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txnUtils.py
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txnUtils.py
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# https://pypi.python.org/pypi/ecdsa/0.10
import ecdsa
import hashlib
import struct
import unittest
import utils
import keyUtils
# Makes a transaction from the inputs
# outputs is a list of [redemptionSatoshis, outputScript]
def makeRawTransaction(outputTransactionHash, sourceIndex, scriptSig, outputs):
def makeOutput(data):
redemptionSatoshis, outputScript = data
return (struct.pack("<Q", redemptionSatoshis).encode('hex') +
'%02x' % len(outputScript.decode('hex')) + outputScript)
formattedOutputs = ''.join(map(makeOutput, outputs))
return (
"01000000" + # 4 bytes version
"01" + # varint for number of inputs
outputTransactionHash.decode('hex')[::-1].encode('hex') + # reverse outputTransactionHash
struct.pack('<L', sourceIndex).encode('hex') +
'%02x' % len(scriptSig.decode('hex')) + scriptSig +
"ffffffff" + # sequence
"%02x" % len(outputs) + # number of outputs
formattedOutputs +
"00000000" # lockTime
)
# Returns [first, sig, pub, rest]
def parseTxn(txn):
first = txn[0:41*2]
scriptLen = int(txn[41*2:42*2], 16)
script = txn[42*2:42*2+2*scriptLen]
sigLen = int(script[0:2], 16)
sig = script[2:2+sigLen*2]
pubLen = int(script[2+sigLen*2:2+sigLen*2+2], 16)
pub = script[2+sigLen*2+2:]
assert(len(pub) == pubLen*2)
rest = txn[42*2+2*scriptLen:]
return [first, sig, pub, rest]
# Substitutes the scriptPubKey into the transaction, appends SIGN_ALL to make the version
# of the transaction that can be signed
def getSignableTxn(parsed):
first, sig, pub, rest = parsed
inputAddr = utils.base58CheckDecode(keyUtils.pubKeyToAddr(pub))
return first + "1976a914" + inputAddr.encode('hex') + "88ac" + rest + "01000000"
# Verifies that a transaction is properly signed, assuming the generated scriptPubKey matches
# the one in the previous transaction's output
def verifyTxnSignature(txn):
parsed = parseTxn(txn)
signableTxn = getSignableTxn(parsed)
hashToSign = hashlib.sha256(hashlib.sha256(signableTxn.decode('hex')).digest()).digest().encode('hex')
assert(parsed[1][-2:] == '01') # hashtype
sig = keyUtils.derSigToHexSig(parsed[1][:-2])
public_key = parsed[2]
vk = ecdsa.VerifyingKey.from_string(public_key[2:].decode('hex'), curve=ecdsa.SECP256k1)
assert(vk.verify_digest(sig.decode('hex'), hashToSign.decode('hex')))
def makeSignedTransaction(privateKey, outputTransactionHash, sourceIndex, scriptPubKey, outputs):
myTxn_forSig = (makeRawTransaction(outputTransactionHash, sourceIndex, scriptPubKey, outputs)
+ "01000000") # hash code
s256 = hashlib.sha256(hashlib.sha256(myTxn_forSig.decode('hex')).digest()).digest()
sk = ecdsa.SigningKey.from_string(privateKey.decode('hex'), curve=ecdsa.SECP256k1)
sig = sk.sign_digest(s256, sigencode=ecdsa.util.sigencode_der) + '\01' # 01 is hashtype
pubKey = keyUtils.privateKeyToPublicKey(privateKey)
scriptSig = utils.varstr(sig).encode('hex') + utils.varstr(pubKey.decode('hex')).encode('hex')
signed_txn = makeRawTransaction(outputTransactionHash, sourceIndex, scriptSig, outputs)
verifyTxnSignature(signed_txn)
return signed_txn
class TestTxnUtils(unittest.TestCase):
def test_verifyParseTxn(self):
txn = ("0100000001a97830933769fe33c6155286ffae34db44c6b8783a2d8ca52ebee6414d399ec300000000" +
"8a47" +
"304402202c2e1a746c556546f2c959e92f2d0bd2678274823cc55e11628284e4a13016f80220797e716835f9dbcddb752cd0115a970a022ea6f2d8edafff6e087f928e41baac01" +
"41" +
"04392b964e911955ed50e4e368a9476bc3f9dcc134280e15636430eb91145dab739f0d68b82cf33003379d885a0b212ac95e9cddfd2d391807934d25995468bc55" +
"ffffffff02015f0000000000001976a914c8e90996c7c6080ee06284600c684ed904d14c5c88ac204e000000000000" +
"1976a914348514b329fda7bd33c7b2336cf7cd1fc9544c0588ac00000000")
