mirror of
https://github.com/jrnl-org/jrnl.git
synced 2025-05-10 08:38:32 +02:00
29234ddc35
* updated README.md: - corrected information about encryption - made additions based on proposed changes to overview.md - made other changes for clarity and grammar * ongoing changes to overview.md * added note that `pycrypto` is required made other small changes for grammar and clarity * added new python decryption script to encryption.md * updated encryption.md to clarify dependencies other relatively small changes for clarity straightened quotes Co-authored-by: Guy B. deBros <guydebros@users.noreply.github.com>
136 lines
3.9 KiB
Markdown
136 lines
3.9 KiB
Markdown
# Encryption
|
|
|
|
## A Note on Security
|
|
|
|
While `jrnl` follows best practices, total security is never possible in the
|
|
real world. There are a number of ways that people can at least partially
|
|
compromise your `jrnl` data. See the [Privacy and Security](./security.md) page
|
|
for more information.
|
|
|
|
## Dependencies
|
|
|
|
As of version 2.0, `jrnl`'s encryption functions require
|
|
[`cryptography`](https://pypi.org/project/cryptography/), which is available in
|
|
the Python Package Index (PyPI) and can be installed using `pip`:
|
|
|
|
``` sh
|
|
pip3 install cryptography
|
|
```
|
|
|
|
Previous versions of `jrnl` require
|
|
[`pycrypto`](https://pypi.org/project/pycrypto/):
|
|
|
|
```sh
|
|
pip3 install pycrypto
|
|
```
|
|
|
|
## Encrypting and Decrypting
|
|
|
|
Existing plain text journal files can be encrypted using the `--encrypt`
|
|
command:
|
|
|
|
``` sh
|
|
jrnl --encrypt [FILENAME]
|
|
```
|
|
|
|
You can then enter a new password, and the unencrypted file will replaced with
|
|
the new encrypted file.
|
|
|
|
This command also works to change the password for a journal file that is
|
|
already encrypted. `jrnl` will prompt you for the current password and then new
|
|
password.
|
|
|
|
Conversely,
|
|
|
|
``` sh
|
|
jrnl --decrypt [FILENAME]
|
|
```
|
|
|
|
replaces the encrypted journal file with a plain text file. You can also specify
|
|
a filename, e.g., `jrnl --decrypt plain_text_copy.txt`, to leave the original
|
|
encrypted file untouched and create a new plain text file next to it.
|
|
|
|
## Storing Passwords in Your Keychain
|
|
|
|
There is no method to recover or reset your `jrnl` password. If you lose it,
|
|
your data will be inaccessible forever.
|
|
|
|
For this reason, when encrypting a journal, `jrnl` asks whether you would like
|
|
to store the password in your system's keychain. An added benefit is that you
|
|
will not need to enter the password when interacting with the journal file.
|
|
|
|
If you don't initially store the password in your keychain but decide to do so
|
|
later---or if you want to store it in one computer's keychain but not in another
|
|
computer's---you can run `jrnl --encrypt` on an encrypted journal and use the
|
|
same password again. This will trigger the keychain storage prompt.
|
|
|
|
## Manual Decryption
|
|
|
|
Should you ever want to decrypt your journal manually, you can do so with any
|
|
program that supports the AES algorithm in CBC. The key used for encryption is
|
|
the SHA-256 hash of your password. The IV (initialization vector) is stored in
|
|
the first 16 bytes of the encrypted file. The plain text is encoded in UTF-8 and
|
|
padded according to PKCS\#7 before being encrypted.
|
|
|
|
Here is a Python script that you can use to decrypt your journal:
|
|
|
|
``` python
|
|
#!/usr/bin/env python3
|
|
|
|
import base64
|
|
import getpass
|
|
from pathlib import Path
|
|
from cryptography.fernet import Fernet
|
|
from cryptography.hazmat.backends import default_backend
|
|
from cryptography.hazmat.primitives import hashes
|
|
from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
|
|
|
|
|
|
filepath = input("journal file path: ")
|
|
password = getpass.getpass("Password: ")
|
|
|
|
with open(Path(filepath),"rb") as f:
|
|
ciphertext = f.read()
|
|
|
|
password = password.encode("utf-8")
|
|
kdf = PBKDF2HMAC(
|
|
algorithm=hashes.SHA256(),
|
|
length=32,
|
|
salt=b"\xf2\xd5q\x0e\xc1\x8d.\xde\xdc\x8e6t\x89\x04\xce\xf8",
|
|
iterations=100_000,
|
|
backend=default_backend(),
|
|
)
|
|
|
|
key = base64.urlsafe_b64encode(kdf.derive(password))
|
|
|
|
print(Fernet(key).decrypt(ciphertext).decode('utf-8'))
|
|
```
|
|
|
|
If you're still using `jrnl` version 1.X, the following script serves the same
|
|
purpose:
|
|
|
|
``` python
|
|
#!/usr/bin/env python3
|
|
|
|
import argparse
|
|
from Crypto.Cipher import AES
|
|
import getpass
|
|
import hashlib
|
|
import sys
|
|
|
|
parser = argparse.ArgumentParser()
|
|
parser.add_argument("filepath", help="journal file to decrypt")
|
|
args = parser.parse_args()
|
|
|
|
pwd = getpass.getpass()
|
|
key = hashlib.sha256(pwd.encode('utf-8')).digest()
|
|
|
|
with open(args.filepath, 'rb') as f:
|
|
ciphertext = f.read()
|
|
|
|
crypto = AES.new(key, AES.MODE_CBC, ciphertext[:16])
|
|
plain = crypto.decrypt(ciphertext[16:])
|
|
plain = plain.strip(plain[-1:])
|
|
plain = plain.decode("utf-8")
|
|
print(plain)
|
|
```
|