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#!/usr/bin/env python3
#
# Copyright (C) 2015 Peter Todd
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
# WARNING: Do not run this on a wallet with a non-trivial amount of BTC. This
# utility has had very little testing and is being published as a
# proof-of-concept only.
# Requires python-bitcoinlib w/ sendmany support:
#
# https://github.com/petertodd/python-bitcoinlib/commit/6a0a2b9429edea318bea7b65a68a950cae536790
import argparse
import logging
import sys
import os
import bitcoin.rpc
from bitcoin.core import *
from bitcoin.core.script import *
from bitcoin.wallet import *
parser = argparse.ArgumentParser(
description="Publish text in the blockchain, suitably padded for easy recovery with strings",
formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument('-n', action='store_true',
dest='dryrun',
help="Dry-run; don't actually send the transactions")
parser.add_argument("-q","--quiet",action="count",default=0,
help="Be more quiet.")
parser.add_argument("-v","--verbose",action="count",default=0,
help="Be more verbose. Both -v and -q may be used multiple times.")
parser.add_argument("--min-len",action="store",type=int,default=20,
help="Minimum text length; shorter text is padded to this length")
parser.add_argument("-f","--fee-per-kb",action="store",type=float,default=0.0002,
help="Fee-per-KB")
parser.add_argument("-k","--privkey",action="store",type=str,default=None,
help="Specify private key")
net_parser = parser.add_mutually_exclusive_group()
net_parser.add_argument('-t','--testnet', action='store_true',
dest='testnet',
help='Use testnet')
net_parser.add_argument('-r','--regtest', action='store_true',
dest='regtest',
help='Use regtest')
parser.add_argument('fd', type=argparse.FileType('rb'), metavar='FILE',
help='Text file')
args = parser.parse_args()
# Setup logging
args.verbosity = args.verbose - args.quiet
if args.verbosity == 0:
logging.root.setLevel(logging.INFO)
elif args.verbosity >= 1:
logging.root.setLevel(logging.DEBUG)
elif args.verbosity == -1:
logging.root.setLevel(logging.WARNING)
elif args.verbosity <= -2:
logging.root.setLevel(logging.ERROR)
if args.testnet:
bitcoin.SelectParams('testnet')
elif args.regtest:
bitcoin.SelectParams('regtest')
proxy = bitcoin.rpc.Proxy()
if args.privkey is None:
args.privkey = CBitcoinSecret.from_secret_bytes(os.urandom(32))
else:
args.privkey = CBitcoinSecret(args.privkey)
logging.info('Using keypair %s %s' % (b2x(args.privkey.pub), args.privkey))
# Turn the text file into padded lines
if args.fd is sys.stdin:
# work around a bug where even though we specified binary encoding we get
# the sys.stdin instead.
args.fd = sys.stdin.buffer
raw_padded_lines = [b'\x00' + line.rstrip().ljust(args.min_len) + b'\x00' for line in args.fd.readlines()]
# combine lines if < MAX_SCRIPT_ELEMENT_SIZE
padded_lines = []
prev_line = b'\x00'
for line in raw_padded_lines:
if len(prev_line) + len(line) <= MAX_SCRIPT_ELEMENT_SIZE:
prev_line = prev_line + line[1:]
else:
padded_lines.append(prev_line)
prev_line = line
if prev_line:
padded_lines.append(prev_line)
scripts = []
while padded_lines:
def make_scripts(lines, n):
# The n makes sure every p2sh addr is unique; the pubkey lets us
# control the order the vin order vs. just using hashlocks.
redeemScript = []
for chunk in reversed(lines):
if len(chunk) > MAX_SCRIPT_ELEMENT_SIZE:
parser.exit('Lines must be less than %d characters; got %d characters' %\
(MAX_SCRIPT_ELEMENT_SIZE, len(chunk)))
redeemScript.extend([OP_HASH160, Hash160(chunk), OP_EQUALVERIFY])
redeemScript = CScript(redeemScript +
[args.privkey.pub, OP_CHECKSIGVERIFY,
n, OP_DROP, # deduplicate push dropped to meet BIP62 rules
OP_DEPTH, 0, OP_EQUAL]) # prevent scriptSig malleability
return CScript(lines) + redeemScript, redeemScript
scriptSig = redeemScript = None
for i in range(len(padded_lines)):
next_scriptSig, next_redeemScript = make_scripts(padded_lines[0:i+1], len(scripts))
# FIXME: magic numbers!
if len(next_redeemScript) > 520 or len(next_scriptSig) > 1600-100:
padded_lines = padded_lines[i:]
break
else:
scriptSig = next_scriptSig
redeemScript = next_redeemScript
else:
padded_lines = []
scripts.append((scriptSig, redeemScript))
# pay to the redeemScripts to make them spendable
# the 41 accounts for the size of the CTxIn itself
payments = {P2SHBitcoinAddress.from_redeemScript(redeemScript):int(((len(scriptSig)+41)/1000 * args.fee_per_kb)*COIN)
for scriptSig, redeemScript in scripts}
prevouts_by_scriptPubKey = None
if not args.dryrun:
txid = proxy.sendmany('', payments, 0)
logging.info('Sent pre-pub tx: %s' % b2lx(txid))
tx = proxy.getrawtransaction(txid)
prevouts_by_scriptPubKey = {txout.scriptPubKey:COutPoint(txid, i) for i, txout in enumerate(tx.vout)}
else:
prevouts_by_scriptPubKey = {redeemScript.to_p2sh_scriptPubKey():COutPoint(b'\x00'*32, i)
for i, (scriptSig, redeemScript) in enumerate(scripts)}
logging.debug('Payments: %r' % payments)
logging.info('Total cost: %s BTC' % str_money_value(sum(amount for addr, amount in payments.items())))
# Create unsigned tx for SignatureHash
vout = [CTxOut(0, CScript([OP_RETURN]))]
unsigned_vin = []
for scriptSig, redeemScript in scripts:
scriptPubKey = redeemScript.to_p2sh_scriptPubKey()
txin = CTxIn(prevouts_by_scriptPubKey[scriptPubKey])
unsigned_vin.append(txin)
unsigned_tx = CTransaction(unsigned_vin, vout)
# Sign!
signed_vin = []
for i, (scriptSig, redeemScript) in enumerate(scripts):
sighash = SignatureHash(redeemScript, unsigned_tx, i, SIGHASH_NONE)
sig = args.privkey.sign(sighash) + bytes([SIGHASH_NONE])
signed_scriptSig = CScript([sig] + list(scriptSig))
txin = CTxIn(unsigned_vin[i].prevout, signed_scriptSig)
signed_vin.append(txin)
signed_tx = CTransaction(signed_vin, vout)
if args.dryrun:
serialized_tx = signed_tx.serialize()
logging.info('tx size: %d bytes' % len(serialized_tx))
logging.debug('hex: %s' % b2x(serialized_tx))
else:
# FIXME: the tx could be too long here, but there's no way to get sendmany
# to *not* broadcast the transaction first. This is a proof-of-concept, so
# punting.
logging.debug('Sending publish tx, hex: %s' % b2x(signed_tx.serialize()))
txid = proxy.sendrawtransaction(signed_tx)
logging.info('Sent publish tx: %s' % b2lx(txid))
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