multi: use btcd's btcec/v2 and btcutil modules

This commit was previously split into the following parts to ease
review:
 - 2d746f68: replace imports
 - 4008f0fd: use ecdsa.Signature
 - 849e33d1: remove btcec.S256()
 - b8f6ebbd: use v2 library correctly
 - fa80bca9: bump go modules

watchtower/blob/justice_kit.go

@@ -8,7 +8,7 @@ import (
 	"fmt"
 	"io"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -153,14 +153,14 @@ type JusticeKit struct {
 // commitment to-local output.
 func (b *JusticeKit) CommitToLocalWitnessScript() ([]byte, error) {
 	revocationPubKey, err := btcec.ParsePubKey(
-		b.RevocationPubKey[:], btcec.S256(),
+		b.RevocationPubKey[:],
 	)
 	if err != nil {
 		return nil, err
 	}
 
 	localDelayedPubKey, err := btcec.ParsePubKey(
-		b.LocalDelayPubKey[:], btcec.S256(),
+		b.LocalDelayPubKey[:],
 	)
 	if err != nil {
 		return nil, err
@@ -206,9 +206,7 @@ func (b *JusticeKit) CommitToRemoteWitnessScript() ([]byte, error) {
 	// If this is a blob for an anchor channel, we'll return the p2wsh
 	// output containing a CSV delay of 1.
 	if b.BlobType.IsAnchorChannel() {
-		pk, err := btcec.ParsePubKey(
-			b.CommitToRemotePubKey[:], btcec.S256(),
-		)
+		pk, err := btcec.ParsePubKey(b.CommitToRemotePubKey[:])
 		if err != nil {
 			return nil, err
 		}

watchtower/blob/justice_kit_test.go

@@ -8,7 +8,8 @@ import (
 	"reflect"
 	"testing"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcec/v2/ecdsa"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -255,7 +256,7 @@ func testJusticeKitRemoteWitnessConstruction(
 	t *testing.T, test remoteWitnessTest) {
 
 	// Generate the to-remote pubkey.
-	toRemotePrivKey, err := btcec.NewPrivateKey(btcec.S256())
+	toRemotePrivKey, err := btcec.NewPrivateKey()
 	require.Nil(t, err)
 
 	// Copy the to-remote pubkey into the format expected by our justice
@@ -266,8 +267,7 @@ func testJusticeKitRemoteWitnessConstruction(
 	// Sign a message using the to-remote private key. The exact message
 	// doesn't matter as we won't be validating the signature's validity.
 	digest := bytes.Repeat([]byte("a"), 32)
-	rawToRemoteSig, err := toRemotePrivKey.Sign(digest)
-	require.Nil(t, err)
+	rawToRemoteSig := ecdsa.Sign(toRemotePrivKey, digest)
 
 	// Convert the DER-encoded signature into a fixed-size sig.
 	commitToRemoteSig, err := lnwire.NewSigFromSignature(rawToRemoteSig)
@@ -323,10 +323,10 @@ func TestJusticeKitToLocalWitnessConstruction(t *testing.T) {
 	csvDelay := uint32(144)
 
 	// Generate the revocation and delay private keys.
-	revPrivKey, err := btcec.NewPrivateKey(btcec.S256())
+	revPrivKey, err := btcec.NewPrivateKey()
 	require.Nil(t, err)
 
-	delayPrivKey, err := btcec.NewPrivateKey(btcec.S256())
+	delayPrivKey, err := btcec.NewPrivateKey()
 	require.Nil(t, err)
 
 	// Copy the revocation and delay pubkeys into the format expected by our
@@ -340,8 +340,7 @@ func TestJusticeKitToLocalWitnessConstruction(t *testing.T) {
 	// Sign a message using the revocation private key. The exact message
 	// doesn't matter as we won't be validating the signature's validity.
 	digest := bytes.Repeat([]byte("a"), 32)
-	rawRevSig, err := revPrivKey.Sign(digest)
-	require.Nil(t, err)
+	rawRevSig := ecdsa.Sign(revPrivKey, digest)
 
 	// Convert the DER-encoded signature into a fixed-size sig.
 	commitToLocalSig, err := lnwire.NewSigFromSignature(rawRevSig)

watchtower/config.go

@@ -5,9 +5,9 @@ import (
 	"net"
 	"time"
 
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/tor"
 	"github.com/lightningnetwork/lnd/watchtower/lookout"

watchtower/lookout/justice_descriptor.go

@@ -4,11 +4,11 @@ import (
 	"errors"
 
