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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.
from pypdf._crypt_providers._base import CryptBase
from pypdf.errors import DependencyError
_DEPENDENCY_ERROR_STR = "cryptography>=3.1 is required for AES algorithm"
crypt_provider = ("local_crypt_fallback", "0.0.0")
class CryptRC4(CryptBase):
def __init__(self, key: bytes) -> None:
self.s = bytearray(range(256))
j = 0
for i in range(256):
j = (j + self.s[i] + key[i % len(key)]) % 256
self.s[i], self.s[j] = self.s[j], self.s[i]
def encrypt(self, data: bytes) -> bytes:
s = bytearray(self.s)
out = [0 for _ in range(len(data))]
i, j = 0, 0
for k in range(len(data)):
i = (i + 1) % 256
j = (j + s[i]) % 256
s[i], s[j] = s[j], s[i]
x = s[(s[i] + s[j]) % 256]
out[k] = data[k] ^ x
return bytes(bytearray(out))
def decrypt(self, data: bytes) -> bytes:
return self.encrypt(data)
class CryptAES(CryptBase):
def __init__(self, key: bytes) -> None:
pass
def encrypt(self, data: bytes) -> bytes:
raise DependencyError(_DEPENDENCY_ERROR_STR)
def decrypt(self, data: bytes) -> bytes:
raise DependencyError(_DEPENDENCY_ERROR_STR)
def rc4_encrypt(key: bytes, data: bytes) -> bytes:
return CryptRC4(key).encrypt(data)
def rc4_decrypt(key: bytes, data: bytes) -> bytes:
return CryptRC4(key).decrypt(data)
def aes_ecb_encrypt(key: bytes, data: bytes) -> bytes:
raise DependencyError(_DEPENDENCY_ERROR_STR)
def aes_ecb_decrypt(key: bytes, data: bytes) -> bytes:
raise DependencyError(_DEPENDENCY_ERROR_STR)
def aes_cbc_encrypt(key: bytes, iv: bytes, data: bytes) -> bytes:
raise DependencyError(_DEPENDENCY_ERROR_STR)
def aes_cbc_decrypt(key: bytes, iv: bytes, data: bytes) -> bytes:
raise DependencyError(_DEPENDENCY_ERROR_STR)
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