Barebones Python 3.6+ implementation (no dependencies/standard lib only) of some common cryptographic functions for educational purposes. Feel free to fork the repo and play around with it. Performance is ..abysmal but otherwise it works fine. Please do not use this for anything serious because I am not a security expert.
$ pip install git+https://github.com/mcdallas/cryptotools.git@master#egg=cryptotools
HD Wallets
from cryptotools.BTC import Xprv
>>> m = Xprv.from_mnemonic('impulse prize erode winner pupil fun off addict ...')
>>> m.encode()
'xprv9s21ZrQH143K38bNJiHY54kkjio8o6aw3bRjCbzi8KgRxNy98avUribz1wk85ToSUV2VwVuc73NJWc2YGwpMtqz7bBFUh9Q77RtJeuh2zvy'
>>> m/44/0/0/0
Xprv(path=m/44/0/0/0, key=L1WKXyMwKnp8wPwAtjwiKWunACY5RSUXAzmS6jDRRHcHnDbeRiKu)
>>> m/0./123/5. # Use floats for hardened path, alternative is // e.g m//0/123//5
Xprv(path=m/0h/123/5h, key=L3qskbdzgNu4kwjx2QU63q59khpEHVaSbqd2Pc268Jngiha6mbfQ)
>>> M = m.to_xpub()
>>> (m/123/456).to_xpub() == M/123/456
True
>>> (m/44./0./0./0/0).address('P2PKH') # bip44
'1BTYXdyrBh1yRCDpqyDhoQG896bnzqtaPz'
>>> (m/84./0./0./0/0).address('P2WPKH') # bip84
'bc1qjnx8cq32z2t72tsmuwql3wz22lywlpcm3w52lk'
BIP39 checksum
Say you lost the first of your 12 mnemonic words and you want to filter out the possible mnemonics from 2048 to 128 by veryfing the checksum
from cryptotools.BTC.HD import check, WORDS
phrase = "{x} decrease enjoy credit fold prepare school midnight flower wrong false already"
for word in WORDS:
mnemonic = phrase.format(x=word)
if check(mnemonic):
print(mnemonic)
Sign/Verify message:
import secrets
from cryptotools.ECDSA.secp256k1 import generate_keypair, Message
private, public = generate_keypair()
>>> message = Message(secrets.token_bytes(32))
>>> sig1 = message.sign(private) # ECDSA
>>> sig2 = message.sign_schnorr(private) # Schnorr
>>> message.verify(sig1, public)
True
>>> message.verify(sig2, public)
True
Verify a transaction:
from cryptotools.BTC import Transaction
tx = Transaction.get('454e575aa1ed4427985a9732d753b37dc711675eb7c977637b1eea7f600ed214')
>>> tx
Transaction(inputs=1, outputs=2)
>>> tx.outputs
[Output(type=P2SH, value=0.0266 BTC),
Output(type=P2WSH, value=0.00468 BTC)]
>>> tx.verify() # this runs the bitcoin script
True
Create a transaction and submit it automatically
import os
os.environ['CRYPTOTOOLS_NETWORK'] = 'test' # sets network to testnet (before library import)
from cryptotools.BTC import PrivateKey, send
key = PrivateKey.from_hex('mysupersecretkey')
>>> send(source='n4SbPWR6EmQMsWaQVYYFXiJgjweGKE4XnQ', to={'n2NGrooSecJaiD6ssp4YqFoj9eZ7GrCJ66': 0.46}, fee=0.01, private=key)
'907b92969cb3a16ddb45591bf2530f177b7f10cef4e62c331596a84f66c3b8c3' # txid
Create and broadcast manually
import os
os.environ['CRYPTOTOOLS_NETWORK'] = 'test'
from cryptotools.BTC import PrivateKey, Address
private = PrivateKey.from_hex('mysupersecretkey')
address = Address('n2NGrooSecJaiD6ssp4YqFoj9eZ7GrCJ66')
>>> address.balance()
0.55
>>> send_to = {'n4SbPWR6EmQMsWaQVYYFXiJgjweGKE4XnQ': 0.1, 'n2NGrooSecJaiD6ssp4YqFoj9eZ7GrCJ66': 0.4}
>>> tx = address.send(to=send_to, fee=0.05, private=private)
>>> tx
Transaction(inputs=1, outputs=2)
>>> tx.inputs[0].is_signed()
True
>>> tx.verify() # Make sure transaction is valid before broadcasting
True
>>> tx.broadcast()
'Transaction Submitted'
Create keys/addresses (including segwit)
from cryptotools.BTC import generate_keypair, push, script_to_address, OP
private, public = generate_keypair()
>>> private.hex()
'de4f177274d29f88a5805333e10525f5dd41634455dfadc8849b977802481ccd'
>>> private.wif(compressed=False)
'5KWCAYLo35uZ9ibPTzTUDXESTE6ne8p1eXviYMHwaoS4tpvYCAp'
>>> public.hex()
'047e30fd478b44869850352daef8f5f7a7b5233044018d465431afdc0b436c973e8df1244189d25ae73d90c90cc0f998eb9784adecaecc46e8c536d7d6845fa26e'
>>> public.to_address('P2PKH')
'19dFXDxiD4KrUTNFfcgeekFpQmUC553GzW'
# Simple <key> <OP_CHECKSIG> script
>>> script = push(public.encode(compressed=True)) + OP.CHECKSIG.byte
>>> script_to_address(script, 'P2WSH')
'bc1q8yh8l8ft3220q328hlapqhflpzy6xvkq6u36mctk8gq5pyxm3rwqv5h5dg'
# nested P2WSH into P2SH -- use with caution
>>> script_to_address(script, 'P2WSH-P2SH')
'34eBzenHJEdk5PK9ojuuBZvCRtNhvvysYZ'
from cryptotools.ECDSA.secp256k1 import CURVE, PrivateKey
private = PrivateKey.random()
>>> private.int()
8034465994996476238286561766373949549982328752707977290709076444881813294372
>>> public = private.to_public()
>>> public
PublicKey(102868560361119050321154887315228169307787313299675114268359376451780341556078, 83001804479408277471207716276761041184203185393579361784723900699449806360826)
>>> public.point in CURVE
True
>>> public.to_address('P2WPKH')
'bc1qh2egksgfejqpktc3kkdtuqqrukrpzzp9lr0phn'
By default the library communicates with the bitcoin network (for fetching transactions) via a block explorer but as an alternative you can use a bitcoin node via it's RPC interface. Just set the following enviromental variables
CRYPTOTOOLS_BACKEND=rpc
CRYPTOTOOLS_BACKEND=localhost
CRYPTOTOOLS_RPC_PORT=8332
and optionally
CRYPTOTOOLS_RPC_USER=myuser
CRYPTOTOOLS_RPC_PW=mypassword
to switch the network to Testnet set
CRYPTOTOOLS_NETWORK=test
to run tests
$ python -m unittest
from the project directory