AC-8 System use notification

a. Display [system use notification] to users before granting access to the system that provides privacy and security notices consistent with applicable laws, executive orders, directives, regulations, policies, standards, and guidelines and state that: 1. Users are accessing a U.S. Government system; 2. System usage may be monitored, recorded, and subject to audit; 3. Unauthorized use of the system is prohibited and subject to criminal and civil penalties; and 4. Use of the system indicates consent to monitoring and recording; b. Retain the notification message or banner on the screen until users acknowledge the usage conditions and take explicit actions to log on to or further access the system; and c. For publicly accessible systems: 1. Display system use information [conditions] , before granting further access to the publicly accessible system; 2. Display references, if any, to monitoring, recording, or auditing that are consistent with privacy accommodations for such systems that generally prohibit those activities; and 3. Include a description of the authorized uses of the system.

Quoted verbatim from NIST SP 800-53 Rev 5 (OSCAL catalog), which is in the public domain.