Django Cryptographic Fields

About

django-cryptographic-fields is set of fields that wrap standard Django fields with encryption provided by the python cryptography library. These fields are much more compatible with a 12-factor design since they take their encryption key from the settings file instead of a file on disk used by keyczar.

While keyczar is an excellent tool to use for encryption, it's not compatible with Python 3, and it requires, for hosts like Heroku, that you either check your key file into your git repository for deployment, or implement manual post-deployment processing to write the key stored in an environment variable into a file that keyczar can read.

Getting Started

$ pip install django-cryptographic-fields

Add "cryptographic_fields" to your INSTALLED_APPS setting like this:

INSTALLED_APPS = (

... 'cryptographic_fields',

)

django-cryptographic-fields expects the encryption key to be specified using FIELD_ENCRYPTION_KEY in your project's settings.py file. For example, to load it from the local environment:

import os

FIELD_ENCRYPTION_KEY = os.environ.get('FIELD_ENCRYPTION_KEY', '')

To use an encrypted field in a Django model, use one of the fields from the cryptographic_fields module:

from cryptographic_fields.fields import EncryptedCharField

class EncryptedFieldModel(models.Model):

encrypted_char_field = EncryptedCharField(max_length=100)

For fields that require max_length to be specified, the Encrypted variants of those fields will automatically increase the size of the database field to hold the encrypted form of the content. For example, a 3 character CharField will automatically specify a database field size of 100 characters when EncryptedCharField(max_length=3) is specified.

Due to the nature of the encrypted data, filtering by values contained in encrypted fields won't work properly. Sorting is also not supported.

Generating an Encryption Key

There is a Django management command generate_encryption_key provided with the cryptographic_fields library. Use this command to generate a new encryption key to set as settings.FIELD_ENCRYPTION_KEY.

./manage.py generate_encryption_key

Running this command will print an encryption key to the terminal, which can be configured in your environment or settings file.