feat(reader): add PDF reading support with outline chapters, CLI blocks, and noise filtering (task 7)

app/vendor/pypdf/_crypt_providers/_pycryptodome.py

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+# Copyright (c) 2023, exiledkingcc
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+# * The name of the author may not be used to endorse or promote products
+# derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+import secrets
+
+from Crypto import __version__
+from Crypto.Cipher import AES, ARC4
+from Crypto.Util.Padding import pad, unpad
+
+from pypdf._crypt_providers._base import CryptBase
+from pypdf._utils import logger_warning
+from pypdf.errors import PdfStreamError
+
+crypt_provider = ("pycryptodome", __version__)
+
+
+class CryptRC4(CryptBase):
+    def __init__(self, key: bytes) -> None:
+        self.key = key
+
+    def encrypt(self, data: bytes) -> bytes:
+        return ARC4.ARC4Cipher(self.key).encrypt(data)
+
+    def decrypt(self, data: bytes, *, strict: bool = True) -> bytes:
+        return ARC4.ARC4Cipher(self.key).decrypt(data)
+
+
+class CryptAES(CryptBase):
+    def __init__(self, key: bytes) -> None:
+        self.key = key
+
+    def encrypt(self, data: bytes) -> bytes:
+        iv = secrets.token_bytes(16)
+        padded_data = pad(data, 16)
+        aes = AES.new(self.key, AES.MODE_CBC, iv)
+        return iv + aes.encrypt(padded_data)
+
+    def decrypt(self, data: bytes, *, strict: bool = True) -> bytes:
+        iv = data[:16]
+        data = data[16:]
+        # for empty encrypted data
+        if not data:
+            return data
+
+        if not strict and len(data) % 16 != 0:
+            logger_warning("Adding missing padding.", source=__name__)
+            data = pad(data, 16)
+
+        aes = AES.new(self.key, AES.MODE_CBC, iv)
+        try:
+            padded_data = aes.decrypt(data)
+        except ValueError as exception:
+            # Only raised in strict mode. Non-strict mode fixes padding.
+            raise PdfStreamError(exception)
+
+        try:
+            return unpad(padded_data, 16)
+        except ValueError as exception:
+            if strict:
+                raise PdfStreamError(exception)
+            logger_warning("Ignoring padding error: %(exception)s", source=__name__, exception=exception)
+            return padded_data[: -padded_data[-1]]
+
+
+def rc4_encrypt(key: bytes, data: bytes) -> bytes:
+    return ARC4.ARC4Cipher(key).encrypt(data)
+
+
+def rc4_decrypt(key: bytes, data: bytes) -> bytes:
+    return ARC4.ARC4Cipher(key).decrypt(data)
+
+
+def aes_ecb_encrypt(key: bytes, data: bytes) -> bytes:
+    return AES.new(key, AES.MODE_ECB).encrypt(data)
+
+
+def aes_ecb_decrypt(key: bytes, data: bytes) -> bytes:
+    return AES.new(key, AES.MODE_ECB).decrypt(data)
+
+
+def aes_cbc_encrypt(key: bytes, iv: bytes, data: bytes) -> bytes:
+    return AES.new(key, AES.MODE_CBC, iv).encrypt(data)
+
+
+def aes_cbc_decrypt(key: bytes, iv: bytes, data: bytes) -> bytes:
+    return AES.new(key, AES.MODE_CBC, iv).decrypt(data)