def createScriptSig(self, hashType, signHash):
assert self.signing_key is not None
self.scriptSig.clear()
signature = addressgen.ecdsa_sign(self.signing_key, signHash)
signature = signature + struct.pack("<B", hashType)
#print("signature: {}".format(''.join(['{:02x}'.format(x) for x in signature])))
self.scriptSig.pushData(signature)
public_key = addressgen.get_public_key(self.signing_key)
self.scriptSig.pushData(public_key)
if self.address is None:
self.extractAddressFromInputScript()
self.signed = True
self.signed_hash_type = hashType
def main():
message = None
# Parse arguments first
i = 1
while i < len(sys.argv):
v = sys.argv[1]
if v == '-f':
assert message is None, "you can only specify -f once"
i += 1
data = open(sys.argv[i], 'rb').read()
mime_type, encoding = mimetypes.guess_type(sys.argv[i])
if mime_type is not None:
filename = os.path.basename(sys.argv[i])
message = '\n'.join([
'Content-type: {}{}'.format(mime_type, '; charset={}'.format(encoding) if encoding is not None else ''),
'Content-length: {}'.format(len(data)),
'Content-disposition: attachment; filename={}'.format(filename),
])
message = message.encode('utf8') + b'\n\n' + data
i += 1
# Get coins for input
print('*** Step 1. We need Bitcoins in order to send a message. Give me a Bitcoin private key (it starts with a 5...) to use as an input for the message transaction.')
bitcoin_private_key = input('...Enter Bitcoin private key: ')
# Decode private key, show bitcoin address associated with key
private_key = base58.decode_to_bytes(bitcoin_private_key)[-36:-4]
public_key = addressgen.get_public_key(private_key)
bitcoin_input_address = addressgen.generate_address(public_key, version=0)
print('...The Bitcoin address associated with that private key is: {}'.format(bitcoin_input_address))
# Lookup the unspent outputs associated with the given input...
print('...Looking up unspent outputs on blockchain.info...')
unspent_outputs = filter_unspent_outputs(lookup_unspent_outputs([bitcoin_input_address])[bitcoin_input_address])
# Show the inputs to the user, and ask him which he'd like to use as input.
print('\n*** Step 2. You need to select an input:')
for k, u in enumerate(unspent_outputs):
print('...{}: txid={} n={} value={} confirmations={}'.format(k+1, u['tx_hash'], u['tx_output_n'], Bitcoin.format_money(u['value']), u['confirmations']))
selected_inputs = [int(x.strip())-1 for x in input('Enter inputs (if more than one, separated by commas): ').split(',') if len(x) > 0]
if not all(x >= 0 and x < len(unspent_outputs) for x in selected_inputs):
raise Exception("Invalid input provided")
total_input_amount = sum(unspent_outputs[k]['value'] for k in selected_inputs)
print('...{} BTC selected from {} input{}'.format(Bitcoin.format_money(total_input_amount), len(selected_inputs), 's' if len(selected_inputs) != 1 else ''))
# Ask the user for the change address, defaulting to the same input address
print('\n*** Step 3. Provide a change address (this will not be used if a change address isn\'t necessary)')
bitcoin_change_address = input('...Enter change address (leave blank to use the input address as the change address): ').strip()
if len(bitcoin_change_address) == 0:
bitcoin_change_address = bitcoin_input_address
print('...Change address: {}'.format(bitcoin_change_address))
# Select an encryption method
while True:
print('\n*** Step 4a. Select an encryption method:')
print('...1. None (public message)')
print('...2. RC4')
print('...3. AES-128')
print('...4. AES-256 (best)')
print('...5. RSA (public-key)')
try:
i = int(input('? '))
if i == 1:
encryption_key = b'\x00'
encryption_algorithm = ENCRYPT_NONE
elif i == 2:
required_key_length_message = "RC4 allows for variable-length keys, but longer is better"
encryption_algorithm = ENCRYPT_RC4
elif i == 3:
required_key_length_message = "AES-128 requires a key length of 16 bytes"
encryption_algorithm = ENCRYPT_AES128
elif i == 4:
required_key_length_message = "AES-256 requires a key length of 32 bytes"
encryption_algorithm = ENCRYPT_AES256
elif i == 5:
required_key_length_message = "An RSA public-key is required"
encryption_algorithm = ENCRYPT_RSA
else:
continue
break
except ValueError:
continue
if encryption_algorithm in (ENCRYPT_AES128, ENCRYPT_AES256, ENCRYPT_RC4):
print('\n*** Step 4b. Provide an encryption key. The encryption key will be hashed and used as a Bitcoin address to designate the recipient.')
