mod+waddrmgr: add taproot script address

go.mod

@@ -22,6 +22,7 @@ require (
 	github.com/lightninglabs/gozmq v0.0.0-20191113021534-d20a764486bf
 	github.com/lightninglabs/neutrino v0.13.2
 	github.com/lightningnetwork/lnd/ticker v1.0.0
+	github.com/lightningnetwork/lnd/tlv v1.0.2
 	github.com/stretchr/testify v1.7.0
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
 	golang.org/x/net v0.0.0-20200813134508-3edf25e44fcc

go.sum

@@ -100,6 +100,8 @@ github.com/lightningnetwork/lnd/queue v1.0.1 h1:jzJKcTy3Nj5lQrooJ3aaw9Lau3I0IwvQ
 github.com/lightningnetwork/lnd/queue v1.0.1/go.mod h1:vaQwexir73flPW43Mrm7JOgJHmcEFBWWSl9HlyASoms=
 github.com/lightningnetwork/lnd/ticker v1.0.0 h1:S1b60TEGoTtCe2A0yeB+ecoj/kkS4qpwh6l+AkQEZwU=
 github.com/lightningnetwork/lnd/ticker v1.0.0/go.mod h1:iaLXJiVgI1sPANIF2qYYUJXjoksPNvGNYowB8aRbpX0=
+github.com/lightningnetwork/lnd/tlv v1.0.2 h1:LG7H3Uw/mHYGnEeHRPg+STavAH+UsFvuBflD0PzcYFQ=
+github.com/lightningnetwork/lnd/tlv v1.0.2/go.mod h1:fICAfsqk1IOsC1J7G9IdsWX1EqWRMqEDCNxZJSKr9C4=
 github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.7.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=

waddrmgr/address.go

@@ -57,6 +57,10 @@ const (
 	// uses BIP-0086 (for the derivation path and for calculating the tap
 	// root hash/tweak).
 	TaprootPubKey
+
+	// TaprootScript represents a p2tr (pay-to-taproot) address type that
+	// commits to a script and not just a single key.
+	TaprootScript
 )
 
 const (
@@ -142,6 +146,17 @@ type ManagedScriptAddress interface {
 	Script() ([]byte, error)
 }
 
+// ManagedTaprootScriptAddress extends ManagedScriptAddress and represents a
+// pay-to-taproot script address. It additionally provides information about the
+// script.
+type ManagedTaprootScriptAddress interface {
+	ManagedScriptAddress
+
+	// TaprootScript returns all the information needed to derive the script
+	// tree root hash needed to arrive at the tweaked taproot key.
+	TaprootScript() (*Tapscript, error)
+}
+
 // managedAddress represents a public key address.  It also may or may not have
 // the private key associated with the public key.
 type managedAddress struct {
@@ -796,38 +811,110 @@ var _ ManagedScriptAddress = (*witnessScriptAddress)(nil)
 
 // newWitnessScriptAddress initializes and returns a new
 // pay-to-witness-script-hash address.
-func newWitnessScriptAddress(m *ScopedKeyManager, account uint32, scriptHash,
+func newWitnessScriptAddress(m *ScopedKeyManager, account uint32, scriptIdent,
 	scriptEncrypted []byte, witnessVersion byte,
-	isSecretScript bool) (*witnessScriptAddress, error) {
-
-	var (
-		address btcutil.Address
-		err     error
-	)
+	isSecretScript bool) (ManagedScriptAddress, error) {
 
 	switch witnessVersion {
-	case 0x00:
-		address, err = btcutil.NewAddressWitnessScriptHash(
-			scriptHash, m.rootManager.chainParams,
+	case witnessVersionV0:
+		address, err := btcutil.NewAddressWitnessScriptHash(
+			scriptIdent, m.rootManager.chainParams,
 		)
+		if err != nil {
+			return nil, err
+		}
 
