| |
| import base64 |
| from nacl.signing import VerifyKey |
| from nacl.exceptions import BadSignatureError |
|
|
| MESSAGE_PREFIX = "CHECKIN:" |
|
|
| class SignatureError(Exception): |
| pass |
|
|
| |
| _ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz" |
| _INDEXES = {c: i for i, c in enumerate(_ALPHABET)} |
|
|
| def _b58decode(s: str) -> bytes: |
| if not s: |
| return b"" |
| num = 0 |
| for ch in s: |
| try: |
| num = num * 58 + _INDEXES[ch] |
| except KeyError: |
| raise ValueError("invalid base58 character") from None |
| |
| if num == 0: |
| full = b"\x00" |
| else: |
| byte_len = (num.bit_length() + 7) // 8 |
| full = num.to_bytes(byte_len, "big") |
| |
| pad = len(s) - len(s.lstrip("1")) |
| return b"\x00" * pad + full.lstrip(b"\x00") |
|
|
| def verify_signature(address_base58: str, signature_b64: str, message: str) -> None: |
| try: |
| pubkey_bytes = _b58decode(address_base58) |
| sig_bytes = base64.b64decode(signature_b64) |
| vk = VerifyKey(pubkey_bytes) |
| vk.verify(message.encode("utf-8"), sig_bytes) |
| except (ValueError, BadSignatureError) as e: |
| raise SignatureError(str(e)) |
|
|
