The main Virtuoso Open Server page mentions encryption-at-rest as one of the features:
Virtuoso helps you build powerful solutions applications driven by knowledge graphs derived from a variety of life sciences oriented data sources. For super sensitive competitive information it also includes powerful attribute-based access controls and encryption-at-rest amongst if deep collection of data privacy and security functionality.
However I can’t find any mentions about it in the documentation. Which versions offer support for it? How do I enable it?