You are applying the Bell-LaPadula model to a secure software system. A user with 'Secret' clearance attempts to write data to a 'Top Secret' file. Based on the *-property, what is the outcome?
Trap 1: The write is permitted.
Writing to a higher level is a 'write-up' which is allowed by the simple security property but restricted by the *-property in specific implementations.
Trap 2: The write is denied due to the no-write-down rule.
The user is writing up, not down.
Trap 3: The system allows the write only if encryption is used.
Bell-LaPadula is a formal model not dependent on specific encryption implementations.
- A
The write is denied because the *-property prohibits writing to a higher security level.
The *-property prevents a user from writing to a higher level to prevent information flow leakage.
- B
The write is permitted.
Why wrong: Writing to a higher level is a 'write-up' which is allowed by the simple security property but restricted by the *-property in specific implementations.
- C
The write is denied due to the no-write-down rule.
Why wrong: The user is writing up, not down.
- D
The system allows the write only if encryption is used.
Why wrong: Bell-LaPadula is a formal model not dependent on specific encryption implementations.