Handle edge cases in encryption

**Feature request**
It would be great to have filtering for core.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_filtering` with default `false`.

No files, tests, or entry points are named; first clarify what “core” means and how filtering should behave in production. Done requires an agreed `enable_filtering` configuration option with a default of `false` and verified filtering behavior.

Written by the indexing model from the issue text.