【知识】以太坊地址是否区分大小写

作者: 笔名辉哥 | 来源:发表于2021-05-14 13:24 被阅读0次

以太坊地址区分大小写么？要搞清楚这个问题，我们不妨先在私链上做个实验：

geth> eth.sendTransaction({
    from: eth.accounts[0],
    to: "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
    value: web3.toWei(1, 'ether')
})

geth> eth.sendTransaction({
    from: eth.accounts[0],
    to: "0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
    value: web3.toWei(1, 'ether')
})

geth> eth.getBalance("0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
geth> eth.getBalance("0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")

从实验结果上来看，纯小写地址和纯大写地址实际上是同一个地址，那么是不是由此可以得出以太坊地址不区分大小写呢？我们再看下面这个 remix 上的实验：

pragma solidity ^0.5.0;

contract Foo {
    address bar = 0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa;
}

代码运行结果如下图所示：

remix

结果提示错误，并给了一个大小写混合的正确地址：

This looks like an address but has an invalid checksum. Correct checksummed address: “0xaAaAaAaaAaAaAaaAaAAAAAAAAaaaAaAaAaaAaaAa”. If this is not used as an address, please prepend ’00’. For more information please see https://solidity.readthedocs.io/en/develop/types.html#address-literals

怎么回事？实际上这是因为 EIP-55 规范引入了 checksum 机制。它有什么用处？设想一下，如果你在输入长长的以太坊地址的时候，不小心输错了一个字符，那么很难发现这样的错误，有了 checksum 机制，我们就能在业务程序里校验地址的准确性，从而降低用户输入错误地址的风险，给出一个 golang 代码的例子：

package main

import (
    "flag"
    "fmt"

    "github.com/ethereum/go-ethereum/common"
)

var (
    address = flag.String("address", "", "address")
)

func init() {
    flag.Parse()
}

func main() {
    addressWithChecksum := common.HexToAddress(*address).Hex()

    if addressWithChecksum != *address {
        fmt.Println("  valid: " + addressWithChecksum)
        fmt.Println("invalid: " + *address)
    } else {
        fmt.Println("This address is valid.")
    }
}

代码运行结果如下图所示：