mirror of
https://github.com/lightninglabs/loop.git
synced 2026-08-13 12:33:03 +02:00
6a54be23ae
This commit enables package relayed HTLCs by making the CSV check in the success path optional.
106 lines
3.4 KiB
Go
106 lines
3.4 KiB
Go
package htlc
|
|
|
|
import (
|
|
"github.com/btcsuite/btcd/btcec/v2"
|
|
"github.com/btcsuite/btcd/btcec/v2/schnorr"
|
|
"github.com/btcsuite/btcd/txscript"
|
|
"github.com/decred/dcrd/dcrec/secp256k1/v4"
|
|
"github.com/lightninglabs/taproot-assets/asset"
|
|
"github.com/lightningnetwork/lnd/input"
|
|
"github.com/lightningnetwork/lnd/keychain"
|
|
"github.com/lightningnetwork/lnd/lntypes"
|
|
)
|
|
|
|
// GenSuccessPathScript constructs a script for the success path of the HTLC
|
|
// payment. Optionally includes a CHECKSEQUENCEVERIFY (CSV) of 1 if `csv` is
|
|
// true, to prevent potential pinning attacks when the HTLC is not part of a
|
|
// package relay.
|
|
func GenSuccessPathScript(receiverHtlcKey *btcec.PublicKey,
|
|
swapHash lntypes.Hash, csvOne bool) ([]byte, error) {
|
|
|
|
builder := txscript.NewScriptBuilder()
|
|
|
|
builder.AddData(schnorr.SerializePubKey(receiverHtlcKey))
|
|
builder.AddOp(txscript.OP_CHECKSIGVERIFY)
|
|
builder.AddOp(txscript.OP_SIZE)
|
|
builder.AddInt64(32)
|
|
builder.AddOp(txscript.OP_EQUALVERIFY)
|
|
builder.AddOp(txscript.OP_HASH160)
|
|
builder.AddData(input.Ripemd160H(swapHash[:]))
|
|
// OP_EQUAL will leave 0 or 1 on the stack depending on whether the hash
|
|
// matches.
|
|
// - If it matches and CSV is not used, the script will
|
|
// evaulate to true.
|
|
// - If it matches and CSV is used, we'll have 1 on the stack which is
|
|
// used to verify the CSV condition.
|
|
// - If it does not match, we'll have 0 on the stack which will cause
|
|
// the script to fail even if CSV is used.
|
|
builder.AddOp(txscript.OP_EQUAL)
|
|
|
|
if csvOne {
|
|
// If csvOne is true, we add a CHECKSEQUENCEVERIFY to ensure
|
|
// that the HTLC can only be claimed after at least one
|
|
// confirmation.
|
|
builder.AddOp(txscript.OP_CHECKSEQUENCEVERIFY)
|
|
}
|
|
|
|
return builder.Script()
|
|
}
|
|
|
|
// GenTimeoutPathScript constructs an HtlcScript for the timeout payment path.
|
|
func GenTimeoutPathScript(senderHtlcKey *btcec.PublicKey, csvExpiry int64) (
|
|
[]byte, error) {
|
|
|
|
builder := txscript.NewScriptBuilder()
|
|
builder.AddData(schnorr.SerializePubKey(senderHtlcKey))
|
|
builder.AddOp(txscript.OP_CHECKSIGVERIFY)
|
|
builder.AddInt64(csvExpiry)
|
|
builder.AddOp(txscript.OP_CHECKSEQUENCEVERIFY)
|
|
return builder.Script()
|
|
}
|
|
|
|
// GetOpTrueScript returns a script that always evaluates to true.
|
|
func GetOpTrueScript() ([]byte, error) {
|
|
return txscript.NewScriptBuilder().AddOp(txscript.OP_TRUE).Script()
|
|
}
|
|
|
|
// CreateOpTrueLeaf creates a taproot leaf that always evaluates to true.
|
|
func CreateOpTrueLeaf() (asset.ScriptKey, txscript.TapLeaf,
|
|
*txscript.IndexedTapScriptTree, *txscript.ControlBlock, error) {
|
|
|
|
// Create the taproot OP_TRUE script.
|
|
tapScript, err := GetOpTrueScript()
|
|
if err != nil {
|
|
return asset.ScriptKey{}, txscript.TapLeaf{}, nil, nil, err
|
|
}
|
|
|
|
tapLeaf := txscript.NewBaseTapLeaf(tapScript)
|
|
tree := txscript.AssembleTaprootScriptTree(tapLeaf)
|
|
rootHash := tree.RootNode.TapHash()
|
|
tapKey := txscript.ComputeTaprootOutputKey(
|
|
asset.NUMSPubKey, rootHash[:],
|
|
)
|
|
|
|
merkleRootHash := tree.RootNode.TapHash()
|
|
|
|
controlBlock := &txscript.ControlBlock{
|
|
LeafVersion: txscript.BaseLeafVersion,
|
|
InternalKey: asset.NUMSPubKey,
|
|
}
|
|
tapScriptKey := asset.ScriptKey{
|
|
PubKey: tapKey,
|
|
TweakedScriptKey: &asset.TweakedScriptKey{
|
|
RawKey: keychain.KeyDescriptor{
|
|
PubKey: asset.NUMSPubKey,
|
|
},
|
|
Tweak: merkleRootHash[:],
|
|
},
|
|
}
|
|
if tapKey.SerializeCompressed()[0] ==
|
|
secp256k1.PubKeyFormatCompressedOdd {
|
|
|
|
controlBlock.OutputKeyYIsOdd = true
|
|
}
|
|
|
|
return tapScriptKey, tapLeaf, tree, controlBlock, nil
|
|
}
|