A code calculated during encryption and appended to a message. If the message authentication code calculated during decryption matches the appended code, the message was not altered during transmission. The D system class. A representational tool used in defining behaviours and characteristics of a thing or system . Also see security model .
Multilevel security allows users at different sensitivity levels to access a system concurrently.
The system permits each user to access only the data that he or she is authorized to access. A multilevel device is one on which a number of different levels of data can be processed. Contrast with single-level . Access to an object potentially implies access to the information it contains. They address what happens when these objects are reassigned.