mirror of
https://github.com/HACKERALERT/Picocrypt.git
synced 2024-12-28 10:24:19 +00:00
Delete ChaCha20.py
This commit is contained in:
Evan Su
GitHub
parent
03fca971fb
commit
45a9a4a184
1 changed files with 0 additions and 287 deletions
|
|
@ -1,287 +0,0 @@
|
|||
# ===================================================================
|
||||
#
|
||||
# Copyright (c) 2014, Legrandin <helderijs@gmail.com>
|
||||
# All rights reserved.
|
||||
#
|
||||
# Redistribution and use in source and binary forms, with or without
|
||||
# modification, are permitted provided that the following conditions
|
||||
# are met:
|
||||
#
|
||||
# 1. Redistributions of source code must retain the above copyright
|
||||
# notice, this list of conditions and the following disclaimer.
|
||||
# 2. 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.
|
||||
#
|
||||
# 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 HOLDER 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 Crypto.Random import get_random_bytes
|
||||
|
||||
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, c_ulong,
|
||||
is_writeable_buffer)
|
||||
|
||||
_raw_chacha20_lib = load_pycryptodome_raw_lib("Crypto.Cipher._chacha20",
|
||||
"""
|
||||
int chacha20_init(void **pState,
|
||||
const uint8_t *key,
|
||||
size_t keySize,
|
||||
const uint8_t *nonce,
|
||||
size_t nonceSize);
|
||||
|
||||
int chacha20_destroy(void *state);
|
||||
|
||||
int chacha20_encrypt(void *state,
|
||||
const uint8_t in[],
|
||||
uint8_t out[],
|
||||
size_t len);
|
||||
|
||||
int chacha20_seek(void *state,
|
||||
unsigned long block_high,
|
||||
unsigned long block_low,
|
||||
unsigned offset);
|
||||
int hchacha20( const uint8_t key[32],
|
||||
const uint8_t nonce16[16],
|
||||
uint8_t subkey[32]);
|
||||
""")
|
||||
|
||||
|
||||
def _HChaCha20(key, nonce):
|
||||
|
||||
assert(len(key) == 32)
|
||||
assert(len(nonce) == 16)
|
||||
|
||||
subkey = bytearray(32)
|
||||
result = _raw_chacha20_lib.hchacha20(
|
||||
c_uint8_ptr(key),
|
||||
c_uint8_ptr(nonce),
|
||||
c_uint8_ptr(subkey))
|
||||
if result:
|
||||
raise ValueError("Error %d when deriving subkey with HChaCha20" % result)
|
||||
|
||||
return subkey
|
||||
|
||||
|
||||
class ChaCha20Cipher(object):
|
||||
"""ChaCha20 (or XChaCha20) cipher object.
|
||||
Do not create it directly. Use :py:func:`new` instead.
|
||||
|
||||
:var nonce: The nonce with length 8, 12 or 24 bytes
|
||||
:vartype nonce: bytes
|
||||
"""
|
||||
|
||||
block_size = 1
|
||||
|
||||
def __init__(self, key, nonce):
|
||||
"""Initialize a ChaCha20/XChaCha20 cipher object
|
||||
|
||||
See also `new()` at the module level."""
|
||||
|
||||
self.nonce = _copy_bytes(None, None, nonce)
|
||||
|
||||
# XChaCha20 requires a key derivation with HChaCha20
|
||||
# See 2.3 in https://tools.ietf.org/html/draft-arciszewski-xchacha-03
|
||||
if len(nonce) == 24:
|
||||
key = _HChaCha20(key, nonce[:16])
|
||||
nonce = b'\x00' * 4 + nonce[16:]
|
||||
self._name = "XChaCha20"
|
||||
else:
|
||||
self._name = "ChaCha20"
|
||||
nonce = self.nonce
|
||||
|
||||
self._next = ( self.encrypt, self.decrypt )
|
||||
|
||||
self._state = VoidPointer()
|
||||
result = _raw_chacha20_lib.chacha20_init(
|
||||
self._state.address_of(),
|
||||
c_uint8_ptr(key),
|
||||
c_size_t(len(key)),
|
||||
nonce,
|
||||
c_size_t(len(nonce)))
|
||||
if result:
|
||||
raise ValueError("Error %d instantiating a %s cipher" % (result,
|
||||
self._name))
|
||||
self._state = SmartPointer(self._state.get(),
|
||||
_raw_chacha20_lib.chacha20_destroy)
|
||||
|
||||
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 self.encrypt not in self._next:
|
||||
raise TypeError("Cipher object can only be used for decryption")
|
||||
self._next = ( self.encrypt, )
|
||||
return self._encrypt(plaintext, output)
|
||||
|
||||
def _encrypt(self, plaintext, output):
|
||||
"""Encrypt without FSM checks"""
|
||||
|
||||
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_chacha20_lib.chacha20_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 %s" % (result, self._name))
|
||||
|
||||
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``.
