/usr/lib/python3/dist-packages/cryptography/hazmat/primitives/ciphers/aead.py is in python3-cryptography 2.1.4-1ubuntu1.1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 | # This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function
import os
from cryptography import exceptions, utils
from cryptography.hazmat.backends.openssl import aead
from cryptography.hazmat.backends.openssl.backend import backend
class ChaCha20Poly1305(object):
def __init__(self, key):
if not backend.aead_cipher_supported(self):
raise exceptions.UnsupportedAlgorithm(
"ChaCha20Poly1305 is not supported by this version of OpenSSL",
exceptions._Reasons.UNSUPPORTED_CIPHER
)
utils._check_bytes("key", key)
if len(key) != 32:
raise ValueError("ChaCha20Poly1305 key must be 32 bytes.")
self._key = key
@classmethod
def generate_key(cls):
return os.urandom(32)
def encrypt(self, nonce, data, associated_data):
if associated_data is None:
associated_data = b""
self._check_params(nonce, data, associated_data)
return aead._encrypt(
backend, self, nonce, data, associated_data, 16
)
def decrypt(self, nonce, data, associated_data):
if associated_data is None:
associated_data = b""
self._check_params(nonce, data, associated_data)
return aead._decrypt(
backend, self, nonce, data, associated_data, 16
)
def _check_params(self, nonce, data, associated_data):
utils._check_bytes("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
if len(nonce) != 12:
raise ValueError("Nonce must be 12 bytes")
class AESCCM(object):
def __init__(self, key, tag_length=16):
utils._check_bytes("key", key)
if len(key) not in (16, 24, 32):
raise ValueError("AESCCM key must be 128, 192, or 256 bits.")
self._key = key
if not isinstance(tag_length, int):
raise TypeError("tag_length must be an integer")
if tag_length not in (4, 6, 8, 12, 14, 16):
raise ValueError("Invalid tag_length")
self._tag_length = tag_length
if not backend.aead_cipher_supported(self):
raise exceptions.UnsupportedAlgorithm(
"AESCCM is not supported by this version of OpenSSL",
exceptions._Reasons.UNSUPPORTED_CIPHER
)
@classmethod
def generate_key(cls, bit_length):
if not isinstance(bit_length, int):
raise TypeError("bit_length must be an integer")
if bit_length not in (128, 192, 256):
raise ValueError("bit_length must be 128, 192, or 256")
return os.urandom(bit_length // 8)
def encrypt(self, nonce, data, associated_data):
if associated_data is None:
associated_data = b""
self._check_params(nonce, data, associated_data)
self._validate_lengths(nonce, len(data))
return aead._encrypt(
backend, self, nonce, data, associated_data, self._tag_length
)
def decrypt(self, nonce, data, associated_data):
if associated_data is None:
associated_data = b""
self._check_params(nonce, data, associated_data)
return aead._decrypt(
backend, self, nonce, data, associated_data, self._tag_length
)
def _validate_lengths(self, nonce, data_len):
# For information about computing this, see
# https://tools.ietf.org/html/rfc3610#section-2.1
l_val = 15 - len(nonce)
if 2 ** (8 * l_val) < data_len:
raise ValueError("Nonce too long for data")
def _check_params(self, nonce, data, associated_data):
utils._check_bytes("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
if not 7 <= len(nonce) <= 13:
raise ValueError("Nonce must be between 7 and 13 bytes")
class AESGCM(object):
def __init__(self, key):
utils._check_bytes("key", key)
if len(key) not in (16, 24, 32):
raise ValueError("AESGCM key must be 128, 192, or 256 bits.")
self._key = key
@classmethod
def generate_key(cls, bit_length):
if not isinstance(bit_length, int):
raise TypeError("bit_length must be an integer")
if bit_length not in (128, 192, 256):
raise ValueError("bit_length must be 128, 192, or 256")
return os.urandom(bit_length // 8)
def encrypt(self, nonce, data, associated_data):
if associated_data is None:
associated_data = b""
self._check_params(nonce, data, associated_data)
return aead._encrypt(
backend, self, nonce, data, associated_data, 16
)
def decrypt(self, nonce, data, associated_data):
if associated_data is None:
associated_data = b""
self._check_params(nonce, data, associated_data)
return aead._decrypt(
backend, self, nonce, data, associated_data, 16
)
def _check_params(self, nonce, data, associated_data):
utils._check_bytes("nonce", nonce)
utils._check_bytes("data", data)
utils._check_bytes("associated_data", associated_data)
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