basicswap_miserver/basicswap/protocols/atomic_swap_1.py

# -*- coding: utf-8 -*-

# Copyright (c) 2020 tecnovert
# Distributed under the MIT software license, see the accompanying
# file LICENSE or http://www.opensource.org/licenses/mit-license.php.

from basicswap.util import (
    SerialiseNum,
)
from basicswap.script import (
    OpCodes,
)


def buildContractScript(lock_val, secret_hash, pkh_redeem, pkh_refund, op_lock=OpCodes.OP_CHECKSEQUENCEVERIFY):
    script = bytearray([
        OpCodes.OP_IF,
        OpCodes.OP_SIZE,
        0x01, 0x20,  # 32
        OpCodes.OP_EQUALVERIFY,
        OpCodes.OP_SHA256,
        0x20]) \
        + secret_hash \
        + bytearray([
            OpCodes.OP_EQUALVERIFY,
            OpCodes.OP_DUP,
            OpCodes.OP_HASH160,
            0x14]) \
        + pkh_redeem \
        + bytearray([OpCodes.OP_ELSE, ]) \
        + SerialiseNum(lock_val) \
        + bytearray([
            op_lock,
            OpCodes.OP_DROP,
            OpCodes.OP_DUP,
            OpCodes.OP_HASH160,
            0x14]) \
        + pkh_refund \
        + bytearray([
            OpCodes.OP_ENDIF,
            OpCodes.OP_EQUALVERIFY,
            OpCodes.OP_CHECKSIG])
    return script


def extractScriptSecretHash(script):
    return script[7:39]