jrnl/jrnl/encryption/Jrnlv1Encryption.py
2022-11-05 16:01:09 -07:00

41 lines
1.6 KiB
Python

# Copyright © 2012-2022 jrnl contributors
# License: https://www.gnu.org/licenses/gpl-3.0.html
import hashlib
import logging
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import padding
from cryptography.hazmat.primitives.ciphers import Cipher
from cryptography.hazmat.primitives.ciphers import algorithms
from cryptography.hazmat.primitives.ciphers import modes
from jrnl.encryption.BasePasswordEncryption import BasePasswordEncryption
class Jrnlv1Encryption(BasePasswordEncryption):
def __init__(self, *args, **kwargs) -> None:
super().__init__(*args, **kwargs)
logging.debug("start")
def _encrypt(self, _: str) -> bytes:
raise NotImplementedError
def _decrypt(self, text: bytes) -> str | None:
logging.debug("decrypting")
iv, cipher = text[:16], text[16:]
password = self._password or ""
decryption_key = hashlib.sha256(password.encode(self._encoding)).digest()
decryptor = Cipher(
algorithms.AES(decryption_key), modes.CBC(iv), default_backend()
).decryptor()
try:
plain_padded = decryptor.update(cipher) + decryptor.finalize()
if plain_padded[-1] in (" ", 32):
# Ancient versions of jrnl. Do not judge me.
return plain_padded.decode(self._encoding).rstrip(" ")
else:
unpadder = padding.PKCS7(algorithms.AES.block_size).unpadder()
plain = unpadder.update(plain_padded) + unpadder.finalize()
return plain.decode(self._encoding)
except ValueError:
return None