上QQ阅读APP看书，第一时间看更新

Ethereum

Ethereum is the most popular DApp after Bitcoin. Ethereum is a decentralized platform that allows us to build other blockchain-based DApps on top of it. In Ethereum, we build DApps using Ethereum smart contracts. Smart contracts are applications that run exactly as programmed without any possibility of downtime, censorship, fraud, or third-party interference. Ethereum can be thought of as a platform to deploy and run smart contracts. Ethereum supports two consensus protocols, PoW and PoA (Clique).

The main public Ethereum network uses PoW for consensus. If you want to deploy your own private Ethereum network, then you have to use PoA. PoW requires a lot of computation power to keep the blockchain secure, therefore it's good for public blockchain use, whereas PoA doesn't have any such computation power requirement; instead it requires a few authority nodes in the network to achieve consensus.

You must be wondering why we need smart contracts to build DApps. Why cannot we simply put formatted messages on blockchain in the form of transactions and interpret them on client? Well, using smart contracts gives you both technical and business benefits.