Django Secured Fields

Django encrypted fields with search enabled.

Features

• Automatically encrypt/decrypt field value using cryptography's Fernet
• Built-in search lookup on the encrypted fields from hashlib's SHA-256 hash value. in and isnull lookup also supported.
• Supports most of available Django fields including BinaryField, JSONField, and FileField.

Installation

pip install django-secured-fields

Setup

1. Add secured_fields into INSTALLED_APPS

   # settings.py
   
   INSTALLED_APPS = [
       ...
       'secured_fields',
   ]

2. Generate a new key using for encryption

   $ python manage.py generate_key
   KEY: TtY8MAeXuhdKDd1HfGUwim-vQ8H7fXyRQ9J8pTi_-lg=
   HASH_SALT: 500d492e

3. Put generated key(s) and hash salt in settings

   # settings.py
   
   SECURED_FIELDS_KEY = 'TtY8MAeXuhdKDd1HfGUwim-vQ8H7fXyRQ9J8pTi_-lg='
   # or multiple keys for rotation
   SECURED_FIELDS_KEY = [
       'TtY8MAeXuhdKDd1HfGUwim-vQ8H7fXyRQ9J8pTi_-lg=',
       '...',
   ]
   
   # optional
   SECURED_FILDS_HASH_SALT = '500d492e'

Usage

Simple Usage

# models.py
import secured_fields

phone_number = secured_fields.EncryptedCharField(max_length=10)

Enable Searching

# models.py
import secured_fields

id_card_number = secured_fields.EncryptedCharField(max_length=18, searchable=True)

Supported Fields

• EncryptedBinaryField
• EncryptedBooleanField
• EncryptedCharField
• EncryptedDateField
• EncryptedDateTimeField
• EncryptedDecimalField
• EncryptedFileField
• EncryptedImageField
• EncryptedIntegerField
• EncryptedJSONField
• EncryptedTextField

Settings

Key	Required	Default	Description
SECURED_FIELDS_KEY	Yes		Key(s) for using in encryption/decryption with Fernet. Usually generated from python manage.py generate_key. For rotation keys, use a list of keys instead (see MultiFernet).
SECURED_FIELDS_HASH_SALT	No	''	Salt to append after the field value before hashing. Usually generated from python manage.py generate_key.
SECURED_FIELDS_FILE_STORAGE	No	'secured_fields.storage.EncryptedFileSystemStorage'	File storage class used for storing encrypted file/image fields. See EncryptedStorageMixin

APIs

Field Arguments

Name	Type	Required	Default	Description
searchable	bool	No	False	Enable search function

Encryption

> from secured_fields.fernet import get_fernet

> data = b'test'

> encrypted_data = get_fernet().encrypt(data)
> encrypted_data
b'gAAAAABh2_Ry_thxLTuFFXeMc9hNttah82979JPuMSjnssRB0DmbgwdtEU5dapBgISOST_a_egDc66EG_ZtVu_EqF_69djJwuA=='

> get_fernet().decrypt(encrypted_data)
b'test'

Rotate Keys

> from secured_fields.fernet import get_fernet

> encrypted_data = get_fernet().encrypt(b'test')
> encrypted_data
b'gAAAAABh2_Ry_thxLTuFFXeMc9hNttah82979JPuMSjnssRB0DmbgwdtEU5dapBgISOST_a_egDc66EG_ZtVu_EqF_69djJwuA=='

> rotated_encrypted_data = get_fernet().rotate(encrypted_data)
> get_fernet().decrypt(rotated_encrypted_data)
b'test'

See more details in MultiFernet.rotate.

EncryptedMixin

If you have a field which is not supported by the package, you can use EncryptedMixin to enable encryption and search functionality for that custom field.

import secured_fields
from django.db import models

class EncryptedUUIDField(secured_fields.EncryptedMixin, models.UUIDField):
    pass

task_id = EncryptedUUIDField(searchable=True)

EncryptedStorageMixin

If you use a custom file storage class (e.g. defined in settings.py's DEFAULT_FILE_STORAGE), you can enable file encryption using EncryptedStorageMixin.

import secured_fields
from minio_storage.storage import MinioMediaStorage

class EncryptedMinioMediaStorage(
    secured_fields.EncryptedStorageMixin,
    MinioMediaStorage,
):
    pass

Known Limitation

• in lookup on JSONField is not available
• Large files are not performance-friendly at the moment (see #2)
• Search on BinaryField does not supported at the moment (see #6)
• Changing searchable value in a field with the records in the database is not supported (see #7)

Development

Requirements

• Docker
• Poetry
• MySQL Client
  • brew install mysql-client
  • echo 'export PATH="/usr/local/opt/mysql-client/bin:$PATH"' >> ~/.bash_profile

Running Project

1. Start backend databases

   make up-db

2. Run tests (see: Testing)

Linting

make lint

Testing

make test-pg  # or make test-mysql, make test-sqlite

Fix Formatting

make yapf