mirror of
https://github.com/jazzband/django-fernet-encrypted-fields.git
synced 2026-03-16 22:40:27 +00:00
43c0752252
This commit adds in support for the SALT to be rotated by defining a list of salts within settings.py where the newer salts are added to the start.
The first key will be used to encrypt all new data, and decryption of existing values will be attempted with all given keys in order. This is useful for key rotation: place a new key at the head of the list for use with all new or changed data, but existing values encrypted with old keys will still be accessible
This is based of django-fernet-fields which is a dead package but has some useful features such as this to allow the salt to be rotated in the future for a stronger salt.
```
SALT_KEY = [
'my-newer-salt',
'the-original-salt'
]
```
89 lines
2.6 KiB
Python
89 lines
2.6 KiB
Python
import base64
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from django.conf import settings
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from cryptography.fernet import Fernet, MultiFernet
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives import hashes
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from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
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from django.db import models
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from django.utils.functional import cached_property
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class EncryptedFieldMixin(object):
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@cached_property
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def keys(self):
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keys = []
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salt_keys = settings.SALT_KEY if isinstance(settings.SALT_KEY, list) else [settings.SALT_KEY]
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for salt_key in salt_keys:
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salt = bytes(salt_key, 'utf-8')
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kdf = PBKDF2HMAC(algorithm=hashes.SHA256(),
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length=32,
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salt=salt,
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iterations=100000,
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backend=default_backend())
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keys.append(base64.urlsafe_b64encode(kdf.derive(settings.SECRET_KEY.encode('utf-8'))))
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return keys
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@cached_property
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def f(self):
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if len(self.keys) == 1:
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return Fernet(self.keys[0])
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return MultiFernet([Fernet(k) for k in self.keys])
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def get_internal_type(self):
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"""
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To treat everything as text
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"""
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return 'TextField'
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def get_prep_value(self, value):
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if value:
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if not isinstance(value, str):
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value = str(value)
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return self.f.encrypt(bytes(value, 'utf-8')).decode('utf-8')
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return None
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def get_db_prep_value(self, value, connection, prepared=False):
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if not prepared:
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value = self.get_prep_value(value)
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return value
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def from_db_value(self, value, expression, connection):
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return self.to_python(value)
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def to_python(self, value):
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if value is None or not isinstance(value, str):
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return value
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value = self.f.decrypt(bytes(value, 'utf-8')).decode('utf-8')
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return super(EncryptedFieldMixin, self).to_python(value)
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class EncryptedCharField(EncryptedFieldMixin, models.CharField):
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pass
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class EncryptedTextField(EncryptedFieldMixin, models.TextField):
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pass
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class EncryptedDateTimeField(EncryptedFieldMixin, models.DateTimeField):
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pass
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class EncryptedIntegerField(EncryptedFieldMixin, models.IntegerField):
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pass
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class EncryptedDateField(EncryptedFieldMixin, models.DateField):
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pass
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class EncryptedFloatField(EncryptedFieldMixin, models.FloatField):
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pass
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class EncryptedEmailField(EncryptedFieldMixin, models.EmailField):
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pass
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class EncryptedBooleanField(EncryptedFieldMixin, models.BooleanField):
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pass
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