84 lines
2.7 KiB
Python
84 lines
2.7 KiB
Python
# (c) Copyright 2020 by Coinkite Inc. This file is covered by license found in COPYING-CC.
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#
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import base64, hashlib
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from psbt import ser_compact_size
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from bech32 import decode
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from constants import AF_CLASSIC, AF_P2WPKH, AF_P2WPKH_P2SH
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from pycoin.encoding import a2b_hashed_base58, hash160
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from pysecp256k1 import ec_pubkey_serialize
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from pysecp256k1.recovery import ecdsa_recover, ecdsa_recoverable_signature_parse_compact
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from pysecp256k1.recovery import ecdsa_sign_recoverable, ecdsa_recoverable_signature_serialize_compact
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RFC_SIGNATURE_TEMPLATE = '''\
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-----BEGIN BITCOIN SIGNED MESSAGE-----
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{msg}
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-----BEGIN BITCOIN SIGNATURE-----
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{addr}
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{sig}
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-----END BITCOIN SIGNATURE-----
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'''
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def sig_hdr_base(addr_fmt):
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if addr_fmt in (AF_CLASSIC, "p2pkh"):
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return 31
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elif addr_fmt in (AF_P2WPKH_P2SH, "p2sh-p2wpkh", "p2wpkh-p2sh"):
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return 35
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elif addr_fmt in (AF_P2WPKH, "p2wpkh"):
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return 39
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else:
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raise ValueError
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def bitcoin_hash_message(msg: bytes):
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s = hashlib.sha256()
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s.update(b'\x18Bitcoin Signed Message:\n')
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msg_len = len(msg)
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s.update(ser_compact_size(msg_len))
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s.update(msg)
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return hashlib.sha256(s.digest()).digest()
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def sign_message(sk, msg, addr_fmt=AF_CLASSIC):
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sig_o = ecdsa_sign_recoverable(sk, bitcoin_hash_message(msg))
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sig_bytes, rec_id = ecdsa_recoverable_signature_serialize_compact(sig_o)
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header_byte = rec_id + sig_hdr_base(addr_fmt=addr_fmt)
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return base64.b64encode(bytes([header_byte]) + sig_bytes).decode().strip()
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def verify_message(address, signature, message):
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script = None
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success = False
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h160 = None
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sig_bytes = base64.b64decode(signature)
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rec_id = (sig_bytes[0] - 27) & 0x03 # least two significant bits
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msg_hash = bitcoin_hash_message(message.encode())
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sig = ecdsa_recoverable_signature_parse_compact(sig_bytes[1:], rec_id)
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pubkey = ecdsa_recover(sig, msg_hash)
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rec_pk = ec_pubkey_serialize(pubkey)
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rec_pk_h160 = hash160(rec_pk)
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if address.startswith(("1", "m", "n")):
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raw = a2b_hashed_base58(address)
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h160 = raw[1:]
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elif address.startswith(("3", "2")):
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raw = a2b_hashed_base58(address)
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script = raw[1:]
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elif address.startswith(("bc1q", "tb1q", "bcrt1q")):
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raw = decode("bcrt" if address[:4] == "bcrt" else address[:2], address)
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if len(raw[1]) != 20:
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raise ValueError("p2wsh")
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h160 = bytes(raw[1])
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else:
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raise ValueError("Unsupported address format")
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if script:
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target = bytes([0, 20]) + rec_pk_h160
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target = hash160(target)
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if target == script:
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success = True
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else:
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if rec_pk_h160 == h160:
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success = True
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return success
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