Merge pull request #2481 from joostjager/move-input

multi: move input to separate package

breacharbiter.go

@@ -19,8 +19,8 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
-	"github.com/lightningnetwork/lnd/sweep"
 )
 
 var (
@@ -100,7 +100,7 @@ type BreachConfig struct {
 	// Signer is used by the breach arbiter to generate sweep transactions,
 	// which move coins from previously open channels back to the user's
 	// wallet.
-	Signer lnwallet.Signer
+	Signer input.Signer
 
 	// Store is a persistent resource that maintains information regarding
 	// breached channels. This is used in conjunction with DB to recover
@@ -282,7 +282,7 @@ func convertToSecondLevelRevoke(bo *breachedOutput, breachInfo *retributionInfo,
 
 	// In this case, we'll modify the witness type of this output to
 	// actually prepare for a second level revoke.
-	bo.witnessType = lnwallet.HtlcSecondLevelRevoke
+	bo.witnessType = input.HtlcSecondLevelRevoke
 
 	// We'll also redirect the outpoint to this second level output, so the
 	// spending transaction updates it inputs accordingly.
@@ -346,8 +346,8 @@ func (b *breachArbiter) waitForSpendEvent(breachInfo *retributionInfo,
 		breachedOutput := &breachInfo.breachedOutputs[i]
 
 		// If this isn't an HTLC output, then we can skip it.
-		if breachedOutput.witnessType != lnwallet.HtlcAcceptedRevoke &&
+		if breachedOutput.witnessType != input.HtlcAcceptedRevoke &&
-			breachedOutput.witnessType != lnwallet.HtlcOfferedRevoke {
+			breachedOutput.witnessType != input.HtlcOfferedRevoke {
 			continue
 		}
 
@@ -581,18 +581,18 @@ justiceTxBroadcast:
 		// Compute both the total value of funds being swept and the
 		// amount of funds that were revoked from the counter party.
 		var totalFunds, revokedFunds btcutil.Amount
-		for _, input := range breachInfo.breachedOutputs {
+		for _, inp := range breachInfo.breachedOutputs {
-			totalFunds += input.Amount()
+			totalFunds += inp.Amount()
 
 			// If the output being revoked is the remote commitment
 			// output or an offered HTLC output, it's amount
 			// contributes to the value of funds being revoked from
 			// the counter party.
-			switch input.WitnessType() {
+			switch inp.WitnessType() {
-			case lnwallet.CommitmentRevoke:
+			case input.CommitmentRevoke:
-				revokedFunds += input.Amount()
+				revokedFunds += inp.Amount()
-			case lnwallet.HtlcOfferedRevoke:
+			case input.HtlcOfferedRevoke:
-				revokedFunds += input.Amount()
+				revokedFunds += inp.Amount()
 			default:
 			}
 		}
@@ -755,21 +755,21 @@ func (b *breachArbiter) handleBreachHandoff(breachEvent *ContractBreachEvent) {
 type breachedOutput struct {
 	amt         btcutil.Amount
 	outpoint    wire.OutPoint
-	witnessType lnwallet.WitnessType
+	witnessType input.WitnessType
-	signDesc    lnwallet.SignDescriptor
+	signDesc    input.SignDescriptor
 	confHeight  uint32
 
 	secondLevelWitnessScript []byte
 
-	witnessFunc lnwallet.WitnessGenerator
+	witnessFunc input.WitnessGenerator
 }
 
 // makeBreachedOutput assembles a new breachedOutput that can be used by the
 // breach arbiter to construct a justice or sweep transaction.
 func makeBreachedOutput(outpoint *wire.OutPoint,
-	witnessType lnwallet.WitnessType,
+	witnessType input.WitnessType,
 	secondLevelScript []byte,
-	signDescriptor *lnwallet.SignDescriptor,
+	signDescriptor *input.SignDescriptor,
 	confHeight uint32) breachedOutput {
 
 	amount := signDescriptor.Output.Value
@@ -797,13 +797,13 @@ func (bo *breachedOutput) OutPoint() *wire.OutPoint {
 
 // WitnessType returns the type of witness that must be generated to spend the
 // breached output.
-func (bo *breachedOutput) WitnessType() lnwallet.WitnessType {
+func (bo *breachedOutput) WitnessType() input.WitnessType {
 	return bo.witnessType
 }
 
 // SignDesc returns the breached output's SignDescriptor, which is used during
 // signing to compute the witness.
-func (bo *breachedOutput) SignDesc() *lnwallet.SignDescriptor {
+func (bo *breachedOutput) SignDesc() *input.SignDescriptor {
 	return &bo.signDesc
 }
 
@@ -812,8 +812,8 @@ func (bo *breachedOutput) SignDesc() *lnwallet.SignDescriptor {
 // generation function, which parameterized primarily by the witness type and
 // sign descriptor. The method then returns the witness computed by invoking
 // this function on the first and subsequent calls.
-func (bo *breachedOutput) CraftInputScript(signer lnwallet.Signer, txn *wire.MsgTx,
+func (bo *breachedOutput) CraftInputScript(signer input.Signer, txn *wire.MsgTx,
-	hashCache *txscript.TxSigHashes, txinIdx int) (*lnwallet.InputScript, error) {
+	hashCache *txscript.TxSigHashes, txinIdx int) (*input.Script, error) {
 
 	// First, we ensure that the witness generation function has been
 	// initialized for this breached output.
@@ -842,7 +842,7 @@ func (bo *breachedOutput) HeightHint() uint32 {
 
 // Add compile-time constraint ensuring breachedOutput implements the Input
 // interface.
-var _ sweep.Input = (*breachedOutput)(nil)
+var _ input.Input = (*breachedOutput)(nil)
 
 // retributionInfo encapsulates all the data needed to sweep all the contested
 // funds within a channel whose contract has been breached by the prior
@@ -883,7 +883,7 @@ func newRetributionInfo(chanPoint *wire.OutPoint,
 	if breachInfo.LocalOutputSignDesc != nil {
 		localOutput := makeBreachedOutput(
 			&breachInfo.LocalOutpoint,
-			lnwallet.CommitmentNoDelay,
+			input.CommitmentNoDelay,
 			// No second level script as this is a commitment
 			// output.
 			nil,
@@ -901,7 +901,7 @@ func newRetributionInfo(chanPoint *wire.OutPoint,
 	if breachInfo.RemoteOutputSignDesc != nil {
 		remoteOutput := makeBreachedOutput(
 			&breachInfo.RemoteOutpoint,
-			lnwallet.CommitmentRevoke,
+			input.CommitmentRevoke,
 			// No second level script as this is a commitment
 			// output.
 			nil,
@@ -919,11 +919,11 @@ func newRetributionInfo(chanPoint *wire.OutPoint,
 		// Using the breachedHtlc's incoming flag, determine the
 		// appropriate witness type that needs to be generated in order
 		// to sweep the HTLC output.
-		var htlcWitnessType lnwallet.WitnessType
+		var htlcWitnessType input.WitnessType
 		if breachedHtlc.IsIncoming {
-			htlcWitnessType = lnwallet.HtlcAcceptedRevoke
+			htlcWitnessType = input.HtlcAcceptedRevoke
 		} else {
-			htlcWitnessType = lnwallet.HtlcOfferedRevoke
+			htlcWitnessType = input.HtlcOfferedRevoke
 		}
 
 		htlcOutput := makeBreachedOutput(
@@ -956,13 +956,13 @@ func (b *breachArbiter) createJusticeTx(
 	// outputs, while simultaneously computing the estimated weight of the
 	// transaction.
 	var (
-		spendableOutputs []sweep.Input
+		spendableOutputs []input.Input
-		weightEstimate   lnwallet.TxWeightEstimator
+		weightEstimate   input.TxWeightEstimator
 	)
 
 	// Allocate enough space to potentially hold each of the breached
 	// outputs in the retribution info.
-	spendableOutputs = make([]sweep.Input, 0, len(r.breachedOutputs))
+	spendableOutputs = make([]input.Input, 0, len(r.breachedOutputs))
 
 	// The justice transaction we construct will be a segwit transaction
 	// that pays to a p2wkh output. Components such as the version,
@@ -975,38 +975,38 @@ func (b *breachArbiter) createJusticeTx(
 	// finally adding to our list of spendable outputs.
 	for i := range r.breachedOutputs {
 		// Grab locally scoped reference to breached output.
-		input := &r.breachedOutputs[i]
+		inp := &r.breachedOutputs[i]
 
 		// First, select the appropriate estimated witness weight for
 		// the give witness type of this breached output. If the witness
 		// type is unrecognized, we will omit it from the transaction.
 		var witnessWeight int
-		switch input.WitnessType() {
+		switch inp.WitnessType() {
-		case lnwallet.CommitmentNoDelay:
+		case input.CommitmentNoDelay:
-			witnessWeight = lnwallet.P2WKHWitnessSize
+			witnessWeight = input.P2WKHWitnessSize
 
-		case lnwallet.CommitmentRevoke:
+		case input.CommitmentRevoke:
-			witnessWeight = lnwallet.ToLocalPenaltyWitnessSize
+			witnessWeight = input.ToLocalPenaltyWitnessSize
 
-		case lnwallet.HtlcOfferedRevoke:
+		case input.HtlcOfferedRevoke:
-			witnessWeight = lnwallet.OfferedHtlcPenaltyWitnessSize
+			witnessWeight = input.OfferedHtlcPenaltyWitnessSize
 
-		case lnwallet.HtlcAcceptedRevoke:
+		case input.HtlcAcceptedRevoke:
-			witnessWeight = lnwallet.AcceptedHtlcPenaltyWitnessSize
+			witnessWeight = input.AcceptedHtlcPenaltyWitnessSize
 
-		case lnwallet.HtlcSecondLevelRevoke:
+		case input.HtlcSecondLevelRevoke:
-			witnessWeight = lnwallet.ToLocalPenaltyWitnessSize
+			witnessWeight = input.ToLocalPenaltyWitnessSize
 
 		default:
 			brarLog.Warnf("breached output in retribution info "+
 				"contains unexpected witness type: %v",
-				input.WitnessType())
+				inp.WitnessType())
 			continue
 		}
 		weightEstimate.AddWitnessInput(witnessWeight)
 
 		// Finally, append this input to our list of spendable outputs.
-		spendableOutputs = append(spendableOutputs, input)
+		spendableOutputs = append(spendableOutputs, inp)
 	}
 
 	txWeight := int64(weightEstimate.Weight())
@@ -1016,7 +1016,7 @@ func (b *breachArbiter) createJusticeTx(
 // sweepSpendableOutputsTxn creates a signed transaction from a sequence of
 // spendable outputs by sweeping the funds into a single p2wkh output.
 func (b *breachArbiter) sweepSpendableOutputsTxn(txWeight int64,
-	inputs ...sweep.Input) (*wire.MsgTx, error) {
+	inputs ...input.Input) (*wire.MsgTx, error) {
 
 	// First, we obtain a new public key script from the wallet which we'll
 	// sweep the funds to.
@@ -1078,7 +1078,7 @@ func (b *breachArbiter) sweepSpendableOutputsTxn(txWeight int64,
 	// witness, and attaching it to the transaction. This function accepts
 	// an integer index representing the intended txin index, and the
 	// breached output from which it will spend.
-	addWitness := func(idx int, so sweep.Input) error {
+	addWitness := func(idx int, so input.Input) error {
 		// First, we construct a valid witness for this outpoint and
 		// transaction using the SpendableOutput's witness generation
 		// function.
@@ -1435,7 +1435,7 @@ func (bo *breachedOutput) Encode(w io.Writer) error {
 		return err
 	}
 
-	err := lnwallet.WriteSignDescriptor(w, &bo.signDesc)
+	err := input.WriteSignDescriptor(w, &bo.signDesc)
 	if err != nil {
 		return err
 	}
@@ -1466,7 +1466,7 @@ func (bo *breachedOutput) Decode(r io.Reader) error {
 		return err
 	}
 
-	if err := lnwallet.ReadSignDescriptor(r, &bo.signDesc); err != nil {
+	if err := input.ReadSignDescriptor(r, &bo.signDesc); err != nil {
 		return err
 	}
 
@@ -1479,7 +1479,7 @@ func (bo *breachedOutput) Decode(r io.Reader) error {
 	if _, err := io.ReadFull(r, scratch[:2]); err != nil {
 		return err
 	}
-	bo.witnessType = lnwallet.WitnessType(
+	bo.witnessType = input.WitnessType(
 		binary.BigEndian.Uint16(scratch[:2]),
 	)
 

breacharbiter_test.go

@@ -27,6 +27,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -94,8 +95,8 @@ var (
 		{
 			amt:         btcutil.Amount(1e7),
 			outpoint:    breachOutPoints[0],
-			witnessType: lnwallet.CommitmentNoDelay,
+			witnessType: input.CommitmentNoDelay,
-			signDesc: lnwallet.SignDescriptor{
+			signDesc: input.SignDescriptor{
 				SingleTweak: []byte{
 					0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
 					0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
@@ -138,8 +139,8 @@ var (
 		{
 			amt:         btcutil.Amount(2e9),
 			outpoint:    breachOutPoints[1],
-			witnessType: lnwallet.CommitmentRevoke,
+			witnessType: input.CommitmentRevoke,
-			signDesc: lnwallet.SignDescriptor{
+			signDesc: input.SignDescriptor{
 				SingleTweak: []byte{
 					0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
 					0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
@@ -182,8 +183,8 @@ var (
 		{
 			amt:         btcutil.Amount(3e4),
 			outpoint:    breachOutPoints[2],
-			witnessType: lnwallet.CommitmentDelayOutput,
+			witnessType: input.CommitmentDelayOutput,
-			signDesc: lnwallet.SignDescriptor{
+			signDesc: input.SignDescriptor{
 				SingleTweak: []byte{
 					0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
 					0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
@@ -1009,7 +1010,7 @@ func TestBreachHandoffSuccess(t *testing.T) {
 		ProcessACK: make(chan error, 1),
 		BreachRetribution: &lnwallet.BreachRetribution{
 			BreachTransaction: bobClose.CloseTx,
-			LocalOutputSignDesc: &lnwallet.SignDescriptor{
+			LocalOutputSignDesc: &input.SignDescriptor{
 				Output: &wire.TxOut{
 					PkScript: breachKeys[0],
 				},
@@ -1041,7 +1042,7 @@ func TestBreachHandoffSuccess(t *testing.T) {
 		ProcessACK: make(chan error, 1),
 		BreachRetribution: &lnwallet.BreachRetribution{
 			BreachTransaction: bobClose.CloseTx,
-			LocalOutputSignDesc: &lnwallet.SignDescriptor{
+			LocalOutputSignDesc: &input.SignDescriptor{
 				Output: &wire.TxOut{
 					PkScript: breachKeys[0],
 				},
@@ -1090,7 +1091,7 @@ func TestBreachHandoffFail(t *testing.T) {
 		ProcessACK: make(chan error, 1),
 		BreachRetribution: &lnwallet.BreachRetribution{
 			BreachTransaction: bobClose.CloseTx,
-			LocalOutputSignDesc: &lnwallet.SignDescriptor{
+			LocalOutputSignDesc: &input.SignDescriptor{
 				Output: &wire.TxOut{
 					PkScript: breachKeys[0],
 				},
@@ -1130,7 +1131,7 @@ func TestBreachHandoffFail(t *testing.T) {
 		ProcessACK: make(chan error, 1),
 		BreachRetribution: &lnwallet.BreachRetribution{
 			BreachTransaction: bobClose.CloseTx,
-			LocalOutputSignDesc: &lnwallet.SignDescriptor{
+			LocalOutputSignDesc: &input.SignDescriptor{
 				Output: &wire.TxOut{
 					PkScript: breachKeys[0],
 				},
@@ -1444,7 +1445,7 @@ func createInitChannels(revocationWindow int) (*lnwallet.LightningChannel, *lnwa
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	bobCommitPoint := lnwallet.ComputeCommitmentPoint(bobFirstRevoke[:])
+	bobCommitPoint := input.ComputeCommitmentPoint(bobFirstRevoke[:])
 
 	aliceRoot, err := chainhash.NewHash(aliceKeyPriv.Serialize())
 	if err != nil {
@@ -1455,7 +1456,7 @@ func createInitChannels(revocationWindow int) (*lnwallet.LightningChannel, *lnwa
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	aliceCommitPoint := lnwallet.ComputeCommitmentPoint(aliceFirstRevoke[:])
+	aliceCommitPoint := input.ComputeCommitmentPoint(aliceFirstRevoke[:])
 
 	aliceCommitTx, bobCommitTx, err := lnwallet.CreateCommitmentTxns(channelBal,
 		channelBal, &aliceCfg, &bobCfg, aliceCommitPoint, bobCommitPoint,

chainregistry.go

@@ -25,6 +25,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs/neutrinonotify"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
@@ -63,14 +64,14 @@ const (
 // TODO(halseth): make configurable at startup?
 var defaultBtcChannelConstraints = channeldb.ChannelConstraints{
 	DustLimit:        lnwallet.DefaultDustLimit(),
-	MaxAcceptedHtlcs: lnwallet.MaxHTLCNumber / 2,
+	MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 }
 
 // defaultLtcChannelConstraints is the default set of channel constraints that are
 // meant to be used when initially funding a Litecoin channel.
 var defaultLtcChannelConstraints = channeldb.ChannelConstraints{
 	DustLimit:        defaultLitecoinDustLimit,
-	MaxAcceptedHtlcs: lnwallet.MaxHTLCNumber / 2,
+	MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 }
 
 // chainCode is an enum-like structure for keeping track of the chains
@@ -105,7 +106,7 @@ type chainControl struct {
 
 	feeEstimator lnwallet.FeeEstimator
 
-	signer lnwallet.Signer
+	signer input.Signer
 
 	keyRing keychain.KeyRing
 

contractcourt/briefcase.go

@@ -10,6 +10,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/coreos/bbolt"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
@@ -908,7 +909,7 @@ func encodeIncomingResolution(w io.Writer, i *lnwallet.IncomingHtlcResolution) e
 	if err := binary.Write(w, endian, i.ClaimOutpoint.Index); err != nil {
 		return err
 	}
-	err := lnwallet.WriteSignDescriptor(w, &i.SweepSignDesc)
+	err := input.WriteSignDescriptor(w, &i.SweepSignDesc)
 	if err != nil {
 		return err
 	}
@@ -945,7 +946,7 @@ func decodeIncomingResolution(r io.Reader, h *lnwallet.IncomingHtlcResolution) e
 		return err
 	}
 
-	return lnwallet.ReadSignDescriptor(r, &h.SweepSignDesc)
+	return input.ReadSignDescriptor(r, &h.SweepSignDesc)
 }
 
 func encodeOutgoingResolution(w io.Writer, o *lnwallet.OutgoingHtlcResolution) error {
@@ -977,7 +978,7 @@ func encodeOutgoingResolution(w io.Writer, o *lnwallet.OutgoingHtlcResolution) e
 		return err
 	}
 
-	return lnwallet.WriteSignDescriptor(w, &o.SweepSignDesc)
+	return input.WriteSignDescriptor(w, &o.SweepSignDesc)
 }
 
 func decodeOutgoingResolution(r io.Reader, o *lnwallet.OutgoingHtlcResolution) error {
@@ -1010,7 +1011,7 @@ func decodeOutgoingResolution(r io.Reader, o *lnwallet.OutgoingHtlcResolution) e
 		return err
 	}
 
-	return lnwallet.ReadSignDescriptor(r, &o.SweepSignDesc)
+	return input.ReadSignDescriptor(r, &o.SweepSignDesc)
 }
 
 func encodeCommitResolution(w io.Writer,
@@ -1024,7 +1025,7 @@ func encodeCommitResolution(w io.Writer,
 		return err
 	}
 
-	err = lnwallet.WriteSignDescriptor(w, &c.SelfOutputSignDesc)
+	err = input.WriteSignDescriptor(w, &c.SelfOutputSignDesc)
 	if err != nil {
 		return err
 	}
@@ -1044,7 +1045,7 @@ func decodeCommitResolution(r io.Reader,
 		return err
 	}
 
-	err = lnwallet.ReadSignDescriptor(r, &c.SelfOutputSignDesc)
+	err = input.ReadSignDescriptor(r, &c.SelfOutputSignDesc)
 	if err != nil {
 		return err
 	}

contractcourt/briefcase_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/coreos/bbolt"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
@@ -63,7 +64,7 @@ var (
 		0xb4, 0x12, 0xa3,
 	}
 
-	testSignDesc = lnwallet.SignDescriptor{
+	testSignDesc = input.SignDescriptor{
 		SingleTweak: []byte{
 			0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
 			0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,

contractcourt/chain_arbitrator.go

@@ -11,6 +11,7 @@ import (
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/sweep"
@@ -120,7 +121,7 @@ type ChainArbitratorConfig struct {
 	// Signer is a signer backed by the active lnd node. This should be
 	// capable of producing a signature as specified by a valid
 	// SignDescriptor.
-	Signer lnwallet.Signer
+	Signer input.Signer
 
 	// FeeEstimator will be used to return fee estimates.
 	FeeEstimator lnwallet.FeeEstimator

contractcourt/chain_watcher.go

@@ -14,6 +14,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
@@ -93,7 +94,7 @@ type chainWatcherConfig struct {
 	// signer is the main signer instances that will be responsible for
 	// signing any HTLC and commitment transaction generated by the state
 	// machine.
-	signer lnwallet.Signer
+	signer input.Signer
 
 	// contractBreach is a method that will be called by the watcher if it
 	// detects that a contract breach transaction has been confirmed. Only
@@ -191,13 +192,13 @@ func (c *chainWatcher) Start() error {
 
 	localKey := chanState.LocalChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 	remoteKey := chanState.RemoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
-	multiSigScript, err := lnwallet.GenMultiSigScript(
+	multiSigScript, err := input.GenMultiSigScript(
 		localKey, remoteKey,
 	)
 	if err != nil {
 		return err
 	}
-	pkScript, err := lnwallet.WitnessScriptHash(multiSigScript)
+	pkScript, err := input.WitnessScriptHash(multiSigScript)
 	if err != nil {
 		return err
 	}

contractcourt/channel_arbitrator_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
@@ -542,7 +543,7 @@ func TestChannelArbitratorLocalForceClosePendingHtlc(t *testing.T) {
 	// our commitment transaction got confirmed.
 	outgoingRes := lnwallet.OutgoingHtlcResolution{
 		Expiry: 10,
-		SweepSignDesc: lnwallet.SignDescriptor{
+		SweepSignDesc: input.SignDescriptor{
 			Output: &wire.TxOut{},
 		},
 		SignedTimeoutTx: &wire.MsgTx{

contractcourt/commit_sweep_resolver.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
+	"github.com/lightningnetwork/lnd/input"
 	"io"
 	"io/ioutil"
 
@@ -100,9 +101,9 @@ func (c *commitSweepResolver) Resolve() (ContractResolver, error) {
 		// we'll now craft an input with all the information required
 		// to create a fully valid sweeping transaction to recover
 		// these coins.
-		input := sweep.MakeBaseInput(
+		inp := input.MakeBaseInput(
 			&c.commitResolution.SelfOutPoint,
-			lnwallet.CommitmentNoDelay,
+			input.CommitmentNoDelay,
 			&c.commitResolution.SelfOutputSignDesc,
 			c.broadcastHeight,
 		)
@@ -117,7 +118,7 @@ func (c *commitSweepResolver) Resolve() (ContractResolver, error) {
 		//
 		// TODO: Use time-based sweeper and result chan.
 		c.sweepTx, err = c.Sweeper.CreateSweepTx(
-			[]sweep.Input{&input},
+			[]input.Input{&inp},
 			sweep.FeePreference{
 				ConfTarget: sweepConfTarget,
 			}, 0,

contractcourt/htlc_outgoing_contest_resolver.go

@@ -2,12 +2,12 @@ package contractcourt
 
 import (
 	"fmt"
+	"github.com/lightningnetwork/lnd/input"
 	"io"
 
 	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
-	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
 // htlcOutgoingContestResolver is a ContractResolver that's able to resolve an
@@ -119,7 +119,7 @@ func (h *htlcOutgoingContestResolver) Resolve() (ContractResolver, error) {
 		// re-construct the pkScipt we need to watch.
 		outPointToWatch = h.htlcResolution.SignedTimeoutTx.TxIn[0].PreviousOutPoint
 		witness := h.htlcResolution.SignedTimeoutTx.TxIn[0].Witness
-		scriptToWatch, err = lnwallet.WitnessScriptHash(
+		scriptToWatch, err = input.WitnessScriptHash(
 			witness[len(witness)-1],
 		)
 		if err != nil {

contractcourt/htlc_success_resolver.go

@@ -3,6 +3,7 @@ package contractcourt
 import (
 	"encoding/binary"
 	"fmt"
+	"github.com/lightningnetwork/lnd/input"
 	"io"
 
 	"github.com/lightningnetwork/lnd/channeldb"
@@ -104,7 +105,7 @@ func (h *htlcSuccessResolver) Resolve() (ContractResolver, error) {
 			// need to create an input which contains all the items
 			// required to add this input to a sweeping transaction,
 			// and generate a witness.
-			input := sweep.MakeHtlcSucceedInput(
+			inp := input.MakeHtlcSucceedInput(
 				&h.htlcResolution.ClaimOutpoint,
 				&h.htlcResolution.SweepSignDesc,
 				h.htlcResolution.Preimage[:],
@@ -122,7 +123,7 @@ func (h *htlcSuccessResolver) Resolve() (ContractResolver, error) {
 			// TODO: Use time-based sweeper and result chan.
 			var err error
 			h.sweepTx, err = h.Sweeper.CreateSweepTx(
-				[]sweep.Input{&input},
+				[]input.Input{&inp},
 				sweep.FeePreference{
 					ConfTarget: sweepConfTarget,
 				}, 0,

docs/go-fuzz/wirefuzz.go

@@ -3,8 +3,9 @@ package wirefuzz
 import (
 	"bytes"
 	"fmt"
-	"github.com/lightningnetwork/lnd/lnwire"
 	"reflect"
+
+	"github.com/lightningnetwork/lnd/lnwire"
 )
 
 // Fuzz is used by go-fuzz to fuzz for potentially malicious input

fundingmanager.go

@@ -18,6 +18,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lnrpc"
@@ -1847,12 +1848,12 @@ func makeFundingScript(channel *channeldb.OpenChannel) ([]byte, error) {
 	localKey := channel.LocalChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 	remoteKey := channel.RemoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 
-	multiSigScript, err := lnwallet.GenMultiSigScript(localKey, remoteKey)
+	multiSigScript, err := input.GenMultiSigScript(localKey, remoteKey)
 	if err != nil {
 		return nil, err
 	}
 
-	return lnwallet.WitnessScriptHash(multiSigScript)
+	return input.WitnessScriptHash(multiSigScript)
 }
 
 // waitForFundingConfirmation handles the final stages of the channel funding

fundingmanager_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lnrpc"
@@ -202,7 +203,7 @@ func (n *testNode) AddNewChannel(channel *channeldb.OpenChannel,
 
 func createTestWallet(cdb *channeldb.DB, netParams *chaincfg.Params,
 	notifier chainntnfs.ChainNotifier, wc lnwallet.WalletController,
-	signer lnwallet.Signer, keyRing keychain.SecretKeyRing,
+	signer input.Signer, keyRing keychain.SecretKeyRing,
 	bio lnwallet.BlockChainIO,
 	estimator lnwallet.FeeEstimator) (*lnwallet.LightningWallet, error) {
 
@@ -340,7 +341,7 @@ func createTestFundingManager(t *testing.T, privKey *btcec.PrivateKey,
 			return lnwire.NewMSatFromSatoshis(chanAmt) - reserve
 		},
 		RequiredRemoteMaxHTLCs: func(chanAmt btcutil.Amount) uint16 {
-			return uint16(lnwallet.MaxHTLCNumber / 2)
+			return uint16(input.MaxHTLCNumber / 2)
 		},
 		WatchNewChannel: func(*channeldb.OpenChannel, *btcec.PublicKey) error {
 			return nil

htlcswitch/link.go

@@ -15,6 +15,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
 	"github.com/lightningnetwork/lnd/htlcswitch/hodl"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -348,7 +349,7 @@ func NewChannelLink(cfg ChannelLinkConfig,
 		shortChanID: channel.ShortChanID(),
 		// TODO(roasbeef): just do reserve here?
 		logCommitTimer: time.NewTimer(300 * time.Millisecond),
-		overflowQueue:  newPacketQueue(lnwallet.MaxHTLCNumber / 2),
+		overflowQueue:  newPacketQueue(input.MaxHTLCNumber / 2),
 		htlcUpdates:    make(chan []channeldb.HTLC),
 		quit:           make(chan struct{}),
 	}

htlcswitch/link_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
 	"github.com/lightningnetwork/lnd/htlcswitch/hodl"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -302,7 +303,7 @@ func TestChannelLinkBidirectionalOneHopPayments(t *testing.T) {
 
 	// Send max available payment number in both sides, thereby testing
 	// the property of channel link to cope with overflowing.
-	count := 2 * lnwallet.MaxHTLCNumber
+	count := 2 * input.MaxHTLCNumber
 	resultChan := make(chan *result, count)
 	for i := 0; i < count/2; i++ {
 		go func(i int) {
@@ -1802,7 +1803,7 @@ func TestChannelLinkBandwidthConsistency(t *testing.T) {
 		t.Fatalf("unable to query fee estimator: %v", err)
 	}
 	htlcFee := lnwire.NewMSatFromSatoshis(
-		feePerKw.FeeForWeight(lnwallet.HtlcWeight),
+		feePerKw.FeeForWeight(input.HtlcWeight),
 	)
 
