Add rate limiting for encryption

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

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

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

The issue says the work is in core and concerns encryption rate limiting, but names no file, entry point, or test. Start by locating the core encryption implementation and its existing error-handling tests. Done means the intended rate limit is implemented and error messages provide enough detail for debugging.

Written by the indexing model from the issue text.