BIP-137-iffy Signatures

bip137-sig.py

#!/usr/bin/env python3
# [rights]  Copyright brianddk 2019 https://github.com/brianddk
# [license] Licensed under Apache 2.0 https://www.apache.org/licenses/LICENSE-2.0
# [repo]    https://gist.github.com/brianddk/a26344a0f06f64bcd5a102a3bed164de
# [version] Version 0.1
# [lntip]   BTCLN: https://tippin.me/@dkbriand
# [btctip]  bc1qwc2203uym96u0nmq04pcgqfs9ldqz9l3mz8fpj
# [tipjar]  https://gist.github.com/brianddk/3ec16fbf1d008ea290b0
# [msg]     bip137-sig.py get_digest_msg
# [sig]     KKIBghUdYV8Mp1P2d6eyjWTEnuonthYE+M7plxfnzVFoJouFoVzIzOGskBt3G33WhfgnYhkG+OxZggMUdTT+vy8=

usage = """
USAGE: bip137-sig.py [to_type] [sig]  - convert sig to new type
  to_type - "legacy", "p2sh-segwit" or "native-segwit"
  sig     - The base64 encoded signature to change\
"""

from base64 import b64encode, b64decode
from sys import argv, exit
from os import pathsep
from hashlib import sha256

# create a digest of this file, equivalent to the following:
#   grep -v "^#..sig" bip137-sig.py | dos2unix | sha256sum
def get_digest_msg(file):
    lines = []
    with open(file, 'r') as infile:
        for line in infile.readlines():
            lines.append(line)
            if line.startswith("# [sig]"): sig = lines.pop().split()[-1]
            if line.startswith("# [btctip]"): addr = line.split()[-1]
    sha256sum = sha256()
    sha256sum.update(''.join(lines).encode())
    hash = sha256sum.hexdigest()
    return (addr, sig, hash)


# produce the signature for this file as a test
def mk_sig(file, path):
    from trezorlib.ui import ClickUI
    from trezorlib.tools import parse_path
    from trezorlib.btc import get_address, sign_message, verify_message
    from trezorlib.messages import InputScriptType
    from trezorlib.client import TrezorClient
    from trezorlib.transport import get_transport

    addr, sig, msg = get_digest_msg(file)
    device = get_transport()
    client = TrezorClient(transport=device, ui=ClickUI())
    if path == "verify":
        rtn = verify_message(client, "Bitcoin", addr, b64decode(sig), msg)
    else:        
        n, st = (parse_path(path), InputScriptType.SPENDWITNESS)
        parsed = get_address(client, "Bitcoin", n, script_type=st)
        if parsed == addr:
            rtn = sign_message(client, "Bitcoin", n, msg, script_type=st)
            rtn = b64encode(rtn.signature).decode()
        else:
            print("Bad derivation path provided")
            exit(4)
    client.close()
    return rtn


# convert to or from a BIP-0137 signature
def convert_sig(to_type, sig):
    bstr = b64decode(sig)
    hdr = bstr[0]

    types = ["legacy-uncompressed", "legacy", "p2sh-segwit", "native-segwit"]

    if to_type in types:
        to_idx = types.index(to_type)
    else:
        print(usage)
        exit(1)

    if hdr < 27 or hdr > 42:
        print("Bad Sig Header")
        eixt(2)

    recId     = hdr % 27 % 4
    from_idx  = hdr % 27 // 4
    from_type = types[from_idx]

    hdr = 27 + 4 * to_idx + recId

    bstr = bytes([hdr]) + bstr[1:]
    sig = b64encode(bstr)
    print(from_type, "-->", to_type, sig.decode())


if __name__ == '__main__':
    if(len(argv) > 2):
        if argv[1] == "mk_sig":
            print(mk_sig(argv[0], argv[2]))
        else:
            type = argv[1]
            sig = argv[2]
            convert_sig(argv[1], argv[2])
    elif len(argv) > 1 and argv[1] == "get_digest_msg":
        addr, sig, msg = get_digest_msg(argv[0])
        print("\nmsg: ", msg, "\naddr:", addr, "\nsig: ", sig)
        print('\nTREZOR:   trezorctl verify-message "$addr" "$sig" "$msg"')
        print('ELECTRUM: verifymessage("$addr", "$sig", "$msg")')
    else:
        print(usage)
        exit(3)