mirror of
https://github.com/lightninglabs/loop.git
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d554b42ef6
Update LND, Aperture, and Taproot Assets to revisions using the btcd v2 modules, and update lndclient to v0.21.0-3. Migrate Loop chain, transaction, and address types to their corresponding v2 packages. The lndclient release includes the migration from: https://github.com/lightninglabs/lndclient/pull/280 Taproot Assets is temporarily replaced with its btcd v2 revision because the v0.8 release branch has not adopted the new modules. This raises the minimum Go version to 1.26 and changes exported address types.
122 lines
3.3 KiB
Go
122 lines
3.3 KiB
Go
package script
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import (
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"fmt"
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"github.com/btcsuite/btcd/btcec/v2"
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"github.com/btcsuite/btcd/btcec/v2/schnorr"
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"github.com/btcsuite/btcd/btcec/v2/schnorr/musig2"
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"github.com/btcsuite/btcd/txscript/v2"
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"github.com/lightningnetwork/lnd/input"
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)
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const (
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// TaprootMultiSigWitnessSize evaluates to 66 bytes:
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// - num_witness_elements: 1 byte
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// - sig_varint_len: 1 byte
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// - <sig>: 64 bytes
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TaprootMultiSigWitnessSize = 1 + 1 + 64
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// TaprootExpiryScriptSize evaluates to 39 bytes:
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// - OP_DATA: 1 byte (trader_key length)
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// - <trader_key>: 32 bytes
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// - OP_CHECKSIGVERIFY: 1 byte
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// - <reservation_expiry>: 4 bytes
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// - OP_CHECKLOCKTIMEVERIFY: 1 byte
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TaprootExpiryScriptSize = 1 + 32 + 1 + 4 + 1
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// TaprootExpiryWitnessSize evaluates to 140 bytes:
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// - num_witness_elements: 1 byte
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// - trader_sig_varint_len: 1 byte (trader_sig length)
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// - <trader_sig>: 64 bytes
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// - witness_script_varint_len: 1 byte (script length)
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// - <witness_script>: 39 bytes
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// - control_block_varint_len: 1 byte (control block length)
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// - <control_block>: 33 bytes
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TaprootExpiryWitnessSize = 1 + 1 + 64 + 1 + TaprootExpiryScriptSize + 1 + 33
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)
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// ReservationScript returns the tapscript pkscript for the given reservation
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// parameters.
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func ReservationScript(expiry uint32, serverKey,
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clientKey *btcec.PublicKey) ([]byte, error) {
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aggregatedKey, err := TaprootKey(expiry, serverKey, clientKey)
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if err != nil {
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return nil, err
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}
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return PayToWitnessTaprootScript(aggregatedKey.FinalKey)
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}
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// TaprootKey returns the aggregated MuSig2 combined key.
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func TaprootKey(expiry uint32, serverKey,
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clientKey *btcec.PublicKey) (*musig2.AggregateKey, error) {
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expiryLeaf, err := TaprootExpiryScript(expiry, serverKey)
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if err != nil {
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return nil, err
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}
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rootHash := expiryLeaf.TapHash()
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aggregateKey, err := input.MuSig2CombineKeys(
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input.MuSig2Version100RC2,
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[]*btcec.PublicKey{
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clientKey, serverKey,
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}, true,
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&input.MuSig2Tweaks{
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TaprootTweak: rootHash[:],
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},
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)
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if err != nil {
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return nil, fmt.Errorf("error combining keys: %v", err)
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}
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return aggregateKey, nil
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}
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// PayToWitnessTaprootScript creates a new script to pay to a version 1
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// (taproot) witness program.
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func PayToWitnessTaprootScript(taprootKey *btcec.PublicKey) ([]byte, error) {
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builder := txscript.NewScriptBuilder()
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builder.AddOp(txscript.OP_1)
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builder.AddData(schnorr.SerializePubKey(taprootKey))
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return builder.Script()
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}
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// TaprootExpiryScript returns the leaf script of the expiry script path.
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//
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// <server_key> OP_CHECKSIGVERIFY <reservation_expiry> OP_CHECKLOCKTIMEVERIFY.
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func TaprootExpiryScript(expiry uint32,
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serverKey *btcec.PublicKey) (*txscript.TapLeaf, error) {
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builder := txscript.NewScriptBuilder()
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builder.AddData(schnorr.SerializePubKey(serverKey))
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builder.AddOp(txscript.OP_CHECKSIGVERIFY)
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builder.AddInt64(int64(expiry))
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builder.AddOp(txscript.OP_CHECKLOCKTIMEVERIFY)
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script, err := builder.Script()
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if err != nil {
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return nil, err
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}
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leaf := txscript.NewBaseTapLeaf(script)
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return &leaf, nil
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}
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// ExpirySpendWeight returns the weight of the expiry path spend.
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func ExpirySpendWeight() int64 {
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var weightEstimator input.TxWeightEstimator
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weightEstimator.AddWitnessInput(TaprootExpiryWitnessSize)
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weightEstimator.AddP2TROutput()
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return int64(weightEstimator.Weight())
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}
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