pretty ugly. But got the hash from the bip143 example.

This commit is contained in:
Tadge Dryja 2016-02-20 00:42:07 -08:00
parent 233ec9538c
commit f6cf4b87f0

@ -5,8 +5,10 @@ import (
"encoding/binary"
"encoding/hex"
"fmt"
"io"
"io/ioutil"
"log"
"math"
"strings"
"github.com/btcsuite/btcd/txscript"
@ -16,36 +18,130 @@ import (
const (
inspk0 = "2103c9f4836b9a4f77fc0d81f7bcb01b7f1b35916864b9476c241ce9fc198bd25432ac"
inamt0 = uint64(625000000)
inamt0 = int64(625000000)
inspk1 = "00141d0f172a0ecb48aee1be1f2687d2963ae33f71a1"
inamt1 = uint64(600000000)
inamt1 = int64(600000000)
)
func outpointBytesLil(op wire.OutPoint) []byte {
var buf bytes.Buffer
// ignore errors because.. whatever
_ = binary.Write(&buf, binary.LittleEndian, op.Index)
// calcWitnessSignatureHash is the witnessified version of calcSignatureHash
func calcWitnessSignatureHash(
hashType txscript.SigHashType, tx *wire.MsgTx, idx int, amt int64) []byte {
// in the script.go calcSignatureHash(), idx is assumed safe, so I guess
// that's OK here too...
b := op.Hash[:]
return append(b, buf.Bytes()...)
// first get hashPrevOuts, hashSequence, and hashOutputs
hashPrevOuts := calcHashPrevOuts(tx, hashType)
hashSequence := calcHashSequence(tx, hashType)
hashOutputs := calcHashOutputs(tx, idx, hashType)
var buf4 [4]byte // buffer for 4-byte stuff
var buf8 [8]byte // buffer for 8-byte stuff
var pre []byte // the pre-image we're generating
binary.LittleEndian.PutUint32(buf4[:], uint32(tx.Version))
pre = append(pre, buf4[:]...)
pre = append(pre, hashPrevOuts.Bytes()...)
pre = append(pre, hashSequence.Bytes()...)
// outpoint being spent
pre = append(pre, tx.TxIn[idx].PreviousOutPoint.Hash.Bytes()...)
binary.LittleEndian.PutUint32(buf4[:], tx.TxIn[idx].PreviousOutPoint.Index)
pre = append(pre, buf4[:]...)
// scriptCode which is some new thing
sCode := []byte{0x19, 0x76, 0xa9, 0x14}
sCode = append(sCode, tx.TxIn[idx].SignatureScript[2:22]...)
sCode = append(sCode, []byte{0x88, 0xac}...)
pre = append(pre, sCode...)
// amount being signed off
binary.LittleEndian.PutUint64(buf8[:], uint64(amt))
pre = append(pre, buf8[:]...)
// nsequence of input
binary.LittleEndian.PutUint32(buf4[:], tx.TxIn[idx].Sequence)
pre = append(pre, buf4[:]...)
pre = append(pre, hashOutputs.Bytes()...)
// locktime
binary.LittleEndian.PutUint32(buf4[:], tx.LockTime)
pre = append(pre, buf4[:]...)
// hashType... in 4 bytes, instead of 1, because reasons.
binary.LittleEndian.PutUint32(buf4[:], uint32(hashType))
pre = append(pre, buf4[:]...)
fmt.Printf("pre: %x\n", pre)
hsh := wire.DoubleSha256SH(pre)
return hsh.Bytes()
}
func calcSignatureHash(
hashType txscript.SigHashType, tx *wire.MsgTx, idx int) []byte {
return nil
// calcHashPrevOuts makes a single hash of all previous outputs in the tx
func calcHashPrevOuts(tx *wire.MsgTx, hType txscript.SigHashType) wire.ShaHash {
// skip this (0x00) for anyonecanpay
if hType == txscript.SigHashAnyOneCanPay {
var empty [32]byte
return empty
}
// if sighash_ALL, hash of all txin outpoints, sequentially.
// if other sighash type, 0x00 * 32
func calcHashPrevOuts(tx *wire.MsgTx) [32]byte {
var pre []byte
for _, in := range tx.TxIn {
// in.PreviousOutPoint.Hash
// first append 32 byte hash
pre = append(pre, in.PreviousOutPoint.Hash.Bytes()...)
