> For the complete documentation index, see [llms.txt](https://liuchengxu.gitbook.io/blockchain/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://liuchengxu.gitbook.io/blockchain/misc/blockchain-consensus.md).

# 区块链共识

区块链就技术层面而言，共识（consensus）是核心。

共识是为了防双花（double spending）

区块链中的共识主要有四类：

* PBFT: Practical Byzantine Fault Tolerance，实用拜占庭容错
* PoW: Proof of Work, 工作量证明
* PoS: Proof of Stake, 权益证明
* DPoS: Delegated Proof of Stake, 委托权益证明

除了区块链共识，现在还经常提到一个概念：DAG（Directed Acyclic Graph，有向无环图）

## PoW

代表：Bitcoin, Ethereum, Litecoin, Zcash, Dogecoin

难度最大的链

## PoS

## DPoS

## PoA

参考：

\[1] [浅谈区块链共识机制与分布式一致性算法](https://bitcointalk.org/index.php?topic=1543391.0)

\[2] [Concensus in Blockchain Systems. In Short.](https://medium.com/@chrshmmmr/consensus-in-blockchain-systems-in-short-691fc7d1fefe)

\[3]  \[4] [A Hitchhiker’s Guide to Consensus Algorithms](https://hackernoon.com/a-hitchhikers-guide-to-consensus-algorithms-d81aae3eb0e3)