The Bell-LaPadula model is a multilevel state machine model. It's security policy was developed out of the security policy that is used by the U.S. Department of Defense, and supports MAC (Mandatory access control).
Mandatory Access control is determined by the access rights that are associated by the different security levels which are associated with subjects and objects.
Support for DAC (Discretionary access control) by checking access rights with an active matrix.
The DoD has a five levels of classification;
- Top Secret
- Secret
- Confidential
- Unclassified
Subjects with clearances other than 'unclassified' may access resources, at or below their clearance level on a 'need to know' basis.
In essence, this means if their job task requires them to have knowledge of, or access areas within the top three levels they may do so.
This shows that the La-Padula model is based on the Confidentiality of objects, and does not address integrity or availability.
Being based on the state machine, it employs the lattice model with mandatory access controls. The tiers of the lattice are used to define the classification levels within the organizations security policy.
The properties of the lattice are defined by the following two rules;
- The Simple Secure Property states that a subject may not read data with a higher classification level.
"No read up."
- The Security Property states that a subject may not write data to a lower classification level.
"No write down."
These are the only transitions within the Bell-LaPadula model that are permitted, which is referenced as the two states of security for the state machine model.
Copyright ©2002-2006 Testbusters.net. All Rights Reserved.
Testbusters.net is not sponsored, endorsed or affiliated by any associated vendor.
Associated venders include, but are not limited to, Microsoft®, Cisco®, CompTIA®, Novell® etc.
