コード例 #1
0
def is_vout_spendable(vout, source):
    source = script.make_canonical(source)
    scriptpubkey_hex = vout['scriptPubKey']['hex']
    c_scriptpubkey = bitcoinlib.core.CScript(
        bitcoinlib.core.x(scriptpubkey_hex))
    vout_address = script.scriptpubkey_to_address(c_scriptpubkey)
    if not vout_address:
        return False
    if vout_address == source:
        return True
    return False
コード例 #2
0
ファイル: __init__.py プロジェクト: tokenly/counterparty-lib
def is_scriptpubkey_spendable(scriptpubkey_hex, source, multisig_inputs=False):
    c_scriptpubkey = bitcoinlib.core.CScript(bitcoinlib.core.x(scriptpubkey_hex))
    vout_address = script.scriptpubkey_to_address(c_scriptpubkey)
    if not vout_address:
        return False

    source = script.make_canonical(source)

    if vout_address == source:
        return True

    return False
コード例 #3
0
ファイル: __init__.py プロジェクト: vcgato29/counterparty-lib
def is_scriptpubkey_spendable(scriptpubkey_hex, source, multisig_inputs=False):
    c_scriptpubkey = bitcoinlib.core.CScript(bitcoinlib.core.x(scriptpubkey_hex))

    try:
        vout_address = script.scriptpubkey_to_address(c_scriptpubkey)
    except exceptions.DecodeError:
        return False

    if not vout_address:
        return False

    source = script.make_canonical(source)

    if vout_address == source:
        return True

    return False
コード例 #4
0
def construct (db, tx_info, encoding='auto',
               fee_per_kb=config.DEFAULT_FEE_PER_KB,
               estimate_fee_per_kb=None, estimate_fee_per_kb_nblocks=config.ESTIMATE_FEE_NBLOCKS,
               regular_dust_size=config.DEFAULT_REGULAR_DUST_SIZE,
               multisig_dust_size=config.DEFAULT_MULTISIG_DUST_SIZE,
               op_return_value=config.DEFAULT_OP_RETURN_VALUE,
               exact_fee=None, fee_provided=0, provided_pubkeys=None, dust_return_pubkey=None,
               allow_unconfirmed_inputs=False, unspent_tx_hash=None, custom_inputs=None, disable_utxo_locks=False):

    if estimate_fee_per_kb is None:
        estimate_fee_per_kb = config.ESTIMATE_FEE_PER_KB

    global UTXO_LOCKS

    desired_encoding = encoding
    (source, destination_outputs, data) = tx_info

    if dust_return_pubkey:
        dust_return_pubkey = binascii.unhexlify(dust_return_pubkey)

    # Source.
        # If public key is necessary for construction of (unsigned)
        # transaction, use the public key provided, or find it from the
        # blockchain.
    if source:
        script.validate(source)

    source_is_p2sh = script.is_p2sh(source)

    # Sanity checks.
    if exact_fee and not isinstance(exact_fee, int):
        raise exceptions.TransactionError('Exact fees must be in satoshis.')
    if not isinstance(fee_provided, int):
        raise exceptions.TransactionError('Fee provided must be in satoshis.')

    if UTXO_LOCKS is None and config.UTXO_LOCKS_MAX_ADDRESSES > 0:  # initialize if configured
        UTXO_LOCKS = util.DictCache(size=config.UTXO_LOCKS_MAX_ADDRESSES)

    '''Destinations'''

    # Destination outputs.
        # Replace multi‐sig addresses with multi‐sig pubkeys. Check that the
        # destination output isn’t a dust output. Set null values to dust size.
    destination_outputs_new = []
    for (address, value) in destination_outputs:

        # Value.
        if script.is_multisig(address):
            dust_size = multisig_dust_size
        else:
            dust_size = regular_dust_size
        if value == None:
            value = dust_size
        elif value < dust_size:
            raise exceptions.TransactionError('Destination output is dust.')

        # Address.
        script.validate(address)
        if script.is_multisig(address):
            destination_outputs_new.append((backend.multisig_pubkeyhashes_to_pubkeys(address, provided_pubkeys), value))
        else:
            destination_outputs_new.append((address, value))

    destination_outputs = destination_outputs_new
    destination_btc_out = sum([value for address, value in destination_outputs])


    '''Data'''

    if data:
        # Data encoding methods (choose and validate).
        if encoding == 'auto':
            if len(data) + len(config.PREFIX) <= config.OP_RETURN_MAX_SIZE:
                encoding = 'opreturn'
            else:
                encoding = 'multisig'

        elif encoding not in ('pubkeyhash', 'multisig', 'opreturn'):
            raise exceptions.TransactionError('Unknown encoding‐scheme.')


        if encoding == 'multisig':
            # dust_return_pubkey should be set or explicitly set to False to use the default configured for the node
            #  the default for the node is optional so could fail
            if (source_is_p2sh and dust_return_pubkey is None) or (dust_return_pubkey is False and config.P2SH_DUST_RETURN_PUBKEY is None):
                raise exceptions.TransactionError("Can't use multisig encoding when source is P2SH and no dust_return_pubkey is provided.")
            elif dust_return_pubkey is False:
                dust_return_pubkey = binascii.unhexlify(config.P2SH_DUST_RETURN_PUBKEY)

        # Divide data into chunks.
        if encoding == 'pubkeyhash':
            # Prefix is also a suffix here.
            chunk_size = 20 - 1 - 8
        elif encoding == 'multisig':
            # Two pubkeys, minus length byte, minus prefix, minus two nonces,
            # minus two sign bytes.
            chunk_size = (33 * 2) - 1 - 8 - 2 - 2
        elif encoding == 'opreturn':
            chunk_size = config.OP_RETURN_MAX_SIZE
            if len(data) + len(config.PREFIX) > chunk_size:
                raise exceptions.TransactionError('One `OP_RETURN` output per transaction.')
        data_array = list(chunks(data, chunk_size))

        # Data outputs.
        if encoding == 'multisig':
            data_value = multisig_dust_size
        elif encoding == 'opreturn':
            data_value = op_return_value
        else:
            # Pay‐to‐PubKeyHash, e.g.
            data_value = regular_dust_size
        data_output = (data_array, data_value)

        if not dust_return_pubkey:
            if encoding == 'multisig':
                dust_return_pubkey = get_dust_return_pubkey(source, provided_pubkeys, encoding)
            else:
                dust_return_pubkey = None
    else:
        data_array = []
        data_output = None
        dust_return_pubkey = None

    data_btc_out = sum([data_value for data_chunk in data_array])

    '''Inputs'''

    # Calculate collective size of outputs, for fee calculation.
    p2pkhsize = 25 + 9
    if encoding == 'multisig':
        data_output_size = 81       # 71 for the data
    elif encoding == 'opreturn':
        data_output_size = 90       # 80 for the data
    else:
        data_output_size = p2pkhsize   # Pay‐to‐PubKeyHash (25 for the data?)
    outputs_size = (p2pkhsize * len(destination_outputs)) + (len(data_array) * data_output_size)

    # Get inputs.
    multisig_inputs = not data

    use_inputs = custom_inputs  # Array of UTXOs, as retrieved by listunspent function from bitcoind
    if custom_inputs is None:
        if unspent_tx_hash is not None:
            unspent = backend.get_unspent_txouts(source, unconfirmed=allow_unconfirmed_inputs, unspent_tx_hash=unspent_tx_hash, multisig_inputs=multisig_inputs)
        else:
            unspent = backend.get_unspent_txouts(source, unconfirmed=allow_unconfirmed_inputs, multisig_inputs=multisig_inputs)

