[FIXED] How to authenticate with encrypted email as username?

Issue

In my Django web-app, I would like the user to authenticate itself with an encrypted email address that would simply be the username. Due to the existing GDPR regulations in my country, I have to encrypt e-mail addresses and by doing it with the help of Python Cryptography and Fernet functions, each string is different after encryption, even if two strings are encrypted with one and the same key. Is it possible to authenticate the user without errors in such a situation? If this is possible, where can I read a little more about it?

EDIT: Maybe I incorrectly specified: Django uses username and password for authentication, if the encrypted email is username, when logging in, the user will enter the email when logging in, i.e. [email protected]. The database keeps an encrypted version of this email, so when using authenticate(request, username, password), it will look for a user with the username [email protected], not the encrypted version. If at this point I would like to decrypt the user's e-mail from the database and compare it with the e-mail that the user entered when logging in, app would probably has to decrypt all e-mails in the database, and then check if and which one is [email protected] and here, in my opinion, it becomes quite problematic, because I have the impression that it is a not good solution in terms of time and server load. Is there any other way that I will be able to compare the e-mail entered when logging in and the encrypted e-mail in the database?

Solution

There's a good read here How do I encrypt and decrypt a string in python?. To know the how-to around what you need. Plus, you described the solution quite well, so take a look at the following packages from the Django community which achieve what you are looking for:

https://github.com/orcasgit/django-fernet-fields/

https://github.com/orcasgit/django-fernet-fields/blob/master/fernet_fields/fields.py#L117 It includes an Encrypted email field

https://github.com/patowc/django-encrypted-field

Answered By - misraX