January 20, 2021 Outline

Reading: text, §5–5.2.1
Due: Homework #1, due January 22; Project selection, due January 22

1. Lattices
   1. Properties of a lattice: trichotomy, upper and lower bounds
   2. Examples

2. Bell-LaPadula Model: intuitive, security classifications only
   1. Show level, categories, define clearance and classification
   2. Lattice: poset with ≤ relation reflexive, antisymmetric, transitive; greatest lower bound, least upper bound
   3. Apply lattice
      1. Set of classes SC is a partially ordered set under relation dom with glb (greatest lower bound), lub (least upper bound) operators
      2. Note: dom is reflexive, transitive, antisymmetric
      3. Example: (A, C) dom (A′, C′) iff A ≤ A′ and C ⊆ C′;
         lub((A, C), (A′, C′)) = (max(A, A′), C ∪ C′); and
         glb((A, C), (A′, C′})) = (min(A, A′), C ∩ C′})
   4. Simple security condition (no reads up), *-property (no writes down), discretionary security property
   5. Basic Security Theorem: if it is secure and transformations follow these rules, it will remain secure
   6. Maximum, current security level

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Matt Bishop Office: 2209 Watershed Sciences Phone: +1 (530) 752-8060 Email: mabishop@ucdavis.edu

ECS 235B, Foundations of Computer and Information Security Version of January 13, 2021 at 11:03PM

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