        # filter out any locked UTXOs to prevent creating transactions that spend the same UTXO when they're created at the same time
        if UTXO_LOCKS is not None and source in UTXO_LOCKS:
            unspentkeys = {make_outkey(output) for output in unspent}
            filtered_unspentkeys = unspentkeys - UTXO_LOCKS[source].keys()
            unspent = [output for output in unspent if make_outkey(output) in filtered_unspentkeys]

        unspent = backend.sort_unspent_txouts(unspent)
        logger.debug('Sorted candidate UTXOs: {}'.format([print_coin(coin) for coin in unspent]))
        use_inputs = unspent

    # use backend estimated fee_per_kb
    if estimate_fee_per_kb:
        estimated_fee_per_kb = backend.fee_per_kb(estimate_fee_per_kb_nblocks)
        if estimated_fee_per_kb is not None:
            fee_per_kb = max(estimated_fee_per_kb, fee_per_kb)  # never drop below the default fee_per_kb

    logger.debug('Fee/KB {:.8f}'.format(fee_per_kb / config.UNIT))

    inputs = []
    btc_in = 0
    change_quantity = 0
    sufficient_funds = False
    final_fee = fee_per_kb
    desired_input_count = 1

    if encoding == 'multisig' and data_array and util.enabled('bytespersigop'):
        desired_input_count = len(data_array) * 2

    for coin in use_inputs:
        logger.debug('New input: {}'.format(print_coin(coin)))
        inputs.append(coin)
        btc_in += round(coin['amount'] * config.UNIT)

        size = 181 * len(inputs) + outputs_size + 10
        necessary_fee = int(size / 1000 * fee_per_kb)

        # If exact fee is specified, use that. Otherwise, calculate size of tx
        # and base fee on that (plus provide a minimum fee for selling BTC).
        if exact_fee:
            final_fee = exact_fee
        else:
            final_fee = max(fee_provided, necessary_fee)

        # Check if good.
        btc_out = destination_btc_out + data_btc_out
        change_quantity = btc_in - (btc_out + final_fee)
        logger.debug('Size: {} Fee: {:.8f} Change quantity: {:.8f} BTC'.format(size, final_fee / config.UNIT, change_quantity / config.UNIT))
        # If change is necessary, must not be a dust output.
        if change_quantity == 0 or change_quantity >= regular_dust_size:
            sufficient_funds = True
            if len(inputs) >= desired_input_count:
                break

    if not sufficient_funds:
        # Approximate needed change, fee by with most recently calculated
        # quantities.
        btc_out = destination_btc_out + data_btc_out
        total_btc_out = btc_out + max(change_quantity, 0) + final_fee
        raise exceptions.BalanceError('Insufficient {} at address {}. (Need approximately {} {}.) To spend unconfirmed coins, use the flag `--unconfirmed`. (Unconfirmed coins cannot be spent from multi‐sig addresses.)'.format(config.BTC, source, total_btc_out / config.UNIT, config.BTC))

    # Lock the source's inputs (UTXOs) chosen for this transaction
    if UTXO_LOCKS is not None and not disable_utxo_locks:
        if source not in UTXO_LOCKS:
            UTXO_LOCKS[source] = cachetools.TTLCache(
                UTXO_LOCKS_PER_ADDRESS_MAXSIZE, config.UTXO_LOCKS_MAX_AGE)

        for input in inputs:
            UTXO_LOCKS[source][make_outkey(input)] = input

        logger.debug("UTXO locks: Potentials ({}): {}, Used: {}, locked UTXOs: {}".format(
            len(unspent), [make_outkey(coin) for coin in unspent],
            [make_outkey(input) for input in inputs], list(UTXO_LOCKS[source].keys())))

    '''Finish'''

    # Change output.
    if change_quantity:
        if script.is_multisig(source):
            change_address = backend.multisig_pubkeyhashes_to_pubkeys(source, provided_pubkeys)
        else:
            change_address = source
        change_output = (change_address, change_quantity)
    else:
        change_output = None

    # in bitcoin core v0.12.1 a -bytespersigop was added that messes with bare multisig transactions,
    #  as a safeguard we fall back to pubkeyhash encoding when unsure
    # when len(inputs) > len(data_outputs) there's more bytes:sigops ratio and we can safely continue
    if encoding == 'multisig' and inputs and data_output and len(inputs) < len(data_array) * 2 and util.enabled('bytespersigop'):
        # if auto encoding we can do pubkeyhash encoding instead
        if desired_encoding == 'auto':
            return construct(db, tx_info,
                             encoding='pubkeyhash',
                             fee_per_kb=fee_per_kb,
                             regular_dust_size=regular_dust_size,
                             multisig_dust_size=multisig_dust_size,
                             op_return_value=op_return_value,
                             exact_fee=exact_fee, fee_provided=fee_provided, provided_pubkeys=provided_pubkeys,
                             allow_unconfirmed_inputs=allow_unconfirmed_inputs, unspent_tx_hash=unspent_tx_hash, custom_inputs=custom_inputs)
        # otherwise raise exception
        else:
            raise exceptions.EncodingError("multisig will be rejected by Bitcoin Core >= v0.12.1, you should use `encoding=auto` or `encoding=pubkeyhash`")

    # Serialise inputs and outputs.
    unsigned_tx = serialise(encoding, inputs, destination_outputs,
                            data_output, change_output,
                            dust_return_pubkey=dust_return_pubkey)
    unsigned_tx_hex = binascii.hexlify(unsigned_tx).decode('utf-8')


    '''Sanity Check'''

    from counterpartylib.lib import blocks

    # Desired transaction info.
    (desired_source, desired_destination_outputs, desired_data) = tx_info
    desired_source = script.make_canonical(desired_source)
    desired_destination = script.make_canonical(desired_destination_outputs[0][0]) if desired_destination_outputs else ''
    # NOTE: Include change in destinations for BTC transactions.
    # if change_output and not desired_data and desired_destination != config.UNSPENDABLE:
    #    if desired_destination == '':
    #        desired_destination = desired_source
    #    else:
    #        desired_destination += '-{}'.format(desired_source)
    # NOTE
    if desired_data == None:
        desired_data = b''

    # Parsed transaction info.
    try:
        parsed_source, parsed_destination, x, y, parsed_data = blocks._get_tx_info(unsigned_tx_hex)
    except exceptions.BTCOnlyError:
        # Skip BTC‐only transactions.
        return unsigned_tx_hex
    desired_source = script.make_canonical(desired_source)

