Add rate limiting for encryption

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

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

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

Start by reconciling the title's request for encryption rate limiting with the body’s request for more descriptive route errors. No files, tests, or entry points are named, so clarify the intended behavior and affected routes before locating the implementation. Done should be defined with specific rate-limit and error-message expectations.

Written by the indexing model from the issue text.