CoBAC: A Coordinate-Based Access Control Architecture for Scalable Multi-Tenant RAG Systems

Retrieval-Augmented Generation (RAG) reduces AI hallucination, but applying it to organiza-tional knowledge bases introduces a critical security vulnerability: the Hallucination of Authority.Standard retrieval pipelines lack granular access awareness, risking the exposure of sensitive datato unauthorized users. Existing mechanisms (RBAC, ABAC) rely on inefficient post-filtering,discarding up to 72% of retrieved context. CoBAC (Coordinate-Based Access Control) is a de-terministic architecture enforcing Pre-Retrieval Filtering. By coupling data storage coordinateswith a 6-dimensional access manifold, CoBAC ensures that only authorized chunks are retrieved.Benchmarks demonstrate a 25x reduction in storage overhead, a 50x improvement in write efficiency,and optimal token utilization.