The cryptographic signing API in Django is available to any app for cryptographically-secure signatures on values. Django itself makes use of this in various higher-level features:
Signing serialised data (e.g. JSON documents).
Unique tokens for a user session, password reset request, messages, etc.
Prevention of cross-site or replay attacks by adding (and then expecting) unique values for the request.
Generating a unique salt for hash functions.
From this post:
Changing it should not affect this application.