parsed = parseTxn(txn)
self.assertEqual(parsed[0], "0100000001a97830933769fe33c6155286ffae34db44c6b8783a2d8ca52ebee6414d399ec300000000")
self.assertEqual(parsed[1], "304402202c2e1a746c556546f2c959e92f2d0bd2678274823cc55e11628284e4a13016f80220797e716835f9dbcddb752cd0115a970a022ea6f2d8edafff6e087f928e41baac01")
self.assertEqual(parsed[2], "04392b964e911955ed50e4e368a9476bc3f9dcc134280e15636430eb91145dab739f0d68b82cf33003379d885a0b212ac95e9cddfd2d391807934d25995468bc55")
self.assertEqual(parsed[3], "ffffffff02015f0000000000001976a914c8e90996c7c6080ee06284600c684ed904d14c5c88ac204e000000000000" +
"1976a914348514b329fda7bd33c7b2336cf7cd1fc9544c0588ac00000000")
def test_verifySignableTxn(self):
txn = ("0100000001a97830933769fe33c6155286ffae34db44c6b8783a2d8ca52ebee6414d399ec300000000" +
"8a47" +
"304402202c2e1a746c556546f2c959e92f2d0bd2678274823cc55e11628284e4a13016f80220797e716835f9dbcddb752cd0115a970a022ea6f2d8edafff6e087f928e41baac01" +
"41" +
"04392b964e911955ed50e4e368a9476bc3f9dcc134280e15636430eb91145dab739f0d68b82cf33003379d885a0b212ac95e9cddfd2d391807934d25995468bc55" +
"ffffffff02015f0000000000001976a914c8e90996c7c6080ee06284600c684ed904d14c5c88ac204e000000000000" +
"1976a914348514b329fda7bd33c7b2336cf7cd1fc9544c0588ac00000000")
parsed = parseTxn(txn)
myTxn_forSig = ("0100000001a97830933769fe33c6155286ffae34db44c6b8783a2d8ca52ebee6414d399ec300000000" +
"1976a914" + "167c74f7491fe552ce9e1912810a984355b8ee07" + "88ac" +
"ffffffff02015f0000000000001976a914c8e90996c7c6080ee06284600c684ed904d14c5c88ac204e000000000000" +
"1976a914348514b329fda7bd33c7b2336cf7cd1fc9544c0588ac00000000" +
"01000000")
signableTxn = getSignableTxn(parsed)
self.assertEqual(signableTxn, myTxn_forSig)
def test_verifyTxn(self):
txn = ("0100000001a97830933769fe33c6155286ffae34db44c6b8783a2d8ca52ebee6414d399ec300000000" +
"8a47" +
"304402202c2e1a746c556546f2c959e92f2d0bd2678274823cc55e11628284e4a13016f80220797e716835f9dbcddb752cd0115a970a022ea6f2d8edafff6e087f928e41baac01" +
"41" +
"04392b964e911955ed50e4e368a9476bc3f9dcc134280e15636430eb91145dab739f0d68b82cf33003379d885a0b212ac95e9cddfd2d391807934d25995468bc55" +
"ffffffff02015f0000000000001976a914c8e90996c7c6080ee06284600c684ed904d14c5c88ac204e000000000000" +
"1976a914348514b329fda7bd33c7b2336cf7cd1fc9544c0588ac00000000")
verifyTxnSignature(txn)
def test_makeRawTransaction(self):
#http://bitcoin.stackexchange.com/questions/3374/how-to-redeem-a-basic-tx
txn = makeRawTransaction(
"f2b3eb2deb76566e7324307cd47c35eeb88413f971d88519859b1834307ecfec", # output transaction hash
1, # sourceIndex
"76a914010966776006953d5567439e5e39f86a0d273bee88ac", # scriptSig
[[99900000, #satoshis
"76a914097072524438d003d23a2f23edb65aae1bb3e46988ac"]], # outputScript
) + "01000000" # hash code type
self.assertEqual(txn,
"0100000001eccf7e3034189b851985d871f91384b8ee357cd47c3024736e5676eb2debb3f2" +
"010000001976a914010966776006953d5567439e5e39f86a0d273bee88acffffffff" +
"01605af405000000001976a914097072524438d003d23a2f23edb65aae1bb3e46988ac" +
"0000000001000000")
def test_makeSignedTransaction(self):
# Transaction from
# https://blockchain.info/tx/901a53e7a3ca96ed0b733c0233aad15f11b0c9e436294aa30c367bf06c3b7be8
# From 133t to 1KKKK
privateKey = keyUtils.wifToPrivateKey("5Kb6aGpijtrb8X28GzmWtbcGZCG8jHQWFJcWugqo3MwKRvC8zyu") #133t
signed_txn = makeSignedTransaction(privateKey,
"c39e394d41e6be2ea58c2d3a78b8c644db34aeff865215c633fe6937933078a9", # output (prev) transaction hash
0, # sourceIndex
keyUtils.addrHashToScriptPubKey("133txdxQmwECTmXqAr9RWNHnzQ175jGb7e"),
[[24321, #satoshis
keyUtils.addrHashToScriptPubKey("1KKKK6N21XKo48zWKuQKXdvSsCf95ibHFa")],
[20000, keyUtils.addrHashToScriptPubKey("15nhZbXnLMknZACbb3Jrf1wPCD9DWAcqd7")]]
)
verifyTxnSignature(signed_txn)
if __name__ == '__main__':
unittest.main()