Lecture 7: April 13, 2026

Reading: text, §5.3, 6.1–6.2, 6.4
Assignments: Homework 2, due April 24, 2026

1. Greetings and felicitations!

2. Example: Trusted Solaris

3. Tranquility
   1. Declassification problem
   2. Strong tranquility
   3. Weak tranquility

4. Requirements of integrity models

5. Biba Model (strict integrity policy)

6. Clark-Wilson Model
   1. Theme: military model does not provide enough controls for commercial fraud, etc. because it does not cover the right aspects of integrity
   2. Components
      1. Constrained Data Items (CDI) to which the model applies
      2. Unconstrained Data Items (UDIs) to which no integrity checks are applied
      3. Integrity Verification Procedures (IVP) that verify conformance to the integrity spec when IVP is run
      4. Transaction Procedures (TP) takes system from one well-formed state to another

   ---

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

   ECS 153A, Computer & Information Security & Privacy I Version of April 12, 2026 at 3:06PM

   You can also obtain a PDF version of this.