CODEWITHSUNDEEP
pythondjangosecurityencryption
Peter Nimroot
Peter Nimroot

Reputation: 545

Is there a simple way to handle SECRET_KEY update for encrypted fields?

Let's begin with two assumptions:

  1. Some of database fields like third party access tokens are encrypted using e.g. Fernet and SECRET_KEY as encryption key.
  2. SECRET_KEY needs to be changed, because of security problem.

What would be the best thing to do in such situation? I assume that I should change the SECRET_KEY immediately after I've fixed the security hole, however if I do that I'll essentially lose access to all of the encrypted data.

What I have came up with is to first do a migration, which would temporarily replace encrypted fields with simple charfields/textfields + data migration to unencrypt stored values. Then change the SECRET_KEY. Finally bring the encrypted fields back, again with a data migration to encrypt stored values.

It seems like a great hassle though, is there a better/simpler/faster way to handle such situation?

Upvotes: 0

Views: 1067

Answers (1)

Burhan Khalid
Burhan Khalid

Reputation: 174632

Since you only have one secret key, your only resort is to re-encrypt the entire database.

The proper way is to first not use django's SECRET_KEY for database tasks (even django doesn't use it for things like user passwords) and implement a key-rotation algorithm for your sensitive data.

django-fernet-fields provides this function out of the box; however it assumes you are rotating keys as best practice and not as consequence of a compromise.

Best-practice key rotation relies on "encryption at use" where a secret is unencrypted with the old key and re-encrypted with the new key upon use. Eventually your most used secrets are re-encrypted and you can do an audit to invalidate or force the re-encryption of the remaining entries.

Upvotes: 1

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