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A classification-based information confidentiality model restricting subject accesses to prevent forbidden information flow. The simple security property restricts reading above clearance; the Bell-LaPadula star property restricts information flow through current reads and writes. It is not a complete data integrity policy.

The Bell-LaPadula model protects information confidentiality by controlling information flow between security levels. Its simple security property says that a subject may read only objects whose classification does not exceed its maximum clearance:Thus a user cleared for confidential material cannot directly read a secret file. A readwrite permission includes reading and must satisfy the same restriction. This is an access control rule about who can learn existing contents; it says nothing by itself about where a cleared subject can subsequently copy them.