Esempio n. 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
}
Esempio n. 2
0
// signFundingTx generates signatures for all the inputs in the funding tx
// belonging to Bob.
// NOTE: This generates the full witness stack.
func (b *bobNode) signFundingTx(fundingTx *wire.MsgTx) ([]*lnwallet.InputScript, error) {
	bobInputScripts := make([]*lnwallet.InputScript, 0, len(b.availableOutputs))
	bobPkScript := b.changeOutputs[0].PkScript

	inputValue := int64(7e8)
	hashCache := txscript.NewTxSigHashes(fundingTx)
	for i, _ := range fundingTx.TxIn {
		// Alice has already signed this input.
		if fundingTx.TxIn[i].Witness != nil {
			continue
		}

		witness, err := txscript.WitnessScript(fundingTx, hashCache, i,
			inputValue, bobPkScript, txscript.SigHashAll, b.privKey,
			true)
		if err != nil {
			return nil, err
		}

		inputScript := &lnwallet.InputScript{Witness: witness}
		bobInputScripts = append(bobInputScripts, inputScript)
	}

	return bobInputScripts, nil
}
Esempio n. 3
0
// commitSpendNoDelay constructs a valid witness allowing a node to spend their
// settled no-delay output on the counter-party's commitment transaction.
func commitSpendNoDelay(commitScript []byte, outputAmt btcutil.Amount,
	commitPriv *btcec.PrivateKey, sweepTx *wire.MsgTx) (wire.TxWitness, error) {

	// This is just a regular p2wkh spend which looks something like:
	//  * witness: <sig> <pubkey>
	hashCache := txscript.NewTxSigHashes(sweepTx)
	witness, err := txscript.WitnessScript(sweepTx, hashCache, 0,
		int64(outputAmt), commitScript, txscript.SigHashAll,
		commitPriv, true)
	if err != nil {
		return nil, err
	}

	return wire.TxWitness(witness), nil
}
Esempio n. 4
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
}
Esempio n. 5
0
// SendCoins does send coins, but it's very rudimentary
// wit makes it into p2wpkh.  Which is not yet spendable.
func (s *SPVCon) SendCoins(adrs []btcutil.Address, sendAmts []int64) error {
	if len(adrs) != len(sendAmts) {
		return fmt.Errorf("%d addresses and %d amounts", len(adrs), len(sendAmts))
	}
	var err error
	var score, totalSend, fee int64
	dustCutoff := int64(20000) // below this amount, just give to miners
	satPerByte := int64(80)    // satoshis per byte fee; have as arg later
	rawUtxos, err := s.TS.GetAllUtxos()
	if err != nil {
		return err
	}
	var allUtxos SortableUtxoSlice
	// start with utxos sorted by value.

	for _, utxo := range rawUtxos {
		score += utxo.Value
		allUtxos = append(allUtxos, *utxo)
	}
	// smallest and unconfirmed last (because it's reversed)
	sort.Sort(sort.Reverse(allUtxos))

	//	sort.Reverse(allUtxos)
	for _, amt := range sendAmts {
		totalSend += amt
	}
	// important rule in bitcoin, output total > input total is invalid.
	if totalSend > score {
		return fmt.Errorf("trying to send %d but %d available.",
			totalSend, score)
	}

	tx := wire.NewMsgTx() // make new tx
	// add non-change (arg) outputs
	for i, adr := range adrs {
		// make address script 76a914...88ac or 0014...
		outAdrScript, err := txscript.PayToAddrScript(adr)
		if err != nil {
			return err
		}
		// make user specified txout and add to tx
		txout := wire.NewTxOut(sendAmts[i], outAdrScript)
		tx.AddTxOut(txout)
	}

	// generate a utxo slice for your inputs
	var ins utxoSlice

	// add utxos until we've had enough
	nokori := totalSend // nokori is how much is needed on input side
	for _, utxo := range allUtxos {
		// skip unconfirmed.  Or de-prioritize?
		//		if utxo.AtHeight == 0 {
		//			continue
		//		}

