Sometimes we need to encrypt critical information in our Django App. For example, the client might ask you to store the user information in an encrypted format for extra security. Or you might be required to pass some data in the URL in an encrypted format.

Here we will see how can we encrypt and decrypt the information in Django.

Once you are done with the initial setup of the project and added the first app, create a new directory or add a new python package with the name utility in your app.

Create _init__.py  file in the utility directory. Add a new file, name it encryption_util.py  in utility directory.

Encryption:

def encrypt(txt):
    try:
        # convert integer etc to string first
        txt = str(txt)
        # get the key from settings
        cipher_suite = Fernet(settings.ENCRYPT_KEY) # key should be byte
        # #input should be byte, so convert the text to byte
        encrypted_text = cipher_suite.encrypt(txt.encode('ascii'))
        # encode to urlsafe base64 format
        encrypted_text = base64.urlsafe_b64encode(encrypted_text).decode("ascii") 
        return encrypted_text
    except Exception as e:
        # log the error if any
        logging.getLogger("error_logger").error(traceback.format_exc())
        return None

Please note that:

- ENCRYPT_KEY should be kept safe. Keep it in settings_production.py  file and do not commit it to git.

- We are also converting the encoded string to the URL-safe base64 format because we might be required to pass the encoded data to the URL.

- If there is an error, log it and return null.

Decryption:

def decrypt(string):
    try:
        # base64 decode
        txt = base64.urlsafe_b64decode(txt)
        cipher_suite = Fernet(settings.ENCRYPT_KEY)
        decoded_text = cipher_suite.decrypt(txt).decode("ascii")     
        return decoded_text
    except Exception as e:
        # log the error
        logging.getLogger("error_logger").error(traceback.format_exc())
        return None

Dependencies:

- cryptography

Key:

You need to generate the ENCRYPT_KEY using the below process.

- Open terminal in your virtual environment where the cryptography python module is installed.

- Import Fernet.

from cryptography.fernet import Fernet

Fernet.generate_key()

ENCRYPT_KEY = b'iDJpljxUBBsacCZ50GpSBff6Xem0R-giqXXnBFGJ2Rs='

Usage:

from .encryption_util import *

encryption_util.encrypt(username)

Complete code:

from cryptography.fernet import Fernet
import base64
import logging
import traceback
from django.conf import settings

#this is your "password/ENCRYPT_KEY". keep it in settings.py file
#key = Fernet.generate_key() 

def encrypt(txt):
    try:
        # convert integer etc to string first
        txt = str(txt)
        # get the key from settings
        cipher_suite = Fernet(settings.ENCRYPT_KEY) # key should be byte
        # #input should be byte, so convert the text to byte
        encrypted_text = cipher_suite.encrypt(txt.encode('ascii'))
        # encode to urlsafe base64 format
        encrypted_text = base64.urlsafe_b64encode(encrypted_text).decode("ascii") 
        return encrypted_text
    except Exception as e:
        # log the error if any
        logging.getLogger("error_logger").error(traceback.format_exc())
        return None


def decrypt(txt):
    try:
        # base64 decode
        txt = base64.urlsafe_b64decode(txt)
        cipher_suite = Fernet(settings.ENCRYPT_KEY)
        decoded_text = cipher_suite.decrypt(txt).decode("ascii")     
        return decoded_text
    except Exception as e:
        # log the error
        logging.getLogger("error_logger").error(traceback.format_exc())
        return None

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