Past exam of the computer science course of the University of Oxford / 2015 / Computer security / 1 / a / i

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.