aboutsummaryrefslogtreecommitdiff
path: root/frozen_deps/Cryptodome/Cipher/ARC4.py
diff options
context:
space:
mode:
Diffstat (limited to 'frozen_deps/Cryptodome/Cipher/ARC4.py')
-rw-r--r--frozen_deps/Cryptodome/Cipher/ARC4.py137
1 files changed, 137 insertions, 0 deletions
diff --git a/frozen_deps/Cryptodome/Cipher/ARC4.py b/frozen_deps/Cryptodome/Cipher/ARC4.py
new file mode 100644
index 0000000..e640e77
--- /dev/null
+++ b/frozen_deps/Cryptodome/Cipher/ARC4.py
@@ -0,0 +1,137 @@
+# -*- coding: utf-8 -*-
+#
+# Cipher/ARC4.py : ARC4
+#
+# ===================================================================
+# The contents of this file are dedicated to the public domain. To
+# the extent that dedication to the public domain is not available,
+# everyone is granted a worldwide, perpetual, royalty-free,
+# non-exclusive license to exercise all rights associated with the
+# contents of this file for any purpose whatsoever.
+# No rights are reserved.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+# ===================================================================
+
+from Cryptodome.Util.py3compat import b
+
+from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib, VoidPointer,
+ create_string_buffer, get_raw_buffer,
+ SmartPointer, c_size_t, c_uint8_ptr)
+
+
+_raw_arc4_lib = load_pycryptodome_raw_lib("Cryptodome.Cipher._ARC4", """
+ int ARC4_stream_encrypt(void *rc4State, const uint8_t in[],
+ uint8_t out[], size_t len);
+ int ARC4_stream_init(uint8_t *key, size_t keylen,
+ void **pRc4State);
+ int ARC4_stream_destroy(void *rc4State);
+ """)
+
+
+class ARC4Cipher:
+ """ARC4 cipher object. Do not create it directly. Use
+ :func:`Cryptodome.Cipher.ARC4.new` instead.
+ """
+
+ def __init__(self, key, *args, **kwargs):
+ """Initialize an ARC4 cipher object
+
+ See also `new()` at the module level."""
+
+ if len(args) > 0:
+ ndrop = args[0]
+ args = args[1:]
+ else:
+ ndrop = kwargs.pop('drop', 0)
+
+ if len(key) not in key_size:
+ raise ValueError("Incorrect ARC4 key length (%d bytes)" %
+ len(key))
+
+ self._state = VoidPointer()
+ result = _raw_arc4_lib.ARC4_stream_init(c_uint8_ptr(key),
+ c_size_t(len(key)),
+ self._state.address_of())
+ if result != 0:
+ raise ValueError("Error %d while creating the ARC4 cipher"
+ % result)
+ self._state = SmartPointer(self._state.get(),
+ _raw_arc4_lib.ARC4_stream_destroy)
+
+ if ndrop > 0:
+ # This is OK even if the cipher is used for decryption,
+ # since encrypt and decrypt are actually the same thing
+ # with ARC4.
+ self.encrypt(b'\x00' * ndrop)
+
+ self.block_size = 1
+ self.key_size = len(key)
+
+ def encrypt(self, plaintext):
+ """Encrypt a piece of data.
+
+ :param plaintext: The data to encrypt, of any size.
+ :type plaintext: bytes, bytearray, memoryview
+ :returns: the encrypted byte string, of equal length as the
+ plaintext.
+ """
+
+ ciphertext = create_string_buffer(len(plaintext))
+ result = _raw_arc4_lib.ARC4_stream_encrypt(self._state.get(),
+ c_uint8_ptr(plaintext),
+ ciphertext,
+ c_size_t(len(plaintext)))
+ if result:
+ raise ValueError("Error %d while encrypting with RC4" % result)
+ return get_raw_buffer(ciphertext)
+
+ def decrypt(self, ciphertext):
+ """Decrypt a piece of data.
+
+ :param ciphertext: The data to decrypt, of any size.
+ :type ciphertext: bytes, bytearray, memoryview
+ :returns: the decrypted byte string, of equal length as the
+ ciphertext.
+ """
+
+ try:
+ return self.encrypt(ciphertext)
+ except ValueError as e:
+ raise ValueError(str(e).replace("enc", "dec"))
+
+
+def new(key, *args, **kwargs):
+ """Create a new ARC4 cipher.
+
+ :param key:
+ The secret key to use in the symmetric cipher.
+ Its length must be in the range ``[5..256]``.
+ The recommended length is 16 bytes.
+ :type key: bytes, bytearray, memoryview
+
+ :Keyword Arguments:
+ * *drop* (``integer``) --
+ The amount of bytes to discard from the initial part of the keystream.
+ In fact, such part has been found to be distinguishable from random
+ data (while it shouldn't) and also correlated to key.
+
+ The recommended value is 3072_ bytes. The default value is 0.
+
+ :Return: an `ARC4Cipher` object
+
+ .. _3072: http://eprint.iacr.org/2002/067.pdf
+ """
+ return ARC4Cipher(key, *args, **kwargs)
+
+# Size of a data block (in bytes)
+block_size = 1
+# Size of a key (in bytes)
+key_size = range(5, 256+1)