 	// The starting bandwidth of the channel should be exactly the amount
@@ -2242,7 +2243,7 @@ func TestChannelLinkBandwidthConsistencyOverflow(t *testing.T) {
 	// consistency along the way
 	htlcAmt := lnwire.NewMSatFromSatoshis(100000)
 	totalHtlcAmt := lnwire.MilliSatoshi(0)
-	const numHTLCs = lnwallet.MaxHTLCNumber / 2
+	const numHTLCs = input.MaxHTLCNumber / 2
 	var preImages [][32]byte
 	for i := 0; i < numHTLCs; i++ {
 		preImage := addLinkHTLC(htlcID, htlcAmt)
@@ -2280,7 +2281,7 @@ func TestChannelLinkBandwidthConsistencyOverflow(t *testing.T) {
 
 	// TODO(roasbeef): increase sleep
 	time.Sleep(time.Second * 1)
-	commitWeight := lnwallet.CommitWeight + lnwallet.HtlcWeight*numHTLCs
+	commitWeight := input.CommitWeight + input.HtlcWeight*numHTLCs
 	htlcFee := lnwire.NewMSatFromSatoshis(
 		feePerKw.FeeForWeight(commitWeight),
 	)
@@ -2462,7 +2463,7 @@ func TestChannelLinkTrimCircuitsPending(t *testing.T) {
 
 	defaultCommitFee := alice.channel.StateSnapshot().CommitFee
 	htlcFee := lnwire.NewMSatFromSatoshis(
-		feePerKw.FeeForWeight(lnwallet.HtlcWeight),
+		feePerKw.FeeForWeight(input.HtlcWeight),
 	)
 
 	// The starting bandwidth of the channel should be exactly the amount
@@ -2740,7 +2741,7 @@ func TestChannelLinkTrimCircuitsNoCommit(t *testing.T) {
 
 	defaultCommitFee := alice.channel.StateSnapshot().CommitFee
 	htlcFee := lnwire.NewMSatFromSatoshis(
-		feePerKw.FeeForWeight(lnwallet.HtlcWeight),
+		feePerKw.FeeForWeight(input.HtlcWeight),
 	)
 
 	// The starting bandwidth of the channel should be exactly the amount
@@ -2996,7 +2997,7 @@ func TestChannelLinkBandwidthChanReserve(t *testing.T) {
 		t.Fatalf("unable to query fee estimator: %v", err)
 	}
 	htlcFee := lnwire.NewMSatFromSatoshis(
-		feePerKw.FeeForWeight(lnwallet.HtlcWeight),
+		feePerKw.FeeForWeight(input.HtlcWeight),
 	)
 
 	// The starting bandwidth of the channel should be exactly the amount

htlcswitch/mock.go

@@ -23,6 +23,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -747,7 +748,7 @@ type mockSigner struct {
 	key *btcec.PrivateKey
 }
 
-func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx, signDesc *lnwallet.SignDescriptor) ([]byte, error) {
+func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx, signDesc *input.SignDescriptor) ([]byte, error) {
 	amt := signDesc.Output.Value
 	witnessScript := signDesc.WitnessScript
 	privKey := m.key
@@ -758,10 +759,10 @@ func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx, signDesc *lnwallet.SignDescri
 
 	switch {
 	case signDesc.SingleTweak != nil:
-		privKey = lnwallet.TweakPrivKey(privKey,
+		privKey = input.TweakPrivKey(privKey,
 			signDesc.SingleTweak)
 	case signDesc.DoubleTweak != nil:
-		privKey = lnwallet.DeriveRevocationPrivKey(privKey,
+		privKey = input.DeriveRevocationPrivKey(privKey,
 			signDesc.DoubleTweak)
 	}
 
@@ -774,7 +775,7 @@ func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx, signDesc *lnwallet.SignDescri
 
 	return sig[:len(sig)-1], nil
 }
-func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {
+func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *input.SignDescriptor) (*input.Script, error) {
 
 	// TODO(roasbeef): expose tweaked signer from lnwallet so don't need to
 	// duplicate this code?
@@ -783,10 +784,10 @@ func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *lnwallet.SignD
 
 	switch {
 	case signDesc.SingleTweak != nil:
-		privKey = lnwallet.TweakPrivKey(privKey,
+		privKey = input.TweakPrivKey(privKey,
 			signDesc.SingleTweak)
 	case signDesc.DoubleTweak != nil:
-		privKey = lnwallet.DeriveRevocationPrivKey(privKey,
+		privKey = input.DeriveRevocationPrivKey(privKey,
 			signDesc.DoubleTweak)
 	}
 
@@ -797,7 +798,7 @@ func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *lnwallet.SignD
 		return nil, err
 	}
 
-	return &lnwallet.InputScript{
+	return &input.Script{
 		Witness: witnessScript,
 	}, nil
 }

htlcswitch/test_utils.go

@@ -24,6 +24,7 @@ import (
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lnwallet"
@@ -168,7 +169,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 			channelCapacity),
 		ChanReserve:      aliceReserve,
 		MinHTLC:          0,
-		MaxAcceptedHtlcs: lnwallet.MaxHTLCNumber / 2,
+		MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 		CsvDelay:         uint16(csvTimeoutAlice),
 	}
 
@@ -178,7 +179,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 			channelCapacity),
 		ChanReserve:      bobReserve,
 		MinHTLC:          0,
-		MaxAcceptedHtlcs: lnwallet.MaxHTLCNumber / 2,
+		MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 		CsvDelay:         uint16(csvTimeoutBob),
 	}
 
@@ -241,7 +242,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 	if err != nil {
 		return nil, nil, nil, nil, err
 	}
-	bobCommitPoint := lnwallet.ComputeCommitmentPoint(bobFirstRevoke[:])
+	bobCommitPoint := input.ComputeCommitmentPoint(bobFirstRevoke[:])
 
 	aliceRoot, err := chainhash.NewHash(aliceKeyPriv.Serialize())
 	if err != nil {
@@ -252,7 +253,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 	if err != nil {
 		return nil, nil, nil, nil, err
 	}
-	aliceCommitPoint := lnwallet.ComputeCommitmentPoint(aliceFirstRevoke[:])
+	aliceCommitPoint := input.ComputeCommitmentPoint(aliceFirstRevoke[:])
 
 	aliceCommitTx, bobCommitTx, err := lnwallet.CreateCommitmentTxns(aliceAmount,
 		bobAmount, &aliceCfg, &bobCfg, aliceCommitPoint, bobCommitPoint,

input/input.go

@@ -1,9 +1,8 @@
-package sweep
+package input
 
 import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
 // Input represents an abstract UTXO which is to be spent using a sweeping
@@ -17,21 +16,21 @@ type Input interface {
 
 	// WitnessType returns an enum specifying the type of witness that must
 	// be generated in order to spend this output.
-	WitnessType() lnwallet.WitnessType
+	WitnessType() WitnessType
 
 	// SignDesc returns a reference to a spendable output's sign
 	// descriptor, which is used during signing to compute a valid witness
 	// that spends this output.
-	SignDesc() *lnwallet.SignDescriptor
+	SignDesc() *SignDescriptor
 
 	// CraftInputScript returns a valid set of input scripts allowing this
 	// output to be spent. The returns input scripts should target the
 	// input at location txIndex within the passed transaction. The input
 	// scripts generated by this method support spending p2wkh, p2wsh, and
 	// also nested p2sh outputs.
-	CraftInputScript(signer lnwallet.Signer, txn *wire.MsgTx,
+	CraftInputScript(signer Signer, txn *wire.MsgTx,
 		hashCache *txscript.TxSigHashes,
-		txinIdx int) (*lnwallet.InputScript, error)
+		txinIdx int) (*Script, error)
 
 	// BlocksToMaturity returns the relative timelock, as a number of
 	// blocks, that must be built on top of the confirmation height before
@@ -46,8 +45,8 @@ type Input interface {
 
 type inputKit struct {
 	outpoint    wire.OutPoint
-	witnessType lnwallet.WitnessType
+	witnessType WitnessType
-	signDesc    lnwallet.SignDescriptor
+	signDesc    SignDescriptor
 	heightHint  uint32
 }
 
@@ -59,13 +58,13 @@ func (i *inputKit) OutPoint() *wire.OutPoint {
 
 // WitnessType returns the type of witness that must be generated to spend the
 // breached output.
-func (i *inputKit) WitnessType() lnwallet.WitnessType {
+func (i *inputKit) WitnessType() WitnessType {
 	return i.witnessType
 }
 
 // SignDesc returns the breached output's SignDescriptor, which is used during
 // signing to compute the witness.
-func (i *inputKit) SignDesc() *lnwallet.SignDescriptor {
+func (i *inputKit) SignDesc() *SignDescriptor {
 	return &i.signDesc
 }
 
@@ -83,8 +82,8 @@ type BaseInput struct {
 
 // MakeBaseInput assembles a new BaseInput that can be used to construct a
 // sweep transaction.
-func MakeBaseInput(outpoint *wire.OutPoint, witnessType lnwallet.WitnessType,
+func MakeBaseInput(outpoint *wire.OutPoint, witnessType WitnessType,
-	signDescriptor *lnwallet.SignDescriptor, heightHint uint32) BaseInput {
+	signDescriptor *SignDescriptor, heightHint uint32) BaseInput {
 
 	return BaseInput{
 		inputKit{
@@ -100,8 +99,8 @@ func MakeBaseInput(outpoint *wire.OutPoint, witnessType lnwallet.WitnessType,
 // to be spent. The returns input scripts should target the input at location
 // txIndex within the passed transaction. The input scripts generated by this
 // method support spending p2wkh, p2wsh, and also nested p2sh outputs.
-func (bi *BaseInput) CraftInputScript(signer lnwallet.Signer, txn *wire.MsgTx,
+func (bi *BaseInput) CraftInputScript(signer Signer, txn *wire.MsgTx,
-	hashCache *txscript.TxSigHashes, txinIdx int) (*lnwallet.InputScript, error) {
+	hashCache *txscript.TxSigHashes, txinIdx int) (*Script, error) {
 
 	witnessFunc := bi.witnessType.GenWitnessFunc(
 		signer, bi.SignDesc(),
@@ -129,13 +128,13 @@ type HtlcSucceedInput struct {
 // MakeHtlcSucceedInput assembles a new redeem input that can be used to
 // construct a sweep transaction.
 func MakeHtlcSucceedInput(outpoint *wire.OutPoint,
-	signDescriptor *lnwallet.SignDescriptor,
+	signDescriptor *SignDescriptor,
 	preimage []byte, heightHint uint32) HtlcSucceedInput {
 
 	return HtlcSucceedInput{
 		inputKit: inputKit{
 			outpoint:    *outpoint,
-			witnessType: lnwallet.HtlcAcceptedRemoteSuccess,
+			witnessType: HtlcAcceptedRemoteSuccess,
 			signDesc:    *signDescriptor,
 			heightHint:  heightHint,
 		},
@@ -147,21 +146,21 @@ func MakeHtlcSucceedInput(outpoint *wire.OutPoint,
 // to be spent. The returns input scripts should target the input at location
 // txIndex within the passed transaction. The input scripts generated by this
 // method support spending p2wkh, p2wsh, and also nested p2sh outputs.
-func (h *HtlcSucceedInput) CraftInputScript(signer lnwallet.Signer, txn *wire.MsgTx,
+func (h *HtlcSucceedInput) CraftInputScript(signer Signer, txn *wire.MsgTx,
-	hashCache *txscript.TxSigHashes, txinIdx int) (*lnwallet.InputScript, error) {
+	hashCache *txscript.TxSigHashes, txinIdx int) (*Script, error) {
 
 	desc := h.signDesc
 	desc.SigHashes = hashCache
 	desc.InputIndex = txinIdx
 
-	witness, err := lnwallet.SenderHtlcSpendRedeem(
+	witness, err := SenderHtlcSpendRedeem(
 		signer, &desc, txn, h.preimage,
 	)
 	if err != nil {
 		return nil, err
 	}
 
-	return &lnwallet.InputScript{
+	return &Script{
 		Witness: witness,
 	}, nil
 }

input/script_utils.go

@@ -1,9 +1,8 @@
-package lnwallet
+package input
 
 import (
 	"bytes"
 	"crypto/sha256"
-	"encoding/binary"
 	"fmt"
 	"math/big"
 
@@ -22,28 +21,6 @@ var (
 	// SequenceLockTimeSeconds is the 22nd bit which indicates the lock
 	// time is in seconds.
 	SequenceLockTimeSeconds = uint32(1 << 22)
-
-	// TimelockShift is used to make sure the commitment transaction is
-	// spendable by setting the locktime with it so that it is larger than
-	// 500,000,000, thus interpreting it as Unix epoch timestamp and not
-	// a block height. It is also smaller than the current timestamp which
-	// has bit (1 << 30) set, so there is no risk of having the commitment
-	// transaction be rejected. This way we can safely use the lower 24 bits
-	// of the locktime field for part of the obscured commitment transaction
-	// number.
-	TimelockShift = uint32(1 << 29)
-)
-
-const (
-	// StateHintSize is the total number of bytes used between the sequence
-	// number and locktime of the commitment transaction use to encode a hint
-	// to the state number of a particular commitment transaction.
-	StateHintSize = 6
-
-	// maxStateHint is the maximum state number we're able to encode using
-	// StateHintSize bytes amongst the sequence number and locktime fields
-	// of the commitment transaction.
-	maxStateHint uint64 = (1 << 48) - 1
 )
 
 // WitnessScriptHash generates a pay-to-witness-script-hash public key script
@@ -162,7 +139,7 @@ func Ripemd160H(d []byte) []byte {
 	return h.Sum(nil)
 }
 
-// senderHTLCScript constructs the public key script for an outgoing HTLC
+// SenderHTLCScript constructs the public key script for an outgoing HTLC
 // output payment for the sender's version of the commitment transaction. The
 // possible script paths from this output include:
 //
@@ -192,7 +169,7 @@ func Ripemd160H(d []byte) []byte {
 //         OP_CHECKSIG
 //     OP_ENDIF
 // OP_ENDIF
-func senderHTLCScript(senderHtlcKey, receiverHtlcKey,
+func SenderHTLCScript(senderHtlcKey, receiverHtlcKey,
 	revocationKey *btcec.PublicKey, paymentHash []byte) ([]byte, error) {
 
 	builder := txscript.NewScriptBuilder()
@@ -272,14 +249,14 @@ func senderHTLCScript(senderHtlcKey, receiverHtlcKey,
 	return builder.Script()
 }
 
-// senderHtlcSpendRevoke constructs a valid witness allowing the receiver of an
+// SenderHtlcSpendRevokeWithKey constructs a valid witness allowing the receiver of an
 // HTLC to claim the output with knowledge of the revocation private key in the
 // scenario that the sender of the HTLC broadcasts a previously revoked
 // commitment transaction. A valid spend requires knowledge of the private key
 // that corresponds to their revocation base point and also the private key fro
 // the per commitment point, and a valid signature under the combined public
 // key.
-func senderHtlcSpendRevoke(signer Signer, signDesc *SignDescriptor,
+func SenderHtlcSpendRevokeWithKey(signer Signer, signDesc *SignDescriptor,
 	revokeKey *btcec.PublicKey, sweepTx *wire.MsgTx) (wire.TxWitness, error) {
 
 	sweepSig, err := signer.SignOutputRaw(sweepTx, signDesc)
@@ -322,7 +299,7 @@ func SenderHtlcSpendRevoke(signer Signer, signDesc *SignDescriptor,
 		signDesc.DoubleTweak.PubKey(),
 	)
 
-	return senderHtlcSpendRevoke(signer, signDesc, revokeKey, sweepTx)
+	return SenderHtlcSpendRevokeWithKey(signer, signDesc, revokeKey, sweepTx)
 }
 
 // SenderHtlcSpendRedeem constructs a valid witness allowing the receiver of an
@@ -349,11 +326,11 @@ func SenderHtlcSpendRedeem(signer Signer, signDesc *SignDescriptor,
 	return witnessStack, nil
 }
 
-// senderHtlcSpendTimeout constructs a valid witness allowing the sender of an
+// SenderHtlcSpendTimeout constructs a valid witness allowing the sender of an
 // HTLC to activate the time locked covenant clause of a soon to be expired
 // HTLC.  This script simply spends the multi-sig output using the
 // pre-generated HTLC timeout transaction.
-func senderHtlcSpendTimeout(receiverSig []byte, signer Signer,
+func SenderHtlcSpendTimeout(receiverSig []byte, signer Signer,
 	signDesc *SignDescriptor, htlcTimeoutTx *wire.MsgTx) (wire.TxWitness, error) {
 
 	sweepSig, err := signer.SignOutputRaw(htlcTimeoutTx, signDesc)
@@ -375,7 +352,7 @@ func senderHtlcSpendTimeout(receiverSig []byte, signer Signer,
 	return witnessStack, nil
 }
 
-// receiverHTLCScript constructs the public key script for an incoming HTLC
+// ReceiverHTLCScript constructs the public key script for an incoming HTLC
 // output payment for the receiver's version of the commitment transaction. The
 // possible execution paths from this script include:
 //   * The receiver of the HTLC uses its second level HTLC transaction to
@@ -405,7 +382,7 @@ func senderHtlcSpendTimeout(receiverSig []byte, signer Signer,
 //         OP_CHECKSIG
 //     OP_ENDIF
 // OP_ENDIF
-func receiverHTLCScript(cltvExpiry uint32, senderHtlcKey,
+func ReceiverHTLCScript(cltvExpiry uint32, senderHtlcKey,
 	receiverHtlcKey, revocationKey *btcec.PublicKey,
 	paymentHash []byte) ([]byte, error) {
 
@@ -496,7 +473,7 @@ func receiverHTLCScript(cltvExpiry uint32, senderHtlcKey,
 	return builder.Script()
 }
 
-// receiverHtlcSpendRedeem constructs a valid witness allowing the receiver of
+// ReceiverHtlcSpendRedeem constructs a valid witness allowing the receiver of
 // an HTLC to redeem the conditional payment in the event that their commitment
 // transaction is broadcast. This clause transitions the state of the HLTC
 // output into the delay+claim state by activating the off-chain covenant bound
@@ -504,7 +481,7 @@ func receiverHTLCScript(cltvExpiry uint32, senderHtlcKey,
 // signed has a relative timelock delay enforced by its sequence number. This
 // delay give the sender of the HTLC enough time to revoke the output if this
 // is a breach commitment transaction.
-func receiverHtlcSpendRedeem(senderSig, paymentPreimage []byte,
+func ReceiverHtlcSpendRedeem(senderSig, paymentPreimage []byte,
 	signer Signer, signDesc *SignDescriptor,
 	htlcSuccessTx *wire.MsgTx) (wire.TxWitness, error) {
 
@@ -530,11 +507,11 @@ func receiverHtlcSpendRedeem(senderSig, paymentPreimage []byte,
 	return witnessStack, nil
 }
 
-// receiverHtlcSpendRevoke constructs a valid witness allowing the sender of an
+// ReceiverHtlcSpendRevokeWithKey constructs a valid witness allowing the sender of an
 // HTLC within a previously revoked commitment transaction to re-claim the
 // pending funds in the case that the receiver broadcasts this revoked
 // commitment transaction.
-func receiverHtlcSpendRevoke(signer Signer, signDesc *SignDescriptor,
+func ReceiverHtlcSpendRevokeWithKey(signer Signer, signDesc *SignDescriptor,
 	revokeKey *btcec.PublicKey, sweepTx *wire.MsgTx) (wire.TxWitness, error) {
 
 	// First, we'll generate a signature for the sweep transaction.  The
@@ -579,10 +556,10 @@ func ReceiverHtlcSpendRevoke(signer Signer, signDesc *SignDescriptor,
 		signDesc.DoubleTweak.PubKey(),
 	)
 
-	return receiverHtlcSpendRevoke(signer, signDesc, revokeKey, sweepTx)
+	return ReceiverHtlcSpendRevokeWithKey(signer, signDesc, revokeKey, sweepTx)
 }
 
-// receiverHtlcSpendTimeout constructs a valid witness allowing the sender of
+// ReceiverHtlcSpendTimeout constructs a valid witness allowing the sender of
 // an HTLC to recover the pending funds after an absolute timeout in the
 // scenario that the receiver of the HTLC broadcasts their version of the
 // commitment transaction. If the caller has already set the lock time on the
@@ -591,7 +568,7 @@ func ReceiverHtlcSpendRevoke(signer Signer, signDesc *SignDescriptor,
 //
 // NOTE: The target input of the passed transaction MUST NOT have a final
 // sequence number. Otherwise, the OP_CHECKLOCKTIMEVERIFY check will fail.
-func receiverHtlcSpendTimeout(signer Signer, signDesc *SignDescriptor,
+func ReceiverHtlcSpendTimeout(signer Signer, signDesc *SignDescriptor,
 	sweepTx *wire.MsgTx, cltvExpiry int32) (wire.TxWitness, error) {
 
 	// If the caller set a proper timeout value, then we'll apply it
@@ -622,109 +599,7 @@ func receiverHtlcSpendTimeout(signer Signer, signDesc *SignDescriptor,
 	return witnessStack, nil
 }
 
-// createHtlcTimeoutTx creates a transaction that spends the HTLC output on the
+// SecondLevelHtlcScript is the uniform script that's used as the output for
-// commitment transaction of the peer that created an HTLC (the sender). This
-// transaction essentially acts as an off-chain covenant as it spends a 2-of-2
-// multi-sig output. This output requires a signature from both the sender and
-// receiver of the HTLC. By using a distinct transaction, we're able to
-// uncouple the timeout and delay clauses of the HTLC contract. This
-// transaction is locked with an absolute lock-time so the sender can only
-// attempt to claim the output using it after the lock time has passed.
-//
-// In order to spend the HTLC output, the witness for the passed transaction
-// should be:
-// * <0> <sender sig> <receiver sig> <0>
-//
-// NOTE: The passed amount for the HTLC should take into account the required
-// fee rate at the time the HTLC was created. The fee should be able to
-// entirely pay for this (tiny: 1-in 1-out) transaction.
-func createHtlcTimeoutTx(htlcOutput wire.OutPoint, htlcAmt btcutil.Amount,
-	cltvExpiry, csvDelay uint32,
-	revocationKey, delayKey *btcec.PublicKey) (*wire.MsgTx, error) {
-
-	// Create a version two transaction (as the success version of this
-	// spends an output with a CSV timeout), and set the lock-time to the
-	// specified absolute lock-time in blocks.
-	timeoutTx := wire.NewMsgTx(2)
-	timeoutTx.LockTime = cltvExpiry
-
-	// The input to the transaction is the outpoint that creates the
-	// original HTLC on the sender's commitment transaction.
-	timeoutTx.AddTxIn(&wire.TxIn{
-		PreviousOutPoint: htlcOutput,
-	})
-
-	// Next, we'll generate the script used as the output for all second
-	// level HTLC which forces a covenant w.r.t what can be done with all
-	// HTLC outputs.
-	witnessScript, err := secondLevelHtlcScript(revocationKey, delayKey,
-		csvDelay)
-	if err != nil {
-		return nil, err
-	}
-	pkScript, err := WitnessScriptHash(witnessScript)
-	if err != nil {
-		return nil, err
-	}
-
-	// Finally, the output is simply the amount of the HTLC (minus the
-	// required fees), paying to the regular second level HTLC script.
-	timeoutTx.AddTxOut(&wire.TxOut{
-		Value:    int64(htlcAmt),
-		PkScript: pkScript,
-	})
-
-	return timeoutTx, nil
-}
-
-// createHtlcSuccessTx creates a transaction that spends the output on the
-// commitment transaction of the peer that receives an HTLC. This transaction
-// essentially acts as an off-chain covenant as it's only permitted to spend
-// the designated HTLC output, and also that spend can _only_ be used as a
-// state transition to create another output which actually allows redemption
-// or revocation of an HTLC.
-//
-// In order to spend the HTLC output, the witness for the passed transaction
-// should be:
-//   * <0> <sender sig> <recvr sig> <preimage>
-func createHtlcSuccessTx(htlcOutput wire.OutPoint, htlcAmt btcutil.Amount,
-	csvDelay uint32,
-	revocationKey, delayKey *btcec.PublicKey) (*wire.MsgTx, error) {
-
-	// Create a version two transaction (as the success version of this
-	// spends an output with a CSV timeout).
-	successTx := wire.NewMsgTx(2)
-
-	// The input to the transaction is the outpoint that creates the
-	// original HTLC on the sender's commitment transaction.
-	successTx.AddTxIn(&wire.TxIn{
-		PreviousOutPoint: htlcOutput,
-	})
-
-	// Next, we'll generate the script used as the output for all second
-	// level HTLC which forces a covenant w.r.t what can be done with all
-	// HTLC outputs.
-	witnessScript, err := secondLevelHtlcScript(revocationKey, delayKey,
-		csvDelay)
-	if err != nil {
-		return nil, err
-	}
-	pkScript, err := WitnessScriptHash(witnessScript)
-	if err != nil {
-		return nil, err
-	}
-
-	// Finally, the output is simply the amount of the HTLC (minus the
-	// required fees), paying to the timeout script.
-	successTx.AddTxOut(&wire.TxOut{
-		Value:    int64(htlcAmt),
-		PkScript: pkScript,
-	})
-
-	return successTx, nil
-}
-
-// secondLevelHtlcScript is the uniform script that's used as the output for
 // the second-level HTLC transactions. The second level transaction act as a
 // sort of covenant, ensuring that a 2-of-2 multi-sig output can only be
 // spent in a particular way, and to a particular output.
@@ -750,7 +625,7 @@ func createHtlcSuccessTx(htlcOutput wire.OutPoint, htlcAmt btcutil.Amount,
 // TODO(roasbeef): possible renames for second-level
 //  * transition?
 //  * covenant output
-func secondLevelHtlcScript(revocationKey, delayKey *btcec.PublicKey,
+func SecondLevelHtlcScript(revocationKey, delayKey *btcec.PublicKey,
 	csvDelay uint32) ([]byte, error) {
 
 	builder := txscript.NewScriptBuilder()
@@ -790,16 +665,16 @@ func secondLevelHtlcScript(revocationKey, delayKey *btcec.PublicKey,
 	return builder.Script()
 }
 
-// htlcSpendSuccess spends a second-level HTLC output. This function is to be
+// HtlcSpendSuccess spends a second-level HTLC output. This function is to be
 // used by the sender of an HTLC to claim the output after a relative timeout
 // or the receiver of the HTLC to claim on-chain with the pre-image.
-func htlcSpendSuccess(signer Signer, signDesc *SignDescriptor,
+func HtlcSpendSuccess(signer Signer, signDesc *SignDescriptor,
 	sweepTx *wire.MsgTx, csvDelay uint32) (wire.TxWitness, error) {
 
 	// We're required to wait a relative period of time before we can sweep
 	// the output in order to allow the other party to contest our claim of
 	// validity to this version of the commitment transaction.
-	sweepTx.TxIn[0].Sequence = lockTimeToSequence(false, csvDelay)
+	sweepTx.TxIn[0].Sequence = LockTimeToSequence(false, csvDelay)
 
 	// Finally, OP_CSV requires that the version of the transaction
 	// spending a pkscript with OP_CSV within it *must* be >= 2.
@@ -829,10 +704,10 @@ func htlcSpendSuccess(signer Signer, signDesc *SignDescriptor,
 	return witnessStack, nil
 }
 
-// htlcSpendRevoke spends a second-level HTLC output. This function is to be
+// HtlcSpendRevoke spends a second-level HTLC output. This function is to be
 // used by the sender or receiver of an HTLC to claim the HTLC after a revoked
 // commitment transaction was broadcast.
-func htlcSpendRevoke(signer Signer, signDesc *SignDescriptor,
+func HtlcSpendRevoke(signer Signer, signDesc *SignDescriptor,
 	revokeTx *wire.MsgTx) (wire.TxWitness, error) {
 
 	// We don't need any spacial modifications to the transaction as this
@@ -885,11 +760,11 @@ func HtlcSecondLevelSpend(signer Signer, signDesc *SignDescriptor,
 	return witnessStack, nil
 }
 
-// lockTimeToSequence converts the passed relative locktime to a sequence
+// LockTimeToSequence converts the passed relative locktime to a sequence
 // number in accordance to BIP-68.
 // See: https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki
 //  * (Compatibility)
-func lockTimeToSequence(isSeconds bool, locktime uint32) uint32 {
+func LockTimeToSequence(isSeconds bool, locktime uint32) uint32 {
 	if !isSeconds {
 		// The locktime is to be expressed in confirmations.
 		return locktime
@@ -1235,71 +1110,6 @@ func DeriveRevocationPrivKey(revokeBasePriv *btcec.PrivateKey,
 	return priv
 }
 