    # Check desired info against parsed info.
    desired = (desired_source, desired_destination, desired_data)
    parsed = (parsed_source, parsed_destination, parsed_data)
    if desired != parsed:
        # Unlock (revert) UTXO locks
        if UTXO_LOCKS is not None:
            for input in inputs:
                UTXO_LOCKS[source].pop(make_outkey(input), None)

        raise exceptions.TransactionError('Constructed transaction does not parse correctly: {} ≠ {}'.format(desired, parsed))

    return unsigned_tx_hex
コード例 #5
0
def construct(db,
              tx_info,
              encoding='auto',
              fee_per_kb=config.DEFAULT_FEE_PER_KB,
              estimate_fee_per_kb=None,
              estimate_fee_per_kb_nblocks=config.ESTIMATE_FEE_NBLOCKS,
              regular_dust_size=config.DEFAULT_REGULAR_DUST_SIZE,
              multisig_dust_size=config.DEFAULT_MULTISIG_DUST_SIZE,
              op_return_value=config.DEFAULT_OP_RETURN_VALUE,
              exact_fee=None,
              fee_provided=0,
              provided_pubkeys=None,
              dust_return_pubkey=None,
              allow_unconfirmed_inputs=False,
              unspent_tx_hash=None,
              custom_inputs=None,
              disable_utxo_locks=False):

    if estimate_fee_per_kb is None:
        estimate_fee_per_kb = config.ESTIMATE_FEE_PER_KB

    global UTXO_LOCKS

    desired_encoding = encoding
    (source, destination_outputs, data) = tx_info

    if dust_return_pubkey:
        dust_return_pubkey = binascii.unhexlify(dust_return_pubkey)

    # Source.
    # If public key is necessary for construction of (unsigned)
    # transaction, use the public key provided, or find it from the
    # blockchain.
    if source:
        script.validate(source)

    source_is_p2sh = script.is_p2sh(source)

    # Sanity checks.
    if exact_fee and not isinstance(exact_fee, int):
        raise exceptions.TransactionError('Exact fees must be in satoshis.')
    if not isinstance(fee_provided, int):
        raise exceptions.TransactionError('Fee provided must be in satoshis.')

    if UTXO_LOCKS is None and config.UTXO_LOCKS_MAX_ADDRESSES > 0:  # initialize if configured
        UTXO_LOCKS = util.DictCache(size=config.UTXO_LOCKS_MAX_ADDRESSES)
    '''Destinations'''

    # Destination outputs.
    # Replace multi‐sig addresses with multi‐sig pubkeys. Check that the
    # destination output isn’t a dust output. Set null values to dust size.
    destination_outputs_new = []
    for (address, value) in destination_outputs:

        # Value.
        if script.is_multisig(address):
            dust_size = multisig_dust_size
        else:
            dust_size = regular_dust_size
        if value == None:
            value = dust_size
        elif value < dust_size:
            raise exceptions.TransactionError('Destination output is dust.')

        # Address.
        script.validate(address)
        if script.is_multisig(address):
            destination_outputs_new.append(
                (backend.multisig_pubkeyhashes_to_pubkeys(
                    address, provided_pubkeys), value))
        else:
            destination_outputs_new.append((address, value))

    destination_outputs = destination_outputs_new
    destination_btc_out = sum(
        [value for address, value in destination_outputs])
    '''Data'''

    if data:
        # Data encoding methods (choose and validate).
        if encoding == 'auto':
            if len(data) + len(config.PREFIX) <= config.OP_RETURN_MAX_SIZE:
                encoding = 'opreturn'
            else:
                encoding = 'multisig'

        elif encoding not in ('pubkeyhash', 'multisig', 'opreturn'):
            raise exceptions.TransactionError('Unknown encoding‐scheme.')

        if encoding == 'multisig':
            # dust_return_pubkey should be set or explicitly set to False to use the default configured for the node
            #  the default for the node is optional so could fail
            if (source_is_p2sh and dust_return_pubkey is None) or (
                    dust_return_pubkey is False
                    and config.P2SH_DUST_RETURN_PUBKEY is None):
                raise exceptions.TransactionError(
                    "Can't use multisig encoding when source is P2SH and no dust_return_pubkey is provided."
                )
            elif dust_return_pubkey is False:
                dust_return_pubkey = binascii.unhexlify(
                    config.P2SH_DUST_RETURN_PUBKEY)

        # Divide data into chunks.
        if encoding == 'pubkeyhash':
            # Prefix is also a suffix here.
            chunk_size = 20 - 1 - 8
        elif encoding == 'multisig':
            # Two pubkeys, minus length byte, minus prefix, minus two nonces,
            # minus two sign bytes.
            chunk_size = (33 * 2) - 1 - 8 - 2 - 2
        elif encoding == 'opreturn':
            chunk_size = config.OP_RETURN_MAX_SIZE
            if len(data) + len(config.PREFIX) > chunk_size:
                raise exceptions.TransactionError(
                    'One `OP_RETURN` output per transaction.')
        data_array = list(chunks(data, chunk_size))

        # Data outputs.
        if encoding == 'multisig':
            data_value = multisig_dust_size
        elif encoding == 'opreturn':
            data_value = op_return_value
        else:
            # Pay‐to‐PubKeyHash, e.g.
            data_value = regular_dust_size
        data_output = (data_array, data_value)

        if not dust_return_pubkey:
            if encoding == 'multisig':
                dust_return_pubkey = get_dust_return_pubkey(
                    source, provided_pubkeys, encoding)
            else:
                dust_return_pubkey = None
    else:
        data_array = []
        data_output = None
        dust_return_pubkey = None

    data_btc_out = sum([data_value for data_chunk in data_array])
    '''Inputs'''

    # Calculate collective size of outputs, for fee calculation.
    p2pkhsize = 25 + 9
    if encoding == 'multisig':
        data_output_size = 81  # 71 for the data
    elif encoding == 'opreturn':
        data_output_size = 90  # 80 for the data
    else:
        data_output_size = p2pkhsize  # Pay‐to‐PubKeyHash (25 for the data?)
    outputs_size = (p2pkhsize * len(destination_outputs)) + (len(data_array) *
                                                             data_output_size)

    # Get inputs.
    multisig_inputs = not data

    use_inputs = custom_inputs  # Array of UTXOs, as retrieved by listunspent function from bitcoind
    if custom_inputs is None:
        if unspent_tx_hash is not None:
            unspent = backend.get_unspent_txouts(
                source,
                unconfirmed=allow_unconfirmed_inputs,
                unspent_tx_hash=unspent_tx_hash,
                multisig_inputs=multisig_inputs)
        else:
            unspent = backend.get_unspent_txouts(
                source,
                unconfirmed=allow_unconfirmed_inputs,
                multisig_inputs=multisig_inputs)

        # filter out any locked UTXOs to prevent creating transactions that spend the same UTXO when they're created at the same time
        if UTXO_LOCKS is not None and source in UTXO_LOCKS:
            unspentkeys = {make_outkey(output) for output in unspent}
            filtered_unspentkeys = unspentkeys - UTXO_LOCKS[source].keys()
            unspent = [
                output for output in unspent
                if make_outkey(output) in filtered_unspentkeys
            ]

        unspent = backend.sort_unspent_txouts(unspent)
        logger.debug('Sorted candidate UTXOs: {}'.format(
            [print_coin(coin) for coin in unspent]))
        use_inputs = unspent

    # use backend estimated fee_per_kb
    if estimate_fee_per_kb:
        estimated_fee_per_kb = backend.fee_per_kb(estimate_fee_per_kb_nblocks)
        if estimated_fee_per_kb is not None:
            fee_per_kb = max(
                estimated_fee_per_kb,
                fee_per_kb)  # never drop below the default fee_per_kb

    logger.debug('Fee/KB {:.8f}'.format(fee_per_kb / config.UNIT))

    inputs = []
    btc_in = 0
    change_quantity = 0
    sufficient_funds = False
    final_fee = fee_per_kb
    desired_input_count = 1

    if encoding == 'multisig' and data_array and util.enabled('bytespersigop'):
        desired_input_count = len(data_array) * 2

    for coin in use_inputs:
        logger.debug('New input: {}'.format(print_coin(coin)))
        inputs.append(coin)
        btc_in += round(coin['amount'] * config.UNIT)

        size = 181 * len(inputs) + outputs_size + 10
        necessary_fee = int(size / 1000 * fee_per_kb)

