Which is NOT a preference when using proprietary wireless communications?

The correct choice indicates that reliance on PHY (Physical) and MAC (Media Access Control) layer security is not considered a preferred practice when using proprietary wireless communications. This is because security measures that are confined to the PHY and MAC layers can be inadequate against sophisticated threats. These layers primarily deal with the physical transmission of data and the management of access to the medium, but they do not provide comprehensive protection against a variety of cyberattacks, such as those targeting higher-layer protocols and application vulnerabilities.

In proprietary wireless communications, preferences often include end-to-end security measures. Inclusion of encryption and authentication ensures that data is protected in transit and can only be accessed by authorized users. Frequency hopping can help mitigate eavesdropping and jamming attacks by rapidly changing frequencies, which adds another layer of security. Utilizing licensed RF bands can also provide a level of assurance since these bands are regulated, reducing interference and unauthorized access.

By focusing on higher-layer security protocols and broader security measures, organizations can better safeguard their communications against evolving cyber threats. Therefore, simply relying on PHY/MAC layer security does not align with the best practices recommended for secure proprietary wireless communication setups.