What does the simple security (ss) property mean in the Bell-LaPadula model?

The correct answer is A. No read up. In the Bell-LaPadula model, the Simple Security (ss) property states that a subject cannot read data at a classification level higher than their own clearance - 'no read up.' This protects confidentiality by ensuring lower-cleared subjects cannot access more sensitive…

Submitted by parkjh· Apr 18, 2026Access Controls

Question

Options

ANo read up
BNo write down
CNo read down
DNo write up

How the community answered

(33 responses)

A
91% (30)
C
3% (1)
D
6% (2)

Explanation

In the Bell-LaPadula model, the Simple Security (ss) property states that a subject cannot read data at a classification level higher than their own clearance - 'no read up.' This protects confidentiality by ensuring lower-cleared subjects cannot access more sensitive information. The companion rule is the *-property (star property): 'no write down,' which prevents a subject from writing data to a lower classification level (which would leak sensitive information downward).

Topics

#Bell-LaPadula model#Simple Security Property#Access Control Models#Confidentiality

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