Add rate limiting for pagination

**Feature request**
It would be great to have encryption for helpers.

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

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

The title asks for rate limiting on pagination, while the body asks for encryption helpers and an `enable_encryption` option, so clarify the intended scope first. No files, tests, or entry points are named; locate the relevant helper and configuration code only after the request is resolved, then define tests covering the chosen behavior and the default setting.

Written by the indexing model from the issue text.