encryption_key = input('...Enter an encryption key ({}): '.format(required_key_length_message)).encode('utf8')
if encryption_algorithm == ENCRYPT_AES128 and len(encryption_key) != 16:
print('...ERROR: key must have a length of 16 bytes.')
return
elif encryption_algorithm == ENCRYPT_AES256 and len(encryption_key) != 32:
print('...ERROR: key must have a length of 32 bytes.')
return
elif encryption_algorithm == ENCRYPT_RC4 and len(encryption_key) == 0:
print('...ERROR: key must not be empty')
return
elif encryption_algorithm == ENCRYPT_RSA:
encryption_key = get_random_bytes(32)
encrypted_rsa_encryption_keys = []
while True:
print('\n*** Step 4b. Provide the public-key for a recipient (in PEM form):\n')
lines = []
while True:
line = input('')
lines.append(line)
if '-----END PUBLIC KEY-----' in line:
break
public_key = load_public_key('\n'.join(lines))
# encrypt encryption key
encrypted_rsa_encryption_key = encrypt(public_key, encryption_key, algorithm=ENCRYPT_RSA)
encrypted_rsa_encryption_keys.append(struct.pack('<H', len(encrypted_rsa_encryption_key)) + encrypted_rsa_encryption_key)
answer = False
while True:
answer = input('...would you like to add another recipient? (y/N) ').strip().lower()
if answer in ('y', 'yes'):
answer = True
break
if answer in ('n', 'no', ''):
answer = False
break
if not answer:
break
if encryption_algorithm == ENCRYPT_RSA:
bitcoin_delivery_addresses = []
else:
bitcoin_delivery_addresses = [addressgen.generate_address_from_data(encryption_key, version=0)]
print('...Message delivery to:')
for bitcoin_delivery_address in bitcoin_delivery_addresses:
print('... {}'.format(bitcoin_delivery_address))
# Now we ask the user to enter a message
if message is None:
print('\n*** Step 5. Enter your message. End your message by entering \'.\' by itself on a new line.\n...Enter your message:\n')
lines = []
while True:
line = input()
if line == '.':
break
lines.append(line)
message = '\n'.join(lines).encode('utf8')
# Add some temporary headers
message = 'Content-type: text/plain; charset=utf-8\nContent-length: {}\n\n'.format(len(message)).encode('ascii') + message
# Try compressing the message before encryption, this may waste CPU but it's in the interest
# of saving some outputs in the transaction.
print('...Trying to compress the message...', end='')
compressed_message = gzip.compress(message)
if len(compressed_message) < len(message):
print('good!')
message = compressed_message
encryption_algorithm |= 0x80
else:
print('not using because compressed version is larger.')
