[Zoom In Aston] Consensus Algorithm — PBFT (Practical Byzantine Fault Tolerance)

Aston Company
Sep 10, 2018 · 2 min read

X.Blockchain basically reaches consensus by using the PBFT + DPoS mechanism. This is a consensus mechanism proposed by Tendermint, which makes it possible to construct a public & private blockchain by combining the DPoS concept with the conventional PBFT algorithm. Today, we will introduce PBFT Algorithm, one of Consensus Algorithm of X.Blockchain.

PBFT is a consensus algorithm introduced in the late 90s. The existing BFT was able to operate with the assumption of a synchronous environment and had too many performance problems for practical use. It is PBFT what improves such BFT to be able to operate in asynchronous environment, and solves high-speed transaction processing while solving the Byzantine generals problem.

In the PBFT-based consensus algorithm, if (2/3)n or more of all nodes (n) participating in the consensus agree to accept the proposed block, by confirming the proposed block and linking it to the next block in the blockchain , it guarantees that the consensus will be reached in any case to the extent that the proportion of malicious nodes does not exceed 1/3.

PBFT-based algorithms that are heavily used currently are based on the basic consensus procedure as described above. One of them is PBFT + DPoS which is adopted by Tendermint. You can find out more in following contents about primary node that proposes a first block in the PBFT-based consensus algorithm.

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