-// SetStateNumHint encodes the current state number within the passed
-// commitment transaction by re-purposing the locktime and sequence fields in
-// the commitment transaction to encode the obfuscated state number.  The state
-// number is encoded using 48 bits. The lower 24 bits of the lock time are the
-// lower 24 bits of the obfuscated state number and the lower 24 bits of the
-// sequence field are the higher 24 bits. Finally before encoding, the
-// obfuscator is XOR'd against the state number in order to hide the exact
-// state number from the PoV of outside parties.
-func SetStateNumHint(commitTx *wire.MsgTx, stateNum uint64,
-	obfuscator [StateHintSize]byte) error {
-
-	// With the current schema we are only able to encode state num
-	// hints up to 2^48. Therefore if the passed height is greater than our
-	// state hint ceiling, then exit early.
-	if stateNum > maxStateHint {
-		return fmt.Errorf("unable to encode state, %v is greater "+
-			"state num that max of %v", stateNum, maxStateHint)
-	}
-
-	if len(commitTx.TxIn) != 1 {
-		return fmt.Errorf("commitment tx must have exactly 1 input, "+
-			"instead has %v", len(commitTx.TxIn))
-	}
-
-	// Convert the obfuscator into a uint64, then XOR that against the
-	// targeted height in order to obfuscate the state number of the
-	// commitment transaction in the case that either commitment
-	// transaction is broadcast directly on chain.
-	var obfs [8]byte
-	copy(obfs[2:], obfuscator[:])
-	xorInt := binary.BigEndian.Uint64(obfs[:])
-
-	stateNum = stateNum ^ xorInt
-
-	// Set the height bit of the sequence number in order to disable any
-	// sequence locks semantics.
-	commitTx.TxIn[0].Sequence = uint32(stateNum>>24) | wire.SequenceLockTimeDisabled
-	commitTx.LockTime = uint32(stateNum&0xFFFFFF) | TimelockShift
-
-	return nil
-}
-
-// GetStateNumHint recovers the current state number given a commitment
-// transaction which has previously had the state number encoded within it via
-// setStateNumHint and a shared obfuscator.
-//
-// See setStateNumHint for further details w.r.t exactly how the state-hints
-// are encoded.
-func GetStateNumHint(commitTx *wire.MsgTx, obfuscator [StateHintSize]byte) uint64 {
-	// Convert the obfuscator into a uint64, this will be used to
-	// de-obfuscate the final recovered state number.
-	var obfs [8]byte
-	copy(obfs[2:], obfuscator[:])
-	xorInt := binary.BigEndian.Uint64(obfs[:])
-
-	// Retrieve the state hint from the sequence number and locktime
-	// of the transaction.
-	stateNumXor := uint64(commitTx.TxIn[0].Sequence&0xFFFFFF) << 24
-	stateNumXor |= uint64(commitTx.LockTime & 0xFFFFFF)
-
-	// Finally, to obtain the final state number, we XOR by the obfuscator
-	// value to de-obfuscate the state number.
-	return stateNumXor ^ xorInt
-}
-
 // ComputeCommitmentPoint generates a commitment point given a commitment
 // secret. The commitment point for each state is used to randomize each key in
 // the key-ring and also to used as a tweak to derive new public+private keys

input/script_utils_test.go

@@ -1,4 +1,4 @@
-package lnwallet
+package input
 
 import (
 	"bytes"
@@ -6,7 +6,6 @@ import (
 	"encoding/hex"
 	"fmt"
 	"testing"
-	"time"
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
@@ -16,211 +15,6 @@ import (
 	"github.com/lightningnetwork/lnd/keychain"
 )
 
-// TestCommitmentSpendValidation test the spendability of both outputs within
-// the commitment transaction.
-//
-// The following spending cases are covered by this test:
-//   * Alice's spend from the delayed output on her commitment transaction.
-//   * Bob's spend from Alice's delayed output when she broadcasts a revoked
-//     commitment transaction.
-//   * Bob's spend from his unencumbered output within Alice's commitment
-//     transaction.
-func TestCommitmentSpendValidation(t *testing.T) {
-	t.Parallel()
-
-	// We generate a fake output, and the corresponding txin. This output
-	// doesn't need to exist, as we'll only be validating spending from the
-	// transaction that references this.
-	txid, err := chainhash.NewHash(testHdSeed.CloneBytes())
-	if err != nil {
-		t.Fatalf("unable to create txid: %v", err)
-	}
-	fundingOut := &wire.OutPoint{
-		Hash:  *txid,
-		Index: 50,
-	}
-	fakeFundingTxIn := wire.NewTxIn(fundingOut, nil, nil)
-
-	const channelBalance = btcutil.Amount(1 * 10e8)
-	const csvTimeout = uint32(5)
-
-	// We also set up set some resources for the commitment transaction.
-	// Each side currently has 1 BTC within the channel, with a total
-	// channel capacity of 2BTC.
-	aliceKeyPriv, aliceKeyPub := btcec.PrivKeyFromBytes(btcec.S256(),
-		testWalletPrivKey)
-	bobKeyPriv, bobKeyPub := btcec.PrivKeyFromBytes(btcec.S256(),
-		bobsPrivKey)
-
-	revocationPreimage := testHdSeed.CloneBytes()
-	commitSecret, commitPoint := btcec.PrivKeyFromBytes(btcec.S256(),
-		revocationPreimage)
-	revokePubKey := DeriveRevocationPubkey(bobKeyPub, commitPoint)
-
-	aliceDelayKey := TweakPubKey(aliceKeyPub, commitPoint)
-	bobPayKey := TweakPubKey(bobKeyPub, commitPoint)
-
-	aliceCommitTweak := SingleTweakBytes(commitPoint, aliceKeyPub)
-	bobCommitTweak := SingleTweakBytes(commitPoint, bobKeyPub)
-
-	aliceSelfOutputSigner := &mockSigner{
-		privkeys: []*btcec.PrivateKey{aliceKeyPriv},
-	}
-
-	// With all the test data set up, we create the commitment transaction.
-	// We only focus on a single party's transactions, as the scripts are
-	// identical with the roles reversed.
-	//
-	// This is Alice's commitment transaction, so she must wait a CSV delay
-	// of 5 blocks before sweeping the output, while bob can spend
-	// immediately with either the revocation key, or his regular key.
-	keyRing := &CommitmentKeyRing{
-		DelayKey:      aliceDelayKey,
-		RevocationKey: revokePubKey,
-		NoDelayKey:    bobPayKey,
-	}
-	commitmentTx, err := CreateCommitTx(*fakeFundingTxIn, keyRing, csvTimeout,
-		channelBalance, channelBalance, DefaultDustLimit())
-	if err != nil {
-		t.Fatalf("unable to create commitment transaction: %v", nil)
-	}
-
-	delayOutput := commitmentTx.TxOut[0]
-	regularOutput := commitmentTx.TxOut[1]
-
-	// We're testing an uncooperative close, output sweep, so construct a
-	// transaction which sweeps the funds to a random address.
-	targetOutput, err := CommitScriptUnencumbered(aliceKeyPub)
-	if err != nil {
-		t.Fatalf("unable to create target output: %v", err)
-	}
-	sweepTx := wire.NewMsgTx(2)
-	sweepTx.AddTxIn(wire.NewTxIn(&wire.OutPoint{
-		Hash:  commitmentTx.TxHash(),
-		Index: 0,
-	}, nil, nil))
-	sweepTx.AddTxOut(&wire.TxOut{
-		PkScript: targetOutput,
-		Value:    0.5 * 10e8,
-	})
-
-	// First, we'll test spending with Alice's key after the timeout.
-	delayScript, err := CommitScriptToSelf(csvTimeout, aliceDelayKey,
-		revokePubKey)
-	if err != nil {
-		t.Fatalf("unable to generate alice delay script: %v", err)
-	}
-	sweepTx.TxIn[0].Sequence = lockTimeToSequence(false, csvTimeout)
-	signDesc := &SignDescriptor{
-		WitnessScript: delayScript,
-		KeyDesc: keychain.KeyDescriptor{
-			PubKey: aliceKeyPub,
-		},
-		SingleTweak: aliceCommitTweak,
-		SigHashes:   txscript.NewTxSigHashes(sweepTx),
-		Output: &wire.TxOut{
-			Value: int64(channelBalance),
-		},
-		HashType:   txscript.SigHashAll,
-		InputIndex: 0,
-	}
-	aliceWitnessSpend, err := CommitSpendTimeout(aliceSelfOutputSigner,
-		signDesc, sweepTx)
-	if err != nil {
-		t.Fatalf("unable to generate delay commit spend witness: %v", err)
-	}
-	sweepTx.TxIn[0].Witness = aliceWitnessSpend
-	vm, err := txscript.NewEngine(delayOutput.PkScript,
-		sweepTx, 0, txscript.StandardVerifyFlags, nil,
-		nil, int64(channelBalance))
-	if err != nil {
-		t.Fatalf("unable to create engine: %v", err)
-	}
-	if err := vm.Execute(); err != nil {
-		t.Fatalf("spend from delay output is invalid: %v", err)
-	}
-
-	bobSigner := &mockSigner{privkeys: []*btcec.PrivateKey{bobKeyPriv}}
-
-	// Next, we'll test bob spending with the derived revocation key to
-	// simulate the scenario when Alice broadcasts this commitment
-	// transaction after it's been revoked.
-	signDesc = &SignDescriptor{
-		KeyDesc: keychain.KeyDescriptor{
-			PubKey: bobKeyPub,
-		},
-		DoubleTweak:   commitSecret,
-		WitnessScript: delayScript,
-		SigHashes:     txscript.NewTxSigHashes(sweepTx),
-		Output: &wire.TxOut{
-			Value: int64(channelBalance),
-		},
-		HashType:   txscript.SigHashAll,
-		InputIndex: 0,
-	}
-	bobWitnessSpend, err := CommitSpendRevoke(bobSigner, signDesc,
-		sweepTx)
-	if err != nil {
-		t.Fatalf("unable to generate revocation witness: %v", err)
-	}
-	sweepTx.TxIn[0].Witness = bobWitnessSpend
-	vm, err = txscript.NewEngine(delayOutput.PkScript,
-		sweepTx, 0, txscript.StandardVerifyFlags, nil,
-		nil, int64(channelBalance))
-	if err != nil {
-		t.Fatalf("unable to create engine: %v", err)
-	}
-	if err := vm.Execute(); err != nil {
-		t.Fatalf("revocation spend is invalid: %v", err)
-	}
-
-	// In order to test the final scenario, we modify the TxIn of the sweep
-	// transaction to instead point to the regular output (non delay)
-	// within the commitment transaction.
-	sweepTx.TxIn[0] = &wire.TxIn{
-		PreviousOutPoint: wire.OutPoint{
-			Hash:  commitmentTx.TxHash(),
-			Index: 1,
-		},
-	}
-
-	// Finally, we test bob sweeping his output as normal in the case that
-	// Alice broadcasts this commitment transaction.
-	bobScriptP2WKH, err := CommitScriptUnencumbered(bobPayKey)
-	if err != nil {
-		t.Fatalf("unable to create bob p2wkh script: %v", err)
-	}
-	signDesc = &SignDescriptor{
-		KeyDesc: keychain.KeyDescriptor{
-			PubKey: bobKeyPub,
-		},
-		SingleTweak:   bobCommitTweak,
-		WitnessScript: bobScriptP2WKH,
-		SigHashes:     txscript.NewTxSigHashes(sweepTx),
-		Output: &wire.TxOut{
-			Value:    int64(channelBalance),
-			PkScript: bobScriptP2WKH,
-		},
-		HashType:   txscript.SigHashAll,
-		InputIndex: 0,
-	}
-	bobRegularSpend, err := CommitSpendNoDelay(bobSigner, signDesc,
-		sweepTx)
-	if err != nil {
-		t.Fatalf("unable to create bob regular spend: %v", err)
-	}
-	sweepTx.TxIn[0].Witness = bobRegularSpend
-	vm, err = txscript.NewEngine(regularOutput.PkScript,
-		sweepTx, 0, txscript.StandardVerifyFlags, nil,
-		nil, int64(channelBalance))
-	if err != nil {
-		t.Fatalf("unable to create engine: %v", err)
-	}
-	if err := vm.Execute(); err != nil {
-		t.Fatalf("bob p2wkh spend is invalid: %v", err)
-	}
-}
-
 // TestRevocationKeyDerivation tests that given a public key, and a revocation
 // hash, the homomorphic revocation public and private key derivation work
 // properly.
@@ -352,7 +146,7 @@ func TestHTLCSenderSpendValidation(t *testing.T) {
 	revocationKey := DeriveRevocationPubkey(bobKeyPub, commitPoint)
 
 	// Generate the raw HTLC redemption scripts, and its p2wsh counterpart.
-	htlcWitnessScript, err := senderHTLCScript(aliceLocalKey, bobLocalKey,
+	htlcWitnessScript, err := SenderHTLCScript(aliceLocalKey, bobLocalKey,
 		revocationKey, paymentHash[:])
 	if err != nil {
 		t.Fatalf("unable to create htlc sender script: %v", err)
@@ -394,8 +188,8 @@ func TestHTLCSenderSpendValidation(t *testing.T) {
 	// Finally, we'll create mock signers for both of them based on their
 	// private keys. This test simplifies a bit and uses the same key as
 	// the base point for all scripts and derivations.
-	bobSigner := &mockSigner{privkeys: []*btcec.PrivateKey{bobKeyPriv}}
+	bobSigner := &MockSigner{Privkeys: []*btcec.PrivateKey{bobKeyPriv}}
-	aliceSigner := &mockSigner{privkeys: []*btcec.PrivateKey{aliceKeyPriv}}
+	aliceSigner := &MockSigner{Privkeys: []*btcec.PrivateKey{aliceKeyPriv}}
 
 	// We'll also generate a signature on the sweep transaction above
 	// that will act as Bob's signature to Alice for the second level HTLC
@@ -436,7 +230,7 @@ func TestHTLCSenderSpendValidation(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return senderHtlcSpendRevoke(bobSigner, signDesc,
+				return SenderHtlcSpendRevokeWithKey(bobSigner, signDesc,
 					revocationKey, sweepTx)
 			}),
 			true,
@@ -501,7 +295,7 @@ func TestHTLCSenderSpendValidation(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return senderHtlcSpendTimeout(bobRecvrSig, aliceSigner,
+				return SenderHtlcSpendTimeout(bobRecvrSig, aliceSigner,
 					signDesc, sweepTx)
 			}),
 			true,
@@ -607,7 +401,7 @@ func TestHTLCReceiverSpendValidation(t *testing.T) {
 	revocationKey := DeriveRevocationPubkey(aliceKeyPub, commitPoint)
 
 	// Generate the raw HTLC redemption scripts, and its p2wsh counterpart.
-	htlcWitnessScript, err := receiverHTLCScript(cltvTimeout, aliceLocalKey,
+	htlcWitnessScript, err := ReceiverHTLCScript(cltvTimeout, aliceLocalKey,
 		bobLocalKey, revocationKey, paymentHash[:])
 	if err != nil {
 		t.Fatalf("unable to create htlc sender script: %v", err)
@@ -652,8 +446,8 @@ func TestHTLCReceiverSpendValidation(t *testing.T) {
 	// Finally, we'll create mock signers for both of them based on their
 	// private keys. This test simplifies a bit and uses the same key as
 	// the base point for all scripts and derivations.
-	bobSigner := &mockSigner{privkeys: []*btcec.PrivateKey{bobKeyPriv}}
+	bobSigner := &MockSigner{Privkeys: []*btcec.PrivateKey{bobKeyPriv}}
-	aliceSigner := &mockSigner{privkeys: []*btcec.PrivateKey{aliceKeyPriv}}
+	aliceSigner := &MockSigner{Privkeys: []*btcec.PrivateKey{aliceKeyPriv}}
 
 	// We'll also generate a signature on the sweep transaction above
 	// that will act as Alice's signature to Bob for the second level HTLC
@@ -694,7 +488,7 @@ func TestHTLCReceiverSpendValidation(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return receiverHtlcSpendRedeem(aliceSenderSig,
+				return ReceiverHtlcSpendRedeem(aliceSenderSig,
 					bytes.Repeat([]byte{1}, 45), bobSigner,
 					signDesc, sweepTx)
 
@@ -716,7 +510,7 @@ func TestHTLCReceiverSpendValidation(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return receiverHtlcSpendRedeem(aliceSenderSig,
+				return ReceiverHtlcSpendRedeem(aliceSenderSig,
 					paymentPreimage[:], bobSigner,
 					signDesc, sweepTx)
 			}),
@@ -737,7 +531,7 @@ func TestHTLCReceiverSpendValidation(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return receiverHtlcSpendRevoke(aliceSigner,
+				return ReceiverHtlcSpendRevokeWithKey(aliceSigner,
 					signDesc, revocationKey, sweepTx)
 			}),
 			true,
@@ -757,7 +551,7 @@ func TestHTLCReceiverSpendValidation(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return receiverHtlcSpendTimeout(aliceSigner, signDesc,
+				return ReceiverHtlcSpendTimeout(aliceSigner, signDesc,
 					sweepTx, int32(cltvTimeout-2))
 			}),
 			false,
@@ -777,7 +571,7 @@ func TestHTLCReceiverSpendValidation(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return receiverHtlcSpendTimeout(aliceSigner, signDesc,
+				return ReceiverHtlcSpendTimeout(aliceSigner, signDesc,
 					sweepTx, int32(cltvTimeout))
 			}),
 			true,
@@ -880,7 +674,7 @@ func TestSecondLevelHtlcSpends(t *testing.T) {
 	// Finally we'll generate the HTLC script itself that we'll be spending
 	// from. The revocation clause can be claimed by Alice, while Bob can
 	// sweep the output after a particular delay.
-	htlcWitnessScript, err := secondLevelHtlcScript(revocationKey,
+	htlcWitnessScript, err := SecondLevelHtlcScript(revocationKey,
 		delayKey, claimDelay)
 	if err != nil {
 		t.Fatalf("unable to create htlc script: %v", err)
@@ -900,8 +694,8 @@ func TestSecondLevelHtlcSpends(t *testing.T) {
 	// Finally, we'll create mock signers for both of them based on their
 	// private keys. This test simplifies a bit and uses the same key as
 	// the base point for all scripts and derivations.
-	bobSigner := &mockSigner{privkeys: []*btcec.PrivateKey{bobKeyPriv}}
+	bobSigner := &MockSigner{Privkeys: []*btcec.PrivateKey{bobKeyPriv}}
-	aliceSigner := &mockSigner{privkeys: []*btcec.PrivateKey{aliceKeyPriv}}
+	aliceSigner := &MockSigner{Privkeys: []*btcec.PrivateKey{aliceKeyPriv}}
 
 	testCases := []struct {
 		witness func() wire.TxWitness
@@ -923,7 +717,7 @@ func TestSecondLevelHtlcSpends(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return htlcSpendRevoke(aliceSigner, signDesc,
+				return HtlcSpendRevoke(aliceSigner, signDesc,
 					sweepTx)
 			}),
 			false,
@@ -943,7 +737,7 @@ func TestSecondLevelHtlcSpends(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return htlcSpendRevoke(aliceSigner, signDesc,
+				return HtlcSpendRevoke(aliceSigner, signDesc,
 					sweepTx)
 			}),
 			true,
@@ -965,7 +759,7 @@ func TestSecondLevelHtlcSpends(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return htlcSpendSuccess(bobSigner, signDesc,
+				return HtlcSpendSuccess(bobSigner, signDesc,
 					sweepTx, claimDelay-3)
 			}),
 			false,
@@ -986,7 +780,7 @@ func TestSecondLevelHtlcSpends(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return htlcSpendSuccess(bobSigner, signDesc,
+				return HtlcSpendSuccess(bobSigner, signDesc,
 					sweepTx, claimDelay)
 			}),
 			false,
@@ -1007,7 +801,7 @@ func TestSecondLevelHtlcSpends(t *testing.T) {
 					InputIndex:    0,
 				}
 
-				return htlcSpendSuccess(bobSigner, signDesc,
+				return HtlcSpendSuccess(bobSigner, signDesc,
 					sweepTx, claimDelay)
 			}),
 			true,
@@ -1053,97 +847,6 @@ func TestSecondLevelHtlcSpends(t *testing.T) {
 	}
 }
 
-func TestCommitTxStateHint(t *testing.T) {
-	t.Parallel()
-
-	stateHintTests := []struct {
-		name       string
-		from       uint64
-		to         uint64
-		inputs     int
-		shouldFail bool
-	}{
-		{
-			name:       "states 0 to 1000",
-			from:       0,
-			to:         1000,
-			inputs:     1,
-			shouldFail: false,
-		},
-		{
-			name:       "states 'maxStateHint-1000' to 'maxStateHint'",
-			from:       maxStateHint - 1000,
-			to:         maxStateHint,
-			inputs:     1,
-			shouldFail: false,
-		},
-		{
-			name:       "state 'maxStateHint+1'",
-			from:       maxStateHint + 1,
-			to:         maxStateHint + 10,
-			inputs:     1,
-			shouldFail: true,
-		},
-		{
-			name:       "commit transaction with two inputs",
-			inputs:     2,
-			shouldFail: true,
-		},
-	}
-
-	var obfuscator [StateHintSize]byte
-	copy(obfuscator[:], testHdSeed[:StateHintSize])
-	timeYesterday := uint32(time.Now().Unix() - 24*60*60)
-
-	for _, test := range stateHintTests {
-		commitTx := wire.NewMsgTx(2)
-
-		// Add supplied number of inputs to the commitment transaction.
-		for i := 0; i < test.inputs; i++ {
-			commitTx.AddTxIn(&wire.TxIn{})
-		}
-
-		for i := test.from; i <= test.to; i++ {
-			stateNum := uint64(i)
-
-			err := SetStateNumHint(commitTx, stateNum, obfuscator)
-			if err != nil && !test.shouldFail {
-				t.Fatalf("unable to set state num %v: %v", i, err)
-			} else if err == nil && test.shouldFail {
-				t.Fatalf("Failed(%v): test should fail but did not", test.name)
-			}
-
-			locktime := commitTx.LockTime
-			sequence := commitTx.TxIn[0].Sequence
-
-			// Locktime should not be less than 500,000,000 and not larger
-			// than the time 24 hours ago. One day should provide a good
-			// enough buffer for the tests.
-			if locktime < 5e8 || locktime > timeYesterday {
-				if !test.shouldFail {
-					t.Fatalf("The value of locktime (%v) may cause the commitment "+
-						"transaction to be unspendable", locktime)
-				}
-			}
-
-			if sequence&wire.SequenceLockTimeDisabled == 0 {
-				if !test.shouldFail {
-					t.Fatalf("Sequence locktime is NOT disabled when it should be")
-				}
-			}
-
-			extractedStateNum := GetStateNumHint(commitTx, obfuscator)
-			if extractedStateNum != stateNum && !test.shouldFail {
-				t.Fatalf("state number mismatched, expected %v, got %v",
-					stateNum, extractedStateNum)
-			} else if extractedStateNum == stateNum && test.shouldFail {
-				t.Fatalf("Failed(%v): test should fail but did not", test.name)
-			}
-		}
-		t.Logf("Passed: %v", test.name)
-	}
-}
-
 // TestSpecificationKeyDerivation implements the test vectors provided in
 // BOLT-03, Appendix E.
 func TestSpecificationKeyDerivation(t *testing.T) {

input/signdescriptor.go

@@ -1,4 +1,4 @@
-package lnwallet
+package input
 
 import (
 	"encoding/binary"

input/signdescriptor_test.go

@@ -1,4 +1,4 @@
-package lnwallet
+package input
 
 import (
 	"bytes"

input/signer.go

@@ -0,0 +1,41 @@
+package input
+
+import (
+	"github.com/btcsuite/btcd/wire"
+)
+
+// Signer represents an abstract object capable of generating raw signatures as
+// well as full complete input scripts given a valid SignDescriptor and
+// transaction. This interface fully abstracts away signing paving the way for
+// Signer implementations such as hardware wallets, hardware tokens, HSM's, or
+// simply a regular wallet.
+type Signer interface {
+	// SignOutputRaw generates a signature for the passed transaction
+	// according to the data within the passed SignDescriptor.
+	//
+	// NOTE: The resulting signature should be void of a sighash byte.
+	SignOutputRaw(tx *wire.MsgTx, signDesc *SignDescriptor) ([]byte, error)
+
+	// ComputeInputScript generates a complete InputIndex for the passed
+	// transaction with the signature as defined within the passed
+	// SignDescriptor. This method should be capable of generating the
+	// proper input script for both regular p2wkh output and p2wkh outputs
+	// nested within a regular p2sh output.
+	//
+	// NOTE: This method will ignore any tweak parameters set within the
+	// passed SignDescriptor as it assumes a set of typical script
+	// templates (p2wkh, np2wkh, etc).
+	ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor) (*Script, error)
+}
+
+// Script represents any script inputs required to redeem a previous
+// output. This struct is used rather than just a witness, or scripSig in order
+// to accommodate nested p2sh which utilizes both types of input scripts.
+type Script struct {
+	// Witness is the full witness stack required to unlock this output.
+	Witness wire.TxWitness
+
+	// SigScript will only be populated if this is an input script sweeping
+	// a nested p2sh output.
+	SigScript []byte
+}

input/size.go

@@ -1,4 +1,4 @@
-package lnwallet
+package input
 
 import (
 	"github.com/btcsuite/btcd/blockchain"
@@ -359,10 +359,10 @@ const (
 	OfferedHtlcPenaltyWitnessSize = 1 + 1 + 73 + 1 + 33 + 1 + OfferedHtlcScriptSize
 )
 