# Setup the initialization vector using the first input's transaction id
if (encryption_algorithm & 0x7f) == ENCRYPT_AES128:
first_input = unspent_outputs[selected_inputs[0]]
first_input_tx_hash = Bitcoin.hexstring_to_bytes(first_input['tx_hash'], reverse=False)
iv = int.from_bytes(first_input_tx_hash, 'big')
iv = (iv % (1 << 128)).to_bytes(16, 'big')
elif (encryption_algorithm & 0x7f) in (ENCRYPT_AES256, ENCRYPT_RSA):
# Bitcoin tx hashes are 32-bytes, so this is still OK for AES-256
first_input = unspent_outputs[selected_inputs[0]]
first_input_tx_hash = Bitcoin.hexstring_to_bytes(first_input['tx_hash'], reverse=False)
iv = int.from_bytes(first_input_tx_hash, 'big')
iv = (iv % (1 << 256)).to_bytes(32, 'big')
else:
iv = None
# Encrypt the message
if (encryption_algorithm & 0x7f) == ENCRYPT_RSA:
encrypted_message = encrypt(encryption_key, message, algorithm=ENCRYPT_AES256, iv=iv)
else:
encrypted_message = encrypt(encryption_key, message, algorithm=(encryption_algorithm & 0x7f), iv=iv)
# With RSA, the encrypted keys are compressed separately
if (encryption_algorithm& 0x7f) == ENCRYPT_RSA:
print('...Trying to compress the key block...', end='')
encrypted_key_block = b''.join(encrypted_rsa_encryption_keys)
compressed_encrypted_key_block = gzip.compress(encrypted_key_block)
if len(compressed_encrypted_key_block) < len(encrypted_key_block):
print('good!')
encrypted_key_block = b'\x80' + struct.pack('<L', len(compressed_encrypted_key_block)) + compressed_encrypted_key_block
else:
print('not using because compressed version is larger.')
encrypted_key_block = b'\x00' + struct.pack('<L', len(encrypted_key_block)) + encrypted_key_block
print('...Encrypted Key Block is {} bytes'.format(len(encrypted_key_block)))
encrypted_message = encrypted_key_block + encrypted_message
print('...Encrypted message is {} bytes'.format(len(encrypted_message)))
# Build the message header. Prefix the encrypted message with the header.
checksum = sum(encrypted_message) % 256
reserved = 0xff
padding = 0
header = bytes([VERSION, encryption_algorithm, checksum, padding, reserved])
encrypted_message = header + encrypted_message
# Split the encrypted message into pubkeys. We get 119 bytes per pubkey (we reserve
# the first byte in case any future changes to bitcoind require a valid pubkey)
bitcoin_message_pieces = []
for i in range(0, len(encrypted_message), PIECE_SIZE[VERSION]):
piece = encrypted_message[i:i+PIECE_SIZE[VERSION]]
bitcoin_message_pieces.append(b'\xff' + piece)
if len(bitcoin_message_pieces) == 1 and len(bitcoin_message_pieces[0]) < 33:
# This is the only case where we need padding in version 2 messages.
padding = 33 - len(bitcoin_message_pieces[0])
bitcoin_message_pieces[0] = bitcoin_message_pieces[0] + bytes([padding] * padding)
# We have to adjust the header 'padding' value
bitcoin_message_pieces[0] = bitcoin_message_pieces[0][:4] + bytes([padding]) + bitcoin_message_pieces[0][5:]
elif len(bitcoin_message_pieces) > 1 and len(bitcoin_message_pieces[-1]) < 33:
# We shift however many bytes out of the 2nd to last block and into the last one
# to make sure it's at least 33 bytes long
req = 33 - len(bitcoin_message_pieces[-1])
bitcoin_message_pieces[-1] = bytes([bitcoin_message_pieces[-1][0]]) + bitcoin_message_pieces[-2][-req:] + bitcoin_message_pieces[-1][1:]
bitcoin_message_pieces[-2] = bitcoin_message_pieces[-2][:-req]
assert 120 >= len(bitcoin_message_pieces[-2]) >= 33 and 120 >= len(bitcoin_message_pieces[-1]) >= 33
# start building the transaction
tx = Transaction()
# setup the inputs
for n, k in enumerate(selected_inputs):
unspent = unspent_outputs[k]
tx_input = TransactionInput(tx_hash=Bitcoin.hexstring_to_bytes(unspent['tx_hash'], reverse=False),
tx_output_n=unspent['tx_output_n'],
scriptPubKey=Bitcoin.hexstring_to_bytes(unspent['script'], reverse=False),
amount=unspent['value'],
signing_key=private_key)
print('...input {} is {} BTC from {}'.format(n, Bitcoin.format_money(unspent['value']), bitcoin_input_address))
tx.addInput(tx_input)
# setup the outputs. a trigger address isn't really needed, since the encryption
# key can actually be used as the trigger (only those interested will be able to find
# the message, anyway)
# cost of the transaction is (targets + pieces/3 + sacrifice) * SPECIAL_SATOSHI
# peices/3 because we include 3 pieces per output
outputs_count = (len(bitcoin_delivery_addresses) + math.ceil(len(bitcoin_message_pieces) / 3))
approx_tx_cost = MINIMUM_SACRIFICE + outputs_count * SPECIAL_SATOSHI
if approx_tx_cost > total_input_amount:
raise Exception("not enough inputs provided")
tx_change_output = None
tx_change_output_n = None
if total_input_amount > approx_tx_cost:
print('...output (change) to {}'.format(bitcoin_change_address))
tx_change_output = TransactionOutput(bitcoin_change_address, amount=total_input_amount - approx_tx_cost)
tx_change_output_n = tx.addOutput(tx_change_output)
