def include_signature(self, in_index, cp, sig):
"""For receiving counterparty signatures, either
on promise inputs or NN multisigs. If valid,
mark that index as completed if appropriate,
and return True. If invalid, return False.
"""
tp = self.template.ins[in_index].spk_type
pub = self.keys["ins"][in_index][cp]
if tp == "NN":
if len(self.signatures[in_index]) == 0:
self.signatures[in_index] = [None] * self.n_counterparties
sigform = self.signature_form(in_index)
if not btc.verify_tx_input(self.base_form,
in_index,
self.signing_redeem_scripts[in_index],
sig,
self.keys["ins"][in_index][cp],
witness="deadbeef",
amount=self.ins[in_index][1]):
cjxtlog.info(
"Error in include_signature: signature invalid: " + sig)
return False
else:
self.signatures[in_index][cp] = sig
if all([
self.signatures[in_index][x]
for x in range(self.n_counterparties)
]):
self.completed[in_index] = True
return True
elif tp == "p2sh-p2wpkh":
#counterparty's promise signature
#verification check
scriptCode = "76a914" + btc.hash160(
binascii.unhexlify(pub)) + "88ac"
if not btc.verify_tx_input(self.base_form,
in_index,
scriptCode,
sig,
pub,
witness="deadbeef",
amount=self.ins[in_index][1]):
cjxtlog.info(
"Error in include_signature: signature invalid: " + sig)
return False
else:
self.signatures[in_index] = [sig]
self.completed[in_index] = True
return True
def test_hash160():
assert '0e3397b4abc7a382b3ea2365883c3c7ca5f07600' == \
btc.hash160('The quick brown fox jumps over the lazy dog')
def on_tx_received(self, nick, txhex):
""" Called when the sender-counterparty has sent a transaction proposal.
1. First we check for the expected destination and amount (this is
sufficient to identify our cp, as this info was presumably passed
out of band, as for any normal payment).
2. Then we verify the validity of the proposed non-coinjoin
transaction; if not, reject, otherwise store this as a
fallback transaction in case the protocol doesn't complete.
3. Next, we select utxos from our wallet, to add into the
payment transaction as input. Try to select so as to not
trigger the UIH2 condition, but continue (and inform user)
even if we can't (if we can't select any coins, broadcast the
non-coinjoin payment, if the user agrees).
Proceeding with payjoin:
4. We update the output amount at the destination address.
5. We modify the change amount in the original proposal (which
will be the only other output other than the destination),
reducing it to account for the increased transaction fee
caused by our additional proposed input(s).
6. Finally we sign our own input utxo(s) and re-serialize the
tx, allowing it to be sent back to the counterparty.
7. If the transaction is not fully signed and broadcast within
the time unconfirm_timeout_sec as specified in the joinmarket.cfg,
we broadcast the non-coinjoin fallback tx instead.
"""
try:
tx = btc.deserialize(txhex)
except (IndexError, SerializationError,
SerializationTruncationError) as e:
return (False, 'malformed txhex. ' + repr(e))
self.user_info('obtained proposed fallback (non-coinjoin) ' +\
'transaction from sender:\n' + pprint.pformat(tx))
if len(tx["outs"]) != 2:
return (False,
"Transaction has more than 2 outputs; not supported.")
dest_found = False
destination_index = -1
change_index = -1
proposed_change_value = 0
for index, out in enumerate(tx["outs"]):
if out["script"] == btc.address_to_script(self.destination_addr):
# we found the expected destination; is the amount correct?
if not out["value"] == self.receiving_amount:
return (False,
"Wrong payout value in proposal from sender.")
dest_found = True
destination_index = index
else:
change_found = True
proposed_change_out = out["script"]
proposed_change_value = out["value"]
change_index = index
if not dest_found:
return (False, "Our expected destination address was not found.")
# Verify valid input utxos provided and check their value.
# batch retrieval of utxo data
utxo = {}
ctr = 0
for index, ins in enumerate(tx['ins']):
utxo_for_checking = ins['outpoint']['hash'] + ':' + str(
ins['outpoint']['index'])
utxo[ctr] = [index, utxo_for_checking]
ctr += 1
utxo_data = jm_single().bc_interface.query_utxo_set(
[x[1] for x in utxo.values()])
total_sender_input = 0
for i, u in iteritems(utxo):
if utxo_data[i] is None:
return (False, "Proposed transaction contains invalid utxos")
total_sender_input += utxo_data[i]["value"]
# Check that the transaction *as proposed* balances; check that the
# included fee is within 0.3-3x our own current estimates, if not user
# must decide.
btc_fee = total_sender_input - self.receiving_amount - proposed_change_value
self.user_info("Network transaction fee of fallback tx is: " +
str(btc_fee) + " satoshis.")