        # If exact fee is specified, use that. Otherwise, calculate size of tx
        # and base fee on that (plus provide a minimum fee for selling BTC).
        if exact_fee:
            final_fee = exact_fee
        else:
            final_fee = max(fee_provided, necessary_fee)

        # Check if good.
        btc_out = destination_btc_out + data_btc_out
        change_quantity = btc_in - (btc_out + final_fee)
        logger.debug('Size: {} Fee: {:.8f} Change quantity: {:.8f} BTC'.format(
            size, final_fee / config.UNIT, change_quantity / config.UNIT))
        # If change is necessary, must not be a dust output.
        if change_quantity == 0 or change_quantity >= regular_dust_size:
            sufficient_funds = True
            if len(inputs) >= desired_input_count:
                break

    if not sufficient_funds:
        # Approximate needed change, fee by with most recently calculated
        # quantities.
        btc_out = destination_btc_out + data_btc_out
        total_btc_out = btc_out + max(change_quantity, 0) + final_fee
        raise exceptions.BalanceError(
            'Insufficient {} at address {}. (Need approximately {} {}.) To spend unconfirmed coins, use the flag `--unconfirmed`. (Unconfirmed coins cannot be spent from multi‐sig addresses.)'
            .format(config.BTC, source, total_btc_out / config.UNIT,
                    config.BTC))

    # Lock the source's inputs (UTXOs) chosen for this transaction
    if UTXO_LOCKS is not None and not disable_utxo_locks:
        if source not in UTXO_LOCKS:
            UTXO_LOCKS[source] = cachetools.TTLCache(
                UTXO_LOCKS_PER_ADDRESS_MAXSIZE, config.UTXO_LOCKS_MAX_AGE)

        for input in inputs:
            UTXO_LOCKS[source][make_outkey(input)] = input

        logger.debug(
            "UTXO locks: Potentials ({}): {}, Used: {}, locked UTXOs: {}".
            format(len(unspent), [make_outkey(coin) for coin in unspent],
                   [make_outkey(input) for input in inputs],
                   list(UTXO_LOCKS[source].keys())))
    '''Finish'''

    # Change output.
    if change_quantity:
        if script.is_multisig(source):
            change_address = backend.multisig_pubkeyhashes_to_pubkeys(
                source, provided_pubkeys)
        else:
            change_address = source
        change_output = (change_address, change_quantity)
    else:
        change_output = None

    # in bitcoin core v0.12.1 a -bytespersigop was added that messes with bare multisig transactions,
    #  as a safeguard we fall back to pubkeyhash encoding when unsure
    # when len(inputs) > len(data_outputs) there's more bytes:sigops ratio and we can safely continue
    if encoding == 'multisig' and inputs and data_output and len(
            inputs) < len(data_array) * 2 and util.enabled('bytespersigop'):
        # if auto encoding we can do pubkeyhash encoding instead
        if desired_encoding == 'auto':
            return construct(db,
                             tx_info,
                             encoding='pubkeyhash',
                             fee_per_kb=fee_per_kb,
                             regular_dust_size=regular_dust_size,
                             multisig_dust_size=multisig_dust_size,
                             op_return_value=op_return_value,
                             exact_fee=exact_fee,
                             fee_provided=fee_provided,
                             provided_pubkeys=provided_pubkeys,
                             allow_unconfirmed_inputs=allow_unconfirmed_inputs,
                             unspent_tx_hash=unspent_tx_hash,
                             custom_inputs=custom_inputs)
        # otherwise raise exception
        else:
            raise exceptions.EncodingError(
                "multisig will be rejected by Bitcoin Core >= v0.12.1, you should use `encoding=auto` or `encoding=pubkeyhash`"
            )

    # Serialise inputs and outputs.
    unsigned_tx = serialise(encoding,
                            inputs,
                            destination_outputs,
                            data_output,
                            change_output,
                            dust_return_pubkey=dust_return_pubkey)
    unsigned_tx_hex = binascii.hexlify(unsigned_tx).decode('utf-8')
    '''Sanity Check'''

    from counterpartylib.lib import blocks

    # Desired transaction info.
    (desired_source, desired_destination_outputs, desired_data) = tx_info
    desired_source = script.make_canonical(desired_source)
    desired_destination = script.make_canonical(
        desired_destination_outputs[0]
        [0]) if desired_destination_outputs else ''
    # NOTE: Include change in destinations for BTC transactions.
    # if change_output and not desired_data and desired_destination != config.UNSPENDABLE:
    #    if desired_destination == '':
    #        desired_destination = desired_source
    #    else:
    #        desired_destination += '-{}'.format(desired_source)
    # NOTE
    if desired_data == None:
        desired_data = b''

    # Parsed transaction info.
    try:
        parsed_source, parsed_destination, x, y, parsed_data = blocks._get_tx_info(
            unsigned_tx_hex)
    except exceptions.BTCOnlyError:
        # Skip BTC‐only transactions.
        return unsigned_tx_hex
    desired_source = script.make_canonical(desired_source)

    # Check desired info against parsed info.
    desired = (desired_source, desired_destination, desired_data)
    parsed = (parsed_source, parsed_destination, parsed_data)
    if desired != parsed:
        # Unlock (revert) UTXO locks
        if UTXO_LOCKS is not None:
            for input in inputs:
                UTXO_LOCKS[source].pop(make_outkey(input), None)

        raise exceptions.TransactionError(
            'Constructed transaction does not parse correctly: {} ≠ {}'.format(
                desired, parsed))

    return unsigned_tx_hex
コード例 #6
0
def construct(
    db,
    tx_info,
    encoding='auto',
    fee_per_kb=config.DEFAULT_FEE_PER_KB,
    estimate_fee_per_kb=None,
    estimate_fee_per_kb_conf_target=config.ESTIMATE_FEE_CONF_TARGET,
    estimate_fee_per_kb_mode=config.ESTIMATE_FEE_MODE,
    estimate_fee_per_kb_nblocks=config.ESTIMATE_FEE_CONF_TARGET,
    regular_dust_size=config.DEFAULT_REGULAR_DUST_SIZE,
    multisig_dust_size=config.DEFAULT_MULTISIG_DUST_SIZE,
    op_return_value=config.DEFAULT_OP_RETURN_VALUE,
    exact_fee=None,
    fee_provided=0,
    provided_pubkeys=None,
    dust_return_pubkey=None,
    allow_unconfirmed_inputs=False,
    unspent_tx_hash=None,
    custom_inputs=None,
    disable_utxo_locks=False,
    extended_tx_info=False,
    old_style_api=None,
    segwit=False,
    p2sh_source_multisig_pubkeys=None,
    p2sh_source_multisig_pubkeys_required=None,
    p2sh_pretx_txid=None,
):

    if estimate_fee_per_kb is None:
        estimate_fee_per_kb = config.ESTIMATE_FEE_PER_KB

    global UTXO_LOCKS, UTXO_P2SH_ENCODING_LOCKS

    # lazy assign from config, because when set as default it's evaluated before it's configured
    if old_style_api is None:
        old_style_api = config.OLD_STYLE_API