 	"github.com/btcsuite/btcd/blockchain"
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/btcutil/txsort"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcutil"
-	"github.com/btcsuite/btcutil/txsort"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/watchtower/blob"
 	"github.com/lightningnetwork/lnd/watchtower/wtdb"
@@ -121,7 +121,7 @@ func (p *JusticeDescriptor) commitToRemoteInput() (*breachedInput, error) {
 	} else {
 		// Since the to-remote witness script should just be a regular p2wkh
 		// output, we'll parse it to retrieve the public key.
-		toRemotePubKey, err := btcec.ParsePubKey(toRemoteScript, btcec.S256())
+		toRemotePubKey, err := btcec.ParsePubKey(toRemoteScript)
 		if err != nil {
 			return nil, err
 		}

watchtower/lookout/justice_descriptor_test.go

@@ -5,11 +5,11 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/blockchain"
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/btcutil/txsort"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcutil"
-	"github.com/btcsuite/btcutil/txsort"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -93,13 +93,13 @@ func testJusticeDescriptor(t *testing.T, blobType blob.Type) {
 
 	// Parse the key pairs for all keys used in the test.
 	revSK, revPK := btcec.PrivKeyFromBytes(
-		btcec.S256(), revPrivBytes,
+		revPrivBytes,
 	)
 	_, toLocalPK := btcec.PrivKeyFromBytes(
-		btcec.S256(), toLocalPrivBytes,
+		toLocalPrivBytes,
 	)
 	toRemoteSK, toRemotePK := btcec.PrivKeyFromBytes(
-		btcec.S256(), toRemotePrivBytes,
+		toRemotePrivBytes,
 	)
 
 	// Create the signer, and add the revocation and to-remote privkeys.

watchtower/standalone.go

@@ -4,7 +4,7 @@ import (
 	"net"
 	"sync/atomic"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/brontide"
 	"github.com/lightningnetwork/lnd/tor"
 	"github.com/lightningnetwork/lnd/watchtower/lookout"

watchtower/wtclient/backup_task.go

@@ -4,11 +4,11 @@ import (
 	"fmt"
 
 	"github.com/btcsuite/btcd/blockchain"
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/btcutil/txsort"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcutil"
-	"github.com/btcsuite/btcutil/txsort"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"

watchtower/wtclient/backup_task_internal_test.go

@@ -7,11 +7,11 @@ import (
 	"reflect"
 	"testing"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
 	"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"
@@ -103,13 +103,13 @@ func genTaskTest(
 
 	// Parse the key pairs for all keys used in the test.
 	revSK, revPK := btcec.PrivKeyFromBytes(
-		btcec.S256(), revPrivBytes,
+		revPrivBytes,
 	)
 	_, toLocalPK := btcec.PrivKeyFromBytes(
-		btcec.S256(), toLocalPrivBytes,
+		toLocalPrivBytes,
 	)
 	toRemoteSK, toRemotePK := btcec.PrivKeyFromBytes(
-		btcec.S256(), toRemotePrivBytes,
+		toRemotePrivBytes,
 	)
 
 	// Create the signer, and add the revocation and to-remote privkeys.

watchtower/wtclient/candidate_iterator_test.go

@@ -8,7 +8,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/watchtower/wtdb"
 )
@@ -34,12 +34,11 @@ func randAddr(t *testing.T) net.Addr {
 }
 
 func randTower(t *testing.T) *wtdb.Tower {
-	priv, err := btcec.NewPrivateKey(btcec.S256())
+	priv, err := btcec.NewPrivateKey()
 	if err != nil {
 		t.Fatalf("unable to create private key: %v", err)
 	}
 	pubKey := priv.PubKey()
-	pubKey.Curve = nil
 	return &wtdb.Tower{
 		ID:          wtdb.TowerID(rand.Uint64()),
 		IdentityKey: pubKey,

watchtower/wtclient/client.go

@@ -8,7 +8,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btclog"
 	"github.com/lightningnetwork/lnd/build"

watchtower/wtclient/client_test.go

@@ -7,11 +7,11 @@ import (
 	"testing"
 	"time"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
 	"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"
@@ -67,7 +67,7 @@ var (
 func randPrivKey(t *testing.T) *btcec.PrivateKey {
 	t.Helper()
 
-	sk, err := btcec.NewPrivateKey(btcec.S256())
+	sk, err := btcec.NewPrivateKey()
 	if err != nil {
 		t.Fatalf("unable to generate pubkey: %v", err)
 	}
@@ -401,7 +401,7 @@ func newHarness(t *testing.T, cfg harnessCfg) *testHarness {
 		t.Fatalf("Unable to resolve tower TCP addr: %v", err)
 	}
 