# The recipient will know how to handle this if they see their key...
for i, bitcoin_delivery_address in enumerate(bitcoin_delivery_addresses):
print('...output (target) to {}'.format(bitcoin_delivery_address))
tx_output = TransactionOutput(bitcoin_delivery_address, amount=SPECIAL_SATOSHI)
tx.addOutput(tx_output)
for i in range(0, len(bitcoin_message_pieces), 3):
pieces = bitcoin_message_pieces[i:i+3]
d = b''.join([p[1:] for p in pieces])
header = None
if i == 0:
header = d[:5]
d = d[5:]
if (i + 3) >= len(bitcoin_message_pieces):
if padding > 0:
d = d[:-padding]
print('...output (message) to multisig 1-of-{}{}'.format(len(pieces), ' (header={})'.format(header) if header is not None else ''))
tx_output = TransactionOutput(amount=SPECIAL_SATOSHI)
tx_output.setMultisig(pieces, 1)
tx.addOutput(tx_output)
# we should now be able to figure out how much in fees is required now that the tx is built
recommended_fee = max(MINIMUM_SACRIFICE * SPECIAL_SATOSHI, tx.getRecommendedTransactionFee(per_kb=SACRIFICE_PER_KB))
recommended_tx_cost = recommended_fee + outputs_count * SPECIAL_SATOSHI
if recommended_tx_cost > total_input_amount:
raise Exception("not enough inputs provided ({} BTC required)".format(Bitcoin.format_money(recommended_tx_cost)))
if tx_change_output is not None and recommended_tx_cost == total_input_amount:
# We can remove the output
tx.removeOutput(tx_change_output_n)
tx_change_output = None
if recommended_tx_cost < total_input_amount:
if tx_change_output is None:
print('...output (change) to {}'.format(bitcoin_change_address))
tx_change_output = TransactionOutput(bitcoin_change_address)
tx_change_output_n = tx.addOutput(tx_change_output)
tx_change_output.amount = total_input_amount - recommended_tx_cost
print('...the fee for this transaction is {} BTC'.format(Bitcoin.format_money(tx.totalInput() - tx.totalOutput())))
print('...the total sent is {} BTC (change = {})'.format(Bitcoin.format_money(tx.totalInput()), Bitcoin.format_money(0 if tx_change_output is None else tx.outputs[tx_change_output_n].amount)))
# sign all inputs
tx.sign()
print('...the transaction is {} bytes.'.format(tx.size()))
# Finally, do something with the transaction
print('\n*** Step 6. The transaction is built. What would you like to do with it?')
while True:
print('...1. Show JSON')
print('...2. Show HEX')
print('...3. Push (via blockchain.info/pushtx)')
print('...4. Quit')
try:
command = int(input('? ')) - 1
assert command >= 0 and command < 4
if command == 0:
print(json.dumps(tx.as_dict()))
elif command == 1:
print(Bitcoin.bytes_to_hexstring(tx.serialize(), reverse=False))
elif command == 2:
err = push_transaction(tx.serialize())
if isinstance(err, bool):
print("...pushed {}".format(Bitcoin.bytes_to_hexstring(tx.hash())))
else:
print("...error pushing:", err)
elif command == 3:
break
except EOFError:
break
except:
print('Try again.')