    (source, destination_outputs, data) = tx_info

    if dust_return_pubkey:
        dust_return_pubkey = binascii.unhexlify(dust_return_pubkey)

    if p2sh_source_multisig_pubkeys:
        p2sh_source_multisig_pubkeys = [
            binascii.unhexlify(p) for p in p2sh_source_multisig_pubkeys
        ]

    # Source.
    # If public key is necessary for construction of (unsigned)
    # transaction, use the public key provided, or find it from the
    # blockchain.
    if source:
        script.validate(source)

    source_is_p2sh = script.is_p2sh(source)

    # Normalize source
    if script.is_multisig(source):
        source_address = backend.multisig_pubkeyhashes_to_pubkeys(
            source, provided_pubkeys)
    else:
        source_address = source

    # Sanity checks.
    if exact_fee and not isinstance(exact_fee, int):
        raise exceptions.TransactionError('Exact fees must be in satoshis.')
    if not isinstance(fee_provided, int):
        raise exceptions.TransactionError('Fee provided must be in satoshis.')
    '''Determine encoding method'''

    if data:
        desired_encoding = encoding
        # Data encoding methods (choose and validate).
        if desired_encoding == 'auto':
            if len(data) + len(config.PREFIX) <= config.OP_RETURN_MAX_SIZE:
                encoding = 'opreturn'
            else:
                encoding = 'p2sh' if not old_style_api and util.enabled(
                    'p2sh_encoding'
                ) else 'multisig'  # p2sh is not possible with old_style_api

        elif desired_encoding == 'p2sh' and not util.enabled('p2sh_encoding'):
            raise exceptions.TransactionError('P2SH encoding not enabled yet')

        elif encoding not in ('pubkeyhash', 'multisig', 'opreturn', 'p2sh'):
            raise exceptions.TransactionError('Unknown encoding‐scheme.')
    else:
        # no data
        encoding = None
    '''Destinations'''

    # Destination outputs.
    # Replace multi‐sig addresses with multi‐sig pubkeys. Check that the
    # destination output isn’t a dust output. Set null values to dust size.
    destination_outputs_new = []
    if encoding != 'p2sh':
        for (address, value) in destination_outputs:

            # Value.
            if script.is_multisig(address):
                dust_size = multisig_dust_size
            else:
                dust_size = regular_dust_size
            if value == None:
                value = dust_size
            elif value < dust_size:
                raise exceptions.TransactionError(
                    'Destination output is dust.')

            # Address.
            script.validate(address)
            if script.is_multisig(address):
                destination_outputs_new.append(
                    (backend.multisig_pubkeyhashes_to_pubkeys(
                        address, provided_pubkeys), value))
            else:
                destination_outputs_new.append((address, value))

    destination_outputs = destination_outputs_new
    destination_btc_out = sum(
        [value for address, value in destination_outputs])
    '''Data'''

    if data:
        # @TODO: p2sh encoding require signable dust key
        if encoding == 'multisig':
            # dust_return_pubkey should be set or explicitly set to False to use the default configured for the node
            #  the default for the node is optional so could fail
            if (source_is_p2sh and dust_return_pubkey is None) or (
                    dust_return_pubkey is False
                    and config.P2SH_DUST_RETURN_PUBKEY is None):
                raise exceptions.TransactionError(
                    "Can't use multisig encoding when source is P2SH and no dust_return_pubkey is provided."
                )
            elif dust_return_pubkey is False:
                dust_return_pubkey = binascii.unhexlify(
                    config.P2SH_DUST_RETURN_PUBKEY)

        # Divide data into chunks.
        if encoding == 'pubkeyhash':
            # Prefix is also a suffix here.
            chunk_size = 20 - 1 - 8
        elif encoding == 'multisig':
            # Two pubkeys, minus length byte, minus prefix, minus two nonces,
            # minus two sign bytes.
            chunk_size = (33 * 2) - 1 - 8 - 2 - 2
        elif encoding == 'p2sh':
            chunk_size = p2sh_encoding.maximum_data_chunk_size()
        elif encoding == 'opreturn':
            chunk_size = config.OP_RETURN_MAX_SIZE
            if len(data) + len(config.PREFIX) > chunk_size:
                raise exceptions.TransactionError(
                    'One `OP_RETURN` output per transaction.')
        data_array = list(chunks(data, chunk_size))

        # Data outputs.
        if encoding == 'multisig':
            data_value = multisig_dust_size
        elif encoding == 'p2sh':
            data_value = 0  # this will be calculated later
        elif encoding == 'opreturn':
            data_value = op_return_value
        else:
            # Pay‐to‐PubKeyHash, e.g.
            data_value = regular_dust_size
        data_output = (data_array, data_value)

        if not dust_return_pubkey:
            if encoding == 'multisig' or encoding == 'p2sh' and not source_is_p2sh:
                dust_return_pubkey = get_dust_return_pubkey(
                    source, provided_pubkeys, encoding)
            else:
                dust_return_pubkey = None
    else:
        data_value = 0
        data_array = []
        data_output = None
        dust_return_pubkey = None

    data_btc_out = data_value * len(data_array)
    logger.getChild('p2shdebug').debug(
        'data_btc_out=%s (data_value=%d len(data_array)=%d)' %
        (data_btc_out, data_value, len(data_array)))
    '''Inputs'''
    btc_in = 0
    final_fee = 0
    # Calculate collective size of outputs, for fee calculation.
    p2pkhsize = 25 + 9
    if encoding == 'multisig':
        data_output_size = 81  # 71 for the data
    elif encoding == 'opreturn':
        # prefix + data + 10 bytes script overhead
        data_output_size = len(config.PREFIX) + 10
        if data is not None:
            data_output_size = data_output_size + len(data)
    else:
        data_output_size = p2pkhsize  # Pay‐to‐PubKeyHash (25 for the data?)
    outputs_size = (p2pkhsize * len(destination_outputs)) + (len(data_array) *
                                                             data_output_size)

    if encoding == 'p2sh':
        # calculate all the p2sh outputs
        size_for_fee, datatx_necessary_fee, data_value, data_btc_out = p2sh_encoding.calculate_outputs(
            destination_outputs, data_array, fee_per_kb)
        # replace the data value
        data_output = (data_array, data_value)
    else:
        sum_data_output_size = len(data_array) * data_output_size
        size_for_fee = (
            (25 + 9) * len(destination_outputs)) + sum_data_output_size

    if not (encoding == 'p2sh' and p2sh_pretx_txid):
        inputs, change_quantity, n_btc_in, n_final_fee = construct_coin_selection(
            encoding, data_array, source, allow_unconfirmed_inputs,
            unspent_tx_hash, custom_inputs, fee_per_kb, estimate_fee_per_kb,
            estimate_fee_per_kb_nblocks, exact_fee, size_for_fee, fee_provided,
            destination_btc_out, data_btc_out, regular_dust_size,
            disable_utxo_locks)
        btc_in = n_btc_in
        final_fee = n_final_fee
    else:
        # when encoding is P2SH and the pretx txid is passed we can skip coinselection
        inputs, change_quantity = None, None
    '''Finish'''

