Handle edge cases in encryption

**Problem**
When working with middleware, 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 locating the middleware encryption error-handling entry points and any existing tests, then identify the edge cases covered by the issue. Clarify the expected behavior for each case before making changes. Done means errors provide useful, detailed messages and the relevant cases are covered by tests.

Written by the indexing model from the issue text.