moving to scripts

asq-env/lib/python3.9/site-packages/cryptography/hazmat/primitives/cmac.py

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+# 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 import _get_backend
+from cryptography.hazmat.backends.interfaces import Backend, CMACBackend
+from cryptography.hazmat.primitives import ciphers
+
+
+class CMAC(object):
+    def __init__(
+        self,
+        algorithm: ciphers.BlockCipherAlgorithm,
+        backend: typing.Optional[Backend] = None,
+        ctx=None,
+    ):
+        backend = _get_backend(backend)
+        if not isinstance(backend, CMACBackend):
+            raise UnsupportedAlgorithm(
+                "Backend object does not implement CMACBackend.",
+                _Reasons.BACKEND_MISSING_INTERFACE,
+            )
+
+        if not isinstance(algorithm, ciphers.BlockCipherAlgorithm):
+            raise TypeError("Expected instance of BlockCipherAlgorithm.")
+        self._algorithm = algorithm
+
+        self._backend = backend
+        if ctx is None:
+            self._ctx = self._backend.create_cmac_ctx(self._algorithm)
+        else:
+            self._ctx = ctx
+
+    def update(self, data: bytes) -> None:
+        if self._ctx is None:
+            raise AlreadyFinalized("Context was already finalized.")
+
+        utils._check_bytes("data", data)
+        self._ctx.update(data)
+
+    def finalize(self) -> bytes:
+        if self._ctx is None:
+            raise AlreadyFinalized("Context was already finalized.")
+        digest = self._ctx.finalize()
+        self._ctx = None
+        return digest
+
+    def verify(self, signature: bytes) -> None:
+        utils._check_bytes("signature", signature)
+        if self._ctx is None:
+            raise AlreadyFinalized("Context was already finalized.")
+
+        ctx, self._ctx = self._ctx, None
+        ctx.verify(signature)
+
+    def copy(self) -> "CMAC":
+        if self._ctx is None:
+            raise AlreadyFinalized("Context was already finalized.")
+        return CMAC(
+            self._algorithm, backend=self._backend, ctx=self._ctx.copy()
+        )