bazarr/libs/beaker/crypto/pyca_cryptography.py
2018-09-16 20:33:04 -04:00

52 lines
1.3 KiB
Python

"""Encryption module that uses pyca/cryptography"""
import os
import json
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.ciphers import (
Cipher, algorithms, modes
)
def aesEncrypt(data, key):
# Generate a random 96-bit IV.
iv = os.urandom(12)
# Construct an AES-GCM Cipher object with the given key and a
# randomly generated IV.
encryptor = Cipher(
algorithms.AES(key),
modes.GCM(iv),
backend=default_backend()
).encryptor()
# Encrypt the plaintext and get the associated ciphertext.
# GCM does not require padding.
ciphertext = encryptor.update(data) + encryptor.finalize()
return iv + encryptor.tag + ciphertext
def aesDecrypt(data, key):
iv = data[:12]
tag = data[12:28]
ciphertext = data[28:]
# Construct a Cipher object, with the key, iv, and additionally the
# GCM tag used for authenticating the message.
decryptor = Cipher(
algorithms.AES(key),
modes.GCM(iv, tag),
backend=default_backend()
).decryptor()
# Decryption gets us the authenticated plaintext.
# If the tag does not match an InvalidTag exception will be raised.
return decryptor.update(ciphertext) + decryptor.finalize()
has_aes = True
def getKeyLength():
return 32