DISCUSSION [NIST SP 800-171 R2]

Organizations can employ full-device encryption or container-based encryption to protect the confidentiality of CUI on mobile devices and computing platforms. Container-based encryption provides a more fine-grained approach to the encryption of data and information including encrypting selected data structures such as files, records, or fields.

Further Discussion

Ensure CUI is encrypted on all mobile devices and mobile computing platforms that process, store, or transmit CUI including smartphones, tablets, and e-readers.

When CMMC requires cryptography, it is to protect the confidentiality of CUI. FIPS-validated cryptography means the cryptographic module has to have been tested and validated to meet FIPS 140-1 or-2 requirements. Simply using an approved algorithm is not sufficient – the module (software and/or hardware) used to implement the algorithm must be separately validated under FIPS 140. Accordingly, FIPS-validated cryptography is required to meet CMMC practices that protect CUI when transmitted or stored outside the protected environment of the covered contractor information system (including wireless/remote access). Encryption used for other purposes, such as within applications or devices within the protected environment of the covered contractor information system, would not need to be FIPS-validated.

This practice, AC.L2-3.1.19, requires that CUI be encrypted on mobile devices and extends three other CUI protection practices (MP.L2-3.8.1, MP.L2-3.8.2, and SC.L2-3.13.16):

MP.L2-3.8.1 requires that media containing CUI be protected.

MP.L2-3.8.2 limits access to CUI to authorized users.

Finally, SC.L2-3.13.16 requires confidentiality of CUI at rest.

This practice, AC.L2-3.1.19, also leverages SC.L2-3.13.11, which specifies that the algorithms used must be FIPS-validated, and SC.L2-3.13.10, which specifies that any cryptographic keys in use must be protected.

Example

You are in charge of mobile device security. You configure all laptops to use the full-disk encryption technology built into the operating system. This approach is FIPS-validated and encrypts all files, folders, and volumes.

Phones and tablets pose a greater technical challenge with their wide range of manufacturers and operating systems. You select a proprietary mobile device management (MDM) solution to enforce FIPS-validated encryption on those devices [a,b].

Potential Considerations

Is a list maintained of mobile devices and mobile computing platforms that are permitted to process, store, or transmit CUI [a]?

Is CUI encrypted on mobile devices using FIPS-validated algorithms [b]?

Copyright

Copyright 2020, 2021 Carnegie Mellon University and The Johns Hopkins University Applied Physics Laboratory LLC.

Copyright 2021 Futures, Inc.

This material is based upon work funded and supported by the Department of Defense under Contract No. FA8702-15-D-0002 with Carnegie Mellon University for the operation of the Software Engineering Institute, a federally funded research and development center, and under Contract No. HQ0034-13-D-0003 and Contract No. N00024-13-D-6400 with the Johns Hopkins University Applied Physics Laboratory LLC, a University Affiliated Research Center.

The view, opinions, and/or findings contained in this material are those of the author(s) and should not be construed as an official Government position, policy, or decision, unless designated by other documentation.

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