    if change_quantity:
        change_output = (source_address, change_quantity)
    else:
        change_output = None

    unsigned_pretx_hex = None
    unsigned_tx_hex = None

    pretx_txid = None
    if encoding == 'p2sh':
        assert not (segwit and p2sh_pretx_txid
                    )  # shouldn't do old style with segwit enabled

        if p2sh_pretx_txid:
            pretx_txid = p2sh_pretx_txid if isinstance(
                p2sh_pretx_txid,
                bytes) else binascii.unhexlify(p2sh_pretx_txid)
            unsigned_pretx = None
        else:
            destination_value_sum = sum(
                [value for (destination, value) in destination_outputs])
            source_value = destination_value_sum

            if change_output:
                # add the difference between source and destination to the change
                change_value = change_output[1] + (destination_value_sum -
                                                   source_value)
                change_output = (change_output[0], change_value)

            unsigned_pretx = serializer.serialise_p2sh_pretx(
                inputs,
                source=source_address,
                source_value=source_value,
                data_output=data_output,
                change_output=change_output,
                pubkey=dust_return_pubkey,
                multisig_pubkeys=p2sh_source_multisig_pubkeys,
                multisig_pubkeys_required=p2sh_source_multisig_pubkeys_required
            )
            unsigned_pretx_hex = binascii.hexlify(unsigned_pretx).decode(
                'utf-8')

        # with segwit we already know the txid and can return both
        if segwit:
            #pretx_txid = hashlib.sha256(unsigned_pretx).digest()  # this should be segwit txid
            ptx = CTransaction.stream_deserialize(
                io.BytesIO(unsigned_pretx))  # could be a non-segwit tx anyways
            txid_ba = bytearray(ptx.GetTxid())
            txid_ba.reverse()
            pretx_txid = bytes(
                txid_ba)  # gonna leave the malleability problem to upstream
            logger.getChild('p2shdebug').debug('pretx_txid %s' % pretx_txid)
            print('pretx txid:', binascii.hexlify(pretx_txid))

        if unsigned_pretx:
            # we set a long lock on this, don't want other TXs to spend from it
            UTXO_P2SH_ENCODING_LOCKS[make_outkey_vin(unsigned_pretx, 0)] = True

        # only generate the data TX if we have the pretx txId
        if pretx_txid:
            source_input = None
            if script.is_p2sh(source):
                source_input = select_any_coin_from_source(source)
                if not source_input:
                    raise exceptions.TransactionError(
                        'Unable to select source input for p2sh source address'
                    )

            unsigned_datatx = serializer.serialise_p2sh_datatx(
                pretx_txid,
                source=source_address,
                source_input=source_input,
                destination_outputs=destination_outputs,
                data_output=data_output,
                pubkey=dust_return_pubkey,
                multisig_pubkeys=p2sh_source_multisig_pubkeys,
                multisig_pubkeys_required=p2sh_source_multisig_pubkeys_required
            )
            unsigned_datatx_hex = binascii.hexlify(unsigned_datatx).decode(
                'utf-8')

            # let the rest of the code work it's magic on the data tx
            unsigned_tx_hex = unsigned_datatx_hex
        else:
            # we're just gonna return the pretx, it doesn't require any of the further checks
            logger.warn('old_style_api = %s' % old_style_api)
            return return_result([unsigned_pretx_hex],
                                 old_style_api=old_style_api)

    else:
        # Serialise inputs and outputs.
        unsigned_tx = serializer.serialise(
            encoding,
            inputs,
            destination_outputs,
            data_output,
            change_output,
            dust_return_pubkey=dust_return_pubkey)
        unsigned_tx_hex = binascii.hexlify(unsigned_tx).decode('utf-8')
    '''Sanity Check'''

    # Desired transaction info.
    (desired_source, desired_destination_outputs, desired_data) = tx_info
    desired_source = script.make_canonical(desired_source)
    desired_destination = script.make_canonical(
        desired_destination_outputs[0]
        [0]) if desired_destination_outputs else ''
    # NOTE: Include change in destinations for BTC transactions.
    # if change_output and not desired_data and desired_destination != config.UNSPENDABLE:
    #    if desired_destination == '':
    #        desired_destination = desired_source
    #    else:
    #        desired_destination += '-{}'.format(desired_source)
    # NOTE
    if desired_data == None:
        desired_data = b''

    # Parsed transaction info.
    try:
        if pretx_txid and unsigned_pretx:
            backend.cache_pretx(pretx_txid, unsigned_pretx)
        parsed_source, parsed_destination, x, y, parsed_data, extra = blocks._get_tx_info(
            unsigned_tx_hex, p2sh_is_segwit=script.is_bech32(desired_source))

        if encoding == 'p2sh':
            # make_canonical can't determine the address, so we blindly change the desired to the parsed
            desired_source = parsed_source

        if pretx_txid and unsigned_pretx:
            backend.clear_pretx(pretx_txid)
    except exceptions.BTCOnlyError:
        # Skip BTC‐only transactions.
        if extended_tx_info:
            return {
                'btc_in': btc_in,
                'btc_out': destination_btc_out + data_btc_out,
                'btc_change': change_quantity,
                'btc_fee': final_fee,
                'tx_hex': unsigned_tx_hex,
            }
        logger.getChild('p2shdebug').debug('BTC-ONLY')
        return return_result([unsigned_pretx_hex, unsigned_tx_hex],
                             old_style_api=old_style_api)
    desired_source = script.make_canonical(desired_source)

    # Check desired info against parsed info.
    desired = (desired_source, desired_destination, desired_data)
    parsed = (parsed_source, parsed_destination, parsed_data)
    if desired != parsed:
        # Unlock (revert) UTXO locks
        if UTXO_LOCKS is not None and inputs:
            for input in inputs:
                UTXO_LOCKS[source].pop(make_outkey(input), None)

        raise exceptions.TransactionError(
            'Constructed transaction does not parse correctly: {} ≠ {}'.format(
                desired, parsed))

    if extended_tx_info:
        return {
            'btc_in': btc_in,
            'btc_out': destination_btc_out + data_btc_out,
            'btc_change': change_quantity,
            'btc_fee': final_fee,
            'tx_hex': unsigned_tx_hex,
        }
    return return_result([unsigned_pretx_hex, unsigned_tx_hex],
                         old_style_api=old_style_api)
コード例 #7
0
def construct (db, tx_info, encoding='auto',
               fee_per_kb=config.DEFAULT_FEE_PER_KB,
               regular_dust_size=config.DEFAULT_REGULAR_DUST_SIZE,
               multisig_dust_size=config.DEFAULT_MULTISIG_DUST_SIZE,
               op_return_value=config.DEFAULT_OP_RETURN_VALUE,
               exact_fee=None, fee_provided=0, provided_pubkeys=None,
               allow_unconfirmed_inputs=False):

    (source, destination_outputs, data) = tx_info

    # Sanity checks.
    if exact_fee and not isinstance(exact_fee, int):
        raise exceptions.TransactionError('Exact fees must be in satoshis.')
    if not isinstance(fee_provided, int):
        raise exceptions.TransactionError('Fee provided must be in satoshis.')


