What is called the type of access control where there are pairs of elements that have the least upper bound of values and greatest lower bound of values?

Question

Options

• AMandatory model
• BDiscretionary model
• CLattice model
• DRule model

• A
  2% (1)
• B
  2% (1)
• C
  90% (43)
• D
  6% (3)

Explanation

Lattice-based access control defines security levels as a mathematical lattice structure, where every pair of elements has a least upper bound (LUB) (the lowest level that dominates both) and a greatest lower bound (GLB) (the highest level dominated by both) - this is the defining property of a lattice, making C correct.

• A (Mandatory model) is wrong because MAC describes who enforces access decisions (the system, not the owner), not the mathematical structure of the security levels themselves. MAC can use a lattice, but the lattice is the structure, not the enforcement mechanism.
• B (Discretionary model) is wrong because DAC lets resource owners control access permissions - it's about delegation of control, with no inherent mathematical ordering of levels.
• D (Rule model) is wrong because rule-based access control grants access based on predefined conditions or rules (e.g., firewall ACLs), not on a bounded partial-order structure.

Memory tip: Think "Lattice = LUB + GLB" - the two Ls in Lattice match the two bounds. If a question mentions least upper bound or greatest lower bound, the answer is always the lattice model.

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