# Brewer-Nash (Chinese Wall) Model One-sentence definition: **Conflict-of-interest** access model where a subject’s access to one dataset restricts access to competitor datasets. ## Key Facts - Dynamic rules change based on prior access (history-based). - Prevents information flows between conflicting classes (e.g., consulting clients). - Supports read rules and sanitized write rules for public information. - Common in financial services, consulting, legal. - **Verify:** check official (ISC)² CBK and current exam outline. ## Exam Relevance - Identify dynamic, conflict-based restriction scenario. **Mnemonic:** “Once inside one wall, others are closed.” ## Mini Scenario Q: Analyst worked on Pharma A; can they access Pharma B data? A: Denied due to conflict class under Brewer-Nash. ## Revision Checklist - Define dynamic separation vs static. - Provide two industries using it. - Explain sanitized info exception. ## Related [[Lattice-Based Access Control (LBAC)]] · [[Noninterference and Information Flow]] · [[Clark-Wilson Integrity Model]] · [[Access Control to Data Assets]] · [[Threat Modeling (STRIDE, Attack Surface)]] · [[Domain 3 - Index]]