    '''Destinations'''

    # Destination outputs.
        # Replace multi‐sig addresses with multi‐sig pubkeys. Check that the
        # destination output isn’t a dust output. Set null values to dust size.
    destination_outputs_new = []
    for (address, value) in destination_outputs:

        # Value.
        if script.is_multisig(address):
            dust_size = multisig_dust_size
        else:
            dust_size = regular_dust_size
        if value == None:
            value = dust_size
        elif value < dust_size:
            raise exceptions.TransactionError('Destination output is dust.')

        # Address.
        script.validate(address)
        if script.is_multisig(address):
            destination_outputs_new.append((backend.multisig_pubkeyhashes_to_pubkeys(address, provided_pubkeys), value))
        else:
            destination_outputs_new.append((address, value))

    destination_outputs = destination_outputs_new
    destination_btc_out = sum([value for address, value in destination_outputs])


    '''Data'''

    # Data encoding methods (choose and validate).
    if data:
        if encoding == 'auto':
            if len(data) + len(config.PREFIX) <= config.OP_RETURN_MAX_SIZE:
                encoding = 'opreturn'
            else:
                encoding = 'multisig'
        elif encoding not in ('pubkeyhash', 'multisig', 'opreturn'):
            raise exceptions.TransactionError('Unknown encoding‐scheme.')

    # Divide data into chunks.
    if data:
        if encoding == 'pubkeyhash':
            # Prefix is also a suffix here.
            chunk_size = 20 - 1 - 8
        elif encoding == 'multisig':
            # Two pubkeys, minus length byte, minus prefix, minus two nonces,
            # minus two sign bytes.
            chunk_size = (33 * 2) - 1 - 8 - 2 - 2
        elif encoding == 'opreturn':
            chunk_size = config.OP_RETURN_MAX_SIZE
            if len(data) + len(config.PREFIX) > chunk_size:
                raise exceptions.TransactionError('One `OP_RETURN` output per transaction.')
        data_array = list(chunks(data, chunk_size))
    else:
        data_array = []

    # Data outputs.
    if data:
        if encoding == 'multisig':
            data_value = multisig_dust_size
        elif encoding == 'opreturn':
            data_value = op_return_value
        else:
            # Pay‐to‐PubKeyHash, e.g.
            data_value = regular_dust_size
        data_output = (data_array, data_value)
    else:
        data_output = None
    data_btc_out = sum([data_value for data_chunk in data_array])


    '''Inputs'''

    # Source.
        # If public key is necessary for construction of (unsigned)
        # transaction, use the public key provided, or find it from the
        # blockchain.
    if source:
        script.validate(source)
    if encoding == 'multisig':
        dust_return_pubkey = get_dust_return_pubkey(source, provided_pubkeys, encoding)
    else:
        dust_return_pubkey = None

    # Calculate collective size of outputs, for fee calculation.
    if encoding == 'multisig':
        data_output_size = 81       # 71 for the data
    elif encoding == 'opreturn':
        data_output_size = 90       # 80 for the data
    else:
        data_output_size = 25 + 9   # Pay‐to‐PubKeyHash (25 for the data?)
    outputs_size = ((25 + 9) * len(destination_outputs)) + (len(data_array) * data_output_size)

    # Get inputs.
    multisig_inputs = not data
    unspent = backend.get_unspent_txouts(source, unconfirmed=allow_unconfirmed_inputs, multisig_inputs=multisig_inputs)
    unspent = backend.sort_unspent_txouts(unspent)
    logger.debug('Sorted UTXOs: {}'.format([print_coin(coin) for coin in unspent]))

    inputs = []
    btc_in = 0
    change_quantity = 0
    sufficient_funds = False
    final_fee = fee_per_kb
    for coin in unspent:
        logger.debug('New input: {}'.format(print_coin(coin)))
        inputs.append(coin)
        btc_in += round(coin['amount'] * config.UNIT)

        # If exact fee is specified, use that. Otherwise, calculate size of tx
        # and base fee on that (plus provide a minimum fee for selling BTC).
        if exact_fee:
            final_fee = exact_fee
        else:
            size = 181 * len(inputs) + outputs_size + 10
            necessary_fee = (int(size / 1000) + 1) * fee_per_kb
            final_fee = max(fee_provided, necessary_fee)
            assert final_fee >= 1 * fee_per_kb

        # Check if good.
        btc_out = destination_btc_out + data_btc_out
        change_quantity = btc_in - (btc_out + final_fee)
        logger.debug('Change quantity: {} BTC'.format(change_quantity / config.UNIT))
        # If change is necessary, must not be a dust output.
        if change_quantity == 0 or change_quantity >= regular_dust_size:
            sufficient_funds = True
            break

    if not sufficient_funds:
        # Approximate needed change, fee by with most recently calculated
        # quantities.
        btc_out = destination_btc_out + data_btc_out
        total_btc_out = btc_out + max(change_quantity, 0) + final_fee
        raise exceptions.BalanceError('Insufficient {} at address {}. (Need approximately {} {}.) To spend unconfirmed coins, use the flag `--unconfirmed`. (Unconfirmed coins cannot be spent from multi‐sig addresses.)'.format(config.BTC, source, total_btc_out / config.UNIT, config.BTC))


    '''Finish'''

    # Change output.
    if change_quantity:
        if script.is_multisig(source):
            change_address = backend.multisig_pubkeyhashes_to_pubkeys(source, provided_pubkeys)
        else:
            change_address = source
        change_output = (change_address, change_quantity)
    else:
        change_output = None


    # Serialise inputs and outputs.
    unsigned_tx = serialise(encoding, inputs, destination_outputs,
                            data_output, change_output,
                            dust_return_pubkey=dust_return_pubkey)
    unsigned_tx_hex = binascii.hexlify(unsigned_tx).decode('utf-8')


    '''Sanity Check'''

    from counterpartylib.lib import blocks

    # Desired transaction info.
    (desired_source, desired_destination_outputs, desired_data) = tx_info
    desired_source = script.make_canonical(desired_source)
    desired_destination = script.make_canonical(desired_destination_outputs[0][0]) if desired_destination_outputs else ''
    # NOTE: Include change in destinations for BTC transactions.
    # if change_output and not desired_data and desired_destination != config.UNSPENDABLE:
    #    if desired_destination == '':
    #        desired_destination = desired_source
    #    else:
    #        desired_destination += '-{}'.format(desired_source)
    # NOTE
    if desired_data == None:
        desired_data = b''

    # Parsed transaction info.
    try:
        parsed_source, parsed_destination, x, y, parsed_data = blocks.get_tx_info2(unsigned_tx_hex)
    except exceptions.BTCOnlyError:
        # Skip BTC‐only transactions.
        return unsigned_tx_hex
    desired_source = script.make_canonical(desired_source)

    # Check desired info against parsed info.
    desired = (desired_source, desired_destination, desired_data)
    parsed = (parsed_source, parsed_destination, parsed_data)
    if desired != parsed:
        raise exceptions.TransactionError('Constructed transaction does not parse correctly: {} ≠ {}'.format(desired, parsed))

    return unsigned_tx_hex
コード例 #8
0
def construct(db,
              tx_info,
              encoding='auto',
              fee_per_kb=config.DEFAULT_FEE_PER_KB,
              regular_dust_size=config.DEFAULT_REGULAR_DUST_SIZE,
              multisig_dust_size=config.DEFAULT_MULTISIG_DUST_SIZE,
              op_return_value=config.DEFAULT_OP_RETURN_VALUE,
              exact_fee=None,
              fee_provided=0,
              provided_pubkeys=None,
              allow_unconfirmed_inputs=False):

    (source, destination_outputs, data) = tx_info

    # Sanity checks.
    if exact_fee and not isinstance(exact_fee, int):
        raise exceptions.TransactionError('Exact fees must be in satoshis.')
    if not isinstance(fee_provided, int):
        raise exceptions.TransactionError('Fee provided must be in satoshis.')
    '''Destinations'''

    # Destination outputs.
    # Replace multi‐sig addresses with multi‐sig pubkeys. Check that the
    # destination output isn’t a dust output. Set null values to dust size.
    destination_outputs_new = []
    for (address, value) in destination_outputs:

        # Value.
        if script.is_multisig(address):
            dust_size = multisig_dust_size
        else:
            dust_size = regular_dust_size
        if value == None:
            value = dust_size
        elif value < dust_size:
            raise exceptions.TransactionError('Destination output is dust.')

