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Security Models Explained — Overview (Part 1)

Security Architecture & EngineeringCISSP

Security models are the mathematical backbone behind access control — where a security policy states a goal in plain language, a security model turns it into rules a system can actually enforce. This is Part 1 of our Security Models series (CISSP Domain 3: Security Architecture and Engineering): a direct overview of every model before we dive into each one in depth.

What you will learn

• The state machine, lattice, and information flow models — the shared foundation every other model builds on
• Bell-LaPadula — confidentiality: no read up, no write down
• Biba — integrity: no read down, no write up (Bell-LaPadula turned inside out)
• Clark-Wilson — commercial integrity via well-formed transactions and separation of duties
• Brewer-Nash (Chinese Wall) — dynamic access control to prevent conflicts of interest
• Noninterference — closing the covert-channel gap Bell-LaPadula leaves open
• Graham-Denning — how subjects and objects are securely created, deleted, and assigned rights
• Harrison-Ruzzo-Ullman (HRU) — how access rights safely propagate through a system
• Take-Grant — modeling rights transfer as a directed graph

Parts in this series

1. Bell-LaPadula Model Explained — Security Models (Part 2)
2. Biba Model Explained — Security Models (Part 3)
3. Clark-Wilson Model Explained — Security Models (Part 4)
4. Brewer-Nash Model Explained — Security Models (Part 5)
5. Graham-Denning Model Explained — Security Models (Part 6)
6. Harrison-Ruzzo-Ullman (HRU) Model Explained — Security Models (Part 7)
7. Take-Grant Model Explained — Security Models (Part 8)
8. Noninterference Model Explained — Security Models (Part 9)

More in Security Architecture & Engineering

• Cryptography Explained — Overview (Part 1)
• Secure Access Service Edge (SASE) Explained