|
||||
"""
|
||||
|
||||
if self.decrypt not in self._next:
|
||||
raise TypeError("Cipher object can only be used for encryption")
|
||||
self._next = ( self.decrypt, )
|
||||
|
||||
try:
|
||||
return self._encrypt(ciphertext, output)
|
||||
except ValueError as e:
|
||||
raise ValueError(str(e).replace("enc", "dec"))
|
||||
|
||||
def seek(self, position):
|
||||
"""Seek to a certain position in the key stream.
|
||||
|
||||
Args:
|
||||
position (integer):
|
||||
The absolute position within the key stream, in bytes.
|
||||
"""
|
||||
|
||||
position, offset = divmod(position, 64)
|
||||
block_low = position & 0xFFFFFFFF
|
||||
block_high = position >> 32
|
||||
|
||||
result = _raw_chacha20_lib.chacha20_seek(
|
||||
self._state.get(),
|
||||
c_ulong(block_high),
|
||||
c_ulong(block_low),
|
||||
offset
|
||||
)
|
||||
if result:
|
||||
raise ValueError("Error %d while seeking with %s" % (result, self._name))
|
||||
|
||||
|
||||
def _derive_Poly1305_key_pair(key, nonce):
|
||||
"""Derive a tuple (r, s, nonce) for a Poly1305 MAC.
|
||||
|
||||
If nonce is ``None``, a new 12-byte nonce is generated.
|
||||
"""
|
||||
|
||||
if len(key) != 32:
|
||||
raise ValueError("Poly1305 with ChaCha20 requires a 32-byte key")
|
||||
|
||||
if nonce is None:
|
||||
padded_nonce = nonce = get_random_bytes(12)
|
||||
elif len(nonce) == 8:
|
||||
# See RFC7538, 2.6: [...] ChaCha20 as specified here requires a 96-bit
|
||||
# nonce. So if the provided nonce is only 64-bit, then the first 32
|
||||
# bits of the nonce will be set to a constant number.
|
||||
# This will usually be zero, but for protocols with multiple senders it may be
|
||||
# different for each sender, but should be the same for all
|
||||
# invocations of the function with the same key by a particular
|
||||
# sender.
|
||||
padded_nonce = b'\x00\x00\x00\x00' + nonce
|
||||
elif len(nonce) == 12:
|
||||
padded_nonce = nonce
|
||||
else:
|
||||
raise ValueError("Poly1305 with ChaCha20 requires an 8- or 12-byte nonce")
|
||||
|
||||
rs = new(key=key, nonce=padded_nonce).encrypt(b'\x00' * 32)
|
||||
return rs[:16], rs[16:], nonce
|
||||
|
||||
|
||||
def new(**kwargs):
|
||||
"""Create a new ChaCha20 or XChaCha20 cipher
|
||||
|
||||
Keyword Args:
|
||||
key (bytes/bytearray/memoryview): The secret key to use.
|
||||
It must be 32 bytes long.
|
||||
nonce (bytes/bytearray/memoryview): A mandatory value that
|
||||
must never be reused for any other encryption
|
||||
done with this key.
|
||||
|
||||
For ChaCha20, it must be 8 or 12 bytes long.
|
||||
|
||||
For XChaCha20, it must be 24 bytes long.
|
||||
|
||||
If not provided, 8 bytes will be randomly generated
|
||||
(you can find them back in the ``nonce`` attribute).
|
||||
|
||||
:Return: a :class:`Crypto.Cipher.ChaCha20.ChaCha20Cipher` object
|
||||
"""
|
||||
|
||||
try:
|
||||
key = kwargs.pop("key")
|
||||
except KeyError as e:
|
||||
raise TypeError("Missing parameter %s" % e)
|
||||
|
||||
nonce = kwargs.pop("nonce", None)
|
||||
if nonce is None:
|
||||
nonce = get_random_bytes(8)
|
||||
|
||||
if len(key) != 32:
|
||||
raise ValueError("ChaCha20/XChaCha20 key must be 32 bytes long")
|
||||
|
||||
if len(nonce) not in (8, 12, 24):
|
||||
raise ValueError("Nonce must be 8/12 bytes(ChaCha20) or 24 bytes (XChaCha20)")
|
||||
|
||||
if kwargs:
|
||||
raise TypeError("Unknown parameters: " + str(kwargs))
|
||||
|
||||
return ChaCha20Cipher(key, nonce)
|
||||
|
||||
# Size of a data block (in bytes)
|
||||
block_size = 1
|
||||
|
||||
# Size of a key (in bytes)
|
||||
key_size = 32
|
||||
Loading…
Reference in a new issue