// then make a buffer, put 4 byte index in lil' endian and append that
var buf [4]byte
binary.LittleEndian.PutUint32(buf[:], in.PreviousOutPoint.Index)
pre = append(pre, buf[:]...)
}
fmt.Printf("pre: %x\n", pre)
return wire.DoubleSha256SH(pre)
}
return wire.DoubleSha256SH(tx.TxIn[0].SignatureScript)
// calcHashSequence is hash of txins' seq numbers, lil' endian, stuck together
func calcHashSequence(tx *wire.MsgTx, hType txscript.SigHashType) wire.ShaHash {
// skip (0x00) for single, none, anyonecanpay
if hType == txscript.SigHashSingle || hType == txscript.SigHashNone ||
hType == txscript.SigHashAnyOneCanPay {
var empty [32]byte
return empty
}
var pre []byte
for _, in := range tx.TxIn {
var buf [4]byte
binary.LittleEndian.PutUint32(buf[:], in.Sequence)
pre = append(pre, buf[:]...)
}
fmt.Printf("pre: %x\n", pre)
return wire.DoubleSha256SH(pre)
}
// calcHashOutputs also wants a input index, which it only uses for
// sighash single. If it's not sighash single, just put a 0 or whatever.
func calcHashOutputs(
tx *wire.MsgTx, inIndex int, hType txscript.SigHashType) wire.ShaHash {
if hType == txscript.SigHashNone ||
(hType == txscript.SigHashSingle && inIndex <= len(tx.TxOut)) {
var empty [32]byte
return empty
}
if hType == txscript.SigHashSingle {
var buf bytes.Buffer
writeTxOut(&buf, 0, 0, tx.TxOut[inIndex])
return wire.DoubleSha256SH(buf.Bytes())
}
var pre []byte
for _, out := range tx.TxOut {
var buf bytes.Buffer
writeTxOut(&buf, 0, 0, out)
pre = append(pre, buf.Bytes()...)
}
fmt.Printf("pre: %x\n", pre)
return wire.DoubleSha256SH(pre)
}
func main() {
@ -88,4 +184,72 @@ func main() {
fmt.Printf(uspv.TxToString(ttx))
hxh := calcWitnessSignatureHash(txscript.SigHashAll, ttx, 1, inamt1)
fmt.Printf("got sigHash %x\n", hxh)
}
// pver can be 0, doesn't do anything in these. Same for msg.Version
// writeVarInt serializes val to w using a variable number of bytes depending
// on its value.
func writeVarInt(w io.Writer, pver uint32, val uint64) error {
if val < 0xfd {
_, err := w.Write([]byte{uint8(val)})
return err
}
if val <= math.MaxUint16 {
var buf [3]byte
buf[0] = 0xfd
binary.LittleEndian.PutUint16(buf[1:], uint16(val))
_, err := w.Write(buf[:])
return err
}
if val <= math.MaxUint32 {
var buf [5]byte
buf[0] = 0xfe
binary.LittleEndian.PutUint32(buf[1:], uint32(val))
_, err := w.Write(buf[:])
return err
}
var buf [9]byte
buf[0] = 0xff
binary.LittleEndian.PutUint64(buf[1:], val)
_, err := w.Write(buf[:])
return err
}
// writeVarBytes serializes a variable length byte array to w as a varInt
// containing the number of bytes, followed by the bytes themselves.
func writeVarBytes(w io.Writer, pver uint32, bytes []byte) error {
slen := uint64(len(bytes))
err := writeVarInt(w, pver, slen)
if err != nil {
return err
}
_, err = w.Write(bytes)
if err != nil {
return err
}
return nil
}
// writeTxOut encodes to into the bitcoin protocol encoding for a transaction
// output (TxOut) to w.
func writeTxOut(w io.Writer, pver uint32, version int32, to *wire.TxOut) error {
var buf [8]byte
binary.LittleEndian.PutUint64(buf[:], uint64(to.Value))
_, err := w.Write(buf[:])
if err != nil {
return err
}
err = writeVarBytes(w, pver, to.PkScript)
if err != nil {
return err
}
return nil
}