ERC20 协议

ERC-20 是一个协议标准，定义了在 Ethereum 网络上发行 tokens 的规则与标准。

Basically, an ERC-20 token is just a contract that keeps track of who owns how much of that token, and some functions so those users can transfer their tokens to other addresses

ERC-20 tokens 是直接在 Ethereum blockchain 上发行和交易的。