102 lines
2.5 KiB
Go
102 lines
2.5 KiB
Go
package lnwallet
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import (
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"bytes"
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"fmt"
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"github.com/btcsuite/btcd/txscript"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcutil"
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)
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// scriptHashPkScript...
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func scriptHashPkScript(scriptBytes []byte) ([]byte, error) {
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bldr := txscript.NewScriptBuilder()
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bldr.AddOp(txscript.OP_HASH160)
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bldr.AddData(btcutil.Hash160(scriptBytes))
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bldr.AddOp(txscript.OP_EQUAL)
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return bldr.Script()
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}
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// getFundingPkScript generates the non-p2sh'd multisig script for 2 of 2
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// pubkeys.
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func genFundingPkScript(aPub, bPub []byte) ([]byte, error) {
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if len(aPub) != 33 || len(bPub) != 33 {
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return nil, fmt.Errorf("Pubkey size error. Compressed pubkeys only")
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}
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if bytes.Compare(aPub, bPub) == -1 { // swap to sort pubkeys if needed
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aPub, bPub = bPub, aPub
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}
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bldr := txscript.NewScriptBuilder()
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// Require 2 signatures, so from both of the pubkeys
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bldr.AddOp(txscript.OP_2)
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// add both pubkeys (sorted)
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bldr.AddData(aPub)
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bldr.AddData(bPub)
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// 2 keys total. In case that wasn't obvious.
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bldr.AddOp(txscript.OP_2)
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// Good ol OP_CHECKMULTISIG. Don't forget the zero!
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bldr.AddOp(txscript.OP_CHECKMULTISIG)
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// get byte slice
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return bldr.Script()
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}
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// fundMultiSigOut creates a TxOut for the funding transaction.
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// Give it the two pubkeys and it'll give you the p2sh'd txout.
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// You don't have to remember the p2sh preimage, as long as you remember the
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// pubkeys involved.
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func fundMultiSigOut(aPub, bPub []byte, amt int64) ([]byte, *wire.TxOut, error) {
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if amt < 0 {
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return nil, nil, fmt.Errorf("Can't create FundTx script with negative coins")
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}
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// p2shify
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redeemScript, err := genFundingPkScript(aPub, bPub)
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if err != nil {
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return nil, nil, err
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}
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pkScript, err := scriptHashPkScript(redeemScript)
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if err != nil {
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return nil, nil, err
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}
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return redeemScript, wire.NewTxOut(amt, pkScript), nil
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}
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// the scriptsig to put on a P2SH input
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func spendMultiSig(redeemScript, sigA, sigB []byte) ([]byte, error) {
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bldr := txscript.NewScriptBuilder()
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// add a 0 for some multisig fun
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bldr.AddOp(txscript.OP_0)
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// add sigA
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bldr.AddData(sigA)
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// add sigB
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bldr.AddData(sigB)
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// preimage goes on AT THE ENDDDD
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bldr.AddData(redeemScript)
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// that's all, get bytes
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return bldr.Script()
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}
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// findScriptOutputIndex...
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// only finds first matchin, assumes unique pkScripts
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func findScriptOutputIndex(tx *wire.MsgTx, script []byte) (bool, uint32) {
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found := false
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index := uint32(0)
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for i, txOut := range tx.TxOut {
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if bytes.Equal(txOut.PkScript, script) {
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found = true
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index = uint32(i)
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break
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}
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}
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return found, index
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}
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