Final answer:
A multilevel security (MLS) system is a computer security framework designed to handle data of various classification levels, accessed by users with corresponding security clearances, while adhering to strict access control policies.
Step-by-step explanation:
A multilevel security (MLS) system is a type of computer security system that allows information at different classification levels to be accessed by users with different security clearances within the same system. To work effectively, MLS employs security policies, such as the Bell-LaPadula model, to maintain the confidentiality of classified information. In a typical multilevel security system, data items are classified at different levels, such as confidential, secret, or top-secret, and users are given a corresponding security clearance.
The system enforces two primary rules: the no read-up policy (a subject with a lower clearance should not read data at a higher level) and the no write-down policy (a subject with a higher clearance should not write data to a lower level), collectively ensuring that sensitive information is only disclosed to authorized individuals. MLS systems can be found in government, military, and certain private sector environments, where protection of sensitive data is crucial.