pass
print("...exiting")
def main():
message = None
# Parse arguments first
i = 1
while i < len(sys.argv):
v = sys.argv[1]
if v == '-f':
assert message is None, "you can only specify -f once"
i += 1
data = open(sys.argv[i], 'rb').read()
mime_type, encoding = mimetypes.guess_type(sys.argv[i])
if mime_type is not None:
filename = os.path.basename(sys.argv[i])
message = '\n'.join([
'Content-type: {}{}'.format(
mime_type, '; charset={}'.format(encoding)
if encoding is not None else ''),
'Content-length: {}'.format(len(data)),
'Content-disposition: attachment; filename={}'.format(
filename),
])
message = message.encode('utf8') + b'\n\n' + data
i += 1
# Get coins for input
print(
'*** Step 1. We need Bitcoins in order to send a message. Give me a Bitcoin private key (it starts with a 5...) to use as an input for the message transaction.'
)
bitcoin_private_key = input('...Enter Bitcoin private key: ')
# Decode private key, show bitcoin address associated with key
private_key = base58.decode_to_bytes(bitcoin_private_key)[-36:-4]
public_key = addressgen.get_public_key(private_key)
bitcoin_input_address = addressgen.generate_address(public_key, version=0)
print('...The Bitcoin address associated with that private key is: {}'.
format(bitcoin_input_address))
# Lookup the unspent outputs associated with the given input...
print('...Looking up unspent outputs on blockchain.info...')
unspent_outputs = filter_unspent_outputs(
lookup_unspent_outputs([bitcoin_input_address])[bitcoin_input_address])
# Show the inputs to the user, and ask him which he'd like to use as input.
print('\n*** Step 2. You need to select an input:')
for k, u in enumerate(unspent_outputs):
print('...{}: txid={} n={} value={} confirmations={}'.format(
k + 1, u['tx_hash'], u['tx_output_n'],
Bitcoin.format_money(u['value']), u['confirmations']))
selected_inputs = [
int(x.strip()) - 1
for x in input('Enter inputs (if more than one, separated by commas): '
).split(',') if len(x) > 0
]
if not all(x >= 0 and x < len(unspent_outputs) for x in selected_inputs):
raise Exception("Invalid input provided")
total_input_amount = sum(unspent_outputs[k]['value']
for k in selected_inputs)
print('...{} BTC selected from {} input{}'.format(
Bitcoin.format_money(total_input_amount), len(selected_inputs),
's' if len(selected_inputs) != 1 else ''))
# Ask the user for the change address, defaulting to the same input address
print(
'\n*** Step 3. Provide a change address (this will not be used if a change address isn\'t necessary)'
)
bitcoin_change_address = input(
'...Enter change address (leave blank to use the input address as the change address): '
).strip()
if len(bitcoin_change_address) == 0:
bitcoin_change_address = bitcoin_input_address
print('...Change address: {}'.format(bitcoin_change_address))
# Select an encryption method
while True:
print('\n*** Step 4a. Select an encryption method:')
print('...1. None (public message)')
print('...2. RC4')
print('...3. AES-128')
print('...4. AES-256 (best)')
print('...5. RSA (public-key)')
try:
i = int(input('? '))
if i == 1:
encryption_key = b'\x00'
encryption_algorithm = ENCRYPT_NONE
elif i == 2:
required_key_length_message = "RC4 allows for variable-length keys, but longer is better"
encryption_algorithm = ENCRYPT_RC4
elif i == 3:
required_key_length_message = "AES-128 requires a key length of 16 bytes"
encryption_algorithm = ENCRYPT_AES128
elif i == 4:
required_key_length_message = "AES-256 requires a key length of 32 bytes"
encryption_algorithm = ENCRYPT_AES256
elif i == 5:
required_key_length_message = "An RSA public-key is required"
encryption_algorithm = ENCRYPT_RSA
else:
continue
break
except ValueError:
continue
if encryption_algorithm in (ENCRYPT_AES128, ENCRYPT_AES256, ENCRYPT_RC4):
print(
'\n*** Step 4b. Provide an encryption key. The encryption key will be hashed and used as a Bitcoin address to designate the recipient.'
