# Copyright 2013 Donald Stufft and individual contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
from typing import SupportsBytes, Type, TypeVar
import nacl.bindings
from nacl import encoding
_EncryptedMessage = TypeVar("_EncryptedMessage", bound="EncryptedMessage")
[docs]class EncryptedMessage(bytes):
"""
A bytes subclass that holds a messaged that has been encrypted by a
:class:`SecretBox`.
"""
_nonce: bytes
_ciphertext: bytes
@classmethod
def _from_parts(
cls: Type[_EncryptedMessage],
nonce: bytes,
ciphertext: bytes,
combined: bytes,
) -> _EncryptedMessage:
obj = cls(combined)
obj._nonce = nonce
obj._ciphertext = ciphertext
return obj
@property
def nonce(self) -> bytes:
"""
The nonce used during the encryption of the :class:`EncryptedMessage`.
"""
return self._nonce
@property
def ciphertext(self) -> bytes:
"""
The ciphertext contained within the :class:`EncryptedMessage`.
"""
return self._ciphertext
class StringFixer:
def __str__(self: SupportsBytes) -> str:
return str(self.__bytes__())
def bytes_as_string(bytes_in: bytes) -> str:
return bytes_in.decode("ascii")
[docs]def random(size: int = 32) -> bytes:
return os.urandom(size)
[docs]def randombytes_deterministic(
size: int, seed: bytes, encoder: encoding.Encoder = encoding.RawEncoder
) -> bytes:
"""
Returns ``size`` number of deterministically generated pseudorandom bytes
from a seed
:param size: int
:param seed: bytes
:param encoder: The encoder class used to encode the produced bytes
:rtype: bytes
"""
raw_data = nacl.bindings.randombytes_buf_deterministic(size, seed)
return encoder.encode(raw_data)