Add rate limiting for encryption

**Problem**
When working with controllers, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

No files, tests, or concrete entry points are named. First clarify whether the task is rate limiting for encryption or more descriptive controller errors, then locate the affected controller entry point and its relevant tests; done should mean the agreed behavior is implemented and verified by those tests.

Written by the indexing model from the issue text.