)
encryption_key = input('...Enter an encryption key ({}): '.format(
required_key_length_message)).encode('utf8')
if encryption_algorithm == ENCRYPT_AES128 and len(
encryption_key) != 16:
print('...ERROR: key must have a length of 16 bytes.')
return
elif encryption_algorithm == ENCRYPT_AES256 and len(
encryption_key) != 32:
print('...ERROR: key must have a length of 32 bytes.')
return
elif encryption_algorithm == ENCRYPT_RC4 and len(encryption_key) == 0:
print('...ERROR: key must not be empty')
return
elif encryption_algorithm == ENCRYPT_RSA:
encryption_key = get_random_bytes(32)
encrypted_rsa_encryption_keys = []
while True:
print(
'\n*** Step 4b. Provide the public-key for a recipient (in PEM form):\n'
)
lines = []
while True:
line = input('')
lines.append(line)
if '-----END PUBLIC KEY-----' in line:
break
public_key = load_public_key('\n'.join(lines))
# encrypt encryption key
encrypted_rsa_encryption_key = encrypt(public_key,
encryption_key,
algorithm=ENCRYPT_RSA)
encrypted_rsa_encryption_keys.append(
struct.pack('<H', len(encrypted_rsa_encryption_key)) +
encrypted_rsa_encryption_key)
answer = False
while True:
answer = input(
'...would you like to add another recipient? (y/N) '
).strip().lower()
if answer in ('y', 'yes'):
answer = True
break
if answer in ('n', 'no', ''):
answer = False
break
if not answer:
break
if encryption_algorithm == ENCRYPT_RSA:
bitcoin_delivery_addresses = []
else:
bitcoin_delivery_addresses = [
addressgen.generate_address_from_data(encryption_key, version=0)
]
print('...Message delivery to:')
for bitcoin_delivery_address in bitcoin_delivery_addresses:
print('... {}'.format(bitcoin_delivery_address))
# Now we ask the user to enter a message
if message is None:
print(
'\n*** Step 5. Enter your message. End your message by entering \'.\' by itself on a new line.\n...Enter your message:\n'
)
lines = []
while True:
line = input()
if line == '.':
break
lines.append(line)
message = '\n'.join(lines).encode('utf8')
# Add some temporary headers
message = 'Content-type: text/plain; charset=utf-8\nContent-length: {}\n\n'.format(
len(message)).encode('ascii') + message
# Try compressing the message before encryption, this may waste CPU but it's in the interest
# of saving some outputs in the transaction.
print('...Trying to compress the message...', end='')
compressed_message = gzip.compress(message)
if len(compressed_message) < len(message):
print('good!')
message = compressed_message
encryption_algorithm |= 0x80
else:
print('not using because compressed version is larger.')
# Setup the initialization vector using the first input's transaction id
if (encryption_algorithm & 0x7f) == ENCRYPT_AES128:
first_input = unspent_outputs[selected_inputs[0]]
first_input_tx_hash = Bitcoin.hexstring_to_bytes(
first_input['tx_hash'], reverse=False)
iv = int.from_bytes(first_input_tx_hash, 'big')
iv = (iv % (1 << 128)).to_bytes(16, 'big')
elif (encryption_algorithm & 0x7f) in (ENCRYPT_AES256, ENCRYPT_RSA):
# Bitcoin tx hashes are 32-bytes, so this is still OK for AES-256
first_input = unspent_outputs[selected_inputs[0]]
first_input_tx_hash = Bitcoin.hexstring_to_bytes(
first_input['tx_hash'], reverse=False)
iv = int.from_bytes(first_input_tx_hash, 'big')
iv = (iv % (1 << 256)).to_bytes(32, 'big')
else:
iv = None
# Encrypt the message
if (encryption_algorithm & 0x7f) == ENCRYPT_RSA:
encrypted_message = encrypt(encryption_key,
message,
algorithm=ENCRYPT_AES256,
iv=iv)
else:
encrypted_message = encrypt(encryption_key,
message,
algorithm=(encryption_algorithm & 0x7f),
iv=iv)
# With RSA, the encrypted keys are compressed separately
if (encryption_algorithm & 0x7f) == ENCRYPT_RSA:
print('...Trying to compress the key block...', end='')
encrypted_key_block = b''.join(encrypted_rsa_encryption_keys)
compressed_encrypted_key_block = gzip.compress(encrypted_key_block)
if len(compressed_encrypted_key_block) < len(encrypted_key_block):
print('good!')
