the previous chapter, we discussed the Ethereum blockchain. Ethereum is a public blockchain; anyone can read the blockchain data and make legitimate changes. Anyone can write a new block into the chain. Ethereum is fully autonomous and is not controlled by anyone. The smart contract is written in Solidity, as a nearly Turing complete language, that can run on the Ethereum virtual machine (EVM) to execute various transactions. Developers can build and deploy decentralized applications (DApps) using these smart contracts. Ether is a cryptocurrency in Ethereum, and acts as fuel for every operation in Ethereum, including executing smart contracts, DApps, transactions, and so on. However, this is not the only way to build a blockchain.
Blockchains that require an access control layer built into the blockchain...