT algorithms have gained recent attention. This paper aims to introduce asynchronous BFT algorithms and provide insights for future research by examining representative studies.

 

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Synchronous BFTs

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Asynchronous BFTs

(1) ACS-based BFTs

(2) DAG-based BFTs

• HashGraph
• Aleph
• DAG-Rider
• Tusk

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Hybrid BFTs

• Narwhal
• Dumbo-Bolt Transformer
• Ditto
• Bullshark

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Conclusion

  In this paper, we discussed the scalability issues and vulnerability to Byzantine faults in existing synchronous BFT consensus algorithms, and demonstrated how these can be addressed using asynchronous BFT consensus algorithms through recent research examples. We believe that this provides insights for practical BFT consensus algorithm research, considering the expected increase in demand for blockchain in the future.