mirror of
https://github.com/PiBrewing/craftbeerpi4.git
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174 lines
6 KiB
Python
174 lines
6 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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from __future__ import absolute_import, division, print_function
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import os
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from cryptography import exceptions, utils
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from cryptography.hazmat.backends.openssl import aead
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from cryptography.hazmat.backends.openssl.backend import backend
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class ChaCha20Poly1305(object):
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_MAX_SIZE = 2 ** 32
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def __init__(self, key):
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if not backend.aead_cipher_supported(self):
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raise exceptions.UnsupportedAlgorithm(
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"ChaCha20Poly1305 is not supported by this version of OpenSSL",
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exceptions._Reasons.UNSUPPORTED_CIPHER,
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)
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utils._check_byteslike("key", key)
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if len(key) != 32:
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raise ValueError("ChaCha20Poly1305 key must be 32 bytes.")
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self._key = key
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@classmethod
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def generate_key(cls):
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return os.urandom(32)
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def encrypt(self, nonce, data, associated_data):
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if associated_data is None:
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associated_data = b""
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if len(data) > self._MAX_SIZE or len(associated_data) > self._MAX_SIZE:
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# This is OverflowError to match what cffi would raise
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raise OverflowError(
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"Data or associated data too long. Max 2**32 bytes"
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)
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self._check_params(nonce, data, associated_data)
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return aead._encrypt(backend, self, nonce, data, associated_data, 16)
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def decrypt(self, nonce, data, associated_data):
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if associated_data is None:
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associated_data = b""
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self._check_params(nonce, data, associated_data)
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return aead._decrypt(backend, self, nonce, data, associated_data, 16)
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def _check_params(self, nonce, data, associated_data):
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utils._check_byteslike("nonce", nonce)
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utils._check_bytes("data", data)
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utils._check_bytes("associated_data", associated_data)
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if len(nonce) != 12:
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raise ValueError("Nonce must be 12 bytes")
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class AESCCM(object):
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_MAX_SIZE = 2 ** 32
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def __init__(self, key, tag_length=16):
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utils._check_byteslike("key", key)
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if len(key) not in (16, 24, 32):
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raise ValueError("AESCCM key must be 128, 192, or 256 bits.")
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self._key = key
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if not isinstance(tag_length, int):
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raise TypeError("tag_length must be an integer")
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if tag_length not in (4, 6, 8, 10, 12, 14, 16):
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raise ValueError("Invalid tag_length")
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self._tag_length = tag_length
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@classmethod
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def generate_key(cls, bit_length):
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if not isinstance(bit_length, int):
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raise TypeError("bit_length must be an integer")
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if bit_length not in (128, 192, 256):
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raise ValueError("bit_length must be 128, 192, or 256")
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return os.urandom(bit_length // 8)
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def encrypt(self, nonce, data, associated_data):
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if associated_data is None:
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associated_data = b""
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if len(data) > self._MAX_SIZE or len(associated_data) > self._MAX_SIZE:
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# This is OverflowError to match what cffi would raise
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raise OverflowError(
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"Data or associated data too long. Max 2**32 bytes"
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)
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self._check_params(nonce, data, associated_data)
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self._validate_lengths(nonce, len(data))
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return aead._encrypt(
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backend, self, nonce, data, associated_data, self._tag_length
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)
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def decrypt(self, nonce, data, associated_data):
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if associated_data is None:
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associated_data = b""
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self._check_params(nonce, data, associated_data)
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return aead._decrypt(
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backend, self, nonce, data, associated_data, self._tag_length
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)
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def _validate_lengths(self, nonce, data_len):
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# For information about computing this, see
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# https://tools.ietf.org/html/rfc3610#section-2.1
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l_val = 15 - len(nonce)
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if 2 ** (8 * l_val) < data_len:
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raise ValueError("Data too long for nonce")
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def _check_params(self, nonce, data, associated_data):
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utils._check_byteslike("nonce", nonce)
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utils._check_bytes("data", data)
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utils._check_bytes("associated_data", associated_data)
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if not 7 <= len(nonce) <= 13:
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raise ValueError("Nonce must be between 7 and 13 bytes")
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class AESGCM(object):
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_MAX_SIZE = 2 ** 32
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def __init__(self, key):
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utils._check_byteslike("key", key)
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if len(key) not in (16, 24, 32):
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raise ValueError("AESGCM key must be 128, 192, or 256 bits.")
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self._key = key
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@classmethod
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def generate_key(cls, bit_length):
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if not isinstance(bit_length, int):
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raise TypeError("bit_length must be an integer")
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if bit_length not in (128, 192, 256):
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raise ValueError("bit_length must be 128, 192, or 256")
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return os.urandom(bit_length // 8)
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def encrypt(self, nonce, data, associated_data):
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if associated_data is None:
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associated_data = b""
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if len(data) > self._MAX_SIZE or len(associated_data) > self._MAX_SIZE:
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# This is OverflowError to match what cffi would raise
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raise OverflowError(
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"Data or associated data too long. Max 2**32 bytes"
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)
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self._check_params(nonce, data, associated_data)
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return aead._encrypt(backend, self, nonce, data, associated_data, 16)
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def decrypt(self, nonce, data, associated_data):
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if associated_data is None:
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associated_data = b""
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self._check_params(nonce, data, associated_data)
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return aead._decrypt(backend, self, nonce, data, associated_data, 16)
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def _check_params(self, nonce, data, associated_data):
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utils._check_byteslike("nonce", nonce)
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utils._check_bytes("data", data)
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utils._check_bytes("associated_data", associated_data)
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if len(nonce) < 8 or len(nonce) > 128:
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raise ValueError("Nonce must be between 8 and 128 bytes")
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