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Add some examples of spending transaction outputs
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‎README‎

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@@ -50,7 +50,11 @@ CBlockHeader, nValue etc. Otherwise Python naming conventions are followed.
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Example Code
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------------
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See examples/ directory.
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See examples/ directory. For instance this example creates a transaction
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spending a pay-to-script-hash transaction output:
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$ PYTHONPATH=. examples/spend-pay-to-script-hash-txout.py
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01000000012db211b32295f7ca3e9cdd9f3f0ea12bd938f8fc62c372f1147882dea35a197e000000006b483045022100a4dc2dcebc908e7ea791f69cf99b55b28e709f37d6da1a9da79cff511e47192f02206bdb1f1a67ff0715510717852e452a12bea0076388ca72ae523e9998f053185a01210378d430274f8c5ec1321338151e9f27f4c676a008bdf8638d07c0b6be9ab35c71ffffffff01a0860100000000001976a91479fbfc3f34e7745860d76137da68f362380c606c88ac00000000
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Selecting the chain to use

‎bitcoin/tests/test_wallet.py‎

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import unittest
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from bitcoin.core import b2x
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from bitcoin.core import b2x, x
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from bitcoin.core.script import CScript
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from bitcoin.wallet import *
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class Test_CBitcoinAddress(unittest.TestCase):
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self.assertEqual(a.nVersion, 196)
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def test_from_scriptPubKey(self):
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def T(hex_scriptpubkey, expected_str_address):
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scriptPubKey = CScript(x(hex_scriptpubkey))
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self.assertEqual(str(CBitcoinAddress.from_scriptPubKey(scriptPubKey)),
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expected_str_address)
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T('a914000000000000000000000000000000000000000087', '31h1vYVSYuKP6AhS86fbRdMw9XHieotbST')
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class Test_CBitcoinSecret(unittest.TestCase):
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def test(self):
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def T(base58_privkey, expected_hex_pubkey, expected_is_compressed_value):

‎bitcoin/wallet.py‎

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from __future__ import absolute_import, division, print_function, unicode_literals
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import sys
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bchr = chr
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bord = ord
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if sys.version > '3':
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long = int
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bchr = lambda x: bytes([x])
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bord = lambda x: x
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import bitcoin
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class CBitcoinAddress(bitcoin.base58.CBase58Data):
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"""A Bitcoin address"""
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@classmethod
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def from_scriptPubKey(cls, scriptPubKey):
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if scriptPubKey.is_p2sh():
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return cls.from_bytes(scriptPubKey[2:22], bitcoin.params.BASE58_PREFIXES['SCRIPT_ADDR'])
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else:
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# FIXME: add pay-to-pubkey-hash
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raise CBitcoinAddressError('scriptPubKey not recognized')
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def to_scriptPubKey(self):
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"""Convert an address to a scriptPubKey"""
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if self.nVersion == bitcoin.params.BASE58_PREFIXES['PUBKEY_ADDR']:
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class CBitcoinSecret(bitcoin.base58.CBase58Data, CKey):
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"""A base58-encoded secret key"""
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@classmethod
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def from_secret_bytes(cls, secret, compressed=True):
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"""Create a secret key from a 32-byte secret"""
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self = cls.from_bytes(secret + b'\x01' if compressed else b'',
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bitcoin.params.BASE58_PREFIXES['SECRET_KEY'])
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self.__init__(None)
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return self
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def __init__(self, s):
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if self.nVersion != bitcoin.params.BASE58_PREFIXES['SECRET_KEY']:
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raise CBitcoinSecretError('Not a base58-encoded secret key: got nVersion=%d; expected nVersion=%d' % \

