/usr/lib/python2.7/dist-packages/nacl/bindings/crypto_secretbox.py is in python-nacl 1.0.1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | # 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.
from __future__ import absolute_import, division, print_function
from nacl._sodium import ffi, lib
from nacl.exceptions import CryptoError
crypto_secretbox_KEYBYTES = lib.crypto_secretbox_keybytes()
crypto_secretbox_NONCEBYTES = lib.crypto_secretbox_noncebytes()
crypto_secretbox_ZEROBYTES = lib.crypto_secretbox_zerobytes()
crypto_secretbox_BOXZEROBYTES = lib.crypto_secretbox_boxzerobytes()
def crypto_secretbox(message, nonce, key):
"""
Encrypts and returns the message ``message`` with the secret ``key`` and
the nonce ``nonce``.
:param message: bytes
:param nonce: bytes
:param key: bytes
:rtype: bytes
"""
if len(key) != crypto_secretbox_KEYBYTES:
raise ValueError("Invalid key")
if len(nonce) != crypto_secretbox_NONCEBYTES:
raise ValueError("Invalid nonce")
padded = b"\x00" * crypto_secretbox_ZEROBYTES + message
ciphertext = ffi.new("unsigned char[]", len(padded))
if lib.crypto_secretbox(ciphertext, padded, len(padded), nonce, key) != 0:
raise CryptoError("Encryption failed")
ciphertext = ffi.buffer(ciphertext, len(padded))
return ciphertext[crypto_secretbox_BOXZEROBYTES:]
def crypto_secretbox_open(ciphertext, nonce, key):
"""
Decrypt and returns the encrypted message ``ciphertext`` with the secret
``key`` and the nonce ``nonce``.
:param ciphertext: bytes
:param nonce: bytes
:param key: bytes
:rtype: bytes
"""
if len(key) != crypto_secretbox_KEYBYTES:
raise ValueError("Invalid key")
if len(nonce) != crypto_secretbox_NONCEBYTES:
raise ValueError("Invalid nonce")
padded = b"\x00" * crypto_secretbox_BOXZEROBYTES + ciphertext
plaintext = ffi.new("unsigned char[]", len(padded))
if lib.crypto_secretbox_open(
plaintext, padded, len(padded), nonce, key) != 0:
raise CryptoError("Decryption failed. Ciphertext failed verification")
plaintext = ffi.buffer(plaintext, len(padded))
return plaintext[crypto_secretbox_ZEROBYTES:]
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