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georgemarshall / django-cryptography

Easily encrypt data in Django
https://django-cryptography.readthedocs.io/
BSD 3-Clause "New" or "Revised" License
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SECRET_KEY is still used for some calculations even if CRYPTOGRAPHY_KEY is set #56

Open glennmatthews opened 3 years ago

glennmatthews commented 3 years ago

Per the documentation,

CRYPTOGRAPHY_KEY Default: None When value is None a key will be derived from SECRET_KEY. Otherwise the value will be used for the key.

This documentation is incorrect, or at least incomplete. I can confirm that even when CRYPTOGRAPHY_KEY is set, some calculations still use SECRET_KEY. This can be demonstrated by populating some encrypted fields, then changing SECRET_KEY - a BadSignature error will be reported on trying to access the fields, but changing SECRET_KEY back to its old value will restore normal operation.

glennmatthews commented 3 years ago

In other words, once you begin using this library, you may never change SECRET_KEY again, even if you're defining CRYPTOGRAPHY_KEY as the documentation recommends.

genericmoniker commented 3 years ago

Duplicate of #37?

ron8mcr commented 2 years ago

Faced the same issue. Steps to reproduce:

  1. Start new project, install django-cryptography, set both SECRET_KEY and CRYPTOGRAPHY_KEY
  2. Add at least 1 instance of model with encrypted field
  3. Change value of SECRET_KEY

Expected result: encrypted fields may be decrypted as CRYPTOGRAPHY_KEY wasn't changed Actual result: BadSignature because encryption key changed.

shearichard commented 3 months ago

FWIW I've just attempted to replicate this issue and with ...

Django==4.2.11 django-cryptography==1.1

.... the dependency on SECRET_KEY is still the case.

Just doing a PR to reflect the situation in the documentation.