def test_add_privkeys():
with pytest.raises(Exception) as e_info:
btc.add_privkeys("aa" * 32, "bb" * 32 + "01", True)
def scan_for_coinjoins(privkey, amount, filename):
"""Given a file which contains encrypted coinjoin proposals,
and a private key for a pubkey with a known utxo existing
which we can spend, scan the entries in the file, all assumed
to be ECIES encrypted to a pubkey, for one which is encrypted
to *this* pubkey, if found, output the retrieved partially signed
transaction, and destination key, address to a list which is
returned to the caller.
Only if the retrieved coinjoin transaction passes basic checks
on validity in terms of amount paid, is it returned.
This is an elementary implementation that will obviously fail
any performance test (i.e. moderately large lists).
Note that the tweaked output address must be of type p2sh/p2wpkh.
"""
try:
with open(filename, "rb") as f:
msgs = f.readlines()
except:
print("Failed to read from file: ", filename)
return
valid_coinjoins = []
for msg in msgs:
try:
decrypted_msg = decrypt_message(msg, privkey)
tweak, tx = deserialize_coinjoin_proposal(decrypted_msg)
except:
print("Could not decrypt message, skipping")
continue
if not tweak:
print("Could not decrypt message, reason: " + str(tx))
continue
#We analyse the content of the transaction to check if it follows
#our requirements
try:
deserialized_tx = btc.deserialize(tx)
except:
print("Proposed transaction is not correctly formatted, skipping.")
continue
#construct our receiving address according to the tweak
pubkey = btc.privkey_to_pubkey(privkey)
tweak, destnpt, my_destn_addr = create_recipient_address(pubkey,
tweak=tweak,
segwit=True)
#add_privkeys requires both inputs to be compressed (or un-) consistently.
tweak_priv = tweak + "01"
my_destn_privkey = btc.add_privkeys(tweak_priv, privkey, True)
my_output_index = -1
for i, o in enumerate(deserialized_tx['outs']):
addr = btc.script_to_address(o['script'], get_p2sh_vbyte())
if addr == my_destn_addr:
print('found our output address: ', my_destn_addr)
my_output_index = i
break
if my_output_index == -1:
print("Proposal doesn't contain our output address, rejecting")
continue
my_output_amount = deserialized_tx['outs'][i]['value']
required_amount = amount - 2 * estimate_tx_fee(3, 3, 'p2sh-p2wpkh')
if my_output_amount < required_amount:
print("Proposal pays too little, difference is: ",
required_amount - my_output_amount)
continue
#now we know output is acceptable to us, we should check that the
#ctrprty input is signed and the other input is ours, but will do this
#later; if it's not, it just won't work so NBD for now.
valid_coinjoins.append((my_destn_addr, my_destn_privkey, tx))
return valid_coinjoins