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Which of the following answers BEST describes the Bell …

Which of the following answers BEST describes the Bell La-Padula model of storage and access control of
classified information?

PrepAway - Latest Free Exam Questions & Answers

A.
No read up and No write down

B.
No write up, no read down

C.
No read over and no write up

D.
No reading from higher classification levels

Explanation:
Three main rules are used and enforced in the Bell-LaPadula model:
The simple security (SS) rule, the *-property (star property) rule, and the strong star property rule. The simple
security rule states that a subject at a given security level cannot read data that reside at a higher security level.
The *-property rule (star property rule) states that a subject in a given security level cannot write information to
a lower security level. The simple security rule is referred to as the “no read up” rule, and the *-property rule is
referred to as the “no write down” rule.
The third rule, the strong star property rule, states that a subject that has read and write capabilities can only
perform those functions at the same security level; nothing higher and nothing lower. So, for a subject to be
able to read and write to an object, the clearance and classification must be equal.
Incorrect Answers:
B: No write up, no read down is not the best description of the Bell-LaPadula model.
C: No read over and no write up is not the best description of the Bell-LaPadula model.
D: No reading from higher classification levels is not the best description of the Bell-LaPadula model.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, pp. 369-370


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