fee_est = estimate_tx_fee(len(tx['ins']),
len(tx['outs']),
txtype=self.wallet.get_txtype())
fee_ok = False
if btc_fee > 0.3 * fee_est and btc_fee < 3 * fee_est:
fee_ok = True
else:
if self.user_check("Is this transaction fee acceptable? (y/n):"):
fee_ok = True
if not fee_ok:
return (False,
"Proposed transaction fee not accepted due to tx fee: " +
str(btc_fee))
# This direct rpc call currently assumes Core 0.17, so not using now.
# It has the advantage of (a) being simpler and (b) allowing for any
# non standard coins.
#
#res = jm_single().bc_interface.rpc('testmempoolaccept', [txhex])
#print("Got this result from rpc call: ", res)
#if not res["accepted"]:
# return (False, "Proposed transaction was rejected from mempool.")
# Manual verification of the transaction signatures. Passing this
# test does imply that the transaction is valid (unless there is
# a double spend during the process), but is restricted to standard
# types: p2pkh, p2wpkh, p2sh-p2wpkh only. Double spend is not counted
# as a risk as this is a payment.
for i, u in iteritems(utxo):
if "txinwitness" in tx["ins"][u[0]]:
ver_amt = utxo_data[i]["value"]
try:
ver_sig, ver_pub = tx["ins"][u[0]]["txinwitness"]
except Exception as e:
self.user_info("Segwit error: " + repr(e))
return (False, "Segwit input not of expected type, "
"either p2sh-p2wpkh or p2wpkh")
# note that the scriptCode is the same whether nested or not
# also note that the scriptCode has to be inferred if we are
# only given a transaction serialization.
scriptCode = "76a914" + btc.hash160(
unhexlify(ver_pub)) + "88ac"
else:
scriptCode = None
ver_amt = None
scriptSig = btc.deserialize_script(tx["ins"][u[0]]["script"])
if len(scriptSig) != 2:
return (
False,
"Proposed transaction contains unsupported input type")
ver_sig, ver_pub = scriptSig
if not btc.verify_tx_input(txhex,
u[0],
utxo_data[i]['script'],
ver_sig,
ver_pub,
scriptCode=scriptCode,
amount=ver_amt):
return (False, "Proposed transaction is not correctly signed.")
# At this point we are satisfied with the proposal. Record the fallback
# in case the sender disappears and the payjoin tx doesn't happen:
self.user_info(
"We'll use this serialized transaction to broadcast if your"
" counterparty fails to broadcast the payjoin version:")
self.user_info(txhex)
# Keep a local copy for broadcast fallback:
self.fallback_tx = txhex
# Now we add our own inputs:
# See the gist comment here:
# https://gist.github.com/AdamISZ/4551b947789d3216bacfcb7af25e029e#gistcomment-2799709
# which sets out the decision Bob must make.
# In cases where Bob can add any amount, he selects one utxo
# to keep it simple.
# In cases where he must choose at least X, he selects one utxo
# which provides X if possible, otherwise defaults to a normal
# selection algorithm.
# In those cases where he must choose X but X is unavailable,
# he selects all coins, and proceeds anyway with payjoin, since
# it has other advantages (CIOH and utxo defrag).
my_utxos = {}
largest_out = max(self.receiving_amount, proposed_change_value)
max_sender_amt = max([u['value'] for u in utxo_data])
not_uih2 = False
if max_sender_amt < largest_out:
# just select one coin.
# have some reasonable lower limit but otherwise choose
# randomly; note that this is actually a great way of
# sweeping dust ...
self.user_info("Choosing one coin at random")
try:
my_utxos = self.wallet.select_utxos(self.mixdepth,
jm_single().DUST_THRESHOLD,
select_fn=select_one_utxo)
except:
return self.no_coins_fallback()
not_uih2 = True
else:
# get an approximate required amount assuming 4 inputs, which is
# fairly conservative (but guess by necessity).
fee_for_select = estimate_tx_fee(len(tx['ins']) + 4,
2,
txtype=self.wallet.get_txtype())
approx_sum = max_sender_amt - self.receiving_amount + fee_for_select
try:
my_utxos = self.wallet.select_utxos(self.mixdepth, approx_sum)
not_uih2 = True
except Exception:
# TODO probably not logical to always sweep here.
self.user_info("Sweeping all coins in this mixdepth.")
my_utxos = self.wallet.get_utxos_by_mixdepth()[self.mixdepth]
if my_utxos == {}:
return self.no_coins_fallback()
if not_uih2:
self.user_info("The proposed tx does not trigger UIH2, which "
"means it is indistinguishable from a normal "
"payment. This is the ideal case. Continuing..")
else:
self.user_info("The proposed tx does trigger UIH2, which it makes "
"it somewhat distinguishable from a normal payment,"
" but proceeding with payjoin..")
