slight update
This commit is contained in:
167
week05/easy/env/lib/python3.12/site-packages/Crypto/Cipher/Salsa20.py
vendored
Normal file
167
week05/easy/env/lib/python3.12/site-packages/Crypto/Cipher/Salsa20.py
vendored
Normal file
@ -0,0 +1,167 @@
|
||||
# -*- coding: utf-8 -*-
|
||||
#
|
||||
# Cipher/Salsa20.py : Salsa20 stream cipher (http://cr.yp.to/snuffle.html)
|
||||
#
|
||||
# Contributed by Fabrizio Tarizzo <fabrizio@fabriziotarizzo.org>.
|
||||
#
|
||||
# ===================================================================
|
||||
# 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 Crypto.Util.py3compat import _copy_bytes
|
||||
from Crypto.Util._raw_api import (load_pycryptodome_raw_lib,
|
||||
create_string_buffer,
|
||||
get_raw_buffer, VoidPointer,
|
||||
SmartPointer, c_size_t,
|
||||
c_uint8_ptr, is_writeable_buffer)
|
||||
|
||||
from Crypto.Random import get_random_bytes
|
||||
|
||||
_raw_salsa20_lib = load_pycryptodome_raw_lib("Crypto.Cipher._Salsa20",
|
||||
"""
|
||||
int Salsa20_stream_init(uint8_t *key, size_t keylen,
|
||||
uint8_t *nonce, size_t nonce_len,
|
||||
void **pSalsaState);
|
||||
int Salsa20_stream_destroy(void *salsaState);
|
||||
int Salsa20_stream_encrypt(void *salsaState,
|
||||
const uint8_t in[],
|
||||
uint8_t out[], size_t len);
|
||||
""")
|
||||
|
||||
|
||||
class Salsa20Cipher:
|
||||
"""Salsa20 cipher object. Do not create it directly. Use :py:func:`new`
|
||||
instead.
|
||||
|
||||
:var nonce: The nonce with length 8
|
||||
:vartype nonce: byte string
|
||||
"""
|
||||
|
||||
def __init__(self, key, nonce):
|
||||
"""Initialize a Salsa20 cipher object
|
||||
|
||||
See also `new()` at the module level."""
|
||||
|
||||
if len(key) not in key_size:
|
||||
raise ValueError("Incorrect key length for Salsa20 (%d bytes)" % len(key))
|
||||
|
||||
if len(nonce) != 8:
|
||||
raise ValueError("Incorrect nonce length for Salsa20 (%d bytes)" %
|
||||
len(nonce))
|
||||
|
||||
self.nonce = _copy_bytes(None, None, nonce)
|
||||
|
||||
self._state = VoidPointer()
|
||||
result = _raw_salsa20_lib.Salsa20_stream_init(
|
||||
c_uint8_ptr(key),
|
||||
c_size_t(len(key)),
|
||||
c_uint8_ptr(nonce),
|
||||
c_size_t(len(nonce)),
|
||||
self._state.address_of())
|
||||
if result:
|
||||
raise ValueError("Error %d instantiating a Salsa20 cipher")
|
||||
self._state = SmartPointer(self._state.get(),
|
||||
_raw_salsa20_lib.Salsa20_stream_destroy)
|
||||
|
||||
self.block_size = 1
|
||||
self.key_size = len(key)
|
||||
|
||||
def encrypt(self, plaintext, output=None):
|
||||
"""Encrypt a piece of data.
|
||||
|
||||
Args:
|
||||
plaintext(bytes/bytearray/memoryview): The data to encrypt, of any size.
|
||||
Keyword Args:
|
||||
output(bytes/bytearray/memoryview): The location where the ciphertext
|
||||
is written to. If ``None``, the ciphertext is returned.
|
||||
Returns:
|
||||
If ``output`` is ``None``, the ciphertext is returned as ``bytes``.
|
||||
Otherwise, ``None``.
|
||||
"""
|
||||
|
||||
if output is None:
|
||||
ciphertext = create_string_buffer(len(plaintext))
|
||||
else:
|
||||
ciphertext = output
|
||||
|
||||
if not is_writeable_buffer(output):
|
||||
raise TypeError("output must be a bytearray or a writeable memoryview")
|
||||
|
||||
if len(plaintext) != len(output):
|
||||
raise ValueError("output must have the same length as the input"
|
||||
" (%d bytes)" % len(plaintext))
|
||||
|
||||
result = _raw_salsa20_lib.Salsa20_stream_encrypt(
|
||||
self._state.get(),
|
||||
c_uint8_ptr(plaintext),
|
||||
c_uint8_ptr(ciphertext),
|
||||
c_size_t(len(plaintext)))
|
||||
if result:
|
||||
raise ValueError("Error %d while encrypting with Salsa20" % result)
|
||||
|
||||
if output is None:
|
||||
return get_raw_buffer(ciphertext)
|
||||
else:
|
||||
return None
|
||||
|
||||
def decrypt(self, ciphertext, output=None):
|
||||
"""Decrypt a piece of data.
|
||||
|
||||
Args:
|
||||
ciphertext(bytes/bytearray/memoryview): The data to decrypt, of any size.
|
||||
Keyword Args:
|
||||
output(bytes/bytearray/memoryview): The location where the plaintext
|
||||
is written to. If ``None``, the plaintext is returned.
|
||||
Returns:
|
||||
If ``output`` is ``None``, the plaintext is returned as ``bytes``.
|
||||
Otherwise, ``None``.
|
||||
"""
|
||||
|
||||
try:
|
||||
return self.encrypt(ciphertext, output=output)
|
||||
except ValueError as e:
|
||||
raise ValueError(str(e).replace("enc", "dec"))
|
||||
|
||||
|
||||
def new(key, nonce=None):
|
||||
"""Create a new Salsa20 cipher
|
||||
|
||||
:keyword key: The secret key to use. It must be 16 or 32 bytes long.
|
||||
:type key: bytes/bytearray/memoryview
|
||||
|
||||
:keyword nonce:
|
||||
A value that must never be reused for any other encryption
|
||||
done with this key. It must be 8 bytes long.
|
||||
|
||||
If not provided, a random byte string will be generated (you can read
|
||||
it back via the ``nonce`` attribute of the returned object).
|
||||
:type nonce: bytes/bytearray/memoryview
|
||||
|
||||
:Return: a :class:`Crypto.Cipher.Salsa20.Salsa20Cipher` object
|
||||
"""
|
||||
|
||||
if nonce is None:
|
||||
nonce = get_random_bytes(8)
|
||||
|
||||
return Salsa20Cipher(key, nonce)
|
||||
|
||||
# Size of a data block (in bytes)
|
||||
block_size = 1
|
||||
|
||||
# Size of a key (in bytes)
|
||||
key_size = (16, 32)
|
||||
|
Reference in New Issue
Block a user