Bitcoin Cash tree signature

main.go

package main

import (
	"fmt"
	"github.com/btcsuite/btcd/btcec"
	"encoding/hex"
	"crypto/sha256"
	"github.com/btcsuite/btcd/txscript"
	"github.com/cpacia/bchutil"
	"github.com/btcsuite/btcd/chaincfg"
	"github.com/btcsuite/btcd/wire"
	"github.com/btcsuite/btcd/chaincfg/chainhash"
	"bytes"
)

func main() {
	// Create the keys
	b1, _ := hex.DecodeString("7aa6f244ab964b29195fcda35119f3c2ac2987544552140762fae158309f9370")
	key1, _ := btcec.PrivKeyFromBytes(btcec.S256(), b1)
	b2, _ := hex.DecodeString("02d9d13cbb800123c03401247b64bdc4599f8745f0ae65e0040bd2510f7adfb5")
	key2, _ := btcec.PrivKeyFromBytes(btcec.S256(), b2)
	b3, _ := hex.DecodeString("887637c7f3dbf5fe545f8b7289f7560ee489ff2461c0e88af198a8eae5c6b694")
	key3, _ := btcec.PrivKeyFromBytes(btcec.S256(), b3)
	b4, _ := hex.DecodeString("a3be9fb58097fd582efd096858c848934d73f984b3cc4fb73ab74d5e5406825d")
	key4, _ := btcec.PrivKeyFromBytes(btcec.S256(), b4)
	b5, _ := hex.DecodeString("f5bdf62dae621bfea15439dd2e647e6ac1ce6cb3b2f9f593b7cb45a10a03e22c")
	key5, _ := btcec.PrivKeyFromBytes(btcec.S256(), b5)
	b6, _ := hex.DecodeString("83f182eb806b7a718ca2ff2d909c09a59bd073afe3404242de3d4f241e5bc818")
	key6, _ := btcec.PrivKeyFromBytes(btcec.S256(), b6)
	b7, _ := hex.DecodeString("1160a52d2e6e345013d6389abcc249377c915ad4a103530e9f9acab9eeac6d12")
	key7, _ := btcec.PrivKeyFromBytes(btcec.S256(), b7)
	b8, _ := hex.DecodeString("c589ec735c91b3acafa13de995b227d57333645d8fdd94e545cc2927351c7a9f")
	key8, _ := btcec.PrivKeyFromBytes(btcec.S256(), b8)

	// Hash into tree
	k1 := sha256.Sum256(key1.PubKey().SerializeCompressed())
	k2 := sha256.Sum256(key2.PubKey().SerializeCompressed())
	k3 := sha256.Sum256(key3.PubKey().SerializeCompressed())
	k4 := sha256.Sum256(key4.PubKey().SerializeCompressed())
	k5 := sha256.Sum256(key5.PubKey().SerializeCompressed())
	k6 := sha256.Sum256(key6.PubKey().SerializeCompressed())
	k7 := sha256.Sum256(key7.PubKey().SerializeCompressed())
	k8 := sha256.Sum256(key8.PubKey().SerializeCompressed())
	x1 := sha256.Sum256(append(k1[:], k2[:]...))
	x2 := sha256.Sum256(append(k3[:], k4[:]...))
	x3 := sha256.Sum256(append(k5[:], k6[:]...))
	x4 := sha256.Sum256(append(k7[:], k8[:]...))
	y1 := sha256.Sum256(append(x1[:], x2[:]...))
	y2 := sha256.Sum256(append(x3[:], x4[:]...))
	r := sha256.Sum256(append(y1[:], y2[:]...))

	// Build redeem script
	builder := txscript.NewScriptBuilder().
		AddOp(txscript.OP_6).
		AddOp(txscript.OP_PICK).
		AddOp(txscript.OP_SHA256).
		AddOp(txscript.OP_SWAP).
		AddOp(txscript.OP_IF).
		AddOp(txscript.OP_SWAP).
		AddOp(txscript.OP_ENDIF).
		AddOp(txscript.OP_CAT).
		AddOp(txscript.OP_SHA256).
		AddOp(txscript.OP_SWAP).
		AddOp(txscript.OP_IF).
		AddOp(txscript.OP_SWAP).
		AddOp(txscript.OP_ENDIF).
		AddOp(txscript.OP_CAT).
		AddOp(txscript.OP_SHA256).
		AddOp(txscript.OP_SWAP).
		AddOp(txscript.OP_IF).
		AddOp(txscript.OP_SWAP).
		AddOp(txscript.OP_ENDIF).
		AddOp(txscript.OP_CAT).
		AddOp(txscript.OP_SHA256).
		AddData(r[:]).
		AddOp(txscript.OP_EQUALVERIFY).
		AddOp(txscript.OP_CHECKSIG)
	redeemScript, _ := builder.Script()

	// Create payment address
	addr, _ := bchutil.NewCashAddressScriptHash(redeemScript, &chaincfg.MainNetParams)
	fmt.Printf("address: %s\n", addr.String())

	// Build input
	val := int64(71905)
	prevHash, _ := chainhash.NewHashFromStr("93628593212ebe9d57086117eb6c643146d3a10e063151d5ba8e7c5f6d619ee9")
	prevIndex := uint32(0)
	op := wire.NewOutPoint(prevHash, prevIndex)
	in := wire.NewTxIn(op, []byte{}, [][]byte{})

	// Calculate the fee
	feePerByte := 5
	fee := int64(336 * feePerByte)

	// Build output
	outAddr, _ := bchutil.DecodeAddress("qqm82pnlfh5dkepv0dyky4zuwd04hw6chcucjwnhpz", &chaincfg.MainNetParams)
	outScript, _ := bchutil.PayToAddrScript(outAddr)
	out := wire.NewTxOut(val-fee, outScript)

	// Build transaction
	tx := &wire.MsgTx{
		Version:  wire.TxVersion,
		TxIn:     []*wire.TxIn{in},
		TxOut:    []*wire.TxOut{out},
		LockTime: 0,
	}

	// Sign input
	sig, _ := bchutil.RawTxInSignature(tx, 0, redeemScript, txscript.SigHashAll, key5, val)
	sigBuilder := txscript.NewScriptBuilder().
		AddData(sig).
		AddData(key5.PubKey().SerializeCompressed()).
		AddData(y1[:]).
		AddOp(txscript.OP_0).
		AddData(x4[:]).
		AddOp(txscript.OP_1).
		AddData(k6[:]).
		AddOp(txscript.OP_1).
		AddData(redeemScript)
	scriptSig, _ := sigBuilder.Script()
	tx.TxIn[0].SignatureScript = scriptSig

	// Print out raw transaction
	var b []byte
	buf := bytes.NewBuffer(b)
	tx.BtcEncode(buf, 1, wire.BaseEncoding)
	fmt.Printf("raw tx: %s\n", hex.EncodeToString(buf.Bytes()))
	fmt.Printf("txid: %s\n", tx.TxHash())
}