Type 3 cryptographic algorithms are NIST standards to be used for protecting all unclassified, sensitive, non-Warner Amendment government information or commercial information. Type 4 cryptographic algorithms are commercial algorithms that are not NIST standards. In order to facilitate interoperability among diverse user communities, security devices may contain more than one type of algorithm. For instance, a Type 1 STU-III terminal also contains a Type 2 algorithm. Modern cryptographic algorithms and security devices can protect all of these integrated applications.
Users can often utilize one device for all applications.
Security may include different protection services, depending on the application and device. All secure telephone terminals protect information from unauthorized disclosure to varying degrees. Most provide some type of authentication of the terminals and access control for the person or computer using the terminal. Users should specify the type and level of protection desired when procuring a secure telephone terminal. All security devices that encrypt information are subject to U.S. export control.