The confidentiality of CUI stored on digital media is protected during transport using cryptographic mechanisms or alternative physical safeguards.
Implement cryptographic mechanisms to protect the confidentiality of CUI stored on digital media during transport unless otherwise protected by alternative physical safeguards.
This requirement applies to portable storage devices (e.g., USB memory sticks, digital video disks, compact disks, external or removable hard disk drives). See [NIST CRYPTO]. [SP 800-111] provides guidance on storage encryption technologies for end user devices.