‎examples/spend-p2sh-txout.py‎

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#!/usr/bin/python3
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# Distributed under the MIT/X11 software license, see the accompanying
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# file COPYING or http://www.opensource.org/licenses/mit-license.php.
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"""Low-level example of how to spend a P2SH/BIP16 txout"""
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import hashlib
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from bitcoin import SelectParams
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from bitcoin.core import b2x, lx, COIN, COutPoint, CTxOut, CTxIn, CTransaction, Hash160
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from bitcoin.core.script import CScript, OP_DUP, OP_HASH160, OP_EQUALVERIFY, OP_CHECKSIG, SignatureHash, SIGHASH_ALL
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from bitcoin.core.scripteval import VerifyScript, SCRIPT_VERIFY_P2SH
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from bitcoin.wallet import CBitcoinAddress, CBitcoinSecret
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SelectParams('mainnet')
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# Create the (in)famous correct brainwallet secret key.
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h = hashlib.sha256(b'correct horse battery staple').digest()
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seckey = CBitcoinSecret.from_secret_bytes(h)
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# Create a redeemScript. Similar to a scriptPubKey the redeemScript must be
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# satisfied for the funds to be spent.
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txin_redeemScript = CScript([seckey.pub, OP_CHECKSIG])
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print(b2x(txin_redeemScript))
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# Create the magic P2SH scriptPubKey format from that redeemScript. You should
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# look at the CScript.to_p2sh_scriptPubKey() function in bitcoin.core.script to
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# understand what's happening, as well as read BIP16:
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# https://github.com/bitcoin/bips/blob/master/bip-0016.mediawiki
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txin_scriptPubKey = txin_redeemScript.to_p2sh_scriptPubKey()
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# Convert the P2SH scriptPubKey to a base58 Bitcoin address and print it.
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# You'll need to send some funds to it to create a txout to spend.
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txin_p2sh_address = CBitcoinAddress.from_scriptPubKey(txin_scriptPubKey)
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print('Pay to:',str(txin_p2sh_address))
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# Same as the txid:vout the createrawtransaction RPC call requires
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#
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# lx() takes *little-endian* hex and converts it to bytes; in Bitcoin
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# transaction hashes are shown little-endian rather than the usual big-endian.
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# There's also a corresponding x() convenience function that takes big-endian
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# hex and converts it to bytes.
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txid = lx('bff785da9f8169f49be92fa95e31f0890c385bfb1bd24d6b94d7900057c617ae')
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vout = 0
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# Create the txin structure, which includes the outpoint. The scriptSig
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# defaults to being empty.
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txin = CTxIn(COutPoint(txid, vout))
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# Create the txout. This time we create the scriptPubKey from a Bitcoin
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# address.
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txout = CTxOut(0.0005*COIN, CBitcoinAddress('323uf9MgLaSn9T7vDaK1cGAZ2qpvYUuqSp').to_scriptPubKey())
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# Create the unsigned transaction.
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tx = CTransaction([txin],[txout])
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# Calculate the signature hash for that transaction. Note how the script we use
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# is the redeemScript, not the scriptPubKey. That's because when the CHECKSIG
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# operation happens EvalScript() will be evaluating the redeemScript, so the
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# corresponding SignatureHash() function will use that same script when it
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# replaces the scriptSig in the transaction being hashed with the script being
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# executed.
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sighash = SignatureHash(txin_redeemScript, tx, 0, SIGHASH_ALL)
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# Now sign it. We have to append the type of signature we want to the end, in
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# this case the usual SIGHASH_ALL.
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sig = seckey.sign(sighash) + bytes([SIGHASH_ALL])
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# Set the scriptSig of our transaction input appropriately.
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txin.scriptSig = CScript([sig, txin_redeemScript])
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# Verify the signature worked. This calls EvalScript() and actually executes
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# the opcodes in the scripts to see if everything worked out. If it doesn't an
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# exception will be raised.
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print(b2x(txin_scriptPubKey))
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VerifyScript(txin.scriptSig, txin_scriptPubKey, tx, 0, (SCRIPT_VERIFY_P2SH,))
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# Done! Print the transaction to standard output with the bytes-to-hex
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# function.
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print(b2x(tx.serialize()))

‎examples/spend-pay-to-script-hash-txout.py‎

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#!/usr/bin/python3
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# Distributed under the MIT/X11 software license, see the accompanying
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# file COPYING or http://www.opensource.org/licenses/mit-license.php.
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"""Low-level example of how to spend a standard pay-to-pubkey-hash txout"""
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import hashlib
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from bitcoin import SelectParams
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from bitcoin.core import b2x, lx, COIN, COutPoint, CTxOut, CTxIn, CTransaction, Hash160
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from bitcoin.core.script import CScript, OP_DUP, OP_HASH160, OP_EQUALVERIFY, OP_CHECKSIG, SignatureHash, SIGHASH_ALL
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from bitcoin.core.scripteval import VerifyScript, SCRIPT_VERIFY_P2SH
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from bitcoin.wallet import CBitcoinAddress, CBitcoinSecret
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SelectParams('mainnet')
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# Create the (in)famous correct brainwallet secret key.
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h = hashlib.sha256(b'correct horse battery staple').digest()
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seckey = CBitcoinSecret.from_secret_bytes(h)
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# Same as the txid:vout the createrawtransaction RPC call requires
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#
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# lx() takes *little-endian* hex and converts it to bytes; in Bitcoin
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# transaction hashes are shown little-endian rather than the usual big-endian.
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# There's also a corresponding x() convenience function that takes big-endian
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# hex and converts it to bytes.
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txid = lx('7e195aa3de827814f172c362fcf838d92ba10e3f9fdd9c3ecaf79522b311b22d')
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vout = 0
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# Create the txin structure, which includes the outpoint. The scriptSig
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# defaults to being empty.
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txin = CTxIn(COutPoint(txid, vout))
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# We also need the scriptPubKey of the output we're spending because
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# SignatureHash() replaces the transaction scriptSig's with it.
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#
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# Here we'll create that scriptPubKey from scratch using the pubkey that
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# corresponds to the secret key we generated above.
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txin_scriptPubKey = CScript([OP_DUP, OP_HASH160, Hash160(seckey.pub), OP_EQUALVERIFY, OP_CHECKSIG])
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# Create the txout. This time we create the scriptPubKey from a Bitcoin
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# address.
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txout = CTxOut(0.001*COIN, CBitcoinAddress('1C7zdTfnkzmr13HfA2vNm5SJYRK6nEKyq8').to_scriptPubKey())
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# Create the unsigned transaction.
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tx = CTransaction([txin],[txout])
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# Calculate the signature hash for that transaction.
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sighash = SignatureHash(txin_scriptPubKey, tx, 0, SIGHASH_ALL)
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# Now sign it. We have to append the type of signature we want to the end, in
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# this case the usual SIGHASH_ALL.
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sig = seckey.sign(sighash) + bytes([SIGHASH_ALL])
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# Set the scriptSig of our transaction input appropriately.
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txin.scriptSig = CScript([sig, seckey.pub])
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# Verify the signature worked. This calls EvalScript() and actually executes
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# the opcodes in the scripts to see if everything worked out. If it doesn't an
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# exception will be raised.
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VerifyScript(txin.scriptSig, txin_scriptPubKey, tx, 0, (SCRIPT_VERIFY_P2SH,))
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# Done! Print the transaction to standard output with the bytes-to-hex
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# function.
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print(b2x(tx.serialize()))

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