<P> The Bell--LaPadula Model (BLP) is a state machine model used for enforcing access control in government and military applications . It was developed by David Elliott Bell and Leonard J. LaPadula, subsequent to strong guidance from Roger R. Schell, to formalize the U.S. Department of Defense (DoD) multilevel security (MLS) policy . The model is a formal state transition model of computer security policy that describes a set of access control rules which use security labels on objects and clearances for subjects . Security labels range from the most sensitive (e.g., "Top Secret"), down to the least sensitive (e.g., "Unclassified" or "Public"). </P> <P> The Bell--LaPadula model is an example of a model where there is no clear distinction between protection and security . </P>

Explain the bell — lapadula model. also describe the five components of an information flow model