-	case 0x01:
-		address, err = btcutil.NewAddressTaproot(
-			scriptHash, m.rootManager.chainParams,
+		return &witnessScriptAddress{
+			baseScriptAddress: baseScriptAddress{
+				manager:         m,
+				account:         account,
+				scriptEncrypted: scriptEncrypted,
+			},
+			address:        address,
+			witnessVersion: witnessVersion,
+			isSecretScript: isSecretScript,
+		}, nil
+
+	case witnessVersionV1:
+		address, err := btcutil.NewAddressTaproot(
+			scriptIdent, m.rootManager.chainParams,
 		)
+		if err != nil {
+			return nil, err
+		}
+
+		// Lift the x-only coordinate of the tweaked public key.
+		tweakedPubKey, err := schnorr.ParsePubKey(scriptIdent)
+		if err != nil {
+			return nil, fmt.Errorf("error lifting public key from "+
+				"script ident: %v", err)
+		}
+
+		return &taprootScriptAddress{
+			witnessScriptAddress: witnessScriptAddress{
+				baseScriptAddress: baseScriptAddress{
+					manager:         m,
+					account:         account,
+					scriptEncrypted: scriptEncrypted,
+				},
+				address:        address,
+				witnessVersion: witnessVersion,
+				isSecretScript: isSecretScript,
+			},
+			TweakedPubKey: tweakedPubKey,
+		}, nil
+
+	default:
+		return nil, fmt.Errorf("unsupported witness version %d",
+			witnessVersion)
 	}
+}
+
+// taprootScriptAddress represents a pay-to-taproot address that commits to a
+// script.
+type taprootScriptAddress struct {
+	witnessScriptAddress
+
+	TweakedPubKey *btcec.PublicKey
+}
+
+// Enforce taprootScriptAddress satisfies the ManagedTaprootScriptAddress
+// interface.
+var _ ManagedTaprootScriptAddress = (*taprootScriptAddress)(nil)
+
+// AddrType returns the address type of the managed address. This can be used
+// to quickly discern the address type without further processing
+//
+// This is part of the ManagedAddress interface implementation.
+func (a *taprootScriptAddress) AddrType() AddressType {
+	return TaprootScript
+}
+
+// Address returns the btcutil.Address which represents the managed address.
+// This will be a pay-to-witness-script-hash address.
+//
+// This is part of the ManagedAddress interface implementation.
+func (a *taprootScriptAddress) Address() btcutil.Address {
+	return a.address
+}
+
+// AddrHash returns the script hash for the address.
+//
+// This is part of the ManagedAddress interface implementation.
+func (a *taprootScriptAddress) AddrHash() []byte {
+	return schnorr.SerializePubKey(a.TweakedPubKey)
+}
+
+// TaprootScript returns all the information needed to derive the script tree
+// root hash needed to arrive at the tweaked taproot key.
+func (a *taprootScriptAddress) TaprootScript() (*Tapscript, error) {
+	// Need to decrypt our internal script first. We need to be unlocked for
+	// this.
+	script, err := a.Script()
 	if err != nil {
 		return nil, err
 	}
 
-	return &witnessScriptAddress{
-		baseScriptAddress: baseScriptAddress{
-			manager:         m,
-			account:         account,
-			scriptEncrypted: scriptEncrypted,
-		},
-		address:        address,
-		witnessVersion: witnessVersion,
-		isSecretScript: isSecretScript,
-	}, nil
+	// Decode the additional TLV encoded data.
+	return tlvDecodeTaprootTaprootScript(script)
 }

waddrmgr/manager_test.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcec/v2/schnorr"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/btcutil/hdkeychain"
 	"github.com/btcsuite/btcd/chaincfg"
@@ -892,6 +893,7 @@ func testImportScript(tc *testContext) bool {
 		name           string
 		in             []byte
 		isWitness      bool
+		isTaproot      bool
 		witnessVersion byte
 		isSecretScript bool
 		blockstamp     BlockStamp
@@ -973,18 +975,23 @@ func testImportScript(tc *testContext) bool {
 			},
 		},
 		{
-			name:           "p2tr multisig",
-			isWitness:      true,
+			name:           "p2tr tapscript with all tap leaves",
+			isTaproot:      true,
 			witnessVersion: 1,
 			isSecretScript: true,
-			in: hexToBytes("52210305a662958b547fe25a71cd28fc7ef1c2" +
-				"ad4a79b12f34fc40137824b88e61199d21038552c09d9" +
-				"a709c8cbba6e472307d3f8383f46181895a76e01e258f" +
-				"09033b4a78210205ad9a838cff17d79fee2841bec72e9" +
-				"9b6fd4e62fd9214fcf845b1cf8438062053ae"),
+			// The encoded *Tapscript struct for a script with all
+			// tap script leaves known.
+			in: hexToBytes(
+				"0101000221c00ef94ee79c07cbd1988fffd6e6aea1e2" +
+					"5c3b033a2fd64fe14a9b955e5355f0c60346" +
+					"1d0101c0021876a914f6c97547d73156abb3" +
+					"00ae059905c4acaadd09dd88270101c00222" +
+					"200ef94ee79c07cbd1988fffd6e6aea1e25c" +
+					"3b033a2fd64fe14a9b955e5355f0c6ac",
+			),
 			expected: expectedAddr{
-				address:     "bc1pc57jdm7kcnufnc339fvy2caflj6lkfeqasdfghftl7dd77dfpresqu7vep",
-				addressHash: hexToBytes("c53d26efd6c4f899e2312a584563a9fcb5fb2720ec1a945d2bff9adf79a908f3"),
+				address:     "bc1pu92qt24cl4spyp4rsj9sa3y4ma6a3fszgewcmway9f6f80vgnduq5lnd0u",
+				addressHash: hexToBytes("e15405aab8fd601206a3848b0ec495df75d8a602465d8dbba42a7493bd889b78"),
 				internal:    false,
 				imported:    true,
 				compressed:  true,
@@ -1023,13 +1030,27 @@ func testImportScript(tc *testContext) bool {
 				ns := tx.ReadWriteBucket(waddrmgrNamespaceKey)
 				var err error
 