-// estimateCommitTxWeight estimate commitment transaction weight depending on
+// EstimateCommitTxWeight estimate commitment transaction weight depending on
 // the precalculated weight of base transaction, witness data, which is needed
 // for paying for funding tx, and htlc weight multiplied by their count.
-func estimateCommitTxWeight(count int, prediction bool) int64 {
+func EstimateCommitTxWeight(count int, prediction bool) int64 {
 	// Make prediction about the size of commitment transaction with
 	// additional HTLC.
 	if prediction {

input/test_utils.go

@@ -0,0 +1,189 @@
+package input
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
+)
+
+var (
+
+	// For simplicity a single priv key controls all of our test outputs.
+	testWalletPrivKey = []byte{
+		0x2b, 0xd8, 0x06, 0xc9, 0x7f, 0x0e, 0x00, 0xaf,
+		0x1a, 0x1f, 0xc3, 0x32, 0x8f, 0xa7, 0x63, 0xa9,
+		0x26, 0x97, 0x23, 0xc8, 0xdb, 0x8f, 0xac, 0x4f,
+		0x93, 0xaf, 0x71, 0xdb, 0x18, 0x6d, 0x6e, 0x90,
+	}
+
+	// We're alice :)
+	bobsPrivKey = []byte{
+		0x81, 0xb6, 0x37, 0xd8, 0xfc, 0xd2, 0xc6, 0xda,
+		0x63, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
+		0xd, 0xe7, 0x95, 0xe4, 0xb7, 0x25, 0xb8, 0x4d,
+		0x1e, 0xb, 0x4c, 0xfd, 0x9e, 0xc5, 0x8c, 0xe9,
+	}
+
+	// Use a hard-coded HD seed.
+	testHdSeed = chainhash.Hash{
+		0xb7, 0x94, 0x38, 0x5f, 0x2d, 0x1e, 0xf7, 0xab,
+		0x4d, 0x92, 0x73, 0xd1, 0x90, 0x63, 0x81, 0xb4,
+		0x4f, 0x2f, 0x6f, 0x25, 0x88, 0xa3, 0xef, 0xb9,
+		0x6a, 0x49, 0x18, 0x83, 0x31, 0x98, 0x47, 0x53,
+	}
+)
+
+// MockSigner is a simple implementation of the Signer interface. Each one has
+// a set of private keys in a slice and can sign messages using the appropriate
+// one.
+type MockSigner struct {
+	Privkeys  []*btcec.PrivateKey
+	NetParams *chaincfg.Params
+}
+
+// SignOutputRaw generates a signature for the passed transaction according to
+// the data within the passed SignDescriptor.
+func (m *MockSigner) SignOutputRaw(tx *wire.MsgTx, signDesc *SignDescriptor) ([]byte, error) {
+	pubkey := signDesc.KeyDesc.PubKey
+	switch {
+	case signDesc.SingleTweak != nil:
+		pubkey = TweakPubKeyWithTweak(pubkey, signDesc.SingleTweak)
+	case signDesc.DoubleTweak != nil:
+		pubkey = DeriveRevocationPubkey(pubkey, signDesc.DoubleTweak.PubKey())
+	}
+
+	hash160 := btcutil.Hash160(pubkey.SerializeCompressed())
+	privKey := m.findKey(hash160, signDesc.SingleTweak, signDesc.DoubleTweak)
+	if privKey == nil {
+		return nil, fmt.Errorf("Mock signer does not have key")
+	}
+
+	sig, err := txscript.RawTxInWitnessSignature(tx, signDesc.SigHashes,
+		signDesc.InputIndex, signDesc.Output.Value, signDesc.WitnessScript,
+		txscript.SigHashAll, privKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return sig[:len(sig)-1], nil
+}
+
+// ComputeInputScript generates a complete InputIndex for the passed transaction
+// with the signature as defined within the passed SignDescriptor. This method
+// should be capable of generating the proper input script for both regular
+// p2wkh output and p2wkh outputs nested within a regular p2sh output.
+func (m *MockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor) (*Script, error) {
+	scriptType, addresses, _, err := txscript.ExtractPkScriptAddrs(
+		signDesc.Output.PkScript, m.NetParams)
+	if err != nil {
+		return nil, err
+	}
+
+	switch scriptType {
+	case txscript.PubKeyHashTy:
+		privKey := m.findKey(addresses[0].ScriptAddress(), signDesc.SingleTweak,
+			signDesc.DoubleTweak)
+		if privKey == nil {
+			return nil, fmt.Errorf("Mock signer does not have key for "+
+				"address %v", addresses[0])
+		}
+
+		sigScript, err := txscript.SignatureScript(
+			tx, signDesc.InputIndex, signDesc.Output.PkScript,
+			txscript.SigHashAll, privKey, true,
+		)
+		if err != nil {
+			return nil, err
+		}
+
+		return &Script{SigScript: sigScript}, nil
+
+	case txscript.WitnessV0PubKeyHashTy:
+		privKey := m.findKey(addresses[0].ScriptAddress(), signDesc.SingleTweak,
+			signDesc.DoubleTweak)
+		if privKey == nil {
+			return nil, fmt.Errorf("Mock signer does not have key for "+
+				"address %v", addresses[0])
+		}
+
+		witnessScript, err := txscript.WitnessSignature(tx, signDesc.SigHashes,
+			signDesc.InputIndex, signDesc.Output.Value,
+			signDesc.Output.PkScript, txscript.SigHashAll, privKey, true)
+		if err != nil {
+			return nil, err
+		}
+
+		return &Script{Witness: witnessScript}, nil
+
+	default:
+		return nil, fmt.Errorf("Unexpected script type: %v", scriptType)
+	}
+}
+
+// findKey searches through all stored private keys and returns one
+// corresponding to the hashed pubkey if it can be found. The public key may
+// either correspond directly to the private key or to the private key with a
+// tweak applied.
+func (m *MockSigner) findKey(needleHash160 []byte, singleTweak []byte,
+	doubleTweak *btcec.PrivateKey) *btcec.PrivateKey {
+
+	for _, privkey := range m.Privkeys {
+		// First check whether public key is directly derived from private key.
+		hash160 := btcutil.Hash160(privkey.PubKey().SerializeCompressed())
+		if bytes.Equal(hash160, needleHash160) {
+			return privkey
+		}
+
+		// Otherwise check if public key is derived from tweaked private key.
+		switch {
+		case singleTweak != nil:
+			privkey = TweakPrivKey(privkey, singleTweak)
+		case doubleTweak != nil:
+			privkey = DeriveRevocationPrivKey(privkey, doubleTweak)
+		default:
+			continue
+		}
+		hash160 = btcutil.Hash160(privkey.PubKey().SerializeCompressed())
+		if bytes.Equal(hash160, needleHash160) {
+			return privkey
+		}
+	}
+	return nil
+}
+
+// pubkeyFromHex parses a Bitcoin public key from a hex encoded string.
+func pubkeyFromHex(keyHex string) (*btcec.PublicKey, error) {
+	bytes, err := hex.DecodeString(keyHex)
+	if err != nil {
+		return nil, err
+	}
+	return btcec.ParsePubKey(bytes, btcec.S256())
+}
+
+// privkeyFromHex parses a Bitcoin private key from a hex encoded string.
+func privkeyFromHex(keyHex string) (*btcec.PrivateKey, error) {
+	bytes, err := hex.DecodeString(keyHex)
+	if err != nil {
+		return nil, err
+	}
+	key, _ := btcec.PrivKeyFromBytes(btcec.S256(), bytes)
+	return key, nil
+
+}
+
+// pubkeyToHex serializes a Bitcoin public key to a hex encoded string.
+func pubkeyToHex(key *btcec.PublicKey) string {
+	return hex.EncodeToString(key.SerializeCompressed())
+}
+
+// privkeyFromHex serializes a Bitcoin private key to a hex encoded string.
+func privkeyToHex(key *btcec.PrivateKey) string {
+	return hex.EncodeToString(key.Serialize())
+}

input/txout.go

@@ -1,4 +1,4 @@
-package lnwallet
+package input
 
 import (
 	"encoding/binary"

input/txout_test.go

@@ -1,4 +1,4 @@
-package lnwallet
+package input
 
 import (
 	"bytes"

input/witnessgen.go

@@ -1,4 +1,4 @@
-package lnwallet
+package input
 
 import (
 	"fmt"
@@ -125,7 +125,7 @@ func (wt WitnessType) String() string {
 // outputs. This function acts as an abstraction layer, hiding the details of
 // the underlying script.
 type WitnessGenerator func(tx *wire.MsgTx, hc *txscript.TxSigHashes,
-	inputIndex int) (*InputScript, error)
+	inputIndex int) (*Script, error)
 
 // GenWitnessFunc will return a WitnessGenerator function that an output uses
 // to generate the witness and optionally the sigScript for a sweep
@@ -135,7 +135,7 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 	descriptor *SignDescriptor) WitnessGenerator {
 
 	return func(tx *wire.MsgTx, hc *txscript.TxSigHashes,
-		inputIndex int) (*InputScript, error) {
+		inputIndex int) (*Script, error) {
 
 		desc := descriptor
 		desc.SigHashes = hc
@@ -148,7 +148,7 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 
@@ -158,7 +158,7 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 
@@ -168,7 +168,7 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 
@@ -178,7 +178,7 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 
@@ -188,7 +188,7 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 
@@ -198,7 +198,7 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 
@@ -208,7 +208,7 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 
@@ -216,22 +216,22 @@ func (wt WitnessType) GenWitnessFunc(signer Signer,
 			// We pass in a value of -1 for the timeout, as we
 			// expect the caller to have already set the lock time
 			// value.
-			witness, err := receiverHtlcSpendTimeout(signer, desc, tx, -1)
+			witness, err := ReceiverHtlcSpendTimeout(signer, desc, tx, -1)
 			if err != nil {
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 
 		case HtlcSecondLevelRevoke:
-			witness, err := htlcSpendRevoke(signer, desc, tx)
+			witness, err := HtlcSpendRevoke(signer, desc, tx)
 			if err != nil {
 				return nil, err
 			}
 
-			return &InputScript{
+			return &Script{
 				Witness: witness,
 			}, nil
 

invoices/invoiceregistry.go

@@ -4,11 +4,11 @@ import (
 	"bytes"
 	"crypto/sha256"
 	"fmt"
-	"github.com/btcsuite/btcd/chaincfg"
 	"sync"
 	"sync/atomic"
 	"time"
 
+	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcutil"
 	"github.com/davecgh/go-spew/spew"

lnrpc/signrpc/config_active.go

@@ -3,7 +3,7 @@
 package signrpc
 
 import (
-	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/macaroons"
 )
 
@@ -29,5 +29,5 @@ type Config struct {
 	// Signer is the signer instance that backs the signer RPC server. The
 	// job of the signer RPC server is simply to proxy valid requests to
 	// the active signer instance.
-	Signer lnwallet.Signer
+	Signer input.Signer
 }

lnrpc/signrpc/signer_server.go

@@ -13,9 +13,10 @@ import (
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnrpc"
-	"github.com/lightningnetwork/lnd/lnwallet"
+
 	"google.golang.org/grpc"
 	"gopkg.in/macaroon-bakery.v2/bakery"
 )
@@ -206,7 +207,7 @@ func (s *Server) SignOutputRaw(ctx context.Context, in *SignReq) (*SignResp, err
 
 	// With the transaction deserialized, we'll now convert sign descs so
 	// we can feed it into the actual signer.
-	signDescs := make([]*lnwallet.SignDescriptor, 0, len(in.SignDescs))
+	signDescs := make([]*input.SignDescriptor, 0, len(in.SignDescs))
 	for _, signDesc := range in.SignDescs {
 		keyDesc := signDesc.KeyDesc
 
@@ -278,7 +279,7 @@ func (s *Server) SignOutputRaw(ctx context.Context, in *SignReq) (*SignResp, err
 		// Finally, with verification and parsing complete, we can
 		// construct the final sign descriptor to generate the proper
 		// signature for this input.
-		signDescs = append(signDescs, &lnwallet.SignDescriptor{
+		signDescs = append(signDescs, &input.SignDescriptor{
 			KeyDesc: keychain.KeyDescriptor{
 				KeyLocator: keyLoc,
 				PubKey:     targetPubKey,
@@ -353,13 +354,13 @@ func (s *Server) ComputeInputScript(ctx context.Context,
 
 	sigHashCache := txscript.NewTxSigHashes(&txToSign)
 
-	signDescs := make([]*lnwallet.SignDescriptor, 0, len(in.SignDescs))
+	signDescs := make([]*input.SignDescriptor, 0, len(in.SignDescs))
 	for _, signDesc := range in.SignDescs {
 		// For this method, the only fields that we care about are the
 		// hash type, and the information concerning the output as we
 		// only know how to provide full witnesses for outputs that we
 		// solely control.
-		signDescs = append(signDescs, &lnwallet.SignDescriptor{
+		signDescs = append(signDescs, &input.SignDescriptor{
 			Output: &wire.TxOut{
 				Value:    signDesc.Output.Value,
 				PkScript: signDesc.Output.PkScript,

lnwallet/btcwallet/signer.go

@@ -10,6 +10,7 @@ import (
 	base "github.com/btcsuite/btcwallet/wallet"
 	"github.com/btcsuite/btcwallet/walletdb"
 	"github.com/go-errors/errors"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
@@ -132,18 +133,18 @@ func (b *BtcWallet) fetchPrivKey(keyDesc *keychain.KeyDescriptor) (*btcec.Privat
 // maybeTweakPrivKey examines the single and double tweak parameters on the
 // passed sign descriptor and may perform a mapping on the passed private key
 // in order to utilize the tweaks, if populated.
-func maybeTweakPrivKey(signDesc *lnwallet.SignDescriptor,
+func maybeTweakPrivKey(signDesc *input.SignDescriptor,
 	privKey *btcec.PrivateKey) (*btcec.PrivateKey, error) {
 
 	var retPriv *btcec.PrivateKey
 	switch {
 
 	case signDesc.SingleTweak != nil:
-		retPriv = lnwallet.TweakPrivKey(privKey,
+		retPriv = input.TweakPrivKey(privKey,
 			signDesc.SingleTweak)
 
 	case signDesc.DoubleTweak != nil:
-		retPriv = lnwallet.DeriveRevocationPrivKey(privKey,
+		retPriv = input.DeriveRevocationPrivKey(privKey,
 			signDesc.DoubleTweak)
 
 	default:
@@ -158,7 +159,7 @@ func maybeTweakPrivKey(signDesc *lnwallet.SignDescriptor,
 //
 // This is a part of the WalletController interface.
 func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) ([]byte, error) {
+	signDesc *input.SignDescriptor) ([]byte, error) {
 
 	witnessScript := signDesc.WitnessScript
 
@@ -199,7 +200,7 @@ func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx,
 //
 // This is a part of the WalletController interface.
 func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {
+	signDesc *input.SignDescriptor) (*input.Script, error) {
 
 	outputScript := signDesc.Output.PkScript
 	walletAddr, err := b.fetchOutputAddr(outputScript)
@@ -214,7 +215,7 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
 	}
 
 	var witnessProgram []byte
-	inputScript := &lnwallet.InputScript{}
+	inputScript := &input.Script{}
 
 	switch {
 
@@ -282,7 +283,7 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
 
 // A compile time check to ensure that BtcWallet implements the Signer
 // interface.
-var _ lnwallet.Signer = (*BtcWallet)(nil)
+var _ input.Signer = (*BtcWallet)(nil)
 
 // SignMessage attempts to sign a target message with the private key that
 // corresponds to the passed public key. If the target private key is unable to

lnwallet/channel.go

@@ -9,17 +9,18 @@ import (
 	"sync"
 
 	"github.com/btcsuite/btcd/blockchain"
-	"github.com/btcsuite/btcd/chaincfg/chainhash"
-	"github.com/davecgh/go-spew/spew"
-	"github.com/lightningnetwork/lnd/chainntnfs"
-	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/lnwire"
-
 	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcutil/txsort"
+	"github.com/davecgh/go-spew/spew"
+
+	"github.com/lightningnetwork/lnd/chainntnfs"
+	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
+	"github.com/lightningnetwork/lnd/lnwire"
 )
 
 var zeroHash chainhash.Hash
@@ -967,16 +968,16 @@ func deriveCommitmentKeys(commitPoint *btcec.PublicKey, isOurCommit bool,
 	keyRing := &CommitmentKeyRing{
 		CommitPoint: commitPoint,
 
-		LocalCommitKeyTweak: SingleTweakBytes(
+		LocalCommitKeyTweak: input.SingleTweakBytes(
 			commitPoint, localChanCfg.PaymentBasePoint.PubKey,
 		),
-		LocalHtlcKeyTweak: SingleTweakBytes(
+		LocalHtlcKeyTweak: input.SingleTweakBytes(
 			commitPoint, localChanCfg.HtlcBasePoint.PubKey,
 		),
-		LocalHtlcKey: TweakPubKey(
+		LocalHtlcKey: input.TweakPubKey(
 			localChanCfg.HtlcBasePoint.PubKey, commitPoint,
 		),
-		RemoteHtlcKey: TweakPubKey(
+		RemoteHtlcKey: input.TweakPubKey(
 			remoteChanCfg.HtlcBasePoint.PubKey, commitPoint,
 		),
 	}
@@ -1003,9 +1004,9 @@ func deriveCommitmentKeys(commitPoint *btcec.PublicKey, isOurCommit bool,
 
 	// With the base points assigned, we can now derive the actual keys
 	// using the base point, and the current commitment tweak.
-	keyRing.DelayKey = TweakPubKey(delayBasePoint, commitPoint)
+	keyRing.DelayKey = input.TweakPubKey(delayBasePoint, commitPoint)
-	keyRing.NoDelayKey = TweakPubKey(noDelayBasePoint, commitPoint)
+	keyRing.NoDelayKey = input.TweakPubKey(noDelayBasePoint, commitPoint)
-	keyRing.RevocationKey = DeriveRevocationPubkey(
+	keyRing.RevocationKey = input.DeriveRevocationPubkey(
 		revocationBasePoint, commitPoint,
 	)
 
@@ -1285,11 +1286,11 @@ type LightningChannel struct {
 	// Signer is the main signer instances that will be responsible for
 	// signing any HTLC and commitment transaction generated by the state
 	// machine.
-	Signer Signer
+	Signer input.Signer
 
 	// signDesc is the primary sign descriptor that is capable of signing
 	// the commitment transaction that spends the multi-sig output.
-	signDesc *SignDescriptor
+	signDesc *input.SignDescriptor
 
 	channelEvents chainntnfs.ChainNotifier
 
@@ -1363,7 +1364,7 @@ type LightningChannel struct {
 // settled channel state. Throughout state transitions, then channel will
 // automatically persist pertinent state to the database in an efficient
 // manner.
-func NewLightningChannel(signer Signer, pCache PreimageCache,
+func NewLightningChannel(signer input.Signer, pCache PreimageCache,
 	state *channeldb.OpenChannel,
 	sigPool *SigPool) (*LightningChannel, error) {
 
@@ -1423,16 +1424,16 @@ func (lc *LightningChannel) createSignDesc() error {
 	localKey := lc.localChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 	remoteKey := lc.remoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 
-	multiSigScript, err := GenMultiSigScript(localKey, remoteKey)
+	multiSigScript, err := input.GenMultiSigScript(localKey, remoteKey)
 	if err != nil {
 		return err
 	}
 
-	fundingPkScript, err := WitnessScriptHash(multiSigScript)
+	fundingPkScript, err := input.WitnessScriptHash(multiSigScript)
 	if err != nil {
 		return err
 	}
-	lc.signDesc = &SignDescriptor{
+	lc.signDesc = &input.SignDescriptor{
 		KeyDesc:       lc.localChanCfg.MultiSigKey,
 		WitnessScript: multiSigScript,
 		Output: &wire.TxOut{
@@ -1616,7 +1617,7 @@ func (lc *LightningChannel) restoreCommitState(
 	if err != nil {
 		return err
 	}
-	localCommitPoint := ComputeCommitmentPoint(ourRevPreImage[:])
+	localCommitPoint := input.ComputeCommitmentPoint(ourRevPreImage[:])
 	remoteCommitPoint := lc.channelState.RemoteCurrentRevocation
 
 	// With the revocation state reconstructed, we can now convert the disk
@@ -1859,7 +1860,7 @@ type HtlcRetribution struct {
 	// SignDesc is a design descriptor capable of generating the necessary
 	// signatures to satisfy the revocation clause of the HTLC's public key
 	// script.
-	SignDesc SignDescriptor
+	SignDesc input.SignDescriptor
 
 	// OutPoint is the target outpoint of this HTLC pointing to the
 	// breached commitment transaction.
@@ -1915,7 +1916,7 @@ type BreachRetribution struct {
 	//
 	// NOTE: A nil value indicates that the local output is considered dust
 	// according to the remote party's dust limit.
-	LocalOutputSignDesc *SignDescriptor
+	LocalOutputSignDesc *input.SignDescriptor
 
 	// LocalOutpoint is the outpoint of the output paying to us (the local
 	// party) within the breach transaction.
@@ -1928,7 +1929,7 @@ type BreachRetribution struct {
 	//
 	// NOTE: A nil value indicates that the local output is considered dust
 	// according to the remote party's dust limit.
-	RemoteOutputSignDesc *SignDescriptor
+	RemoteOutputSignDesc *input.SignDescriptor
 
 	// RemoteOutpoint is the outpoint of the output paying to the remote
 	// party within the breach transaction.
@@ -1983,17 +1984,17 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// number so we can have the proper witness script to sign and include
 	// within the final witness.
 	remoteDelay := uint32(chanState.RemoteChanCfg.CsvDelay)
-	remotePkScript, err := CommitScriptToSelf(
+	remotePkScript, err := input.CommitScriptToSelf(
 		remoteDelay, keyRing.DelayKey, keyRing.RevocationKey,
 	)
 	if err != nil {
 		return nil, err
 	}
-	remoteWitnessHash, err := WitnessScriptHash(remotePkScript)
+	remoteWitnessHash, err := input.WitnessScriptHash(remotePkScript)
 	if err != nil {
 		return nil, err
 	}
-	localPkScript, err := CommitScriptUnencumbered(keyRing.NoDelayKey)
+	localPkScript, err := input.CommitScriptUnencumbered(keyRing.NoDelayKey)
 	if err != nil {
 		return nil, err
 	}
@@ -2019,8 +2020,8 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// commitment outputs. If either is considered dust using the remote
 	// party's dust limit, the respective sign descriptor will be nil.
 	var (
-		localSignDesc  *SignDescriptor
+		localSignDesc  *input.SignDescriptor
-		remoteSignDesc *SignDescriptor
+		remoteSignDesc *input.SignDescriptor
 	)
 
 	// Compute the local and remote balances in satoshis.
@@ -2030,7 +2031,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// If the local balance exceeds the remote party's dust limit,
 	// instantiate the local sign descriptor.
 	if localAmt >= chanState.RemoteChanCfg.DustLimit {
-		localSignDesc = &SignDescriptor{
+		localSignDesc = &input.SignDescriptor{
 			SingleTweak:   keyRing.LocalCommitKeyTweak,
 			KeyDesc:       chanState.LocalChanCfg.PaymentBasePoint,
 			WitnessScript: localPkScript,
@@ -2045,7 +2046,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// Similarly, if the remote balance exceeds the remote party's dust
 	// limit, assemble the remote sign descriptor.
 	if remoteAmt >= chanState.RemoteChanCfg.DustLimit {
-		remoteSignDesc = &SignDescriptor{
+		remoteSignDesc = &input.SignDescriptor{
 			KeyDesc:       chanState.LocalChanCfg.RevocationBasePoint,
 			DoubleTweak:   commitmentSecret,
 			WitnessScript: remotePkScript,
@@ -2081,7 +2082,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 		// as we'll need it if we're revoking an HTLC output on the
 		// remote commitment transaction, and *they* go to the second
 		// level.
-		secondLevelWitnessScript, err := secondLevelHtlcScript(
+		secondLevelWitnessScript, err := input.SecondLevelHtlcScript(
 			keyRing.RevocationKey, keyRing.DelayKey, remoteDelay,
 		)
 		if err != nil {
@@ -2092,7 +2093,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 		// the sender of the HTLC (relative to us). So we'll
 		// re-generate the sender HTLC script.
 		if htlc.Incoming {
-			htlcWitnessScript, err = senderHTLCScript(
+			htlcWitnessScript, err = input.SenderHTLCScript(
 				keyRing.RemoteHtlcKey, keyRing.LocalHtlcKey,
 				keyRing.RevocationKey, htlc.RHash[:],
 			)
@@ -2104,7 +2105,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 			// Otherwise, is this was an outgoing HTLC that we
 			// sent, then from the PoV of the remote commitment
 			// state, they're the receiver of this HTLC.
-			htlcWitnessScript, err = receiverHTLCScript(
+			htlcWitnessScript, err = input.ReceiverHTLCScript(
 				htlc.RefundTimeout, keyRing.LocalHtlcKey,
 				keyRing.RemoteHtlcKey, keyRing.RevocationKey,
 				htlc.RHash[:],
@@ -2114,13 +2115,13 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 			}
 		}
 
-		htlcPkScript, err := WitnessScriptHash(htlcWitnessScript)
+		htlcPkScript, err := input.WitnessScriptHash(htlcWitnessScript)
 		if err != nil {
 			return nil, err
 		}
 
 		htlcRetributions = append(htlcRetributions, HtlcRetribution{
-			SignDesc: SignDescriptor{
+			SignDesc: input.SignDescriptor{
 				KeyDesc:       chanState.LocalChanCfg.RevocationBasePoint,
 				DoubleTweak:   commitmentSecret,
 				WitnessScript: htlcWitnessScript,
@@ -2161,13 +2162,13 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 // htlcTimeoutFee returns the fee in satoshis required for an HTLC timeout
 // transaction based on the current fee rate.
 func htlcTimeoutFee(feePerKw SatPerKWeight) btcutil.Amount {
-	return feePerKw.FeeForWeight(HtlcTimeoutWeight)
+	return feePerKw.FeeForWeight(input.HtlcTimeoutWeight)
 }
 
 // htlcSuccessFee returns the fee in satoshis required for an HTLC success
 // transaction based on the current fee rate.
 func htlcSuccessFee(feePerKw SatPerKWeight) btcutil.Amount {
-	return feePerKw.FeeForWeight(HtlcSuccessWeight)
+	return feePerKw.FeeForWeight(input.HtlcSuccessWeight)
 }
 
 // htlcIsDust determines if an HTLC output is dust or not depending on two
@@ -2364,7 +2365,7 @@ func (lc *LightningChannel) createCommitmentTx(c *commitment,
 	// on its total weight. Once we have the total weight, we'll multiply
 	// by the current fee-per-kw, then divide by 1000 to get the proper
 	// fee.
-	totalCommitWeight := CommitWeight + (HtlcWeight * numHTLCs)
+	totalCommitWeight := input.CommitWeight + (input.HtlcWeight * numHTLCs)
 
 	// With the weight known, we can now calculate the commitment fee,
 	// ensuring that we account for any dust outputs trimmed above.
@@ -2813,7 +2814,7 @@ func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
 		// Finally, we'll generate a sign descriptor to generate a
 		// signature to give to the remote party for this commitment
 		// transaction. Note we use the raw HTLC amount.
-		sigJob.SignDesc = SignDescriptor{
+		sigJob.SignDesc = input.SignDescriptor{
 			KeyDesc:       localChanCfg.HtlcBasePoint,
 			SingleTweak:   keyRing.LocalHtlcKeyTweak,
 			WitnessScript: htlc.theirWitnessScript,
@@ -2864,7 +2865,7 @@ func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
 		// Finally, we'll generate a sign descriptor to generate a
 		// signature to give to the remote party for this commitment
 		// transaction. Note we use the raw HTLC amount.
-		sigJob.SignDesc = SignDescriptor{
+		sigJob.SignDesc = input.SignDescriptor{
 			KeyDesc:       localChanCfg.HtlcBasePoint,
 			SingleTweak:   keyRing.LocalHtlcKeyTweak,
 			WitnessScript: htlc.theirWitnessScript,
@@ -3559,7 +3560,7 @@ func ChanSyncMsg(c *channeldb.OpenChannel) (*lnwire.ChannelReestablish, error) {
 		NextLocalCommitHeight:  nextLocalCommitHeight,
 		RemoteCommitTailHeight: remoteChainTipHeight,
 		LastRemoteCommitSecret: lastCommitSecret,
-		LocalUnrevokedCommitPoint: ComputeCommitmentPoint(
+		LocalUnrevokedCommitPoint: input.ComputeCommitmentPoint(
 			currentCommitSecret[:],
 		),
 	}, nil
@@ -3627,7 +3628,7 @@ func (lc *LightningChannel) computeView(view *htlcView, remoteChain bool,
 			continue
 		}
 
-		totalHtlcWeight += HtlcWeight
+		totalHtlcWeight += input.HtlcWeight
 	}
 	for _, htlc := range filteredHTLCView.theirUpdates {
 		if htlcIsDust(!remoteChain, !remoteChain, feePerKw,
@@ -3635,10 +3636,10 @@ func (lc *LightningChannel) computeView(view *htlcView, remoteChain bool,
 			continue
 		}
 
-		totalHtlcWeight += HtlcWeight
+		totalHtlcWeight += input.HtlcWeight
 	}
 
-	totalCommitWeight := CommitWeight + totalHtlcWeight
+	totalCommitWeight := input.CommitWeight + totalHtlcWeight
 	return ourBalance, theirBalance, totalCommitWeight, filteredHTLCView
 }
 
@@ -4031,7 +4032,7 @@ func (lc *LightningChannel) ReceiveNewCommitment(commitSig lnwire.Sig,
 	if err != nil {
 		return err
 	}
-	commitPoint := ComputeCommitmentPoint(commitSecret[:])
+	commitPoint := input.ComputeCommitmentPoint(commitSecret[:])
 	keyRing := deriveCommitmentKeys(commitPoint, true, lc.localChanCfg,
 		lc.remoteChanCfg)
 
@@ -4258,7 +4259,7 @@ func (lc *LightningChannel) ReceiveRevocation(revMsg *lnwire.RevokeAndAck) (
 	// revealed secret to derive a revocation key with our revocation base
 	// point, then it matches the current revocation of the remote party.
 	currentCommitPoint := lc.channelState.RemoteCurrentRevocation
-	derivedCommitPoint := ComputeCommitmentPoint(revMsg.Revocation[:])
+	derivedCommitPoint := input.ComputeCommitmentPoint(revMsg.Revocation[:])
 	if !derivedCommitPoint.IsEqual(currentCommitPoint) {
 		return nil, nil, nil, fmt.Errorf("revocation key mismatch")
 	}
@@ -4496,7 +4497,7 @@ func (lc *LightningChannel) NextRevocationKey() (*btcec.PublicKey, error) {
 		return nil, err
 	}
 
-	return ComputeCommitmentPoint(revocation[:]), nil
+	return input.ComputeCommitmentPoint(revocation[:]), nil
 }
 
 // InitNextRevocation inserts the passed commitment point as the _next_
@@ -4872,7 +4873,7 @@ func genHtlcScript(isIncoming, ourCommit bool, timeout uint32, rHash [32]byte,
 	// transaction. So we need to use the receiver's version of HTLC the
 	// script.
 	case isIncoming && ourCommit:
-		witnessScript, err = receiverHTLCScript(timeout,
+		witnessScript, err = input.ReceiverHTLCScript(timeout,
 			keyRing.RemoteHtlcKey, keyRing.LocalHtlcKey,
 			keyRing.RevocationKey, rHash[:])
 
@@ -4880,21 +4881,21 @@ func genHtlcScript(isIncoming, ourCommit bool, timeout uint32, rHash [32]byte,
 	// being added to their commitment transaction, so we use the sender's
 	// version of the HTLC script.
 	case isIncoming && !ourCommit:
-		witnessScript, err = senderHTLCScript(keyRing.RemoteHtlcKey,
+		witnessScript, err = input.SenderHTLCScript(keyRing.RemoteHtlcKey,
 			keyRing.LocalHtlcKey, keyRing.RevocationKey, rHash[:])
 
 	// We're sending an HTLC which is being added to our commitment
 	// transaction. Therefore, we need to use the sender's version of the
 	// HTLC script.
 	case !isIncoming && ourCommit:
-		witnessScript, err = senderHTLCScript(keyRing.LocalHtlcKey,
+		witnessScript, err = input.SenderHTLCScript(keyRing.LocalHtlcKey,
 			keyRing.RemoteHtlcKey, keyRing.RevocationKey, rHash[:])
 
 	// Finally, we're paying the remote party via an HTLC, which is being
 	// added to their commitment transaction. Therefore, we use the
 	// receiver's version of the HTLC script.
 	case !isIncoming && !ourCommit:
-		witnessScript, err = receiverHTLCScript(timeout, keyRing.LocalHtlcKey,
+		witnessScript, err = input.ReceiverHTLCScript(timeout, keyRing.LocalHtlcKey,
 			keyRing.RemoteHtlcKey, keyRing.RevocationKey, rHash[:])
 	}
 	if err != nil {
@@ -4903,7 +4904,7 @@ func genHtlcScript(isIncoming, ourCommit bool, timeout uint32, rHash [32]byte,
 