-	privKey, err := btcec.NewPrivateKey(btcec.S256())
+	privKey, err := btcec.NewPrivateKey()
 	if err != nil {
 		t.Fatalf("Unable to generate tower private key: %v", err)
 	}

watchtower/wtclient/interface.go

@@ -3,7 +3,7 @@ package wtclient
 import (
 	"net"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/tor"

watchtower/wtdb/client_db.go

@@ -7,7 +7,7 @@ import (
 	"math"
 	"net"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/watchtower/blob"

watchtower/wtdb/client_db_test.go

@@ -10,7 +10,7 @@ import (
 	"reflect"
 	"testing"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/watchtower/blob"

watchtower/wtdb/codec_test.go

@@ -10,13 +10,13 @@ import (
 	"testing"
 	"testing/quick"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/tor"
 	"github.com/lightningnetwork/lnd/watchtower/wtdb"
 )
 
 func randPubKey() (*btcec.PublicKey, error) {
-	priv, err := btcec.NewPrivateKey(btcec.S256())
+	priv, err := btcec.NewPrivateKey()
 	if err != nil {
 		return nil, err
 	}

watchtower/wtdb/session_id.go

@@ -3,7 +3,7 @@ package wtdb
 import (
 	"encoding/hex"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 )
 
 // SessionIDSize is 33-bytes; it is a serialized, compressed public key.

watchtower/wtdb/tower.go

@@ -6,7 +6,7 @@ import (
 	"io"
 	"net"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/lnwire"
 )
 

watchtower/wtmock/client_db.go

@@ -5,7 +5,7 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/watchtower/blob"
 	"github.com/lightningnetwork/lnd/watchtower/wtdb"

watchtower/wtmock/keyring.go

@@ -3,7 +3,7 @@ package wtmock
 import (
 	"sync"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/keychain"
 )
 
@@ -39,7 +39,7 @@ func (m *SecretKeyRing) DeriveKey(
 		}, nil
 	}
 
-	privKey, err := btcec.NewPrivateKey(btcec.S256())
+	privKey, err := btcec.NewPrivateKey()
 	if err != nil {
 		return keychain.KeyDescriptor{}, err
 	}

watchtower/wtmock/peer.go

@@ -5,7 +5,7 @@ import (
 	"net"
 	"time"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/watchtower/wtserver"
 )
 

watchtower/wtmock/signer.go

@@ -3,7 +3,8 @@ package wtmock
 import (
 	"sync"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcec/v2/ecdsa"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/input"
@@ -51,7 +52,7 @@ func (s *MockSigner) SignOutputRaw(tx *wire.MsgTx,
 		return nil, err
 	}
 
-	return btcec.ParseDERSignature(sig[:len(sig)-1], btcec.S256())
+	return ecdsa.ParseDERSignature(sig[:len(sig)-1])
 }
 
 // ComputeInputScript is not implemented.

watchtower/wtpolicy/policy.go

@@ -4,8 +4,8 @@ import (
 	"errors"
 	"fmt"
 
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"

watchtower/wtserver/interface.go

@@ -5,7 +5,7 @@ import (
 	"net"
 	"time"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightningnetwork/lnd/watchtower/wtdb"
 )
 

watchtower/wtserver/server.go

@@ -8,9 +8,9 @@ import (
 	"sync"
 	"time"
 
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/connmgr"
-	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/watchtower/wtdb"

watchtower/wtserver/server_test.go

@@ -6,10 +6,10 @@ import (
 	"testing"
 	"time"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/txscript"
-	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/watchtower/blob"
 	"github.com/lightningnetwork/lnd/watchtower/wtdb"
@@ -35,7 +35,7 @@ var (
 func randPubKey(t *testing.T) *btcec.PublicKey {
 	t.Helper()
 
-	sk, err := btcec.NewPrivateKey(btcec.S256())
+	sk, err := btcec.NewPrivateKey()
 	if err != nil {
 		t.Fatalf("unable to generate pubkey: %v", err)
 	}

watchtower/wtwire/wtwire.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"io"
 
-	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
@@ -228,7 +228,7 @@ func ReadElement(r io.Reader, element interface{}) error {
 			return err
 		}
 
-		pubKey, err := btcec.ParsePubKey(b[:], btcec.S256())
+		pubKey, err := btcec.ParsePubKey(b[:])
 		if err != nil {
 			return err
 		}