my_total_in = sum([va['value'] for va in my_utxos.values()])
self.user_info("We selected inputs worth: " + str(my_total_in))
# adjust the output amount at the destination based on our contribution
new_destination_amount = self.receiving_amount + my_total_in
# estimate the required fee for the new version of the transaction
total_ins = len(tx["ins"]) + len(my_utxos.keys())
est_fee = estimate_tx_fee(total_ins,
2,
txtype=self.wallet.get_txtype())
self.user_info("We estimated a fee of: " + str(est_fee))
new_change_amount = total_sender_input + my_total_in - \
new_destination_amount - est_fee
self.user_info("We calculated a new change amount of: " +
str(new_change_amount))
self.user_info("We calculated a new destination amount of: " +
str(new_destination_amount))
# now reconstruct the transaction with the new inputs and the
# amount-changed outputs
new_outs = [{
"address": self.destination_addr,
"value": new_destination_amount
}]
if new_change_amount >= jm_single().BITCOIN_DUST_THRESHOLD:
new_outs.append({
"script": proposed_change_out,
"value": new_change_amount
})
new_ins = [x[1] for x in utxo.values()]
new_ins.extend(my_utxos.keys())
# set locktime for best anonset (Core, Electrum) - most recent block.
# this call should never fail so no catch here.
currentblock = jm_single().bc_interface.rpc("getblockchaininfo",
[])["blocks"]
new_tx = make_shuffled_tx(new_ins, new_outs, False, 2, currentblock)
new_tx_deser = btc.deserialize(new_tx)
# sign our inputs before transfer
our_inputs = {}
for index, ins in enumerate(new_tx_deser['ins']):
utxo = ins['outpoint']['hash'] + ':' + str(
ins['outpoint']['index'])
if utxo not in my_utxos:
continue
script = self.wallet.addr_to_script(my_utxos[utxo]['address'])
amount = my_utxos[utxo]['value']
our_inputs[index] = (script, amount)
txs = self.wallet.sign_tx(btc.deserialize(new_tx), our_inputs)
jm_single().bc_interface.add_tx_notify(
txs,
self.on_tx_unconfirmed,
self.on_tx_confirmed,
self.destination_addr,
wallet_name=jm_single().bc_interface.get_wallet_name(self.wallet),
txid_flag=False,
vb=self.wallet._ENGINE.VBYTE)
# The blockchain interface just abandons monitoring if the transaction
# is not broadcast before the configured timeout; we want to take
# action in this case, so we add an additional callback to the reactor:
reactor.callLater(
jm_single().config.getint("TIMEOUT", "unconfirm_timeout_sec"),
self.broadcast_fallback)
return (True, nick, btc.serialize(txs))
def sign_at_index(self, in_index):
"""Signs with our one key corresponding to one input;
either sole-owned (promise) or NN.
Segwit assumed; uses only p2sh-p2wpkh for sole-owned,
p2wsh for co-owned.
"""
#the pubkey we're signing against:
pub = self.keys["ins"][in_index][self.n]
#the wallet holds the keys for p2sh-p2wpkh addresses directly.
#for p2wsh addresses, we must use the pubkey to construct
#the corresponding p2sh-p2wpkh address in the wallet to extract
#the key. This is obviously stupid for a real world design TODO
addr = self.wallet.pubkey_to_address(pub)
privkey = self.wallet.get_key_from_addr(addr)
#check whether we are multi-signing or single-signing:
tp = self.template.ins[in_index].spk_type
if tp == "p2sh-p2wpkh":
#the main (non-multisig) signing algo(s) return a signed
#tx, not a signature; extract from the temporary tx
txwithsig = btc.deserialize(
self.wallet.sign(self.base_form, in_index, privkey,
self.ins[in_index][1]))
#txinwitness field is [sig, pub]
sig = txwithsig["ins"][in_index]["txinwitness"][0]
#verification check
scriptCode = "76a914" + btc.hash160(
binascii.unhexlify(pub)) + "88ac"
assert btc.verify_tx_input(self.base_form,
in_index,
scriptCode,
sig,
pub,
witness="deadbeef",
amount=self.ins[in_index][1])
self.signatures[in_index] = [sig]
self.completed[in_index] = True
elif tp == "NN":
if len(self.signatures[in_index]) == 0:
self.signatures[in_index] = [None] * self.n_counterparties
sig = btc.p2wsh_multisign(self.base_form,
in_index,
self.signing_redeem_scripts[in_index],
privkey,
amount=self.ins[in_index][1])
assert btc.verify_tx_input(self.base_form,
in_index,
self.signing_redeem_scripts[in_index],
sig,
pub,
witness="deadbeef",
amount=self.ins[in_index][1])
#Note that it's OK to use self.n as the explicit list index
#here, as we *always* do N of N multisig.
self.signatures[in_index][self.n] = sig
if all([
self.signatures[in_index][x]
for x in range(self.n_counterparties)
]):
self.completed[in_index] = True
#in some cases, the sig is used by the caller (to send to counterparty)
return sig