django-pgcrypto

A set of utility functions for dealing with ASCII Armor (http://www.ietf.org/rfc/rfc2440.txt) and padding, and a collection of Django field classes that utilize these functions in a way that is compatible with pgcrypto functions.

Installation

pip install django-pgcrypto

Quickstart

There are several encrypted versions of Django fields that you can use (mostly) as you would use a normal Django field:

from django.db import models
import pgcrypto

class Employee (models.Model):
    name = models.CharField(max_length=100)
    ssn = pgcrypto.EncryptedTextField()
    pay_rate = pgcrypto.EncryptedDecimalField()
    date_hired = pgcrypto.EncryptedDateField(key="datekey", auto_now_add=True)

If not specified when creating the field (as in ssn and pay_rate above), fields are encrypted according to the following settings:

PGCRYPTO_DEFAULT_CIPHER (only aes is currently supported) - The default algorithm to use when encrypting fields.
PGCRYPTO_DEFAULT_KEY (default: settings.SECRET_KEY) - The default key to use for encryption.

You must also make sure the pgcrypto extension is installed in your database. Django makes this easy with a CryptoExtension migration.

Querying

It is possible to filter on encrypted fields as you would normal fields via exact, gt, gte, lt, and lte lookups. For example, querying the model above is possible like so:

Employee.objects.filter(date_hired__gt="1981-01-01", salary__lt=60000)

Caveats

This library encrypts and encodes data in a way that works with pgcrypto's raw encryption functions. All the warnings there about using direct keys and the lack of integrity checking apply here.

This library also predates Django's BinaryField, which is why the fields are essentially TextFields that store armored encrypted data. This may or may not be ideal for your application, and a hypothetical future version might include a switch to store binary data.