encrypted_key_block = b'\x80' + struct.pack(
'<L', len(compressed_encrypted_key_block)
) + compressed_encrypted_key_block
else:
print('not using because compressed version is larger.')
encrypted_key_block = b'\x00' + struct.pack(
'<L', len(encrypted_key_block)) + encrypted_key_block
print('...Encrypted Key Block is {} bytes'.format(
len(encrypted_key_block)))
encrypted_message = encrypted_key_block + encrypted_message
print('...Encrypted message is {} bytes'.format(len(encrypted_message)))
# Build the message header. Prefix the encrypted message with the header.
checksum = sum(encrypted_message) % 256
reserved = 0xff
padding = 0
header = bytes(
[VERSION, encryption_algorithm, checksum, padding, reserved])
encrypted_message = header + encrypted_message
# Split the encrypted message into pubkeys. We get 119 bytes per pubkey (we reserve
# the first byte in case any future changes to bitcoind require a valid pubkey)
bitcoin_message_pieces = []
for i in range(0, len(encrypted_message), PIECE_SIZE[VERSION]):
piece = encrypted_message[i:i + PIECE_SIZE[VERSION]]
bitcoin_message_pieces.append(b'\xff' + piece)
if len(bitcoin_message_pieces) == 1 and len(
bitcoin_message_pieces[0]) < 33:
# This is the only case where we need padding in version 2 messages.
padding = 33 - len(bitcoin_message_pieces[0])
bitcoin_message_pieces[0] = bitcoin_message_pieces[0] + bytes(
[padding] * padding)
# We have to adjust the header 'padding' value
bitcoin_message_pieces[0] = bitcoin_message_pieces[0][:4] + bytes(
[padding]) + bitcoin_message_pieces[0][5:]
elif len(bitcoin_message_pieces) > 1 and len(
bitcoin_message_pieces[-1]) < 33:
# We shift however many bytes out of the 2nd to last block and into the last one
# to make sure it's at least 33 bytes long
req = 33 - len(bitcoin_message_pieces[-1])
bitcoin_message_pieces[-1] = bytes([
bitcoin_message_pieces[-1][0]
]) + bitcoin_message_pieces[-2][-req:] + bitcoin_message_pieces[-1][1:]
bitcoin_message_pieces[-2] = bitcoin_message_pieces[-2][:-req]
assert 120 >= len(bitcoin_message_pieces[-2]) >= 33 and 120 >= len(
bitcoin_message_pieces[-1]) >= 33
# start building the transaction
tx = Transaction()
# setup the inputs
for n, k in enumerate(selected_inputs):
unspent = unspent_outputs[k]
tx_input = TransactionInput(
tx_hash=Bitcoin.hexstring_to_bytes(unspent['tx_hash'],
reverse=False),
tx_output_n=unspent['tx_output_n'],
scriptPubKey=Bitcoin.hexstring_to_bytes(unspent['script'],
reverse=False),
amount=unspent['value'],
signing_key=private_key)
print('...input {} is {} BTC from {}'.format(
n, Bitcoin.format_money(unspent['value']), bitcoin_input_address))
tx.addInput(tx_input)
# setup the outputs. a trigger address isn't really needed, since the encryption
# key can actually be used as the trigger (only those interested will be able to find
# the message, anyway)
# cost of the transaction is (targets + pieces/3 + sacrifice) * SPECIAL_SATOSHI
# peices/3 because we include 3 pieces per output
outputs_count = (len(bitcoin_delivery_addresses) +
math.ceil(len(bitcoin_message_pieces) / 3))
approx_tx_cost = MINIMUM_SACRIFICE + outputs_count * SPECIAL_SATOSHI
if approx_tx_cost > total_input_amount:
raise Exception("not enough inputs provided")
tx_change_output = None
tx_change_output_n = None
if total_input_amount > approx_tx_cost:
print('...output (change) to {}'.format(bitcoin_change_address))
tx_change_output = TransactionOutput(bitcoin_change_address,
amount=total_input_amount -
approx_tx_cost)
tx_change_output_n = tx.addOutput(tx_change_output)
