Ejemplo n.º 1
1
// spendNestedWitnessPubKey generates both a sigScript, and valid witness for
// spending the passed pkScript with the specified input amount. The generated
// sigScript is the version 0 p2wkh witness program corresponding to the queried
// key. The witness stack is identical to that of one which spends a regular
// p2wkh output. The input amount *must* correspond to the output value of the
// previous pkScript, or else verification will fail since the new sighash
// digest algorithm defined in BIP0143 includes the input value in the sighash.
func spendNestedWitnessPubKeyHash(txIn *wire.TxIn, pkScript []byte,
	inputValue int64, chainParams *chaincfg.Params, secrets SecretsSource,
	tx *wire.MsgTx, hashCache *txscript.TxSigHashes, idx int) error {

	// First we need to obtain the key pair related to this p2sh output.
	_, addrs, _, err := txscript.ExtractPkScriptAddrs(pkScript,
		chainParams)
	if err != nil {
		return err
	}
	privKey, compressed, err := secrets.GetKey(addrs[0])
	if err != nil {
		return err
	}
	pubKey := privKey.PubKey()

	var pubKeyHash []byte
	if compressed {
		pubKeyHash = btcutil.Hash160(pubKey.SerializeCompressed())
	} else {
		pubKeyHash = btcutil.Hash160(pubKey.SerializeUncompressed())
	}

	// Next, we'll generate a valid sigScript that'll allow us to spend
	// the p2sh output. The sigScript will contain only a single push of
	// the p2wkh witness program corresponding to the matching public key
	// of this address.
	p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(pubKeyHash, chainParams)
	if err != nil {
		return err
	}
	witnessProgram, err := txscript.PayToAddrScript(p2wkhAddr)
	if err != nil {
		return err
	}
	bldr := txscript.NewScriptBuilder()
	bldr.AddData(witnessProgram)
	sigScript, err := bldr.Script()
	if err != nil {
		return err
	}
	txIn.SignatureScript = sigScript

	// With the sigScript in place, we'll next generate the proper witness
	// that'll allow us to spend the p2wkh output.
	witnessScript, err := txscript.WitnessScript(tx, hashCache, idx,
		inputValue, witnessProgram, txscript.SigHashAll, privKey, compressed)
	if err != nil {
		return err
	}

	txIn.Witness = witnessScript

	return nil
}
Ejemplo n.º 2
0
// spendWitnessKeyHash generates, and sets a valid witness for spending the
// passed pkScript with the specified input amount. The input amount *must*
// correspond to the output value of the previous pkScript, or else verification
// will fail since the new sighash digest algorithm defined in BIP0143 includes
// the input value in the sighash.
func spendWitnessKeyHash(txIn *wire.TxIn, pkScript []byte,
	inputValue int64, chainParams *chaincfg.Params, secrets SecretsSource,
	tx *wire.MsgTx, hashCache *txscript.TxSigHashes, idx int) error {

	// First obtain the key pair associated with this p2wkh address.
	_, addrs, _, err := txscript.ExtractPkScriptAddrs(pkScript,
		chainParams)
	if err != nil {
		return err
	}
	privKey, compressed, err := secrets.GetKey(addrs[0])
	if err != nil {
		return err
	}
	pubKey := privKey.PubKey()

	// Once we have the key pair, generate a p2wkh address type, respecting
	// the compression type of the generated key.
	var pubKeyHash []byte
	if compressed {
		pubKeyHash = btcutil.Hash160(pubKey.SerializeCompressed())
	} else {
		pubKeyHash = btcutil.Hash160(pubKey.SerializeUncompressed())
	}
	p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(pubKeyHash, chainParams)
	if err != nil {
		return err
	}

	// With the concrete address type, we can now generate the
	// corresponding witness program to be used to generate a valid witness
	// which will allow us to spend this output.
	witnessProgram, err := txscript.PayToAddrScript(p2wkhAddr)
	if err != nil {
		return err
	}
	witnessScript, err := txscript.WitnessScript(tx, hashCache, idx,
		inputValue, witnessProgram, txscript.SigHashAll, privKey, true)
	if err != nil {
		return err
	}

	txIn.Witness = witnessScript

	return nil
}