 	// Now that we have the redeem scripts, create the P2WSH public key
 	// script for the output itself.
-	htlcP2WSH, err := WitnessScriptHash(witnessScript)
+	htlcP2WSH, err := input.WitnessScriptHash(witnessScript)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -4972,7 +4973,7 @@ func (lc *LightningChannel) getSignedCommitTx() (*wire.MsgTx, error) {
 	ourKey := lc.localChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 	theirKey := lc.remoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 
-	commitTx.TxIn[0].Witness = SpendMultiSig(
+	commitTx.TxIn[0].Witness = input.SpendMultiSig(
 		lc.signDesc.WitnessScript, ourKey,
 		ourSig, theirKey, theirSig,
 	)
@@ -4990,7 +4991,7 @@ type CommitOutputResolution struct {
 
 	// SelfOutputSignDesc is a fully populated sign descriptor capable of
 	// generating a valid signature to sweep the output paying to us.
-	SelfOutputSignDesc SignDescriptor
+	SelfOutputSignDesc input.SignDescriptor
 
 	// MaturityDelay is the relative time-lock, in blocks for all outputs
 	// that pay to the local party within the broadcast commitment
@@ -5046,7 +5047,7 @@ type UnilateralCloseSummary struct {
 // happen in case we have lost state) it should be set to an empty struct, in
 // which case we will attempt to sweep the non-HTLC output using the passed
 // commitPoint.
-func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
+func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer input.Signer,
 	pCache PreimageCache, commitSpend *chainntnfs.SpendDetail,
 	remoteCommit channeldb.ChannelCommitment,
 	commitPoint *btcec.PublicKey) (*UnilateralCloseSummary, error) {
@@ -5074,7 +5075,7 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 	// Before we can generate the proper sign descriptor, we'll need to
 	// locate the output index of our non-delayed output on the commitment
 	// transaction.
-	selfP2WKH, err := CommitScriptUnencumbered(keyRing.NoDelayKey)
+	selfP2WKH, err := input.CommitScriptUnencumbered(keyRing.NoDelayKey)
 	if err != nil {
 		return nil, fmt.Errorf("unable to create self commit script: %v", err)
 	}
@@ -5103,7 +5104,7 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 		localPayBase := chanState.LocalChanCfg.PaymentBasePoint
 		commitResolution = &CommitOutputResolution{
 			SelfOutPoint: *selfPoint,
-			SelfOutputSignDesc: SignDescriptor{
+			SelfOutputSignDesc: input.SignDescriptor{
 				KeyDesc:       localPayBase,
 				SingleTweak:   keyRing.LocalCommitKeyTweak,
 				WitnessScript: selfP2WKH,
@@ -5190,7 +5191,7 @@ type IncomingHtlcResolution struct {
 	// SweepSignDesc is a sign descriptor that has been populated with the
 	// necessary items required to spend the sole output of the above
 	// transaction.
-	SweepSignDesc SignDescriptor
+	SweepSignDesc input.SignDescriptor
 }
 
 // OutgoingHtlcResolution houses the information necessary to sweep any
@@ -5230,7 +5231,7 @@ type OutgoingHtlcResolution struct {
 	// SweepSignDesc is a sign descriptor that has been populated with the
 	// necessary items required to spend the sole output of the above
 	// transaction.
-	SweepSignDesc SignDescriptor
+	SweepSignDesc input.SignDescriptor
 }
 
 // HtlcResolutions contains the items necessary to sweep HTLC's on chain
@@ -5250,7 +5251,7 @@ type HtlcResolutions struct {
 // newOutgoingHtlcResolution generates a new HTLC resolution capable of
 // allowing the caller to sweep an outgoing HTLC present on either their, or
 // the remote party's commitment transaction.
-func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelConfig,
+func newOutgoingHtlcResolution(signer input.Signer, localChanCfg *channeldb.ChannelConfig,
 	commitHash chainhash.Hash, htlc *channeldb.HTLC, keyRing *CommitmentKeyRing,
 	feePerKw SatPerKWeight, dustLimit btcutil.Amount, csvDelay uint32, localCommit bool,
 ) (*OutgoingHtlcResolution, error) {
@@ -5266,14 +5267,14 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	if !localCommit {
 		// First, we'll re-generate the script used to send the HTLC to
 		// the remote party within their commitment transaction.
-		htlcReceiverScript, err := receiverHTLCScript(htlc.RefundTimeout,
+		htlcReceiverScript, err := input.ReceiverHTLCScript(htlc.RefundTimeout,
 			keyRing.LocalHtlcKey, keyRing.RemoteHtlcKey,
 			keyRing.RevocationKey, htlc.RHash[:],
 		)
 		if err != nil {
 			return nil, err
 		}
-		htlcScriptHash, err := WitnessScriptHash(htlcReceiverScript)
+		htlcScriptHash, err := input.WitnessScriptHash(htlcReceiverScript)
 		if err != nil {
 			return nil, err
 		}
@@ -5283,7 +5284,7 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 		return &OutgoingHtlcResolution{
 			Expiry:        htlc.RefundTimeout,
 			ClaimOutpoint: op,
-			SweepSignDesc: SignDescriptor{
+			SweepSignDesc: input.SignDescriptor{
 				KeyDesc:       localChanCfg.HtlcBasePoint,
 				SingleTweak:   keyRing.LocalHtlcKeyTweak,
 				WitnessScript: htlcReceiverScript,
@@ -5318,12 +5319,12 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	// With the transaction created, we can generate a sign descriptor
 	// that's capable of generating the signature required to spend the
 	// HTLC output using the timeout transaction.
-	htlcCreationScript, err := senderHTLCScript(keyRing.LocalHtlcKey,
+	htlcCreationScript, err := input.SenderHTLCScript(keyRing.LocalHtlcKey,
 		keyRing.RemoteHtlcKey, keyRing.RevocationKey, htlc.RHash[:])
 	if err != nil {
 		return nil, err
 	}
-	timeoutSignDesc := SignDescriptor{
+	timeoutSignDesc := input.SignDescriptor{
 		KeyDesc:       localChanCfg.HtlcBasePoint,
 		SingleTweak:   keyRing.LocalHtlcKeyTweak,
 		WitnessScript: htlcCreationScript,
@@ -5337,7 +5338,7 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 
 	// With the sign desc created, we can now construct the full witness
 	// for the timeout transaction, and populate it as well.
-	timeoutWitness, err := senderHtlcSpendTimeout(
+	timeoutWitness, err := input.SenderHtlcSpendTimeout(
 		htlc.Signature, signer, &timeoutSignDesc, timeoutTx,
 	)
 	if err != nil {
@@ -5348,18 +5349,18 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	// Finally, we'll generate the script output that the timeout
 	// transaction creates so we can generate the signDesc required to
 	// complete the claim process after a delay period.
-	htlcSweepScript, err := secondLevelHtlcScript(
+	htlcSweepScript, err := input.SecondLevelHtlcScript(
 		keyRing.RevocationKey, keyRing.DelayKey, csvDelay,
 	)
 	if err != nil {
 		return nil, err
 	}
-	htlcScriptHash, err := WitnessScriptHash(htlcSweepScript)
+	htlcScriptHash, err := input.WitnessScriptHash(htlcSweepScript)
 	if err != nil {
 		return nil, err
 	}
 
-	localDelayTweak := SingleTweakBytes(
+	localDelayTweak := input.SingleTweakBytes(
 		keyRing.CommitPoint, localChanCfg.DelayBasePoint.PubKey,
 	)
 	return &OutgoingHtlcResolution{
@@ -5370,7 +5371,7 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 			Hash:  timeoutTx.TxHash(),
 			Index: 0,
 		},
-		SweepSignDesc: SignDescriptor{
+		SweepSignDesc: input.SignDescriptor{
 			KeyDesc:       localChanCfg.DelayBasePoint,
 			SingleTweak:   localDelayTweak,
 			WitnessScript: htlcSweepScript,
@@ -5390,7 +5391,7 @@ func newOutgoingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 // they can just sweep the output immediately with knowledge of the pre-image.
 //
 // TODO(roasbeef) consolidate code with above func
-func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelConfig,
+func newIncomingHtlcResolution(signer input.Signer, localChanCfg *channeldb.ChannelConfig,
 	commitHash chainhash.Hash, htlc *channeldb.HTLC, keyRing *CommitmentKeyRing,
 	feePerKw SatPerKWeight, dustLimit btcutil.Amount, csvDelay uint32,
 	localCommit bool, preimage [32]byte) (*IncomingHtlcResolution, error) {
@@ -5405,14 +5406,14 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	if !localCommit {
 		// First, we'll re-generate the script the remote party used to
 		// send the HTLC to us in their commitment transaction.
-		htlcSenderScript, err := senderHTLCScript(
+		htlcSenderScript, err := input.SenderHTLCScript(
 			keyRing.RemoteHtlcKey, keyRing.LocalHtlcKey,
 			keyRing.RevocationKey, htlc.RHash[:],
 		)
 		if err != nil {
 			return nil, err
 		}
-		htlcScriptHash, err := WitnessScriptHash(htlcSenderScript)
+		htlcScriptHash, err := input.WitnessScriptHash(htlcSenderScript)
 		if err != nil {
 			return nil, err
 		}
@@ -5423,7 +5424,7 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 			Preimage:      preimage,
 			ClaimOutpoint: op,
 			CsvDelay:      csvDelay,
-			SweepSignDesc: SignDescriptor{
+			SweepSignDesc: input.SignDescriptor{
 				KeyDesc:       localChanCfg.HtlcBasePoint,
 				SingleTweak:   keyRing.LocalHtlcKeyTweak,
 				WitnessScript: htlcSenderScript,
@@ -5452,14 +5453,14 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 
 	// Once we've created the second-level transaction, we'll generate the
 	// SignDesc needed spend the HTLC output using the success transaction.
-	htlcCreationScript, err := receiverHTLCScript(htlc.RefundTimeout,
+	htlcCreationScript, err := input.ReceiverHTLCScript(htlc.RefundTimeout,
 		keyRing.RemoteHtlcKey, keyRing.LocalHtlcKey,
 		keyRing.RevocationKey, htlc.RHash[:],
 	)
 	if err != nil {
 		return nil, err
 	}
-	successSignDesc := SignDescriptor{
+	successSignDesc := input.SignDescriptor{
 		KeyDesc:       localChanCfg.HtlcBasePoint,
 		SingleTweak:   keyRing.LocalHtlcKeyTweak,
 		WitnessScript: htlcCreationScript,
@@ -5473,7 +5474,7 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 
 	// Next, we'll construct the full witness needed to satisfy the input
 	// of the success transaction.
-	successWitness, err := receiverHtlcSpendRedeem(
+	successWitness, err := input.ReceiverHtlcSpendRedeem(
 		htlc.Signature, preimage[:], signer, &successSignDesc, successTx,
 	)
 	if err != nil {
@@ -5484,18 +5485,18 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 	// Finally, we'll generate the script that the second-level transaction
 	// creates so we can generate the proper signDesc to sweep it after the
 	// CSV delay has passed.
-	htlcSweepScript, err := secondLevelHtlcScript(
+	htlcSweepScript, err := input.SecondLevelHtlcScript(
 		keyRing.RevocationKey, keyRing.DelayKey, csvDelay,
 	)
 	if err != nil {
 		return nil, err
 	}
-	htlcScriptHash, err := WitnessScriptHash(htlcSweepScript)
+	htlcScriptHash, err := input.WitnessScriptHash(htlcSweepScript)
 	if err != nil {
 		return nil, err
 	}
 
-	localDelayTweak := SingleTweakBytes(
+	localDelayTweak := input.SingleTweakBytes(
 		keyRing.CommitPoint, localChanCfg.DelayBasePoint.PubKey,
 	)
 	return &IncomingHtlcResolution{
@@ -5506,7 +5507,7 @@ func newIncomingHtlcResolution(signer Signer, localChanCfg *channeldb.ChannelCon
 			Hash:  successTx.TxHash(),
 			Index: 0,
 		},
-		SweepSignDesc: SignDescriptor{
+		SweepSignDesc: input.SignDescriptor{
 			KeyDesc:       localChanCfg.DelayBasePoint,
 			SingleTweak:   localDelayTweak,
 			WitnessScript: htlcSweepScript,
@@ -5547,7 +5548,7 @@ func (r *OutgoingHtlcResolution) HtlcPoint() wire.OutPoint {
 // the local key used when generating the HTLC scrips. This function is to be
 // used in two cases: force close, or a unilateral close.
 func extractHtlcResolutions(feePerKw SatPerKWeight, ourCommit bool,
-	signer Signer, htlcs []channeldb.HTLC, keyRing *CommitmentKeyRing,
+	signer input.Signer, htlcs []channeldb.HTLC, keyRing *CommitmentKeyRing,
 	localChanCfg, remoteChanCfg *channeldb.ChannelConfig,
 	commitHash chainhash.Hash, pCache PreimageCache) (*HtlcResolutions, error) {
 
@@ -5692,7 +5693,7 @@ func (lc *LightningChannel) ForceClose() (*LocalForceCloseSummary, error) {
 // NewLocalForceCloseSummary generates a LocalForceCloseSummary from the given
 // channel state.  The passed commitTx must be a fully signed commitment
 // transaction corresponding to localCommit.
-func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
+func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer input.Signer,
 	pCache PreimageCache, commitTx *wire.MsgTx,
 	localCommit channeldb.ChannelCommitment) (*LocalForceCloseSummary, error) {
 
@@ -5707,15 +5708,15 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 	if err != nil {
 		return nil, err
 	}
-	commitPoint := ComputeCommitmentPoint(revocation[:])
+	commitPoint := input.ComputeCommitmentPoint(revocation[:])
 	keyRing := deriveCommitmentKeys(commitPoint, true, &chanState.LocalChanCfg,
 		&chanState.RemoteChanCfg)
-	selfScript, err := CommitScriptToSelf(csvTimeout, keyRing.DelayKey,
+	selfScript, err := input.CommitScriptToSelf(csvTimeout, keyRing.DelayKey,
 		keyRing.RevocationKey)
 	if err != nil {
 		return nil, err
 	}
-	payToUsScriptHash, err := WitnessScriptHash(selfScript)
+	payToUsScriptHash, err := input.WitnessScriptHash(selfScript)
 	if err != nil {
 		return nil, err
 	}
@@ -5745,7 +5746,7 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 	// nil.
 	var commitResolution *CommitOutputResolution
 	if len(delayScript) != 0 {
-		singleTweak := SingleTweakBytes(
+		singleTweak := input.SingleTweakBytes(
 			commitPoint, chanState.LocalChanCfg.DelayBasePoint.PubKey,
 		)
 		localBalance := localCommit.LocalBalance
@@ -5754,7 +5755,7 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 				Hash:  commitTx.TxHash(),
 				Index: delayIndex,
 			},
-			SelfOutputSignDesc: SignDescriptor{
+			SelfOutputSignDesc: input.SignDescriptor{
 				KeyDesc:       chanState.LocalChanCfg.DelayBasePoint,
 				SingleTweak:   singleTweak,
 				WitnessScript: selfScript,
@@ -5916,7 +5917,7 @@ func (lc *LightningChannel) CompleteCooperativeClose(localSig, remoteSig []byte,
 	// pubkeys+sigs on the stack.
 	ourKey := lc.localChanCfg.MultiSigKey.PubKey.SerializeCompressed()
 	theirKey := lc.remoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
-	witness := SpendMultiSig(lc.signDesc.WitnessScript, ourKey,
+	witness := input.SpendMultiSig(lc.signDesc.WitnessScript, ourKey,
 		localSig, theirKey, remoteSig)
 	closeTx.TxIn[0].Witness = witness
 
@@ -6121,7 +6122,7 @@ func (lc *LightningChannel) generateRevocation(height uint64) (*lnwire.RevokeAnd
 		return nil, err
 	}
 
-	revocationMsg.NextRevocationKey = ComputeCommitmentPoint(nextCommitSecret[:])
+	revocationMsg.NextRevocationKey = input.ComputeCommitmentPoint(nextCommitSecret[:])
 	revocationMsg.ChanID = lnwire.NewChanIDFromOutPoint(
 		&lc.channelState.FundingOutpoint)
 
@@ -6142,19 +6143,19 @@ func CreateCommitTx(fundingOutput wire.TxIn,
 	// output after a relative block delay, or the remote node can claim
 	// the funds with the revocation key if we broadcast a revoked
 	// commitment transaction.
-	ourRedeemScript, err := CommitScriptToSelf(csvTimeout, keyRing.DelayKey,
+	ourRedeemScript, err := input.CommitScriptToSelf(csvTimeout, keyRing.DelayKey,
 		keyRing.RevocationKey)
 	if err != nil {
 		return nil, err
 	}
-	payToUsScriptHash, err := WitnessScriptHash(ourRedeemScript)
+	payToUsScriptHash, err := input.WitnessScriptHash(ourRedeemScript)
 	if err != nil {
 		return nil, err
 	}
 
 	// Next, we create the script paying to them. This is just a regular
 	// P2WPKH output, without any added CSV delay.
-	theirWitnessKeyHash, err := CommitScriptUnencumbered(keyRing.NoDelayKey)
+	theirWitnessKeyHash, err := input.CommitScriptUnencumbered(keyRing.NoDelayKey)
 	if err != nil {
 		return nil, err
 	}
@@ -6223,7 +6224,7 @@ func CreateCooperativeCloseTx(fundingTxIn wire.TxIn,
 // CalcFee returns the commitment fee to use for the given
 // fee rate (fee-per-kw).
 func (lc *LightningChannel) CalcFee(feeRate SatPerKWeight) btcutil.Amount {
-	return feeRate.FeeForWeight(CommitWeight)
+	return feeRate.FeeForWeight(input.CommitWeight)
 }
 
 // RemoteNextRevocation returns the channelState's RemoteNextRevocation.

lnwallet/channel_test.go

@@ -18,6 +18,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -403,7 +404,7 @@ func TestCheckCommitTxSize(t *testing.T) {
 		}
 
 		actualCost := blockchain.GetTransactionWeight(btcutil.NewTx(commitTx))
-		estimatedCost := estimateCommitTxWeight(count, false)
+		estimatedCost := input.EstimateCommitTxWeight(count, false)
 
 		diff := int(estimatedCost - actualCost)
 		if 0 > diff || BaseCommitmentTxSizeEstimationError < diff {
@@ -624,7 +625,7 @@ func TestForceClose(t *testing.T) {
 
 	// Factoring in the fee rate, Alice's amount should properly reflect
 	// that we've added two additional HTLC to the commitment transaction.
-	totalCommitWeight := CommitWeight + (HtlcWeight * 2)
+	totalCommitWeight := input.CommitWeight + (input.HtlcWeight * 2)
 	feePerKw := SatPerKWeight(aliceChannel.channelState.LocalCommitment.FeePerKw)
 	commitFee := feePerKw.FeeForWeight(totalCommitWeight)
 	expectedAmount := (aliceChannel.Capacity / 2) - htlcAmount.ToSatoshis() - commitFee
@@ -680,7 +681,7 @@ func TestForceClose(t *testing.T) {
 		Value:    htlcResolution.SweepSignDesc.Output.Value,
 	})
 	htlcResolution.SweepSignDesc.InputIndex = 0
-	sweepTx.TxIn[0].Witness, err = htlcSpendSuccess(aliceChannel.Signer,
+	sweepTx.TxIn[0].Witness, err = input.HtlcSpendSuccess(aliceChannel.Signer,
 		&htlcResolution.SweepSignDesc, sweepTx,
 		uint32(aliceChannel.channelState.LocalChanCfg.CsvDelay))
 	if err != nil {
@@ -741,7 +742,7 @@ func TestForceClose(t *testing.T) {
 		Value:    inHtlcResolution.SweepSignDesc.Output.Value,
 	})
 	inHtlcResolution.SweepSignDesc.InputIndex = 0
-	sweepTx.TxIn[0].Witness, err = htlcSpendSuccess(aliceChannel.Signer,
+	sweepTx.TxIn[0].Witness, err = input.HtlcSpendSuccess(aliceChannel.Signer,
 		&inHtlcResolution.SweepSignDesc, sweepTx,
 		uint32(aliceChannel.channelState.LocalChanCfg.CsvDelay))
 	if err != nil {
@@ -5007,7 +5008,7 @@ func TestChannelUnilateralCloseHtlcResolution(t *testing.T) {
 
 	// With the transaction constructed, we'll generate a witness that
 	// should be valid for it, and verify using an instance of Script.
-	sweepTx.TxIn[0].Witness, err = receiverHtlcSpendTimeout(
+	sweepTx.TxIn[0].Witness, err = input.ReceiverHtlcSpendTimeout(
 		aliceChannel.Signer, &outHtlcResolution.SweepSignDesc,
 		sweepTx, int32(outHtlcResolution.Expiry),
 	)
@@ -5041,7 +5042,7 @@ func TestChannelUnilateralCloseHtlcResolution(t *testing.T) {
 	inHtlcResolution.SweepSignDesc.SigHashes = txscript.NewTxSigHashes(
 		sweepTx,
 	)
-	sweepTx.TxIn[0].Witness, err = SenderHtlcSpendRedeem(
+	sweepTx.TxIn[0].Witness, err = input.SenderHtlcSpendRedeem(
 		aliceChannel.Signer, &inHtlcResolution.SweepSignDesc,
 		sweepTx, preimageBob[:],
 	)
@@ -5172,7 +5173,7 @@ func TestChannelUnilateralClosePendingCommit(t *testing.T) {
 		Value:    aliceSignDesc.Output.Value,
 	})
 	aliceSignDesc.SigHashes = txscript.NewTxSigHashes(sweepTx)
-	sweepTx.TxIn[0].Witness, err = CommitSpendNoDelay(
+	sweepTx.TxIn[0].Witness, err = input.CommitSpendNoDelay(
 		aliceChannel.Signer, &aliceSignDesc, sweepTx,
 	)
 	if err != nil {

lnwallet/config.go

@@ -4,6 +4,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 )
 
@@ -37,7 +38,7 @@ type Config struct {
 	// used to generate signature for all inputs to potential funding
 	// transactions, as well as for spends from the funding transaction to
 	// update the commitment state.
-	Signer Signer
+	Signer input.Signer
 
 	// FeeEstimator is the implementation that the wallet will use for the
 	// calculation of on-chain transaction fees.

lnwallet/interface.go

@@ -253,30 +253,6 @@ type BlockChainIO interface {
 	GetBlock(blockHash *chainhash.Hash) (*wire.MsgBlock, error)
 }
 
-// Signer represents an abstract object capable of generating raw signatures as
-// well as full complete input scripts given a valid SignDescriptor and
-// transaction. This interface fully abstracts away signing paving the way for
-// Signer implementations such as hardware wallets, hardware tokens, HSM's, or
-// simply a regular wallet.
-type Signer interface {
-	// SignOutputRaw generates a signature for the passed transaction
-	// according to the data within the passed SignDescriptor.
-	//
-	// NOTE: The resulting signature should be void of a sighash byte.
-	SignOutputRaw(tx *wire.MsgTx, signDesc *SignDescriptor) ([]byte, error)
-
-	// ComputeInputScript generates a complete InputIndex for the passed
-	// transaction with the signature as defined within the passed
-	// SignDescriptor. This method should be capable of generating the
-	// proper input script for both regular p2wkh output and p2wkh outputs
-	// nested within a regular p2sh output.
-	//
-	// NOTE: This method will ignore any tweak parameters set within the
-	// passed SignDescriptor as it assumes a set of typical script
-	// templates (p2wkh, np2wkh, etc).
-	ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor) (*InputScript, error)
-}
-
 // MessageSigner represents an abstract object capable of signing arbitrary
 // messages. The capabilities of this interface are used to sign announcements
 // to the network, or just arbitrary messages that leverage the wallet's keys

lnwallet/interface_test.go

@@ -35,6 +35,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
@@ -353,7 +354,7 @@ func loadTestCredits(miner *rpctest.Harness, w *lnwallet.LightningWallet,
 func createTestWallet(tempTestDir string, miningNode *rpctest.Harness,
 	netParams *chaincfg.Params, notifier chainntnfs.ChainNotifier,
 	wc lnwallet.WalletController, keyRing keychain.SecretKeyRing,
-	signer lnwallet.Signer, bio lnwallet.BlockChainIO) (*lnwallet.LightningWallet, error) {
+	signer input.Signer, bio lnwallet.BlockChainIO) (*lnwallet.LightningWallet, error) {
 
 	dbDir := filepath.Join(tempTestDir, "cdb")
 	cdb, err := channeldb.Open(dbDir)
@@ -434,7 +435,7 @@ func testDualFundingReservationWorkflow(miner *rpctest.Harness,
 		ChanReserve:      fundingAmount / 100,
 		MaxPendingAmount: lnwire.NewMSatFromSatoshis(fundingAmount),
 		MinHTLC:          1,
-		MaxAcceptedHtlcs: lnwallet.MaxHTLCNumber / 2,
+		MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 		CsvDelay:         csvDelay,
 	}
 	err = aliceChanReservation.CommitConstraints(channelConstraints)
@@ -866,7 +867,7 @@ func testSingleFunderReservationWorkflow(miner *rpctest.Harness,
 		ChanReserve:      fundingAmt / 100,
 		MaxPendingAmount: lnwire.NewMSatFromSatoshis(fundingAmt),
 		MinHTLC:          1,
-		MaxAcceptedHtlcs: lnwallet.MaxHTLCNumber / 2,
+		MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 		CsvDelay:         csvDelay,
 	}
 	err = aliceChanReservation.CommitConstraints(channelConstraints)
@@ -1528,7 +1529,7 @@ func testPublishTransaction(r *rpctest.Harness,
 
 		// Now we can populate the sign descriptor which we'll use to
 		// generate the signature.
-		signDesc := &lnwallet.SignDescriptor{
+		signDesc := &input.SignDescriptor{
 			KeyDesc: keychain.KeyDescriptor{
 				PubKey: pubKey.PubKey,
 			},
@@ -1783,10 +1784,10 @@ func testSignOutputUsingTweaks(r *rpctest.Harness,
 	commitSecret, commitPoint := btcec.PrivKeyFromBytes(btcec.S256(),
 		commitPreimage)
 
-	revocationKey := lnwallet.DeriveRevocationPubkey(pubKey.PubKey, commitPoint)
+	revocationKey := input.DeriveRevocationPubkey(pubKey.PubKey, commitPoint)
-	commitTweak := lnwallet.SingleTweakBytes(commitPoint, pubKey.PubKey)
+	commitTweak := input.SingleTweakBytes(commitPoint, pubKey.PubKey)
 
-	tweakedPub := lnwallet.TweakPubKey(pubKey.PubKey, commitPoint)
+	tweakedPub := input.TweakPubKey(pubKey.PubKey, commitPoint)
 
 	// As we'd like to test both single and double tweaks, we'll repeat
 	// the same set up twice. The first will use a regular single tweak,
@@ -1856,7 +1857,7 @@ func testSignOutputUsingTweaks(r *rpctest.Harness,
 		// private tweak value as the key in the script is derived
 		// based on this tweak value and the key we originally
 		// generated above.
-		signDesc := &lnwallet.SignDescriptor{
+		signDesc := &input.SignDescriptor{
 			KeyDesc: keychain.KeyDescriptor{
 				PubKey: baseKey.PubKey,
 			},
@@ -2392,8 +2393,8 @@ func runTests(t *testing.T, walletDriver *lnwallet.WalletDriver,
 	var (
 		bio lnwallet.BlockChainIO
 
-		aliceSigner lnwallet.Signer
+		aliceSigner input.Signer
-		bobSigner   lnwallet.Signer
+		bobSigner   input.Signer
 
 		aliceKeyRing keychain.SecretKeyRing
 		bobKeyRing   keychain.SecretKeyRing

lnwallet/parameters.go

@@ -3,10 +3,11 @@ package lnwallet
 import (
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcwallet/wallet/txrules"
+	"github.com/lightningnetwork/lnd/input"
 )
 
 // DefaultDustLimit is used to calculate the dust HTLC amount which will be
 // send to other node during funding process.
 func DefaultDustLimit() btcutil.Amount {
-	return txrules.GetDustThreshold(P2WSHSize, txrules.DefaultRelayFeePerKb)
+	return txrules.GetDustThreshold(input.P2WSHSize, txrules.DefaultRelayFeePerKb)
 }

lnwallet/reservation.go

@@ -9,6 +9,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -49,18 +50,6 @@ func (c *ChannelContribution) toChanConfig() channeldb.ChannelConfig {
 	return *c.ChannelConfig
 }
 
-// InputScript represents any script inputs required to redeem a previous
-// output. This struct is used rather than just a witness, or scripSig in order
-// to accommodate nested p2sh which utilizes both types of input scripts.
-type InputScript struct {
-	// Witness is the full witness stack required to unlock this output.
-	Witness wire.TxWitness
-
-	// SigScript will only be populated if this is an input script sweeping
-	// a nested p2sh output.
-	SigScript []byte
-}
-
 // ChannelReservation represents an intent to open a lightning payment channel
 // with a counterparty. The funding processes from reservation to channel opening
 // is a 3-step process. In order to allow for full concurrency during the
@@ -102,8 +91,8 @@ type ChannelReservation struct {
 
 	// In order of sorted inputs. Sorting is done in accordance
 	// to BIP-69: https://github.com/bitcoin/bips/blob/master/bip-0069.mediawiki.
-	ourFundingInputScripts   []*InputScript
+	ourFundingInputScripts   []*input.Script
-	theirFundingInputScripts []*InputScript
+	theirFundingInputScripts []*input.Script
 
 	// Our signature for their version of the commitment transaction.
 	ourCommitmentSig   []byte
@@ -149,7 +138,7 @@ func NewChannelReservation(capacity, fundingAmt btcutil.Amount,
 		initiator    bool
 	)
 
-	commitFee := commitFeePerKw.FeeForWeight(CommitWeight)
+	commitFee := commitFeePerKw.FeeForWeight(input.CommitWeight)
 	fundingMSat := lnwire.NewMSatFromSatoshis(fundingAmt)
 	capacityMSat := lnwire.NewMSatFromSatoshis(capacity)
 	feeMSat := lnwire.NewMSatFromSatoshis(commitFee)
@@ -320,9 +309,9 @@ func (r *ChannelReservation) CommitConstraints(c *channeldb.ChannelConstraints)
 
 	// Fail if maxHtlcs is above the maximum allowed number of 483.  This
 	// number is specified in BOLT-02.
-	if c.MaxAcceptedHtlcs > uint16(MaxHTLCNumber/2) {
+	if c.MaxAcceptedHtlcs > uint16(input.MaxHTLCNumber/2) {
 		return ErrMaxHtlcNumTooLarge(
-			c.MaxAcceptedHtlcs, uint16(MaxHTLCNumber/2),
+			c.MaxAcceptedHtlcs, uint16(input.MaxHTLCNumber/2),
 		)
 	}
 
@@ -424,7 +413,7 @@ func (r *ChannelReservation) TheirContribution() *ChannelContribution {
 //
 // NOTE: These signatures will only be populated after a call to
 // .ProcessContribution()
-func (r *ChannelReservation) OurSignatures() ([]*InputScript, []byte) {
+func (r *ChannelReservation) OurSignatures() ([]*input.Script, []byte) {
 	r.RLock()
 	defer r.RUnlock()
 	return r.ourFundingInputScripts, r.ourCommitmentSig
@@ -443,7 +432,7 @@ func (r *ChannelReservation) OurSignatures() ([]*InputScript, []byte) {
 // block until the funding transaction obtains the configured number of
 // confirmations. Once the method unblocks, a LightningChannel instance is
 // returned, marking the channel available for updates.
-func (r *ChannelReservation) CompleteReservation(fundingInputScripts []*InputScript,
+func (r *ChannelReservation) CompleteReservation(fundingInputScripts []*input.Script,
 	commitmentSig []byte) (*channeldb.OpenChannel, error) {
 
 	// TODO(roasbeef): add flag for watch or not?
@@ -494,7 +483,7 @@ func (r *ChannelReservation) CompleteReservationSingle(fundingPoint *wire.OutPoi
 //
 // NOTE: These attributes will be unpopulated before a call to
 // .CompleteReservation().
-func (r *ChannelReservation) TheirSignatures() ([]*InputScript, []byte) {
+func (r *ChannelReservation) TheirSignatures() ([]*input.Script, []byte) {
 	r.RLock()
 	defer r.RUnlock()
 	return r.theirFundingInputScripts, r.theirCommitmentSig

lnwallet/sigpool.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -76,7 +77,7 @@ type SignJob struct {
 	// SignDesc is intended to be a full populated SignDescriptor which
 	// encodes the necessary material (keys, witness script, etc) required
 	// to generate a valid signature for the specified input.
-	SignDesc SignDescriptor
+	SignDesc input.SignDescriptor
 
 	// Tx is the transaction to be signed. This is required to generate the
 	// proper sighash for the input to be signed.
@@ -127,7 +128,7 @@ type SigPool struct {
 	started uint32 // To be used atomically.
 	stopped uint32 // To be used atomically.
 
