Is Encrypted Controlled Unclassified Information (CUI) Still Considered CUI?

Encryption Does Not Change CUI Status

This is one of the most commonly misunderstood aspects of CUI handling. Many contractors assume that encrypting CUI data "neutralizes" it — this is incorrect.

The Key Rule

CUI retains its controlled status regardless of whether it is encrypted, compressed, or otherwise transformed. The only way CUI loses its controlled status is through formal decontrol by an authorized authority.

Why This Matters for CMMC

• Encrypted CUI in the cloud is still CUI — your cloud environment must meet CMMC scoping requirements
• Encrypted CUI on removable media still requires proper media handling controls
• Encrypted CUI in transit still counts toward your assessment scope
• Encrypted backups containing CUI are still in-scope assets

The Exception: Cryptographic Erase

While encryption doesn't decontrol CUI, NIST SP 800-88 does allow cryptographic erasure as a valid sanitization method for media disposal. This means if you destroy the encryption keys following approved procedures, the media can be considered sanitized for disposal or reuse purposes.

Bottom line: Use encryption as a security control (it's required in many NIST 800-171 controls), but don't rely on it to reduce your CMMC scope.