		// yeah, lets add this utxo!
		ins = append(ins, utxo)
		// as we add utxos, fill in sigscripts
		// generate previous pkscripts (subscritpt?) for all utxos
		// then make txins with the utxo and prevpk, and insert them into the tx
		// these are all zeroed out during signing but it's an easy way to keep track
		var prevPKs []byte
		if utxo.IsWit {
			//tx.Flags = 0x01
			wa, err := btcutil.NewAddressWitnessPubKeyHash(
				s.TS.Adrs[utxo.KeyIdx].PkhAdr.ScriptAddress(), s.TS.Param)
			prevPKs, err = txscript.PayToAddrScript(wa)
			if err != nil {
				return err
			}
		} else { // otherwise generate directly
			prevPKs, err = txscript.PayToAddrScript(
				s.TS.Adrs[utxo.KeyIdx].PkhAdr)
			if err != nil {
				return err
			}
		}
		tx.AddTxIn(wire.NewTxIn(&utxo.Op, prevPKs, nil))
		nokori -= utxo.Value
		// if nokori is positive, don't bother checking fee yet.
		if nokori < 0 {
			fee = EstFee(tx, satPerByte)
			if nokori < -fee { // done adding utxos: nokori below negative est. fee
				break
			}
		}
	}

	// see if there's enough left to also add a change output

	changeOld, err := s.TS.NewAdr() // change is witnessy
	if err != nil {
		return err
	}
	changeAdr, err := btcutil.NewAddressWitnessPubKeyHash(
		changeOld.ScriptAddress(), s.TS.Param)
	if err != nil {
		return err
	}

	changeScript, err := txscript.PayToAddrScript(changeAdr)
	if err != nil {
		return err
	}

	changeOut := wire.NewTxOut(0, changeScript)
	tx.AddTxOut(changeOut)
	fee = EstFee(tx, satPerByte)
	changeOut.Value = -(nokori + fee)
	if changeOut.Value < dustCutoff {
		// remove last output (change) : not worth it
		tx.TxOut = tx.TxOut[:len(tx.TxOut)-1]
	}

	// sort utxos on the input side.  use this instead of txsort
	// because we want to remember which keys are associated with which inputs
	sort.Sort(ins)

	// sort tx -- this only will change txouts since inputs are already sorted
	txsort.InPlaceSort(tx)

	// tx is ready for signing,
	sigStash := make([][]byte, len(ins))
	witStash := make([][][]byte, len(ins))

	// generate tx-wide hashCache for segwit stuff
	// middle index number doesn't matter for sighashAll.
	hCache := txscript.NewTxSigHashes(tx)

	for i, txin := range tx.TxIn {
		// pick key
		child, err := s.TS.rootPrivKey.Child(
			ins[i].KeyIdx + hdkeychain.HardenedKeyStart)
		if err != nil {
			return err
		}
		priv, err := child.ECPrivKey()
		if err != nil {
			return err
		}

		// This is where witness based sighash types need to happen
		// sign into stash
		if ins[i].IsWit {
			witStash[i], err = txscript.WitnessScript(
				tx, hCache, i, ins[i].Value, txin.SignatureScript,
				txscript.SigHashAll, priv, true)
			if err != nil {
				return err
			}
		} else {
			sigStash[i], err = txscript.SignatureScript(
				tx, i, txin.SignatureScript,
				txscript.SigHashAll, priv, true)
			if err != nil {
				return err
			}
		}
	}
	// swap sigs into sigScripts in txins
	for i, txin := range tx.TxIn {
		if sigStash[i] != nil {
			txin.SignatureScript = sigStash[i]
		}
		if witStash[i] != nil {
			txin.Witness = witStash[i]
			txin.SignatureScript = nil
		}

	}

	//	fmt.Printf("tx: %s", TxToString(tx))
	//	buf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))