-	signer Signer
+	signer input.Signer
 
 	verifyJobs chan VerifyJob
 	signJobs   chan SignJob
@@ -141,7 +142,7 @@ type SigPool struct {
 // NewSigPool creates a new signature pool with the specified number of
 // workers. The recommended parameter for the number of works is the number of
 // physical CPU cores available on the target machine.
-func NewSigPool(numWorkers int, signer Signer) *SigPool {
+func NewSigPool(numWorkers int, signer input.Signer) *SigPool {
 	return &SigPool{
 		signer:     signer,
 		numWorkers: numWorkers,

lnwallet/size_test.go

@@ -8,7 +8,8 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
-	"github.com/lightningnetwork/lnd/lnwallet"
+
+	"github.com/lightningnetwork/lnd/input"
 )
 
 // TestTxWeightEstimator tests that transaction weight estimates are calculated
@@ -106,7 +107,7 @@ func TestTxWeightEstimator(t *testing.T) {
 	}
 
 	for i, test := range testCases {
-		var weightEstimate lnwallet.TxWeightEstimator
+		var weightEstimate input.TxWeightEstimator
 		tx := wire.NewMsgTx(1)
 
 		for j := 0; j < test.numP2PKHInputs; j++ {

lnwallet/test_utils.go

@@ -6,19 +6,17 @@ import (
 	"crypto/sha256"
 	"encoding/binary"
 	"encoding/hex"
-	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 	"sync"
 
 	"github.com/btcsuite/btcd/btcec"
-	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
-	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/shachain"
@@ -143,7 +141,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 			MaxPendingAmount: lnwire.NewMSatFromSatoshis(channelCapacity),
 			ChanReserve:      channelCapacity / 100,
 			MinHTLC:          0,
-			MaxAcceptedHtlcs: MaxHTLCNumber / 2,
+			MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 			CsvDelay:         uint16(csvTimeoutAlice),
 		},
 		MultiSigKey: keychain.KeyDescriptor{
@@ -168,7 +166,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 			MaxPendingAmount: lnwire.NewMSatFromSatoshis(channelCapacity),
 			ChanReserve:      channelCapacity / 100,
 			MinHTLC:          0,
-			MaxAcceptedHtlcs: MaxHTLCNumber / 2,
+			MaxAcceptedHtlcs: input.MaxHTLCNumber / 2,
 			CsvDelay:         uint16(csvTimeoutBob),
 		},
 		MultiSigKey: keychain.KeyDescriptor{
@@ -197,7 +195,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	bobCommitPoint := ComputeCommitmentPoint(bobFirstRevoke[:])
+	bobCommitPoint := input.ComputeCommitmentPoint(bobFirstRevoke[:])
 
 	aliceRoot, err := chainhash.NewHash(aliceKeys[0].Serialize())
 	if err != nil {
@@ -208,7 +206,7 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	aliceCommitPoint := ComputeCommitmentPoint(aliceFirstRevoke[:])
+	aliceCommitPoint := input.ComputeCommitmentPoint(aliceFirstRevoke[:])
 
 	aliceCommitTx, bobCommitTx, err := CreateCommitmentTxns(channelBal,
 		channelBal, &aliceCfg, &bobCfg, aliceCommitPoint, bobCommitPoint,
@@ -300,8 +298,8 @@ func CreateTestChannels() (*LightningChannel, *LightningChannel, func(), error)
 		Packager:                channeldb.NewChannelPackager(shortChanID),
 	}
 
-	aliceSigner := &mockSigner{privkeys: aliceKeys}
+	aliceSigner := &input.MockSigner{Privkeys: aliceKeys}
-	bobSigner := &mockSigner{privkeys: bobKeys}
+	bobSigner := &input.MockSigner{Privkeys: bobKeys}
 
 	pCache := &mockPreimageCache{
 		// hash -> preimage
@@ -389,118 +387,6 @@ func initRevocationWindows(chanA, chanB *LightningChannel) error {
 	return nil
 }
 
-// mockSigner is a simple implementation of the Signer interface. Each one has
-// a set of private keys in a slice and can sign messages using the appropriate
-// one.
-type mockSigner struct {
-	privkeys  []*btcec.PrivateKey
-	netParams *chaincfg.Params
-}
-
-func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx, signDesc *SignDescriptor) ([]byte, error) {
-	pubkey := signDesc.KeyDesc.PubKey
-	switch {
-	case signDesc.SingleTweak != nil:
-		pubkey = TweakPubKeyWithTweak(pubkey, signDesc.SingleTweak)
-	case signDesc.DoubleTweak != nil:
-		pubkey = DeriveRevocationPubkey(pubkey, signDesc.DoubleTweak.PubKey())
-	}
-
-	hash160 := btcutil.Hash160(pubkey.SerializeCompressed())
-	privKey := m.findKey(hash160, signDesc.SingleTweak, signDesc.DoubleTweak)
-	if privKey == nil {
-		return nil, fmt.Errorf("Mock signer does not have key")
-	}
-
-	sig, err := txscript.RawTxInWitnessSignature(tx, signDesc.SigHashes,
-		signDesc.InputIndex, signDesc.Output.Value, signDesc.WitnessScript,
-		txscript.SigHashAll, privKey)
-	if err != nil {
-		return nil, err
-	}
-
-	return sig[:len(sig)-1], nil
-}
-
-func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor) (*InputScript, error) {
-	scriptType, addresses, _, err := txscript.ExtractPkScriptAddrs(
-		signDesc.Output.PkScript, m.netParams)
-	if err != nil {
-		return nil, err
-	}
-
-	switch scriptType {
-	case txscript.PubKeyHashTy:
-		privKey := m.findKey(addresses[0].ScriptAddress(), signDesc.SingleTweak,
-			signDesc.DoubleTweak)
-		if privKey == nil {
-			return nil, fmt.Errorf("Mock signer does not have key for "+
-				"address %v", addresses[0])
-		}
-
-		sigScript, err := txscript.SignatureScript(
-			tx, signDesc.InputIndex, signDesc.Output.PkScript,
-			txscript.SigHashAll, privKey, true,
-		)
-		if err != nil {
-			return nil, err
-		}
-
-		return &InputScript{SigScript: sigScript}, nil
-
-	case txscript.WitnessV0PubKeyHashTy:
-		privKey := m.findKey(addresses[0].ScriptAddress(), signDesc.SingleTweak,
-			signDesc.DoubleTweak)
-		if privKey == nil {
-			return nil, fmt.Errorf("Mock signer does not have key for "+
-				"address %v", addresses[0])
-		}
-
-		witnessScript, err := txscript.WitnessSignature(tx, signDesc.SigHashes,
-			signDesc.InputIndex, signDesc.Output.Value,
-			signDesc.Output.PkScript, txscript.SigHashAll, privKey, true)
-		if err != nil {
-			return nil, err
-		}
-
-		return &InputScript{Witness: witnessScript}, nil
-
-	default:
-		return nil, fmt.Errorf("Unexpected script type: %v", scriptType)
-	}
-}
-
-// findKey searches through all stored private keys and returns one
-// corresponding to the hashed pubkey if it can be found. The public key may
-// either correspond directly to the private key or to the private key with a
-// tweak applied.
-func (m *mockSigner) findKey(needleHash160 []byte, singleTweak []byte,
-	doubleTweak *btcec.PrivateKey) *btcec.PrivateKey {
-
-	for _, privkey := range m.privkeys {
-		// First check whether public key is directly derived from private key.
-		hash160 := btcutil.Hash160(privkey.PubKey().SerializeCompressed())
-		if bytes.Equal(hash160, needleHash160) {
-			return privkey
-		}
-
-		// Otherwise check if public key is derived from tweaked private key.
-		switch {
-		case singleTweak != nil:
-			privkey = TweakPrivKey(privkey, singleTweak)
-		case doubleTweak != nil:
-			privkey = DeriveRevocationPrivKey(privkey, doubleTweak)
-		default:
-			continue
-		}
-		hash160 = btcutil.Hash160(privkey.PubKey().SerializeCompressed())
-		if bytes.Equal(hash160, needleHash160) {
-			return privkey
-		}
-	}
-	return nil
-}
-
 type mockPreimageCache struct {
 	sync.Mutex
 	preimageMap map[[32]byte][]byte

lnwallet/transactions.go

@@ -0,0 +1,202 @@
+package lnwallet
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/input"
+)
+
+const (
+	// StateHintSize is the total number of bytes used between the sequence
+	// number and locktime of the commitment transaction use to encode a hint
+	// to the state number of a particular commitment transaction.
+	StateHintSize = 6
+
+	// MaxStateHint is the maximum state number we're able to encode using
+	// StateHintSize bytes amongst the sequence number and locktime fields
+	// of the commitment transaction.
+	maxStateHint uint64 = (1 << 48) - 1
+)
+
+var (
+	// TimelockShift is used to make sure the commitment transaction is
+	// spendable by setting the locktime with it so that it is larger than
+	// 500,000,000, thus interpreting it as Unix epoch timestamp and not
+	// a block height. It is also smaller than the current timestamp which
+	// has bit (1 << 30) set, so there is no risk of having the commitment
+	// transaction be rejected. This way we can safely use the lower 24 bits
+	// of the locktime field for part of the obscured commitment transaction
+	// number.
+	TimelockShift = uint32(1 << 29)
+)
+
+// createHtlcSuccessTx creates a transaction that spends the output on the
+// commitment transaction of the peer that receives an HTLC. This transaction
+// essentially acts as an off-chain covenant as it's only permitted to spend
+// the designated HTLC output, and also that spend can _only_ be used as a
+// state transition to create another output which actually allows redemption
+// or revocation of an HTLC.
+//
+// In order to spend the HTLC output, the witness for the passed transaction
+// should be:
+//   * <0> <sender sig> <recvr sig> <preimage>
+func createHtlcSuccessTx(htlcOutput wire.OutPoint, htlcAmt btcutil.Amount,
+	csvDelay uint32,
+	revocationKey, delayKey *btcec.PublicKey) (*wire.MsgTx, error) {
+
+	// Create a version two transaction (as the success version of this
+	// spends an output with a CSV timeout).
+	successTx := wire.NewMsgTx(2)
+
+	// The input to the transaction is the outpoint that creates the
+	// original HTLC on the sender's commitment transaction.
+	successTx.AddTxIn(&wire.TxIn{
+		PreviousOutPoint: htlcOutput,
+	})
+
+	// Next, we'll generate the script used as the output for all second
+	// level HTLC which forces a covenant w.r.t what can be done with all
+	// HTLC outputs.
+	witnessScript, err := input.SecondLevelHtlcScript(revocationKey, delayKey,
+		csvDelay)
+	if err != nil {
+		return nil, err
+	}
+	pkScript, err := input.WitnessScriptHash(witnessScript)
+	if err != nil {
+		return nil, err
+	}
+
+	// Finally, the output is simply the amount of the HTLC (minus the
+	// required fees), paying to the timeout script.
+	successTx.AddTxOut(&wire.TxOut{
+		Value:    int64(htlcAmt),
+		PkScript: pkScript,
+	})
+
+	return successTx, nil
+}
+
+// createHtlcTimeoutTx creates a transaction that spends the HTLC output on the
+// commitment transaction of the peer that created an HTLC (the sender). This
+// transaction essentially acts as an off-chain covenant as it spends a 2-of-2
+// multi-sig output. This output requires a signature from both the sender and
+// receiver of the HTLC. By using a distinct transaction, we're able to
+// uncouple the timeout and delay clauses of the HTLC contract. This
+// transaction is locked with an absolute lock-time so the sender can only
+// attempt to claim the output using it after the lock time has passed.
+//
+// In order to spend the HTLC output, the witness for the passed transaction
+// should be:
+// * <0> <sender sig> <receiver sig> <0>
+//
+// NOTE: The passed amount for the HTLC should take into account the required
+// fee rate at the time the HTLC was created. The fee should be able to
+// entirely pay for this (tiny: 1-in 1-out) transaction.
+func createHtlcTimeoutTx(htlcOutput wire.OutPoint, htlcAmt btcutil.Amount,
+	cltvExpiry, csvDelay uint32,
+	revocationKey, delayKey *btcec.PublicKey) (*wire.MsgTx, error) {
+
+	// Create a version two transaction (as the success version of this
+	// spends an output with a CSV timeout), and set the lock-time to the
+	// specified absolute lock-time in blocks.
+	timeoutTx := wire.NewMsgTx(2)
+	timeoutTx.LockTime = cltvExpiry
+
+	// The input to the transaction is the outpoint that creates the
+	// original HTLC on the sender's commitment transaction.
+	timeoutTx.AddTxIn(&wire.TxIn{
+		PreviousOutPoint: htlcOutput,
+	})
+
+	// Next, we'll generate the script used as the output for all second
+	// level HTLC which forces a covenant w.r.t what can be done with all
+	// HTLC outputs.
+	witnessScript, err := input.SecondLevelHtlcScript(revocationKey, delayKey,
+		csvDelay)
+	if err != nil {
+		return nil, err
+	}
+	pkScript, err := input.WitnessScriptHash(witnessScript)
+	if err != nil {
+		return nil, err
+	}
+
+	// Finally, the output is simply the amount of the HTLC (minus the
+	// required fees), paying to the regular second level HTLC script.
+	timeoutTx.AddTxOut(&wire.TxOut{
+		Value:    int64(htlcAmt),
+		PkScript: pkScript,
+	})
+
+	return timeoutTx, nil
+}
+
+// SetStateNumHint encodes the current state number within the passed
+// commitment transaction by re-purposing the locktime and sequence fields in
+// the commitment transaction to encode the obfuscated state number.  The state
+// number is encoded using 48 bits. The lower 24 bits of the lock time are the
+// lower 24 bits of the obfuscated state number and the lower 24 bits of the
+// sequence field are the higher 24 bits. Finally before encoding, the
+// obfuscator is XOR'd against the state number in order to hide the exact
+// state number from the PoV of outside parties.
+func SetStateNumHint(commitTx *wire.MsgTx, stateNum uint64,
+	obfuscator [StateHintSize]byte) error {
+
+	// With the current schema we are only able to encode state num
+	// hints up to 2^48. Therefore if the passed height is greater than our
+	// state hint ceiling, then exit early.
+	if stateNum > maxStateHint {
+		return fmt.Errorf("unable to encode state, %v is greater "+
+			"state num that max of %v", stateNum, maxStateHint)
+	}
+
+	if len(commitTx.TxIn) != 1 {
+		return fmt.Errorf("commitment tx must have exactly 1 input, "+
+			"instead has %v", len(commitTx.TxIn))
+	}
+
+	// Convert the obfuscator into a uint64, then XOR that against the
+	// targeted height in order to obfuscate the state number of the
+	// commitment transaction in the case that either commitment
+	// transaction is broadcast directly on chain.
+	var obfs [8]byte
+	copy(obfs[2:], obfuscator[:])
+	xorInt := binary.BigEndian.Uint64(obfs[:])
+
+	stateNum = stateNum ^ xorInt
+
+	// Set the height bit of the sequence number in order to disable any
+	// sequence locks semantics.
+	commitTx.TxIn[0].Sequence = uint32(stateNum>>24) | wire.SequenceLockTimeDisabled
+	commitTx.LockTime = uint32(stateNum&0xFFFFFF) | TimelockShift
+
+	return nil
+}
+
+// GetStateNumHint recovers the current state number given a commitment
+// transaction which has previously had the state number encoded within it via
+// setStateNumHint and a shared obfuscator.
+//
+// See setStateNumHint for further details w.r.t exactly how the state-hints
+// are encoded.
+func GetStateNumHint(commitTx *wire.MsgTx, obfuscator [StateHintSize]byte) uint64 {
+	// Convert the obfuscator into a uint64, this will be used to
+	// de-obfuscate the final recovered state number.
+	var obfs [8]byte
+	copy(obfs[2:], obfuscator[:])
+	xorInt := binary.BigEndian.Uint64(obfs[:])
+
+	// Retrieve the state hint from the sequence number and locktime
+	// of the transaction.
+	stateNumXor := uint64(commitTx.TxIn[0].Sequence&0xFFFFFF) << 24
+	stateNumXor |= uint64(commitTx.LockTime & 0xFFFFFF)
+
+	// Finally, to obtain the final state number, we XOR by the obfuscator
+	// value to de-obfuscate the state number.
+	return stateNumXor ^ xorInt
+}

lnwallet/transactions_test.go

@@ -5,14 +5,17 @@ import (
 	"encoding/hex"
 	"fmt"
 	"testing"
+	"time"
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/shachain"
@@ -378,7 +381,7 @@ func TestCommitmentAndHTLCTransactions(t *testing.T) {
 			ChannelConstraints: channeldb.ChannelConstraints{
 				DustLimit:        tc.dustLimit,
 				MaxPendingAmount: lnwire.NewMSatFromSatoshis(tc.fundingAmount),
-				MaxAcceptedHtlcs: MaxHTLCNumber,
+				MaxAcceptedHtlcs: input.MaxHTLCNumber,
 				CsvDelay:         tc.localCsvDelay,
 			},
 			MultiSigKey: keychain.KeyDescriptor{
@@ -408,11 +411,11 @@ func TestCommitmentAndHTLCTransactions(t *testing.T) {
 		Capacity:           tc.fundingAmount,
 		RevocationProducer: shachain.NewRevocationProducer(zeroHash),
 	}
-	signer := &mockSigner{
+	signer := &input.MockSigner{
-		privkeys: []*btcec.PrivateKey{
+		Privkeys: []*btcec.PrivateKey{
 			tc.localFundingPrivKey, tc.localPaymentPrivKey,
 		},
-		netParams: tc.netParams,
+		NetParams: tc.netParams,
 	}
 
 	// Construct a LightningChannel manually because we don't have nor need all
@@ -431,7 +434,7 @@ func TestCommitmentAndHTLCTransactions(t *testing.T) {
 
 	// The commitmentPoint is technically hidden in the spec, but we need it to
 	// generate the correct tweak.
-	tweak := SingleTweakBytes(tc.commitmentPoint, tc.localPaymentBasePoint)
+	tweak := input.SingleTweakBytes(tc.commitmentPoint, tc.localPaymentBasePoint)
 	keys := &CommitmentKeyRing{
 		CommitPoint:         tc.commitmentPoint,
 		LocalCommitKeyTweak: tweak,
@@ -910,3 +913,299 @@ func htlcViewFromHTLCs(htlcs []channeldb.HTLC) *htlcView {
 	}
 	return &theHTLCView
 }
+
+func TestCommitTxStateHint(t *testing.T) {
+	t.Parallel()
+
+	stateHintTests := []struct {
+		name       string
+		from       uint64
+		to         uint64
+		inputs     int
+		shouldFail bool
+	}{
+		{
+			name:       "states 0 to 1000",
+			from:       0,
+			to:         1000,
+			inputs:     1,
+			shouldFail: false,
+		},
+		{
+			name:       "states 'maxStateHint-1000' to 'maxStateHint'",
+			from:       maxStateHint - 1000,
+			to:         maxStateHint,
+			inputs:     1,
+			shouldFail: false,
+		},
+		{
+			name:       "state 'maxStateHint+1'",
+			from:       maxStateHint + 1,
+			to:         maxStateHint + 10,
+			inputs:     1,
+			shouldFail: true,
+		},
+		{
+			name:       "commit transaction with two inputs",
+			inputs:     2,
+			shouldFail: true,
+		},
+	}
+
+	var obfuscator [StateHintSize]byte
+	copy(obfuscator[:], testHdSeed[:StateHintSize])
+	timeYesterday := uint32(time.Now().Unix() - 24*60*60)
+
+	for _, test := range stateHintTests {
+		commitTx := wire.NewMsgTx(2)
+
+		// Add supplied number of inputs to the commitment transaction.
+		for i := 0; i < test.inputs; i++ {
+			commitTx.AddTxIn(&wire.TxIn{})
+		}
+
+		for i := test.from; i <= test.to; i++ {
+			stateNum := uint64(i)
+
+			err := SetStateNumHint(commitTx, stateNum, obfuscator)
+			if err != nil && !test.shouldFail {
+				t.Fatalf("unable to set state num %v: %v", i, err)
+			} else if err == nil && test.shouldFail {
+				t.Fatalf("Failed(%v): test should fail but did not", test.name)
+			}
+
+			locktime := commitTx.LockTime
+			sequence := commitTx.TxIn[0].Sequence
+
+			// Locktime should not be less than 500,000,000 and not larger
+			// than the time 24 hours ago. One day should provide a good
+			// enough buffer for the tests.
+			if locktime < 5e8 || locktime > timeYesterday {
+				if !test.shouldFail {
+					t.Fatalf("The value of locktime (%v) may cause the commitment "+
+						"transaction to be unspendable", locktime)
+				}
+			}
+
+			if sequence&wire.SequenceLockTimeDisabled == 0 {
+				if !test.shouldFail {
+					t.Fatalf("Sequence locktime is NOT disabled when it should be")
+				}
+			}
+
+			extractedStateNum := GetStateNumHint(commitTx, obfuscator)
+			if extractedStateNum != stateNum && !test.shouldFail {
+				t.Fatalf("state number mismatched, expected %v, got %v",
+					stateNum, extractedStateNum)
+			} else if extractedStateNum == stateNum && test.shouldFail {
+				t.Fatalf("Failed(%v): test should fail but did not", test.name)
+			}
+		}
+		t.Logf("Passed: %v", test.name)
+	}
+}
+
+// TestCommitmentSpendValidation test the spendability of both outputs within
+// the commitment transaction.
+//
+// The following spending cases are covered by this test:
+//   * Alice's spend from the delayed output on her commitment transaction.
+//   * Bob's spend from Alice's delayed output when she broadcasts a revoked
+//     commitment transaction.
+//   * Bob's spend from his unencumbered output within Alice's commitment
+//     transaction.
+func TestCommitmentSpendValidation(t *testing.T) {
+	t.Parallel()
+
+	// We generate a fake output, and the corresponding txin. This output
+	// doesn't need to exist, as we'll only be validating spending from the
+	// transaction that references this.
+	txid, err := chainhash.NewHash(testHdSeed.CloneBytes())
+	if err != nil {
+		t.Fatalf("unable to create txid: %v", err)
+	}
+	fundingOut := &wire.OutPoint{
+		Hash:  *txid,
+		Index: 50,
+	}
+	fakeFundingTxIn := wire.NewTxIn(fundingOut, nil, nil)
+
+	const channelBalance = btcutil.Amount(1 * 10e8)
+	const csvTimeout = uint32(5)
+
+	// We also set up set some resources for the commitment transaction.
+	// Each side currently has 1 BTC within the channel, with a total
+	// channel capacity of 2BTC.
+	aliceKeyPriv, aliceKeyPub := btcec.PrivKeyFromBytes(btcec.S256(),
+		testWalletPrivKey)
+	bobKeyPriv, bobKeyPub := btcec.PrivKeyFromBytes(btcec.S256(),
+		bobsPrivKey)
+
+	revocationPreimage := testHdSeed.CloneBytes()
+	commitSecret, commitPoint := btcec.PrivKeyFromBytes(btcec.S256(),
+		revocationPreimage)
+	revokePubKey := input.DeriveRevocationPubkey(bobKeyPub, commitPoint)
+
+	aliceDelayKey := input.TweakPubKey(aliceKeyPub, commitPoint)
+	bobPayKey := input.TweakPubKey(bobKeyPub, commitPoint)
+
+	aliceCommitTweak := input.SingleTweakBytes(commitPoint, aliceKeyPub)
+	bobCommitTweak := input.SingleTweakBytes(commitPoint, bobKeyPub)
+
+	aliceSelfOutputSigner := &input.MockSigner{
+		Privkeys: []*btcec.PrivateKey{aliceKeyPriv},
+	}
+
+	// With all the test data set up, we create the commitment transaction.
+	// We only focus on a single party's transactions, as the scripts are
+	// identical with the roles reversed.
+	//
+	// This is Alice's commitment transaction, so she must wait a CSV delay
+	// of 5 blocks before sweeping the output, while bob can spend
+	// immediately with either the revocation key, or his regular key.
+	keyRing := &CommitmentKeyRing{
+		DelayKey:      aliceDelayKey,
+		RevocationKey: revokePubKey,
+		NoDelayKey:    bobPayKey,
+	}
+	commitmentTx, err := CreateCommitTx(*fakeFundingTxIn, keyRing, csvTimeout,
+		channelBalance, channelBalance, DefaultDustLimit())
+	if err != nil {
+		t.Fatalf("unable to create commitment transaction: %v", nil)
+	}
+
+	delayOutput := commitmentTx.TxOut[0]
+	regularOutput := commitmentTx.TxOut[1]
+
+	// We're testing an uncooperative close, output sweep, so construct a
+	// transaction which sweeps the funds to a random address.
+	targetOutput, err := input.CommitScriptUnencumbered(aliceKeyPub)
+	if err != nil {
+		t.Fatalf("unable to create target output: %v", err)
+	}
+	sweepTx := wire.NewMsgTx(2)
+	sweepTx.AddTxIn(wire.NewTxIn(&wire.OutPoint{
+		Hash:  commitmentTx.TxHash(),
+		Index: 0,
+	}, nil, nil))
+	sweepTx.AddTxOut(&wire.TxOut{
+		PkScript: targetOutput,
+		Value:    0.5 * 10e8,
+	})
+
+	// First, we'll test spending with Alice's key after the timeout.
+	delayScript, err := input.CommitScriptToSelf(csvTimeout, aliceDelayKey,
+		revokePubKey)
+	if err != nil {
+		t.Fatalf("unable to generate alice delay script: %v", err)
+	}
+	sweepTx.TxIn[0].Sequence = input.LockTimeToSequence(false, csvTimeout)
+	signDesc := &input.SignDescriptor{
+		WitnessScript: delayScript,
+		KeyDesc: keychain.KeyDescriptor{
+			PubKey: aliceKeyPub,
+		},
+		SingleTweak: aliceCommitTweak,
+		SigHashes:   txscript.NewTxSigHashes(sweepTx),
+		Output: &wire.TxOut{
+			Value: int64(channelBalance),
+		},
+		HashType:   txscript.SigHashAll,
+		InputIndex: 0,
+	}
+	aliceWitnessSpend, err := input.CommitSpendTimeout(aliceSelfOutputSigner,
+		signDesc, sweepTx)
+	if err != nil {
+		t.Fatalf("unable to generate delay commit spend witness: %v", err)
+	}
+	sweepTx.TxIn[0].Witness = aliceWitnessSpend
+	vm, err := txscript.NewEngine(delayOutput.PkScript,
+		sweepTx, 0, txscript.StandardVerifyFlags, nil,
+		nil, int64(channelBalance))
+	if err != nil {
+		t.Fatalf("unable to create engine: %v", err)
+	}
+	if err := vm.Execute(); err != nil {
+		t.Fatalf("spend from delay output is invalid: %v", err)
+	}
+
+	bobSigner := &input.MockSigner{Privkeys: []*btcec.PrivateKey{bobKeyPriv}}
+
+	// Next, we'll test bob spending with the derived revocation key to
+	// simulate the scenario when Alice broadcasts this commitment
+	// transaction after it's been revoked.
+	signDesc = &input.SignDescriptor{
+		KeyDesc: keychain.KeyDescriptor{
+			PubKey: bobKeyPub,
+		},
+		DoubleTweak:   commitSecret,
+		WitnessScript: delayScript,
+		SigHashes:     txscript.NewTxSigHashes(sweepTx),
+		Output: &wire.TxOut{
+			Value: int64(channelBalance),
+		},
+		HashType:   txscript.SigHashAll,
+		InputIndex: 0,
+	}
+	bobWitnessSpend, err := input.CommitSpendRevoke(bobSigner, signDesc,
+		sweepTx)
+	if err != nil {
+		t.Fatalf("unable to generate revocation witness: %v", err)
+	}
+	sweepTx.TxIn[0].Witness = bobWitnessSpend
+	vm, err = txscript.NewEngine(delayOutput.PkScript,
+		sweepTx, 0, txscript.StandardVerifyFlags, nil,
+		nil, int64(channelBalance))
+	if err != nil {
+		t.Fatalf("unable to create engine: %v", err)
+	}
+	if err := vm.Execute(); err != nil {
+		t.Fatalf("revocation spend is invalid: %v", err)
+	}
+
+	// In order to test the final scenario, we modify the TxIn of the sweep
+	// transaction to instead point to the regular output (non delay)
+	// within the commitment transaction.
+	sweepTx.TxIn[0] = &wire.TxIn{
+		PreviousOutPoint: wire.OutPoint{
+			Hash:  commitmentTx.TxHash(),
+			Index: 1,
+		},
+	}
+
+	// Finally, we test bob sweeping his output as normal in the case that
+	// Alice broadcasts this commitment transaction.
+	bobScriptP2WKH, err := input.CommitScriptUnencumbered(bobPayKey)
+	if err != nil {
+		t.Fatalf("unable to create bob p2wkh script: %v", err)
+	}
+	signDesc = &input.SignDescriptor{
+		KeyDesc: keychain.KeyDescriptor{
+			PubKey: bobKeyPub,
+		},
+		SingleTweak:   bobCommitTweak,
+		WitnessScript: bobScriptP2WKH,
+		SigHashes:     txscript.NewTxSigHashes(sweepTx),
+		Output: &wire.TxOut{
+			Value:    int64(channelBalance),
+			PkScript: bobScriptP2WKH,
+		},
+		HashType:   txscript.SigHashAll,
+		InputIndex: 0,
+	}
+	bobRegularSpend, err := input.CommitSpendNoDelay(bobSigner, signDesc,
+		sweepTx)
+	if err != nil {
+		t.Fatalf("unable to create bob regular spend: %v", err)
+	}
+	sweepTx.TxIn[0].Witness = bobRegularSpend
+	vm, err = txscript.NewEngine(regularOutput.PkScript,
+		sweepTx, 0, txscript.StandardVerifyFlags, nil,
+		nil, int64(channelBalance))
+	if err != nil {
+		t.Fatalf("unable to create engine: %v", err)
+	}
+	if err := vm.Execute(); err != nil {
+		t.Fatalf("bob p2wkh spend is invalid: %v", err)
+	}
+}

