Code

Code/venv/lib/python3.13/site-packages/cryptography/hazmat/primitives/padding.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.
+
+from __future__ import annotations
+
+import abc
+
+from cryptography import utils
+from cryptography.hazmat.bindings._rust import (
+    ANSIX923PaddingContext,
+    ANSIX923UnpaddingContext,
+    PKCS7PaddingContext,
+    PKCS7UnpaddingContext,
+)
+
+
+class PaddingContext(metaclass=abc.ABCMeta):
+    @abc.abstractmethod
+    def update(self, data: utils.Buffer) -> bytes:
+        """
+        Pads the provided bytes and returns any available data as bytes.
+        """
+
+    @abc.abstractmethod
+    def finalize(self) -> bytes:
+        """
+        Finalize the padding, returns bytes.
+        """
+
+
+def _byte_padding_check(block_size: int) -> None:
+    if not (0 <= block_size <= 2040):
+        raise ValueError("block_size must be in range(0, 2041).")
+
+    if block_size % 8 != 0:
+        raise ValueError("block_size must be a multiple of 8.")
+
+
+class PKCS7:
+    def __init__(self, block_size: int):
+        _byte_padding_check(block_size)
+        self.block_size = block_size
+
+    def padder(self) -> PaddingContext:
+        return PKCS7PaddingContext(self.block_size)
+
+    def unpadder(self) -> PaddingContext:
+        return PKCS7UnpaddingContext(self.block_size)
+
+
+PaddingContext.register(PKCS7PaddingContext)
+PaddingContext.register(PKCS7UnpaddingContext)
+
+
+class ANSIX923:
+    def __init__(self, block_size: int):
+        _byte_padding_check(block_size)
+        self.block_size = block_size
+
+    def padder(self) -> PaddingContext:
+        return ANSIX923PaddingContext(self.block_size)
+
+    def unpadder(self) -> PaddingContext:
+        return ANSIX923UnpaddingContext(self.block_size)
+
+
+PaddingContext.register(ANSIX923PaddingContext)
+PaddingContext.register(ANSIX923UnpaddingContext)