# The recipient will know how to handle this if they see their key...
for i, bitcoin_delivery_address in enumerate(bitcoin_delivery_addresses):
print('...output (target) to {}'.format(bitcoin_delivery_address))
tx_output = TransactionOutput(bitcoin_delivery_address,
amount=SPECIAL_SATOSHI)
tx.addOutput(tx_output)
for i in range(0, len(bitcoin_message_pieces), 3):
pieces = bitcoin_message_pieces[i:i + 3]
d = b''.join([p[1:] for p in pieces])
header = None
if i == 0:
header = d[:5]
d = d[5:]
if (i + 3) >= len(bitcoin_message_pieces):
if padding > 0:
d = d[:-padding]
print('...output (message) to multisig 1-of-{}{}'.format(
len(pieces),
' (header={})'.format(header) if header is not None else ''))
tx_output = TransactionOutput(amount=SPECIAL_SATOSHI)
tx_output.setMultisig(pieces, 1)
tx.addOutput(tx_output)
# we should now be able to figure out how much in fees is required now that the tx is built
recommended_fee = max(
MINIMUM_SACRIFICE * SPECIAL_SATOSHI,
tx.getRecommendedTransactionFee(per_kb=SACRIFICE_PER_KB))
recommended_tx_cost = recommended_fee + outputs_count * SPECIAL_SATOSHI
if recommended_tx_cost > total_input_amount:
raise Exception("not enough inputs provided ({} BTC required)".format(
Bitcoin.format_money(recommended_tx_cost)))
if tx_change_output is not None and recommended_tx_cost == total_input_amount:
# We can remove the output
tx.removeOutput(tx_change_output_n)
tx_change_output = None
if recommended_tx_cost < total_input_amount:
if tx_change_output is None:
print('...output (change) to {}'.format(bitcoin_change_address))
tx_change_output = TransactionOutput(bitcoin_change_address)
tx_change_output_n = tx.addOutput(tx_change_output)
tx_change_output.amount = total_input_amount - recommended_tx_cost
print('...the fee for this transaction is {} BTC'.format(
Bitcoin.format_money(tx.totalInput() - tx.totalOutput())))
print('...the total sent is {} BTC (change = {})'.format(
Bitcoin.format_money(tx.totalInput()),
Bitcoin.format_money(0 if tx_change_output is None else tx.
outputs[tx_change_output_n].amount)))
# sign all inputs
tx.sign()
print('...the transaction is {} bytes.'.format(tx.size()))
# Finally, do something with the transaction
print(
'\n*** Step 6. The transaction is built. What would you like to do with it?'
)
while True:
print('...1. Show JSON')
print('...2. Show HEX')
print('...3. Push (via blockchain.info/pushtx)')
print('...4. Quit')
try:
command = int(input('? ')) - 1
assert command >= 0 and command < 4
if command == 0:
print(json.dumps(tx.as_dict()))
elif command == 1:
print(Bitcoin.bytes_to_hexstring(tx.serialize(),
reverse=False))
elif command == 2:
err = push_transaction(tx.serialize())
if isinstance(err, bool):
print("...pushed {}".format(
Bitcoin.bytes_to_hexstring(tx.hash())))
else:
print("...error pushing:", err)
elif command == 3:
break
except EOFError:
break
except:
print('Try again.')
pass
print("...exiting")