lnwallet/wallet.go

@@ -19,6 +19,7 @@ import (
 	"github.com/btcsuite/btcutil/txsort"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/shachain"
@@ -167,7 +168,7 @@ type addCounterPartySigsMsg struct {
 	// Should be order of sorted inputs that are theirs. Sorting is done
 	// in accordance to BIP-69:
 	// https://github.com/bitcoin/bips/blob/master/bip-0069.mediawiki.
-	theirFundingInputScripts []*InputScript
+	theirFundingInputScripts []*input.Script
 
 	// This should be 1/2 of the signatures needed to successfully spend our
 	// version of the commitment transaction.
@@ -562,7 +563,7 @@ func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg
 		req.resp <- nil
 		return
 	}
-	reservation.ourContribution.FirstCommitmentPoint = ComputeCommitmentPoint(
+	reservation.ourContribution.FirstCommitmentPoint = input.ComputeCommitmentPoint(
 		firstPreimage[:],
 	)
 
@@ -712,7 +713,7 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	// Finally, add the 2-of-2 multi-sig output which will set up the lightning
 	// channel.
 	channelCapacity := int64(pendingReservation.partialState.Capacity)
-	witnessScript, multiSigOut, err := GenFundingPkScript(
+	witnessScript, multiSigOut, err := input.GenFundingPkScript(
 		ourKey.PubKey.SerializeCompressed(),
 		theirKey.PubKey.SerializeCompressed(), channelCapacity,
 	)
@@ -729,9 +730,9 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 
 	// Next, sign all inputs that are ours, collecting the signatures in
 	// order of the inputs.
-	pendingReservation.ourFundingInputScripts = make([]*InputScript, 0,
+	pendingReservation.ourFundingInputScripts = make([]*input.Script, 0,
 		len(ourContribution.Inputs))
-	signDesc := SignDescriptor{
+	signDesc := input.SignDescriptor{
 		HashType:  txscript.SigHashAll,
 		SigHashes: txscript.NewTxSigHashes(fundingTx),
 	}
@@ -767,7 +768,7 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 	// since the outputs are canonically sorted. If this is a single funder
 	// workflow, then we'll also need to send this to the remote node.
 	fundingTxID := fundingTx.TxHash()
-	_, multiSigIndex := FindScriptOutputIndex(fundingTx, multiSigOut.PkScript)
+	_, multiSigIndex := input.FindScriptOutputIndex(fundingTx, multiSigOut.PkScript)
 	fundingOutpoint := wire.NewOutPoint(&fundingTxID, multiSigIndex)
 	pendingReservation.partialState.FundingOutpoint = *fundingOutpoint
 
@@ -858,7 +859,7 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 
 	// Generate a signature for their version of the initial commitment
 	// transaction.
-	signDesc = SignDescriptor{
+	signDesc = input.SignDescriptor{
 		WitnessScript: witnessScript,
 		KeyDesc:       ourKey,
 		Output:        multiSigOut,
@@ -966,7 +967,7 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 			//
 			// TODO(roasbeef): when dual funder pass actual
 			// height-hint
-			pkScript, err := WitnessScriptHash(
+			pkScript, err := input.WitnessScriptHash(
 				txin.Witness[len(txin.Witness)-1],
 			)
 			if err != nil {
@@ -1013,7 +1014,7 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 	// Re-generate both the witnessScript and p2sh output. We sign the
 	// witnessScript script, but include the p2sh output as the subscript
 	// for verification.
-	witnessScript, _, err := GenFundingPkScript(
+	witnessScript, _, err := input.GenFundingPkScript(
 		ourKey.PubKey.SerializeCompressed(),
 		theirKey.PubKey.SerializeCompressed(),
 		int64(res.partialState.Capacity),
@@ -1165,7 +1166,7 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 	hashCache := txscript.NewTxSigHashes(ourCommitTx)
 	theirKey := pendingReservation.theirContribution.MultiSigKey
 	ourKey := pendingReservation.ourContribution.MultiSigKey
-	witnessScript, _, err := GenFundingPkScript(
+	witnessScript, _, err := input.GenFundingPkScript(
 		ourKey.PubKey.SerializeCompressed(),
 		theirKey.PubKey.SerializeCompressed(), channelValue,
 	)
@@ -1201,13 +1202,13 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 	// With their signature for our version of the commitment transactions
 	// verified, we can now generate a signature for their version,
 	// allowing the funding transaction to be safely broadcast.
-	p2wsh, err := WitnessScriptHash(witnessScript)
+	p2wsh, err := input.WitnessScriptHash(witnessScript)
 	if err != nil {
 		req.err <- err
 		req.completeChan <- nil
 		return
 	}
-	signDesc := SignDescriptor{
+	signDesc := input.SignDescriptor{
 		WitnessScript: witnessScript,
 		KeyDesc:       ourKey,
 		Output: &wire.TxOut{
@@ -1401,7 +1402,7 @@ func coinSelect(feeRate SatPerKWeight, amt btcutil.Amount,
 			return nil, 0, err
 		}
 
-		var weightEstimate TxWeightEstimator
+		var weightEstimate input.TxWeightEstimator
 
 		for _, utxo := range selectedUtxos {
 			switch utxo.AddressType {

macaroons/constraints_test.go

@@ -1,11 +1,12 @@
 package macaroons_test
 
 import (
-	"github.com/lightningnetwork/lnd/macaroons"
-	"gopkg.in/macaroon.v2"
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/lightningnetwork/lnd/macaroons"
+	macaroon "gopkg.in/macaroon.v2"
 )
 
 var (

mock.go

@@ -12,7 +12,9 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
+
 	"github.com/lightningnetwork/lnd/chainntnfs"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
@@ -25,7 +27,7 @@ type mockSigner struct {
 }
 
 func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) ([]byte, error) {
+	signDesc *input.SignDescriptor) ([]byte, error) {
 	amt := signDesc.Output.Value
 	witnessScript := signDesc.WitnessScript
 	privKey := m.key
@@ -36,10 +38,10 @@ func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx,
 
 	switch {
 	case signDesc.SingleTweak != nil:
-		privKey = lnwallet.TweakPrivKey(privKey,
+		privKey = input.TweakPrivKey(privKey,
 			signDesc.SingleTweak)
 	case signDesc.DoubleTweak != nil:
-		privKey = lnwallet.DeriveRevocationPrivKey(privKey,
+		privKey = input.DeriveRevocationPrivKey(privKey,
 			signDesc.DoubleTweak)
 	}
 
@@ -54,7 +56,7 @@ func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx,
 }
 
 func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {
+	signDesc *input.SignDescriptor) (*input.Script, error) {
 
 	// TODO(roasbeef): expose tweaked signer from lnwallet so don't need to
 	// duplicate this code?
@@ -63,10 +65,10 @@ func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx,
 
 	switch {
 	case signDesc.SingleTweak != nil:
-		privKey = lnwallet.TweakPrivKey(privKey,
+		privKey = input.TweakPrivKey(privKey,
 			signDesc.SingleTweak)
 	case signDesc.DoubleTweak != nil:
-		privKey = lnwallet.DeriveRevocationPrivKey(privKey,
+		privKey = input.DeriveRevocationPrivKey(privKey,
 			signDesc.DoubleTweak)
 	}
 
@@ -77,7 +79,7 @@ func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx,
 		return nil, err
 	}
 
-	return &lnwallet.InputScript{
+	return &input.Script{
 		Witness: witnessScript,
 	}, nil
 }

routing/notifications_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/btcsuite/btcutil"
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/chainview"
@@ -87,7 +88,7 @@ func createChannelEdge(ctx *testCtx, bitcoinKey1, bitcoinKey2 []byte,
 	*lnwire.ShortChannelID, error) {
 
 	fundingTx := wire.NewMsgTx(2)
-	_, tx, err := lnwallet.GenFundingPkScript(
+	_, tx, err := input.GenFundingPkScript(
 		bitcoinKey1,
 		bitcoinKey2,
 		int64(chanValue),

routing/pathfind.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/coreos/bbolt"
+
 	"github.com/lightningnetwork/lightning-onion"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/lnwire"

routing/router.go

@@ -16,9 +16,11 @@ import (
 	"github.com/coreos/bbolt"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/go-errors/errors"
+
 	"github.com/lightningnetwork/lightning-onion"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/multimutex"
@@ -1034,13 +1036,13 @@ func (r *ChannelRouter) processUpdate(msg interface{}) error {
 		// Recreate witness output to be sure that declared in channel
 		// edge bitcoin keys and channel value corresponds to the
 		// reality.
-		witnessScript, err := lnwallet.GenMultiSigScript(
+		witnessScript, err := input.GenMultiSigScript(
 			msg.BitcoinKey1Bytes[:], msg.BitcoinKey2Bytes[:],
 		)
 		if err != nil {
 			return err
 		}
-		fundingPkScript, err := lnwallet.WitnessScriptHash(witnessScript)
+		fundingPkScript, err := input.WitnessScriptHash(witnessScript)
 		if err != nil {
 			return err
 		}

routing/router_test.go

@@ -9,14 +9,14 @@ import (
 	"testing"
 	"time"
 
-	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/htlcswitch"
-
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
+
 	"github.com/lightningnetwork/lightning-onion"
+	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 

rpcserver.go

@@ -31,6 +31,7 @@ import (
 	"github.com/lightningnetwork/lnd/build"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/invoices"
 	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/lnrpc"
@@ -1991,7 +1992,7 @@ func (r *rpcServer) PendingChannels(ctx context.Context,
 		localCommitment := pendingChan.LocalCommitment
 		utx := btcutil.NewTx(localCommitment.CommitTx)
 		commitBaseWeight := blockchain.GetTransactionWeight(utx)
-		commitWeight := commitBaseWeight + lnwallet.WitnessCommitmentTxWeight
+		commitWeight := commitBaseWeight + input.WitnessCommitmentTxWeight
 
 		resp.PendingOpenChannels[i] = &lnrpc.PendingChannelsResponse_PendingOpenChannel{
 			Channel: &lnrpc.PendingChannelsResponse_PendingChannel{
@@ -2320,7 +2321,7 @@ func (r *rpcServer) ListChannels(ctx context.Context,
 		localCommit := dbChannel.LocalCommitment
 		utx := btcutil.NewTx(localCommit.CommitTx)
 		commitBaseWeight := blockchain.GetTransactionWeight(utx)
-		commitWeight := commitBaseWeight + lnwallet.WitnessCommitmentTxWeight
+		commitWeight := commitBaseWeight + input.WitnessCommitmentTxWeight
 
 		localBalance := localCommit.LocalBalance
 		remoteBalance := localCommit.RemoteBalance

server.go

@@ -24,13 +24,14 @@ import (
 	"github.com/btcsuite/btcutil"
 	"github.com/coreos/bbolt"
 	"github.com/go-errors/errors"
-	"github.com/lightningnetwork/lightning-onion"
+	sphinx "github.com/lightningnetwork/lightning-onion"
 	"github.com/lightningnetwork/lnd/autopilot"
 	"github.com/lightningnetwork/lnd/brontide"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
 	"github.com/lightningnetwork/lnd/discovery"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/invoices"
 	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/lnpeer"
@@ -913,7 +914,7 @@ func newServer(listenAddrs []net.Addr, chanDB *channeldb.DB, cc *chainControl,
 		RequiredRemoteMaxHTLCs: func(chanAmt btcutil.Amount) uint16 {
 			// By default, we'll permit them to utilize the full
 			// channel bandwidth.
-			return uint16(lnwallet.MaxHTLCNumber / 2)
+			return uint16(input.MaxHTLCNumber / 2)
 		},
 		ZombieSweeperInterval: 1 * time.Minute,
 		ReservationTimeout:    10 * time.Minute,

sweep/sweeper.go

@@ -12,6 +12,7 @@ import (
 	"github.com/btcsuite/btcutil"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
@@ -39,7 +40,7 @@ type pendingInput struct {
 
 	// input is the original struct that contains the input and sign
 	// descriptor.
-	input Input
+	input input.Input
 
 	// ntfnRegCancel is populated with a function that cancels the chain
 	// notifier spend registration.
@@ -111,7 +112,7 @@ type UtxoSweeperConfig struct {
 
 	// Signer is used by the sweeper to generate valid witnesses at the
 	// time the incubated outputs need to be spent.
-	Signer lnwallet.Signer
+	Signer input.Signer
 
 	// SweepTxConfTarget assigns a confirmation target for sweep txes on
 	// which the fee calculation will be based.
@@ -148,7 +149,7 @@ type Result struct {
 // sweepInputMessage structs are used in the internal channel between the
 // SweepInput call and the sweeper main loop.
 type sweepInputMessage struct {
-	input      Input
+	input      input.Input
 	resultChan chan Result
 }
 
@@ -256,7 +257,7 @@ func (s *UtxoSweeper) Stop() error {
 // NOTE: Extreme care needs to be taken that input isn't changed externally.
 // Because it is an interface and we don't know what is exactly behind it, we
 // cannot make a local copy in sweeper.
-func (s *UtxoSweeper) SweepInput(input Input) (chan Result, error) {
+func (s *UtxoSweeper) SweepInput(input input.Input) (chan Result, error) {
 	if input == nil || input.OutPoint() == nil || input.SignDesc() == nil {
 		return nil, errors.New("nil input received")
 	}
@@ -550,7 +551,7 @@ func (s *UtxoSweeper) getInputLists(currentHeight int32,
 	// contain inputs that failed before. Therefore we also add sets
 	// consisting of only new inputs to the list, to make sure that new
 	// inputs are given a good, isolated chance of being published.
-	var newInputs, retryInputs []Input
+	var newInputs, retryInputs []input.Input
 	for _, input := range s.pendingInputs {
 		// Skip inputs that have a minimum publish height that is not
 		// yet reached.
@@ -750,7 +751,7 @@ func (s *UtxoSweeper) waitForSpend(outpoint wire.OutPoint,
 // - Make handling re-orgs easier.
 // - Thwart future possible fee sniping attempts.
 // - Make us blend in with the bitcoind wallet.
-func (s *UtxoSweeper) CreateSweepTx(inputs []Input, feePref FeePreference,
+func (s *UtxoSweeper) CreateSweepTx(inputs []input.Input, feePref FeePreference,
 	currentBlockHeight uint32) (*wire.MsgTx, error) {
 
 	feePerKw, err := DetermineFeePerKw(s.cfg.FeeEstimator, feePref)

sweep/sweeper_test.go

@@ -12,8 +12,8 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/build"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
-	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
 var (
@@ -38,7 +38,7 @@ type sweeperTestContext struct {
 }
 
 var (
-	spendableInputs []*BaseInput
+	spendableInputs []*input.BaseInput
 	testInputCount  int
 
 	testPubKey, _ = btcec.ParsePubKey([]byte{
@@ -53,17 +53,17 @@ var (
 	}, btcec.S256())
 )
 
-func createTestInput(value int64, witnessType lnwallet.WitnessType) BaseInput {
+func createTestInput(value int64, witnessType input.WitnessType) input.BaseInput {
 	hash := chainhash.Hash{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 		byte(testInputCount)}
 
-	input := MakeBaseInput(
+	input := input.MakeBaseInput(
 		&wire.OutPoint{
 			Hash: hash,
 		},
 		witnessType,
-		&lnwallet.SignDescriptor{
+		&input.SignDescriptor{
 			Output: &wire.TxOut{
 				Value: value,
 			},
@@ -83,7 +83,7 @@ func init() {
 	// Create a set of test spendable inputs.
 	for i := 0; i < 5; i++ {
 		input := createTestInput(int64(10000+i*500),
-			lnwallet.CommitmentTimeLock)
+			input.CommitmentTimeLock)
 
 		spendableInputs = append(spendableInputs, &input)
 	}
@@ -303,7 +303,7 @@ func TestDust(t *testing.T) {
 	// Create an input so that the output after paying fees is still
 	// positive (400 sat), but less than the dust limit (537 sat) for the
 	// sweep tx output script (P2WPKH).
-	dustInput := createTestInput(5260, lnwallet.CommitmentTimeLock)
+	dustInput := createTestInput(5260, input.CommitmentTimeLock)
 
 	_, err := ctx.sweeper.SweepInput(&dustInput)
 	if err != nil {
@@ -314,7 +314,7 @@ func TestDust(t *testing.T) {
 	// that the sweep output will not be relayed and not generate the tx.
 
 	// Sweep another input that brings the tx output above the dust limit.
-	largeInput := createTestInput(100000, lnwallet.CommitmentTimeLock)
+	largeInput := createTestInput(100000, input.CommitmentTimeLock)
 
 	_, err = ctx.sweeper.SweepInput(&largeInput)
 	if err != nil {
@@ -344,7 +344,7 @@ func TestNegativeInput(t *testing.T) {
 
 	// Sweep an input large enough to cover fees, so in any case the tx
 	// output will be above the dust limit.
-	largeInput := createTestInput(100000, lnwallet.CommitmentNoDelay)
+	largeInput := createTestInput(100000, input.CommitmentNoDelay)
 	largeInputResult, err := ctx.sweeper.SweepInput(&largeInput)
 	if err != nil {
 		t.Fatal(err)
@@ -353,7 +353,7 @@ func TestNegativeInput(t *testing.T) {
 	// Sweep an additional input with a negative net yield. The weight of
 	// the HtlcAcceptedRemoteSuccess input type adds more in fees than its
 	// value at the current fee level.
-	negInput := createTestInput(2900, lnwallet.HtlcOfferedRemoteTimeout)
+	negInput := createTestInput(2900, input.HtlcOfferedRemoteTimeout)
 	negInputResult, err := ctx.sweeper.SweepInput(&negInput)
 	if err != nil {
 		t.Fatal(err)
@@ -361,7 +361,7 @@ func TestNegativeInput(t *testing.T) {
 
 	// Sweep a third input that has a smaller output than the previous one,
 	// but yields positively because of its lower weight.
-	positiveInput := createTestInput(2800, lnwallet.CommitmentNoDelay)
+	positiveInput := createTestInput(2800, input.CommitmentNoDelay)
 	positiveInputResult, err := ctx.sweeper.SweepInput(&positiveInput)
 	if err != nil {
 		t.Fatal(err)
@@ -390,7 +390,7 @@ func TestNegativeInput(t *testing.T) {
 	ctx.estimator.updateFees(1000, 1000)
 
 	// Create another large input
-	secondLargeInput := createTestInput(100000, lnwallet.CommitmentNoDelay)
+	secondLargeInput := createTestInput(100000, input.CommitmentNoDelay)
 	secondLargeInputResult, err := ctx.sweeper.SweepInput(&secondLargeInput)
 	if err != nil {
 		t.Fatal(err)

sweep/test_utils.go

@@ -9,7 +9,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/chainntnfs"
-	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/input"
 )
 
 var (
@@ -21,15 +21,15 @@ type mockSigner struct {
 }
 
 func (m *mockSigner) SignOutputRaw(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) ([]byte, error) {
+	signDesc *input.SignDescriptor) ([]byte, error) {
 
 	return []byte{}, nil
 }
 
 func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {
+	signDesc *input.SignDescriptor) (*input.Script, error) {
 
-	return &lnwallet.InputScript{}, nil
+	return &input.Script{}, nil
 }
 
 // MockNotifier simulates the chain notifier for test purposes. This type is

sweep/txgenerator.go

@@ -9,6 +9,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/btcsuite/btcwallet/wallet/txrules"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
@@ -21,21 +22,21 @@ var (
 
 // inputSet is a set of inputs that can be used as the basis to generate a tx
 // on.
-type inputSet []Input
+type inputSet []input.Input
 
 // generateInputPartitionings goes through all given inputs and constructs sets
 // of inputs that can be used to generate a sensible transaction. Each set
 // contains up to the configured maximum number of inputs. Negative yield
 // inputs are skipped. No input sets with a total value after fees below the
 // dust limit are returned.
-func generateInputPartitionings(sweepableInputs []Input,
+func generateInputPartitionings(sweepableInputs []input.Input,
 	relayFeePerKW, feePerKW lnwallet.SatPerKWeight,
 	maxInputsPerTx int) ([]inputSet, error) {
 
 	// Calculate dust limit based on the P2WPKH output script of the sweep
 	// txes.
 	dustLimit := txrules.GetDustThreshold(
-		lnwallet.P2WPKHSize,
+		input.P2WPKHSize,
 		btcutil.Amount(relayFeePerKW.FeePerKVByte()),
 	)
 
@@ -113,10 +114,10 @@ func generateInputPartitionings(sweepableInputs []Input,
 // up the utxo set even if it costs us some fees up front.  In the spirit of
 // minimizing any negative externalities we cause for the Bitcoin system as a
 // whole.
-func getPositiveYieldInputs(sweepableInputs []Input, maxInputs int,
+func getPositiveYieldInputs(sweepableInputs []input.Input, maxInputs int,
 	feePerKW lnwallet.SatPerKWeight) (int, btcutil.Amount) {
 
-	var weightEstimate lnwallet.TxWeightEstimator
+	var weightEstimate input.TxWeightEstimator
 
 	// Add the sweep tx output to the weight estimate.
 	weightEstimate.AddP2WKHOutput()
@@ -166,9 +167,9 @@ func getPositiveYieldInputs(sweepableInputs []Input, maxInputs int,
 }
 
 // createSweepTx builds a signed tx spending the inputs to a the output script.
-func createSweepTx(inputs []Input, outputPkScript []byte,
+func createSweepTx(inputs []input.Input, outputPkScript []byte,
 	currentBlockHeight uint32, feePerKw lnwallet.SatPerKWeight,
-	signer lnwallet.Signer) (*wire.MsgTx, error) {
+	signer input.Signer) (*wire.MsgTx, error) {
 
 	inputs, txWeight, csvCount, cltvCount := getWeightEstimate(inputs)
 
@@ -222,7 +223,7 @@ func createSweepTx(inputs []Input, outputPkScript []byte,
 
 	// With all the inputs in place, use each output's unique input script
 	// function to generate the final witness required for spending.
-	addInputScript := func(idx int, tso Input) error {
+	addInputScript := func(idx int, tso input.Input) error {
 		inputScript, err := tso.CraftInputScript(
 			signer, sweepTx, hashCache, idx,
 		)
@@ -254,62 +255,62 @@ func createSweepTx(inputs []Input, outputPkScript []byte,
 // the given input if it would be included in a tx. We also return if the
 // output itself is a nested p2sh output, if so then we need to take into
 // account the extra sigScript data size.
-func getInputWitnessSizeUpperBound(input Input) (int, bool, error) {
+func getInputWitnessSizeUpperBound(inp input.Input) (int, bool, error) {
-	switch input.WitnessType() {
+	switch inp.WitnessType() {
 
 	// Outputs on a remote commitment transaction that pay directly to us.
-	case lnwallet.WitnessKeyHash:
+	case input.WitnessKeyHash:
 		fallthrough
-	case lnwallet.CommitmentNoDelay:
+	case input.CommitmentNoDelay:
-		return lnwallet.P2WKHWitnessSize, false, nil
+		return input.P2WKHWitnessSize, false, nil
 
 	// Outputs on a past commitment transaction that pay directly
 	// to us.
-	case lnwallet.CommitmentTimeLock:
+	case input.CommitmentTimeLock:
-		return lnwallet.ToLocalTimeoutWitnessSize, false, nil
+		return input.ToLocalTimeoutWitnessSize, false, nil
 
 	// Outgoing second layer HTLC's that have confirmed within the
 	// chain, and the output they produced is now mature enough to
 	// sweep.
-	case lnwallet.HtlcOfferedTimeoutSecondLevel:
+	case input.HtlcOfferedTimeoutSecondLevel:
-		return lnwallet.ToLocalTimeoutWitnessSize, false, nil
+		return input.ToLocalTimeoutWitnessSize, false, nil
 
 	// Incoming second layer HTLC's that have confirmed within the
 	// chain, and the output they produced is now mature enough to
 	// sweep.
-	case lnwallet.HtlcAcceptedSuccessSecondLevel:
+	case input.HtlcAcceptedSuccessSecondLevel:
-		return lnwallet.ToLocalTimeoutWitnessSize, false, nil
+		return input.ToLocalTimeoutWitnessSize, false, nil
 
 	// An HTLC on the commitment transaction of the remote party,
 	// that has had its absolute timelock expire.
-	case lnwallet.HtlcOfferedRemoteTimeout:
+	case input.HtlcOfferedRemoteTimeout:
-		return lnwallet.AcceptedHtlcTimeoutWitnessSize, false, nil
+		return input.AcceptedHtlcTimeoutWitnessSize, false, nil
 
 	// An HTLC on the commitment transaction of the remote party,
 	// that can be swept with the preimage.
-	case lnwallet.HtlcAcceptedRemoteSuccess:
+	case input.HtlcAcceptedRemoteSuccess:
-		return lnwallet.OfferedHtlcSuccessWitnessSize, false, nil
+		return input.OfferedHtlcSuccessWitnessSize, false, nil
 
 	// A nested P2SH input that has a p2wkh witness script. We'll mark this
 	// as nested P2SH so the caller can estimate the weight properly
 	// including the sigScript.
-	case lnwallet.NestedWitnessKeyHash:
+	case input.NestedWitnessKeyHash:
-		return lnwallet.P2WKHWitnessSize, true, nil
+		return input.P2WKHWitnessSize, true, nil
 	}
 
 	return 0, false, fmt.Errorf("unexpected witness type: %v",
-		input.WitnessType())
+		inp.WitnessType())
 }
 
 // getWeightEstimate returns a weight estimate for the given inputs.
 // Additionally, it returns counts for the number of csv and cltv inputs.
-func getWeightEstimate(inputs []Input) ([]Input, int64, int, int) {
+func getWeightEstimate(inputs []input.Input) ([]input.Input, int64, int, int) {
 	// We initialize a weight estimator so we can accurately asses the
 	// amount of fees we need to pay for this sweep transaction.
 	//
 	// TODO(roasbeef): can be more intelligent about buffering outputs to
 	// be more efficient on-chain.
-	var weightEstimate lnwallet.TxWeightEstimator
+	var weightEstimate input.TxWeightEstimator
 
 	// Our sweep transaction will pay to a single segwit p2wkh address,
 	// ensure it contributes to our weight estimate.
@@ -319,16 +320,16 @@ func getWeightEstimate(inputs []Input) ([]Input, int64, int, int) {
 	// weight of its witness, and add it to the proper set of spendable
 	// outputs.
 	var (
-		sweepInputs         []Input
+		sweepInputs         []input.Input
 		csvCount, cltvCount int
 	)
 	for i := range inputs {
-		input := inputs[i]
+		inp := inputs[i]
 
 		// For fee estimation purposes, we'll now attempt to obtain an
 		// upper bound on the weight this input will add when fully
 		// populated.
-		size, isNestedP2SH, err := getInputWitnessSizeUpperBound(input)
+		size, isNestedP2SH, err := getInputWitnessSizeUpperBound(inp)
 		if err != nil {
 			log.Warn(err)
 
@@ -345,15 +346,15 @@ func getWeightEstimate(inputs []Input) ([]Input, int64, int, int) {
 			weightEstimate.AddWitnessInput(size)
 		}
 
-		switch input.WitnessType() {
+		switch inp.WitnessType() {
-		case lnwallet.CommitmentTimeLock,
+		case input.CommitmentTimeLock,
-			lnwallet.HtlcOfferedTimeoutSecondLevel,
+			input.HtlcOfferedTimeoutSecondLevel,
-			lnwallet.HtlcAcceptedSuccessSecondLevel:
+			input.HtlcAcceptedSuccessSecondLevel:
 			csvCount++
-		case lnwallet.HtlcOfferedRemoteTimeout:
+		case input.HtlcOfferedRemoteTimeout:
 			cltvCount++
 		}
-		sweepInputs = append(sweepInputs, input)
+		sweepInputs = append(sweepInputs, inp)
 	}
 
 	txWeight := int64(weightEstimate.Weight())

sweep/walletsweep.go

@@ -7,6 +7,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
@@ -152,7 +153,7 @@ func CraftSweepAllTx(feeRate lnwallet.SatPerKWeight, blockHeight uint32,
 	deliveryAddr btcutil.Address, coinSelectLocker CoinSelectionLocker,
 	utxoSource UtxoSource, outpointLocker OutpointLocker,
 	feeEstimator lnwallet.FeeEstimator,
-	signer lnwallet.Signer) (*WalletSweepPackage, error) {
+	signer input.Signer) (*WalletSweepPackage, error) {
 
 	// TODO(roasbeef): turn off ATPL as well when available?
 
