usse/funda-scraper/venv/lib/python3.10/site-packages/cryptography/hazmat/primitives/poly1305.py

61 lines
1.8 KiB
Python

# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
import typing
from cryptography import utils
from cryptography.exceptions import (
AlreadyFinalized,
UnsupportedAlgorithm,
_Reasons,
)
from cryptography.hazmat.backends.openssl.poly1305 import _Poly1305Context
class Poly1305:
_ctx: typing.Optional[_Poly1305Context]
def __init__(self, key: bytes):
from cryptography.hazmat.backends.openssl.backend import backend
if not backend.poly1305_supported():
raise UnsupportedAlgorithm(
"poly1305 is not supported by this version of OpenSSL.",
_Reasons.UNSUPPORTED_MAC,
)
self._ctx = backend.create_poly1305_ctx(key)
def update(self, data: bytes) -> None:
if self._ctx is None:
raise AlreadyFinalized("Context was already finalized.")
utils._check_byteslike("data", data)
self._ctx.update(data)
def finalize(self) -> bytes:
if self._ctx is None:
raise AlreadyFinalized("Context was already finalized.")
mac = self._ctx.finalize()
self._ctx = None
return mac
def verify(self, tag: bytes) -> None:
utils._check_bytes("tag", tag)
if self._ctx is None:
raise AlreadyFinalized("Context was already finalized.")
ctx, self._ctx = self._ctx, None
ctx.verify(tag)
@classmethod
def generate_tag(cls, key: bytes, data: bytes) -> bytes:
p = Poly1305(key)
p.update(data)
return p.finalize()
@classmethod
def verify_tag(cls, key: bytes, data: bytes, tag: bytes) -> None:
p = Poly1305(key)
p.update(data)
p.verify(tag)