	// send it out on the wire.  hope it gets there.
	// we should deal with rejects.  Don't yet.
	err = s.NewOutgoingTx(tx)
	if err != nil {
		return err
	}
	return nil
}
Esempio n. 6
0
func (s *SPVCon) SendOne(u Utxo, adr btcutil.Address) error {
	// fixed fee
	fee := int64(5000)

	sendAmt := u.Value - fee
	tx := wire.NewMsgTx() // make new tx
	// add single output
	outAdrScript, err := txscript.PayToAddrScript(adr)
	if err != nil {
		return err
	}
	// make user specified txout and add to tx
	txout := wire.NewTxOut(sendAmt, outAdrScript)
	tx.AddTxOut(txout)

	var prevPKs []byte
	if u.IsWit {
		//tx.Flags = 0x01
		wa, err := btcutil.NewAddressWitnessPubKeyHash(
			s.TS.Adrs[u.KeyIdx].PkhAdr.ScriptAddress(), s.TS.Param)
		prevPKs, err = txscript.PayToAddrScript(wa)
		if err != nil {
			return err
		}
	} else { // otherwise generate directly
		prevPKs, err = txscript.PayToAddrScript(
			s.TS.Adrs[u.KeyIdx].PkhAdr)
		if err != nil {
			return err
		}
	}

	tx.AddTxIn(wire.NewTxIn(&u.Op, prevPKs, nil))

	var sig []byte
	var wit [][]byte
	hCache := txscript.NewTxSigHashes(tx)

	child, err := s.TS.rootPrivKey.Child(u.KeyIdx + hdkeychain.HardenedKeyStart)

	if err != nil {
		return err
	}
	priv, err := child.ECPrivKey()
	if err != nil {
		return err
	}

	// This is where witness based sighash types need to happen
	// sign into stash
	if u.IsWit {
		wit, err = txscript.WitnessScript(
			tx, hCache, 0, u.Value, tx.TxIn[0].SignatureScript,
			txscript.SigHashAll, priv, true)
		if err != nil {
			return err
		}
	} else {
		sig, err = txscript.SignatureScript(
			tx, 0, tx.TxIn[0].SignatureScript,
			txscript.SigHashAll, priv, true)
		if err != nil {
			return err
		}
	}

	// swap sigs into sigScripts in txins

	if sig != nil {
		tx.TxIn[0].SignatureScript = sig
	}
	if wit != nil {
		tx.TxIn[0].Witness = wit
		tx.TxIn[0].SignatureScript = nil
	}
	return s.NewOutgoingTx(tx)
}
Esempio n. 7
0
// ComputeInputScript generates a complete InputIndex for the passed
// transaction with the signature as defined within the passed SignDescriptor.
// This method is capable of generating the proper input script for both
// regular p2wkh output and p2wkh outputs nested within a regular p2sh output.
//
// This is a part of the WalletController interface.
func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {

	outputScript := signDesc.Output.PkScript
	walletAddr, err := b.fetchOutputAddr(outputScript)
	if err != nil {
		return nil, nil
	}

	pka := walletAddr.(waddrmgr.ManagedPubKeyAddress)
	privKey, err := pka.PrivKey()
	if err != nil {
		return nil, err
	}

	var witnessProgram []byte
	inputScript := &lnwallet.InputScript{}

	// If we're spending p2wkh output nested within a p2sh output, then
	// we'll need to attach a sigScript in addition to witness data.
	switch {
	case pka.IsNestedWitness():
		pubKey := privKey.PubKey()
		pubKeyHash := btcutil.Hash160(pubKey.SerializeCompressed())

		// 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,
			b.netParams)
		if err != nil {
			return nil, err
		}
		witnessProgram, err = txscript.PayToAddrScript(p2wkhAddr)
		if err != nil {
			return nil, err
		}

		bldr := txscript.NewScriptBuilder()
		bldr.AddData(witnessProgram)
		sigScript, err := bldr.Script()
		if err != nil {
			return nil, err
		}

		inputScript.ScriptSig = sigScript
	// Otherwise, this is a regular p2wkh output, so we include the
	// witness program itself as the subscript to generate the proper
	// sighash digest. As part of the new sighash digest algorithm, the
	// p2wkh witness program will be expanded into a regular p2kh
	// script.
	default:
		witnessProgram = outputScript
	}

	// Generate a valid witness stack for the input.
	// TODO(roasbeef): adhere to passed HashType
	witnessScript, err := txscript.WitnessScript(tx, signDesc.SigHashes,
		signDesc.InputIndex, signDesc.Output.Value, witnessProgram,
		txscript.SigHashAll, privKey, true)
	if err != nil {
		return nil, err
	}

	inputScript.Witness = witnessScript

	return inputScript, nil
}