@@ -206,7 +207,7 @@ func CraftSweepAllTx(feeRate lnwallet.SatPerKWeight, blockHeight uint32,
 	// Now that we've locked all the potential outputs to sweep, we'll
 	// assemble an input for each of them, so we can hand it off to the
 	// sweeper to generate and sign a transaction for us.
-	var inputsToSweep []Input
+	var inputsToSweep []input.Input
 	for _, output := range allOutputs {
 		// We'll consult the utxoSource for information concerning this
 		// outpoint, we'll need to properly populate a signDescriptor
@@ -222,7 +223,7 @@ func CraftSweepAllTx(feeRate lnwallet.SatPerKWeight, blockHeight uint32,
 		// we only need to populate the output value and output script.
 		// The rest of the items will be populated internally within
 		// the sweeper via the witness generation function.
-		signDesc := &lnwallet.SignDescriptor{
+		signDesc := &input.SignDescriptor{
 			Output:   outputInfo,
 			HashType: txscript.SigHashAll,
 		}
@@ -232,18 +233,18 @@ func CraftSweepAllTx(feeRate lnwallet.SatPerKWeight, blockHeight uint32,
 		// Based on the output type, we'll map it to the proper witness
 		// type so we can generate the set of input scripts needed to
 		// sweep the output.
-		var witnessType lnwallet.WitnessType
+		var witnessType input.WitnessType
 		switch {
 
 		// If this is a p2wkh output, then we'll assume it's a witness
 		// key hash witness type.
 		case txscript.IsPayToWitnessPubKeyHash(pkScript):
-			witnessType = lnwallet.WitnessKeyHash
+			witnessType = input.WitnessKeyHash
 
 		// If this is a p2sh output, then as since it's under control
 		// of the wallet, we'll assume it's a nested p2sh output.
 		case txscript.IsPayToScriptHash(pkScript):
-			witnessType = lnwallet.NestedWitnessKeyHash
+			witnessType = input.NestedWitnessKeyHash
 
 		// All other output types we count as unknown and will fail to
 		// sweep.
@@ -257,7 +258,7 @@ func CraftSweepAllTx(feeRate lnwallet.SatPerKWeight, blockHeight uint32,
 		// Now that we've constructed the items required, we'll make an
 		// input which can be passed to the sweeper for ultimate
 		// sweeping.
-		input := MakeBaseInput(&output.OutPoint, witnessType, signDesc, 0)
+		input := input.MakeBaseInput(&output.OutPoint, witnessType, signDesc, 0)
 		inputsToSweep = append(inputsToSweep, &input)
 	}
 

test_utils.go

@@ -18,6 +18,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -170,7 +171,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 	if err != nil {
 		return nil, nil, nil, nil, err
 	}
-	bobCommitPoint := lnwallet.ComputeCommitmentPoint(bobFirstRevoke[:])
+	bobCommitPoint := input.ComputeCommitmentPoint(bobFirstRevoke[:])
 
 	aliceRoot, err := chainhash.NewHash(aliceKeyPriv.Serialize())
 	if err != nil {
@@ -181,7 +182,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 	if err != nil {
 		return nil, nil, nil, nil, err
 	}
-	aliceCommitPoint := lnwallet.ComputeCommitmentPoint(aliceFirstRevoke[:])
+	aliceCommitPoint := input.ComputeCommitmentPoint(aliceFirstRevoke[:])
 
 	aliceCommitTx, bobCommitTx, err := lnwallet.CreateCommitmentTxns(channelBal,
 		channelBal, &aliceCfg, &bobCfg, aliceCommitPoint, bobCommitPoint,
@@ -214,7 +215,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 		LocalBalance:  lnwire.NewMSatFromSatoshis(channelBal),
 		RemoteBalance: lnwire.NewMSatFromSatoshis(channelBal),
 		FeePerKw:      btcutil.Amount(feePerKw),
-		CommitFee:     feePerKw.FeeForWeight(lnwallet.CommitWeight),
+		CommitFee:     feePerKw.FeeForWeight(input.CommitWeight),
 		CommitTx:      aliceCommitTx,
 		CommitSig:     bytes.Repeat([]byte{1}, 71),
 	}
@@ -223,7 +224,7 @@ func createTestPeer(notifier chainntnfs.ChainNotifier,
 		LocalBalance:  lnwire.NewMSatFromSatoshis(channelBal),
 		RemoteBalance: lnwire.NewMSatFromSatoshis(channelBal),
 		FeePerKw:      btcutil.Amount(feePerKw),
-		CommitFee:     feePerKw.FeeForWeight(lnwallet.CommitWeight),
+		CommitFee:     feePerKw.FeeForWeight(input.CommitWeight),
 		CommitTx:      bobCommitTx,
 		CommitSig:     bytes.Repeat([]byte{1}, 71),
 	}

utxonursery.go

@@ -8,8 +8,6 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"github.com/lightningnetwork/lnd/sweep"
-
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
@@ -17,7 +15,9 @@ import (
 
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/sweep"
 )
 
 //                          SUMMARY OF OUTPUT STATES
@@ -196,7 +196,7 @@ type NurseryConfig struct {
 	Store NurseryStore
 
 	// Sweep sweeps an input back to the wallet.
-	SweepInput func(input sweep.Input) (chan sweep.Result, error)
+	SweepInput func(input input.Input) (chan sweep.Result, error)
 }
 
 // utxoNursery is a system dedicated to incubating time-locked outputs created
@@ -368,7 +368,7 @@ func (u *utxoNursery) IncubateOutputs(chanPoint wire.OutPoint,
 			&commitResolution.SelfOutPoint,
 			&chanPoint,
 			commitResolution.MaturityDelay,
-			lnwallet.CommitmentTimeLock,
+			input.CommitmentTimeLock,
 			&commitResolution.SelfOutputSignDesc,
 			0,
 		)
@@ -389,7 +389,7 @@ func (u *utxoNursery) IncubateOutputs(chanPoint wire.OutPoint,
 	for _, htlcRes := range incomingHtlcs {
 		htlcOutput := makeKidOutput(
 			&htlcRes.ClaimOutpoint, &chanPoint, htlcRes.CsvDelay,
-			lnwallet.HtlcAcceptedSuccessSecondLevel,
+			input.HtlcAcceptedSuccessSecondLevel,
 			&htlcRes.SweepSignDesc, 0,
 		)
 
@@ -421,7 +421,7 @@ func (u *utxoNursery) IncubateOutputs(chanPoint wire.OutPoint,
 		// indicate this is actually a CLTV output.
 		htlcOutput := makeKidOutput(
 			&htlcRes.ClaimOutpoint, &chanPoint, 0,
-			lnwallet.HtlcOfferedRemoteTimeout,
+			input.HtlcOfferedRemoteTimeout,
 			&htlcRes.SweepSignDesc, htlcRes.Expiry,
 		)
 		kidOutputs = append(kidOutputs, htlcOutput)
@@ -533,13 +533,13 @@ func (u *utxoNursery) NurseryReport(
 				// Preschool outputs are awaiting the
 				// confirmation of the commitment transaction.
 				switch kid.WitnessType() {
-				case lnwallet.CommitmentTimeLock:
+				case input.CommitmentTimeLock:
 					report.AddLimboCommitment(&kid)
 
 				// An HTLC output on our commitment transaction
 				// where the second-layer transaction hasn't
 				// yet confirmed.
-				case lnwallet.HtlcAcceptedSuccessSecondLevel:
+				case input.HtlcAcceptedSuccessSecondLevel:
 					report.AddLimboStage1SuccessHtlc(&kid)
 				}
 
@@ -549,13 +549,13 @@ func (u *utxoNursery) NurseryReport(
 				// We can distinguish them via their witness
 				// types.
 				switch kid.WitnessType() {
-				case lnwallet.CommitmentTimeLock:
+				case input.CommitmentTimeLock:
 					// The commitment transaction has been
 					// confirmed, and we are waiting the CSV
 					// delay to expire.
 					report.AddLimboCommitment(&kid)
 
-				case lnwallet.HtlcOfferedRemoteTimeout:
+				case input.HtlcOfferedRemoteTimeout:
 					// This is an HTLC output on the
 					// commitment transaction of the remote
 					// party. The CLTV timelock has
@@ -563,9 +563,9 @@ func (u *utxoNursery) NurseryReport(
 					// it.
 					report.AddLimboDirectHtlc(&kid)
 
-				case lnwallet.HtlcAcceptedSuccessSecondLevel:
+				case input.HtlcAcceptedSuccessSecondLevel:
 					fallthrough
-				case lnwallet.HtlcOfferedTimeoutSecondLevel:
+				case input.HtlcOfferedTimeoutSecondLevel:
 					// The htlc timeout or success
 					// transaction has confirmed, and the
 					// CSV delay has begun ticking.
@@ -578,17 +578,17 @@ func (u *utxoNursery) NurseryReport(
 				// will contribute towards the recovered
 				// balance.
 				switch kid.WitnessType() {
-				case lnwallet.CommitmentTimeLock:
+				case input.CommitmentTimeLock:
 					// The commitment output was
 					// successfully swept back into a
 					// regular p2wkh output.
 					report.AddRecoveredCommitment(&kid)
 
-				case lnwallet.HtlcAcceptedSuccessSecondLevel:
+				case input.HtlcAcceptedSuccessSecondLevel:
 					fallthrough
-				case lnwallet.HtlcOfferedTimeoutSecondLevel:
+				case input.HtlcOfferedTimeoutSecondLevel:
 					fallthrough
-				case lnwallet.HtlcOfferedRemoteTimeout:
+				case input.HtlcOfferedRemoteTimeout:
 					// This htlc output successfully
 					// resides in a p2wkh output belonging
 					// to the user.
@@ -1301,7 +1301,7 @@ func makeBabyOutput(chanPoint *wire.OutPoint,
 
 	htlcOutpoint := htlcResolution.ClaimOutpoint
 	blocksToMaturity := htlcResolution.CsvDelay
-	witnessType := lnwallet.HtlcOfferedTimeoutSecondLevel
+	witnessType := input.HtlcOfferedTimeoutSecondLevel
 
 	kid := makeKidOutput(
 		&htlcOutpoint, chanPoint, blocksToMaturity, witnessType,
@@ -1380,15 +1380,15 @@ type kidOutput struct {
 }
 
 func makeKidOutput(outpoint, originChanPoint *wire.OutPoint,
-	blocksToMaturity uint32, witnessType lnwallet.WitnessType,
+	blocksToMaturity uint32, witnessType input.WitnessType,
-	signDescriptor *lnwallet.SignDescriptor,
+	signDescriptor *input.SignDescriptor,
 	absoluteMaturity uint32) kidOutput {
 
 	// This is an HTLC either if it's an incoming HTLC on our commitment
 	// transaction, or is an outgoing HTLC on the commitment transaction of
 	// the remote peer.
-	isHtlc := (witnessType == lnwallet.HtlcAcceptedSuccessSecondLevel ||
+	isHtlc := (witnessType == input.HtlcAcceptedSuccessSecondLevel ||
-		witnessType == lnwallet.HtlcOfferedRemoteTimeout)
+		witnessType == input.HtlcOfferedRemoteTimeout)
 
 	// heightHint can be safely set to zero here, because after this
 	// function returns, nursery will set a proper confirmation height in
@@ -1464,7 +1464,7 @@ func (k *kidOutput) Encode(w io.Writer) error {
 		return err
 	}
 
-	return lnwallet.WriteSignDescriptor(w, k.SignDesc())
+	return input.WriteSignDescriptor(w, k.SignDesc())
 }
 
 // Decode takes a byte array representation of a kidOutput and converts it to an
@@ -1509,9 +1509,9 @@ func (k *kidOutput) Decode(r io.Reader) error {
 	if _, err := r.Read(scratch[:2]); err != nil {
 		return err
 	}
-	k.witnessType = lnwallet.WitnessType(byteOrder.Uint16(scratch[:2]))
+	k.witnessType = input.WitnessType(byteOrder.Uint16(scratch[:2]))
 
-	return lnwallet.ReadSignDescriptor(r, &k.signDesc)
+	return input.ReadSignDescriptor(r, &k.signDesc)
 }
 
 // TODO(bvu): copied from channeldb, remove repetition
@@ -1551,4 +1551,4 @@ func readOutpoint(r io.Reader, o *wire.OutPoint) error {
 // Compile-time constraint to ensure kidOutput implements the
 // Input interface.
 
-var _ sweep.Input = (*kidOutput)(nil)
+var _ input.Input = (*kidOutput)(nil)

utxonursery_test.go

@@ -5,8 +5,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/sweep"
 	"io/ioutil"
 	"math"
 	"os"
@@ -21,7 +19,10 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
+	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/sweep"
 )
 
 var (
@@ -108,7 +109,7 @@ var (
 		},
 	}
 
-	signDescriptors = []lnwallet.SignDescriptor{
+	signDescriptors = []input.SignDescriptor{
 		{
 			SingleTweak: []byte{
 				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
@@ -206,7 +207,7 @@ var (
 			breachedOutput: breachedOutput{
 				amt:         btcutil.Amount(13e7),
 				outpoint:    outPoints[1],
-				witnessType: lnwallet.CommitmentTimeLock,
+				witnessType: input.CommitmentTimeLock,
 				confHeight:  uint32(1000),
 			},
 			originChanPoint:  outPoints[0],
@@ -217,7 +218,7 @@ var (
 			breachedOutput: breachedOutput{
 				amt:         btcutil.Amount(24e7),
 				outpoint:    outPoints[2],
-				witnessType: lnwallet.CommitmentTimeLock,
+				witnessType: input.CommitmentTimeLock,
 				confHeight:  uint32(1000),
 			},
 			originChanPoint:  outPoints[0],
@@ -228,7 +229,7 @@ var (
 			breachedOutput: breachedOutput{
 				amt:         btcutil.Amount(2e5),
 				outpoint:    outPoints[3],
-				witnessType: lnwallet.CommitmentTimeLock,
+				witnessType: input.CommitmentTimeLock,
 				confHeight:  uint32(500),
 			},
 			originChanPoint:  outPoints[0],
@@ -239,7 +240,7 @@ var (
 			breachedOutput: breachedOutput{
 				amt:         btcutil.Amount(10e6),
 				outpoint:    outPoints[4],
-				witnessType: lnwallet.CommitmentTimeLock,
+				witnessType: input.CommitmentTimeLock,
 				confHeight:  uint32(500),
 			},
 			originChanPoint:  outPoints[0],
@@ -597,7 +598,7 @@ func createOutgoingRes(onLocalCommitment bool) *lnwallet.OutgoingHtlcResolution
 
 	outgoingRes := lnwallet.OutgoingHtlcResolution{
 		Expiry: 125,
-		SweepSignDesc: lnwallet.SignDescriptor{
+		SweepSignDesc: input.SignDescriptor{
 			Output: &wire.TxOut{
 				Value: 10000,
 			},
@@ -630,7 +631,7 @@ func createCommitmentRes() *lnwallet.CommitOutputResolution {
 	// Set up a commitment output resolution to hand off to nursery.
 	commitRes := lnwallet.CommitOutputResolution{
 		SelfOutPoint: wire.OutPoint{},
-		SelfOutputSignDesc: lnwallet.SignDescriptor{
+		SelfOutputSignDesc: input.SignDescriptor{
 			Output: &wire.TxOut{
 				Value: 10000,
 			},
@@ -1027,15 +1028,15 @@ type nurseryMockSigner struct {
 }
 
 func (m *nurseryMockSigner) SignOutputRaw(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) ([]byte, error) {
+	signDesc *input.SignDescriptor) ([]byte, error) {
 
 	return []byte{}, nil
 }
 
 func (m *nurseryMockSigner) ComputeInputScript(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {
+	signDesc *input.SignDescriptor) (*input.Script, error) {
 
-	return &lnwallet.InputScript{}, nil
+	return &input.Script{}, nil
 }
 
 type mockSweeper struct {
@@ -1044,18 +1045,18 @@ type mockSweeper struct {
 	resultChans map[wire.OutPoint]chan sweep.Result
 	t           *testing.T
 
-	sweepChan chan sweep.Input
+	sweepChan chan input.Input
 }
 
 func newMockSweeper(t *testing.T) *mockSweeper {
 	return &mockSweeper{
 		resultChans: make(map[wire.OutPoint]chan sweep.Result),
-		sweepChan:   make(chan sweep.Input, 1),
+		sweepChan:   make(chan input.Input, 1),
 		t:           t,
 	}
 }
 
-func (s *mockSweeper) sweepInput(input sweep.Input) (chan sweep.Result, error) {
+func (s *mockSweeper) sweepInput(input input.Input) (chan sweep.Result, error) {
 	utxnLog.Debugf("mockSweeper sweepInput called for %v", *input.OutPoint())
 
 	select {

watchtower/blob/justice_kit.go

@@ -12,7 +12,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/txscript"
-	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 
@@ -163,7 +163,7 @@ func (b *JusticeKit) CommitToLocalWitnessScript() ([]byte, error) {
 		return nil, err
 	}
 
-	return lnwallet.CommitScriptToSelf(
+	return input.CommitScriptToSelf(
 		b.CSVDelay, localDelayedPubKey, revocationPubKey,
 	)
 }

watchtower/blob/justice_kit_test.go

@@ -10,7 +10,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/txscript"
-	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/watchtower/blob"
 )
@@ -356,7 +356,7 @@ func TestJusticeKitToLocalWitnessConstruction(t *testing.T) {
 
 	// Compute the expected to-local script, which is a function of the CSV
 	// delay, revocation pubkey and delay pubkey.
-	expToLocalScript, err := lnwallet.CommitScriptToSelf(
+	expToLocalScript, err := input.CommitScriptToSelf(
 		csvDelay, delayPrivKey.PubKey(), revPrivKey.PubKey(),
 	)
 	if err != nil {

watchtower/lookout/justice_descriptor.go

@@ -8,7 +8,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
-	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/watchtower/blob"
 	"github.com/lightningnetwork/lnd/watchtower/wtdb"
 )
@@ -60,7 +60,7 @@ func (p *JusticeDescriptor) commitToLocalInput() (*breachedInput, error) {
 
 	// Compute the witness script hash, which will be used to locate the
 	// input on the breaching commitment transaction.
-	toLocalWitnessHash, err := lnwallet.WitnessScriptHash(toLocalScript)
+	toLocalWitnessHash, err := input.WitnessScriptHash(toLocalScript)
 	if err != nil {
 		return nil, err
 	}
@@ -112,7 +112,7 @@ func (p *JusticeDescriptor) commitToRemoteInput() (*breachedInput, error) {
 
 	// Compute the witness script hash from the to-remote pubkey, which will
 	// be used to locate the input on the breach commitment transaction.
-	toRemoteScriptHash, err := lnwallet.CommitScriptUnencumbered(
+	toRemoteScriptHash, err := input.CommitScriptUnencumbered(
 		toRemotePubKey,
 	)
 	if err != nil {
@@ -226,7 +226,7 @@ func (p *JusticeDescriptor) assembleJusticeTxn(txWeight int64,
 func (p *JusticeDescriptor) CreateJusticeTxn() (*wire.MsgTx, error) {
 	var (
 		sweepInputs    = make([]*breachedInput, 0, 2)
-		weightEstimate lnwallet.TxWeightEstimator
+		weightEstimate input.TxWeightEstimator
 	)
 
 	// Add our reward address to the weight estimate.
@@ -235,10 +235,10 @@ func (p *JusticeDescriptor) CreateJusticeTxn() (*wire.MsgTx, error) {
 	// Add the sweep address's contribution, depending on whether it is a
 	// p2wkh or p2wsh output.
 	switch len(p.JusticeKit.SweepAddress) {
-	case lnwallet.P2WPKHSize:
+	case input.P2WPKHSize:
 		weightEstimate.AddP2WKHOutput()
 
-	case lnwallet.P2WSHSize:
+	case input.P2WSHSize:
 		weightEstimate.AddP2WSHOutput()
 
 	default:
@@ -251,7 +251,7 @@ func (p *JusticeDescriptor) CreateJusticeTxn() (*wire.MsgTx, error) {
 	if err != nil {
 		return nil, err
 	}
-	weightEstimate.AddWitnessInput(lnwallet.ToLocalPenaltyWitnessSize)
+	weightEstimate.AddWitnessInput(input.ToLocalPenaltyWitnessSize)
 	sweepInputs = append(sweepInputs, toLocalInput)
 
 	// If the justice kit specifies that we have to sweep the to-remote
@@ -262,7 +262,7 @@ func (p *JusticeDescriptor) CreateJusticeTxn() (*wire.MsgTx, error) {
 		if err != nil {
 			return nil, err
 		}
-		weightEstimate.AddWitnessInput(lnwallet.P2WKHWitnessSize)
+		weightEstimate.AddWitnessInput(input.P2WKHWitnessSize)
 		sweepInputs = append(sweepInputs, toRemoteInput)
 	}
 
@@ -281,7 +281,7 @@ func (p *JusticeDescriptor) CreateJusticeTxn() (*wire.MsgTx, error) {
 func findTxOutByPkScript(txn *wire.MsgTx,
 	pkScript []byte) (uint32, *wire.TxOut, error) {
 
-	found, index := lnwallet.FindScriptOutputIndex(txn, pkScript)
+	found, index := input.FindScriptOutputIndex(txn, pkScript)
 	if !found {
 		return 0, nil, ErrOutputNotFound
 	}

watchtower/lookout/justice_descriptor_test.go

@@ -13,8 +13,8 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
 	"github.com/davecgh/go-spew/spew"
+	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
-	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/watchtower/blob"
 	"github.com/lightningnetwork/lnd/watchtower/lookout"
@@ -59,7 +59,7 @@ func newMockSigner() *mockSigner {
 }
 
 func (s *mockSigner) SignOutputRaw(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) ([]byte, error) {
+	signDesc *input.SignDescriptor) ([]byte, error) {
 
 	witnessScript := signDesc.WitnessScript
 	amt := signDesc.Output.Value
@@ -81,7 +81,7 @@ func (s *mockSigner) SignOutputRaw(tx *wire.MsgTx,
 }
 
 func (s *mockSigner) ComputeInputScript(tx *wire.MsgTx,
-	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {
+	signDesc *input.SignDescriptor) (*input.Script, error) {
 	return nil, nil
 }
 
@@ -122,7 +122,7 @@ func TestJusticeDescriptor(t *testing.T) {
 	)
 
 	// Construct the to-local witness script.
-	toLocalScript, err := lnwallet.CommitScriptToSelf(
+	toLocalScript, err := input.CommitScriptToSelf(
 		csvDelay, toLocalPK, revPK,
 	)
 	if err != nil {
@@ -130,13 +130,13 @@ func TestJusticeDescriptor(t *testing.T) {
 	}
 
 	// Compute the to-local witness script hash.
-	toLocalScriptHash, err := lnwallet.WitnessScriptHash(toLocalScript)
+	toLocalScriptHash, err := input.WitnessScriptHash(toLocalScript)
 	if err != nil {
 		t.Fatalf("unable to create to-local witness script hash: %v", err)
 	}
 
 	// Compute the to-remote witness script hash.
-	toRemoteScriptHash, err := lnwallet.CommitScriptUnencumbered(toRemotePK)
+	toRemoteScriptHash, err := input.CommitScriptUnencumbered(toRemotePK)
 	if err != nil {
 		t.Fatalf("unable to create to-remote script: %v", err)
 	}
@@ -160,11 +160,11 @@ func TestJusticeDescriptor(t *testing.T) {
 	breachTxID := breachTxn.TxHash()
 
 	// Compute the weight estimate for our justice transaction.
-	var weightEstimate lnwallet.TxWeightEstimator
+	var weightEstimate input.TxWeightEstimator
 	weightEstimate.AddP2WKHOutput()
 	weightEstimate.AddP2WKHOutput()
-	weightEstimate.AddWitnessInput(lnwallet.ToLocalPenaltyWitnessSize)
+	weightEstimate.AddWitnessInput(input.ToLocalPenaltyWitnessSize)
-	weightEstimate.AddWitnessInput(lnwallet.P2WKHWitnessSize)
+	weightEstimate.AddWitnessInput(input.P2WKHWitnessSize)
 	txWeight := weightEstimate.Weight()
 
 	// Create a session info so that simulate agreement of the sweep
@@ -235,7 +235,7 @@ func TestJusticeDescriptor(t *testing.T) {
 	hashCache := txscript.NewTxSigHashes(justiceTxn)
 
 	// Create the sign descriptor used to sign for the to-local input.
-	toLocalSignDesc := &lnwallet.SignDescriptor{
+	toLocalSignDesc := &input.SignDescriptor{
 		KeyDesc: keychain.KeyDescriptor{
 			KeyLocator: revKeyLoc,
 		},
@@ -247,7 +247,7 @@ func TestJusticeDescriptor(t *testing.T) {
 	}
 
 	// Create the sign descriptor used to sign for the to-remote input.
-	toRemoteSignDesc := &lnwallet.SignDescriptor{
+	toRemoteSignDesc := &input.SignDescriptor{
 		KeyDesc: keychain.KeyDescriptor{
 			KeyLocator: toRemoteKeyLoc,
 			PubKey:     toRemotePK,
@@ -274,7 +274,7 @@ func TestJusticeDescriptor(t *testing.T) {
 	// Compute the witness for the to-remote input. The first element is a
 	// DER-encoded signature under the to-remote pubkey. The sighash flag is
 	// also present, so we trim it.
-	toRemoteWitness, err := lnwallet.CommitSpendNoDelay(
+	toRemoteWitness, err := input.CommitSpendNoDelay(
 		signer, toRemoteSignDesc, justiceTxn,
 	)
 	if err != nil {