        # Address.
        script.validate(address)
        if script.is_multisig(address):
            destination_outputs_new.append(
                (backend.multisig_pubkeyhashes_to_pubkeys(
                    address, provided_pubkeys), value))
        else:
            destination_outputs_new.append((address, value))

    destination_outputs = destination_outputs_new
    destination_btc_out = sum(
        [value for address, value in destination_outputs])
    '''Data'''

    # Data encoding methods (choose and validate).
    if data:
        if encoding == 'auto':
            if len(data) <= config.OP_RETURN_MAX_SIZE:
                encoding = 'multisig'  # BTCGuild isn’t mining `OP_RETURN`?!
            else:
                encoding = 'multisig'
        elif encoding not in ('pubkeyhash', 'multisig', 'opreturn'):
            raise exceptions.TransactionError('Unknown encoding‐scheme.')

    # Divide data into chunks.
    if data:
        if encoding == 'pubkeyhash':
            # Prefix is also a suffix here.
            chunk_size = 20 - 1 - 8
        elif encoding == 'multisig':
            # Two pubkeys, minus length byte, minus prefix, minus two nonces,
            # minus two sign bytes.
            chunk_size = (33 * 2) - 1 - 8 - 2 - 2
        elif encoding == 'opreturn':
            chunk_size = config.OP_RETURN_MAX_SIZE
            if len(data) > chunk_size:
                raise exceptions.TransactionError(
                    'One `OP_RETURN` output per transaction.')
        data_array = list(chunks(data, chunk_size))
    else:
        data_array = []

    # Data outputs.
    if data:
        if encoding == 'multisig':
            data_value = multisig_dust_size
        elif encoding == 'opreturn':
            data_value = op_return_value
        else:
            # Pay‐to‐PubKeyHash, e.g.
            data_value = regular_dust_size
        data_output = (data_array, data_value)
    else:
        data_output = None
    data_btc_out = sum([data_value for data_chunk in data_array])
    '''Inputs'''

    # Source.
    # If public key is necessary for construction of (unsigned)
    # transaction, use the public key provided, or find it from the
    # blockchain.
    if source:
        script.validate(source)
    dust_return_pubkey = get_dust_return_pubkey(source, provided_pubkeys,
                                                encoding)

    # Calculate collective size of outputs, for fee calculation.
    if encoding == 'multisig':
        data_output_size = 81  # 71 for the data
    elif encoding == 'opreturn':
        data_output_size = 90  # 80 for the data
    else:
        data_output_size = 25 + 9  # Pay‐to‐PubKeyHash (25 for the data?)
    outputs_size = ((25 + 9) * len(destination_outputs)) + (len(data_array) *
                                                            data_output_size)

    # Get inputs.
    unspent = backend.get_unspent_txouts(source)
    unspent = backend.sort_unspent_txouts(unspent, allow_unconfirmed_inputs)
    logger.debug('Sorted UTXOs: {}'.format(
        [print_coin(coin) for coin in unspent]))

    inputs = []
    btc_in = 0
    change_quantity = 0
    sufficient_funds = False
    final_fee = fee_per_kb
    for coin in unspent:
        logger.debug('New input: {}'.format(print_coin(coin)))
        inputs.append(coin)
        btc_in += round(coin['amount'] * config.UNIT)

        # If exact fee is specified, use that. Otherwise, calculate size of tx
        # and base fee on that (plus provide a minimum fee for selling BTC).
        if exact_fee:
            final_fee = exact_fee
        else:
            size = 181 * len(inputs) + outputs_size + 10
            necessary_fee = (int(size / 1000) + 1) * fee_per_kb
            final_fee = max(fee_provided, necessary_fee)
            assert final_fee >= 1 * fee_per_kb

        # Check if good.
        btc_out = destination_btc_out + data_btc_out
        change_quantity = btc_in - (btc_out + final_fee)
        logger.debug('Change quantity: {} BTC'.format(change_quantity /
                                                      config.UNIT))
        # If change is necessary, must not be a dust output.
        if change_quantity == 0 or change_quantity >= regular_dust_size:
            sufficient_funds = True
            break

    if not sufficient_funds:
        # Approximate needed change, fee by with most recently calculated
        # quantities.
        btc_out = destination_btc_out + data_btc_out
        total_btc_out = btc_out + max(change_quantity, 0) + final_fee
        raise exceptions.BalanceError(
            'Insufficient {} at address {}. (Need approximately {} {}.) To spend unconfirmed coins, use the flag `--unconfirmed`. (Unconfirmed coins cannot be spent from multi‐sig addresses.)'
            .format(config.BTC, source, total_btc_out / config.UNIT,
                    config.BTC))
    '''Finish'''

    # Change output.
    if change_quantity:
        if script.is_multisig(source):
            change_address = backend.multisig_pubkeyhashes_to_pubkeys(
                source, provided_pubkeys)
        else:
            change_address = source
        change_output = (change_address, change_quantity)
    else:
        change_output = None

    # Serialise inputs and outputs.
    unsigned_tx = serialise(encoding,
                            inputs,
                            destination_outputs,
                            data_output,
                            change_output,
                            dust_return_pubkey=dust_return_pubkey)
    unsigned_tx_hex = binascii.hexlify(unsigned_tx).decode('utf-8')
    '''Sanity Check'''

    from counterpartylib.lib import blocks

    # Desired transaction info.
    (desired_source, desired_destination_outputs, desired_data) = tx_info
    desired_source = script.make_canonical(desired_source)
    desired_destination = script.make_canonical(
        desired_destination_outputs[0]
        [0]) if desired_destination_outputs else ''
    # NOTE: Include change in destinations for BTC transactions.
    # if change_output and not desired_data and desired_destination != config.UNSPENDABLE:
    #    if desired_destination == '':
    #        desired_destination = desired_source
    #    else:
    #        desired_destination += '-{}'.format(desired_source)
    # NOTE
    if desired_data == None:
        desired_data = b''

    # Parsed transaction info.
    try:
        parsed_source, parsed_destination, x, y, parsed_data = blocks.get_tx_info2(
            unsigned_tx_hex)
    except exceptions.BTCOnlyError:
        # Skip BTC‐only transactions.
        return unsigned_tx_hex
    desired_source = script.make_canonical(desired_source)

    # Check desired info against parsed info.
    if (desired_source, desired_destination,
            desired_data) != (parsed_source, parsed_destination, parsed_data):
        raise exceptions.TransactionError(
            'constructed transaction does not parse correctly')

    return unsigned_tx_hex