def createGenesisCoinbase(signblockpubkey):
genesis_coinbase = CTransaction()
coinbaseinput = CTxIn(outpoint=COutPoint(0, 0), nSequence=0xffffffff)
coinbaseinput.scriptSig=CScript([hex_str_to_bytes(signblockpubkey)])
genesis_coinbase.vin.append(coinbaseinput)
coinbaseoutput = CTxOut()
coinbaseoutput.nValue = 50 * COIN
coinbaseoutput.scriptPubKey = CScript([OP_DUP, OP_HASH160, hex_str_to_bytes(signblockpubkey),OP_EQUALVERIFY, OP_CHECKSIG])
genesis_coinbase.vout.append(coinbaseoutput)
genesis_coinbase.calc_sha256()
return genesis_coinbase
def create_var_transaction(spendfrom, custom_script, size_bytes, fee_sats):
# Fund and sign a transaction to a given output, padding it to exactly
# size = size_bytes and providing the given fee.
# spendfrom should be a CTransaction with first output to OP_TRUE.
customout = CTxOut(0, custom_script)
# set output amount to required dust
customout.nValue = (len(customout.serialize()) + 148) * 3
ctx = CTransaction()
ctx.vin.append(CTxIn(COutPoint(spendfrom.sha256, 0), b''))
ctx.vout.append(
CTxOut(spendfrom.vout[0].nValue - customout.nValue - fee_sats,
bytes([OP_TRUE])))
ctx.vout.append(customout)
# two padding outputs
ctx.vout.append(CTxOut(0, b''))
ctx.vout.append(CTxOut(0, b''))
size_without_padding = len(ctx.serialize())
padding_needed = size_bytes - size_without_padding
assert padding_needed >= 0, (size_bytes, size_without_padding)
# Now insert padding. We need to be careful due to the flexible
# var_int size.
if padding_needed > 0xFFFF + 4:
# We can fit all padding in one script.
# 4 extra bytes will be used for var_int
ctx.vout[2].scriptPubKey = bytes([OP_RETURN]) * (padding_needed - 4)
padding_needed = 0
elif padding_needed >= 0xFD + 2:
# We can pad most (probably all) using a script that is between
# 253 and 65535 in length. Probably fit everything in one script.
# 2 extra bytes will be used for var_int
scriptsize = min(padding_needed - 2, 0xFFFF)
ctx.vout[2].scriptPubKey = bytes([OP_RETURN]) * scriptsize
padding_needed -= scriptsize + 2
elif padding_needed >= 0xFD:
# 0xFD or 0xFD+1. We can't pad with just one script, so just
# take off some.
ctx.vout[2].scriptPubKey = bytes([OP_RETURN]) * 50
padding_needed -= 50
# extra padding on another output is needed if original padding_needed
# was <= 0xfd+1, or was 0xffff+3 or 0xffff+4 .
assert padding_needed < 0xfd
ctx.vout[3].scriptPubKey = bytes([OP_RETURN]) * padding_needed
ctx.calc_sha256()
assert_equal(len(ctx.serialize()), size_bytes)
return ctx
def create_transaction(spendfrom, custom_script, amount=None):
# Fund and sign a transaction to a given output.
# spendfrom should be a CTransaction with first output to OP_TRUE.
# custom output will go on position 1, after position 0 which will be
# OP_TRUE (so it can be reused).
customout = CTxOut(0, bytes(custom_script))
# set output amount to required dust if not given
customout.nValue = amount or (len(customout.serialize()) + 148) * 3
ctx = CTransaction()
ctx.vin.append(CTxIn(COutPoint(spendfrom.sha256, 0), b''))
ctx.vout.append(CTxOut(0, bytes([OP_TRUE])))
ctx.vout.append(customout)
pad_tx(ctx)
fee = len(ctx.serialize())
ctx.vout[0].nValue = spendfrom.vout[0].nValue - customout.nValue - fee
ctx.rehash()
return ctx
