以太坊改进提案 EIPs

# EIP 55: 混合大小写校验和地址编码

作者 类型 分类 状态 创建时间
Vitalik Buterin vitalik.buterin@ethereum.org, Alex Van de Sande avsa@ethereum.org Standards Track ERC Final 2016-01-14

# 规范

代码:

from ethereum import utils

def checksum_encode(addr): # Takes a 20-byte binary address as input
    o = ''
    v = utils.big_endian_to_int(utils.sha3(addr.hex()))
    for i, c in enumerate(addr.hex()):
        if c in '0123456789':
            o += c
        else:
            o += c.upper() if (v & (2**(255 - 4*i))) else c.lower()
    return '0x'+o

def test(addrstr):
    assert(addrstr == checksum_encode(bytes.fromhex(addrstr[2:])))

test('0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed')
test('0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359')
test('0xdbF03B407c01E7cD3CBea99509d93f8DDDC8C6FB')
test('0xD1220A0cf47c7B9Be7A2E6BA89F429762e7b9aDb')
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在英语中，将地址转换为十六进制，但如果它的第 i 位是字母（即 abcdef 之一）则有：如果小写的十六进制地址的哈希值的第i*4 位为 1，则大写形式打印，否则小写形式打印。

# 原理阐述

优点:

  • 向后兼容许多接受混合大小写的十六进制解析器，允许它随着时间的推移轻松引入
  • 保持长度为40个字符
  • 平均每个地址将有15个校验位，如果输入错误，随机生成的地因抄写错误意外通过检查的净概率为0.0247％。 这比ICAP提高了约50倍，但不如4字节检查代码好。

ICAP: Inter-exchange Client Address Protocal 是与国际银行账号（IBAN）编码部分兼容的以太坊地址编码形式。

# 实现

javascript代码:

const createKeccakHash = require('keccak')

function toChecksumAddress (address) {
  address = address.toLowerCase().replace('0x', '')
  var hash = createKeccakHash('keccak256').update(address).digest('hex')
  var ret = '0x'

  for (var i = 0; i < address.length; i++) {
    if (parseInt(hash[i], 16) >= 8) {
      ret += address[i].toUpperCase()
    } else {
      ret += address[i]
    }
  }

  return ret
}
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> toChecksumAddress('0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359')
'0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359'
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请注意，Keccak256哈希的输入是小写十六进制字符串（即编码为ASCII的十六进制地址）：

    var hash = createKeccakHash('keccak256').update(Buffer.from(address.toLowerCase(), 'ascii')).digest()
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# 测试用例

# All caps
0x52908400098527886E0F7030069857D2E4169EE7
0x8617E340B3D01FA5F11F306F4090FD50E238070D
# All Lower
0xde709f2102306220921060314715629080e2fb77
0x27b1fdb04752bbc536007a920d24acb045561c26
# Normal
0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed
0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359
0xdbF03B407c01E7cD3CBea99509d93f8DDDC8C6FB
0xD1220A0cf47c7B9Be7A2E6BA89F429762e7b9aDb
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# 采用情况

Wallet displays checksummed addresses rejects invalid mixed-case rejects too short rejects too long
Etherwall 2.0.1 Yes Yes Yes Yes
Jaxx 1.2.17 No Yes Yes Yes
MetaMask 3.7.8 Yes Yes Yes Yes
Mist 0.8.10 Yes Yes Yes Yes
MyEtherWallet v3.9.4 Yes Yes Yes Yes
Parity 1.6.6-beta (UI) Yes Yes Yes Yes
Jaxx Liberty 2.0.0 Yes Yes Yes Yes
Coinomi 1.10 Yes Yes Yes Yes
Trust Wallet Yes Yes Yes Yes

# Exchange support for mixed-case address checksums, as of 2017-05-27:

Exchange displays checksummed deposit addresses rejects invalid mixed-case rejects too short rejects too long
Bitfinex No Yes Yes Yes
Coinbase Yes No Yes Yes
GDAX Yes Yes Yes Yes
Kraken No No Yes Yes
Poloniex No No Yes Yes
Shapeshift No No Yes Yes

# 参考引用

  1. EIP 55 issue and discussion https://github.com/ethereum/eips/issues/55
  2. Python example by @Recmo https://github.com/ethereum/eips/issues/55#issuecomment-261521584
  3. Python implementation in ethereum-utils
  4. Ethereumjs-util implementation https://github.com/ethereumjs/ethereumjs-util/blob/75f529458bc7dc84f85fd0446d0fac92d991c262/index.js#L452-L466
  5. Swift implementation in EthereumKit
  6. Kotlin implementation in KEthereum

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