-				if test.isWitness {
+				switch {
+				case test.isWitness:
 					addr, err = tc.manager.ImportWitnessScript(
 						ns, test.in, &test.blockstamp,
 						test.witnessVersion,
 						test.isSecretScript,
 					)
-				} else {
+
+				case test.isTaproot:
+					var script *Tapscript
+					script, err = tlvDecodeTaprootTaprootScript(
+						test.in,
+					)
+					require.NoError(tc.t, err)
+					addr, err = tc.manager.ImportTaprootScript(
+						ns, script, &test.blockstamp,
+						test.witnessVersion,
+						test.isSecretScript,
+					)
+
+				default:
 					addr, err = tc.manager.ImportScript(
 						ns, test.in, &test.blockstamp,
 					)
@@ -1068,10 +1089,21 @@ func testImportScript(tc *testContext) bool {
 					scriptHash[:], chainParams,
 				)
 
-			case test.isWitness && test.witnessVersion == 1:
-				scriptHash := sha256.Sum256(test.in)
+			case test.isTaproot:
+				var (
+					script     *Tapscript
+					taprootKey *btcec.PublicKey
+				)
+				script, err = tlvDecodeTaprootTaprootScript(
+					test.in,
+				)
+				require.NoError(tc.t, err)
+				taprootKey, err = script.TaprootKey()
+				require.NoError(tc.t, err)
+
 				utilAddr, err = btcutil.NewAddressTaproot(
-					scriptHash[:], chainParams,
+					schnorr.SerializePubKey(taprootKey),
+					chainParams,
 				)
 
 			default:

waddrmgr/scoped_manager.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 
 	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcec/v2/schnorr"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/btcutil/hdkeychain"
 	"github.com/btcsuite/btcd/chaincfg"
@@ -147,6 +148,13 @@ func WitnessScriptHashIdentity(script []byte) Identity {
 	}
 }
 
+// TaprootIdentity returns the identity closure for a p2tr script.
+func TaprootIdentity(taprootKey *btcec.PublicKey) Identity {
+	return func() []byte {
+		return schnorr.SerializePubKey(taprootKey)
+	}
+}
+
 // ScopeAddrSchema is the address schema of a particular KeyScope. This will be
 // persisted within the database, and will be consulted when deriving any keys
 // for a particular scope to know how to encode the public keys as addresses.
@@ -2110,6 +2118,36 @@ func (s *ScopedKeyManager) ImportWitnessScript(ns walletdb.ReadWriteBucket,
 	)
 }
 
+// ImportTaprootScript imports a user-provided taproot script into the address
+// manager. The imported script will act as a pay-to-taproot address.
+func (s *ScopedKeyManager) ImportTaprootScript(ns walletdb.ReadWriteBucket,
+	tapscript *Tapscript, bs *BlockStamp, witnessVersion byte,
+	isSecretScript bool) (ManagedTaprootScriptAddress, error) {
+
+	// Make sure we have everything we need to calculate the script root and
+	// tweak the taproot key.
+	taprootKey, err := tapscript.TaprootKey()
+	if err != nil {
+		return nil, fmt.Errorf("error calculating script root: %v", err)
+	}
+
+	script, err := tlvEncodeTaprootScript(tapscript)
+	if err != nil {
+		return nil, fmt.Errorf("error encoding taproot script: %v", err)
+	}
+
+	managedAddr, err := s.importScriptAddress(
+		ns, TaprootIdentity(taprootKey), script, bs,
+		TaprootScript, witnessVersion, isSecretScript,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// We know this is a taproot address at this point.
+	return managedAddr.(ManagedTaprootScriptAddress), nil
+}
+
 // importScriptAddress imports a new pay-to-script or pay-to-witness-script
 // address.
 func (s *ScopedKeyManager) importScriptAddress(ns walletdb.ReadWriteBucket,
@@ -2179,7 +2217,7 @@ func (s *ScopedKeyManager) importScriptAddress(ns walletdb.ReadWriteBucket,
 	// Save the new imported address to the db and update start block (if
 	// needed) in a single transaction.
 	switch addrType {
-	case WitnessScript:
+	case WitnessScript, TaprootScript:
 		err = putWitnessScriptAddress(
 			ns, &s.scope, scriptIdent, ImportedAddrAccount, ssNone,
 			witnessVersion, isSecretScript, encryptedHash,
@@ -2217,7 +2255,7 @@ func (s *ScopedKeyManager) importScriptAddress(ns walletdb.ReadWriteBucket,
 	// should not be cleared out from under the caller.
 	var managedAddr ManagedScriptAddress
 	switch addrType {
-	case WitnessScript:
+	case WitnessScript, TaprootScript:
 		managedAddr, err = newWitnessScriptAddress(
 			s, ImportedAddrAccount, scriptIdent, encryptedScript,
 			witnessVersion, isSecretScript,