What does protecting CUI actually involve, day to day? The government defines a set of security requirements, marking conventions, training obligations, and destruction standards that govern CUI through its entire lifecycle, from the moment it enters your environment to the moment it's destroyed.

These requirements are where compliance becomes concrete. A well-secured system with incorrectly marked documents is still a compliance gap. A trained team without proper sanitization procedures still leaves CUI recoverable on retired equipment.

This section covers each CUI safeguarding obligation: the NIST 800-171 framework that defines what protecting CUI requires, how to correctly mark documents and media, when and how to use CUI cover sheets, the DoD's mandatory annual training requirement and how to satisfy it, and how to sanitize media so CUI is truly unrecoverable.