比特币交易数据解析系列（3）- 隔离见证交易hash

bitbegin in wuhan

Thu Aug 16 2018

隔离见证hash算法文档： https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki

# 数据组成

# 公钥

未压缩公钥：04 + X(32B) + Y(32B) 隔离见证需要的公钥为：03 + X(32B)或者 02 + Y(32B)

# hash算法

# double sha256 (dSHA256)

tx id id = sha256(sha256(data)) = dSHA256(data) 长度为32字节
address checksum

# hash160

hash160(data) = ripemd160(sha256(data))

# address (pubkey-to-addr)

prefix: https://en.bitcoin.it/wiki/List_of_address_prefixes

# legacy address (pubkey-to-legacy-addr)

pubkey-hash = hash160(pubkey) script-pubkey = prefix + pubkey-hash encode58-check(data) = encode58(data + dSHA256(data)[0..3]) address = encode58-check(script-pubkey)

# segwit address (pubkey-to-segwit-addr)

pubkey-hash = hash160(pubkey) redeemScript = 0014 + pubkey-hash pubkey-to-addr(redeemScript)

# hash计算过程

要解析的交易id： fc2344f6c98cc19e5b3d7b716f9eaaeb21ab781393731652c710afd07a5505bf 原始数据内容参考： https://tchain.btc.com/fc2344f6c98cc19e5b3d7b716f9eaaeb21ab781393731652c710afd07a5505bf.rawhex

# 组装未签名交易数据

nVersion:      01000000
txin:              03 373d0980f9293fc5864c02fa7946ab706a1f0a5c5aedb8ee3a7eaf4d17c65e5e 01000000 00 ffffff00
                          df618d78879c213bde156e3ee55d1abe1badf750828aa0587d4a6d7fd2a41df7 00000000 00 ffffff00
                          df618d78879c213bde156e3ee55d1abe1badf750828aa0587d4a6d7fd2a41df7 01000000 00 ffffff00
txout:           02 0084d71700000000 17a9145be3eb3165f9c7ad58d3f49dc7f253ac42499eef87
                          ebd4f20300000000 17a91481dd877be5b3b60e3b1ccf547785744345570b9387
nLockTime: 00000000

UTXO = 373d0980f9293fc5864c02fa7946ab706a1f0a5c5aedb8ee3a7eaf4d17c65e5e UTXO-INDEX = 01000000

OUT-VALUE = 0084d71700000000 OUT-SCRIPT = 17a9145be3eb3165f9c7ad58d3f49dc7f253ac42499eef87

# 计算hash

# 计算 input hash

hashPrevouts = dSHA256([UTXO + UTXO-INDEX] * n)
    = dSHA256(373d0980f9293fc5864c02fa7946ab706a1f0a5c5aedb8ee3a7eaf4d17c65e5e 01000000 
                     df618d78879c213bde156e3ee55d1abe1badf750828aa0587d4a6d7fd2a41df7 00000000
                     df618d78879c213bde156e3ee55d1abe1badf750828aa0587d4a6d7fd2a41df7  01000000)
     = 6a59d58aabff920acf810aeca6359dbad8f0e07d9baa1dfdea7880843d44de72

# 计算 sequence hash

hashSequence = dSHA256([sequence] * n)
    = dSHA256(01000000 00000000 01000000)
    = 89974e58642dbbe1948159e6134c0b1f5b079893ab61cf02417f490cab69e052

# 计算 output hash

hashOutputs =  dSHA256([OUT-VALUE + OUT-SCRIPT] * n)
    = dSHA256(0084d71700000000 17a9145be3eb3165f9c7ad58d3f49dc7f253ac42499eef87
                         ebd4f20300000000 17a91481dd877be5b3b60e3b1ccf547785744345570b9387)
    = 7162a64cfdd10579b3f3a33e73ae59213588794724897d6cfa18f3ccce398b7c

# 计算 hash preimage (for input 1)

For P2WPKH witness program, the scriptCode is 0x1976a914{20-byte-pubkey-hash}88ac

hash preimage = 
      nVersion:             01000000
      hashPrevouts:     6a59d58aabff920acf810aeca6359dbad8f0e07d9baa1dfdea7880843d44de72
      hashSequence:   89974e58642dbbe1948159e6134c0b1f5b079893ab61cf02417f490cab69e052
      outpoint:             373d0980f9293fc5864c02fa7946ab706a1f0a5c5aedb8ee3a7eaf4d17c65e5e 01000000
      scriptCode:          1976a914 {} 88ac
      amount:               {input amount}
      nSequence:         ffffff00
      hashOutputs:      7162a64cfdd10579b3f3a33e73ae59213588794724897d6cfa18f3ccce398b7c
      nLockTime:         00000000
      nHashType:         01000000

sigHash = dSHA256(hash preimage)