# JAAS > JAAS is an enterprise layer on top of Juju that provides centralized controller management, OIDC authentication, and ReBAC authorization. 2026 CC-BY-SA, Canonical Group Ltd ## Pages in this subsection - [Authorization](https://documentation.ubuntu.com/jaas/latest/explanation/jaas-authorization.md): Understand JAAS authorization with Relationship-Based Access Control (ReBAC) for flexible user permissions on controllers, models, and resources. ## Optional - [Top-level llms.txt](https://documentation.ubuntu.com/jaas/latest/llms.txt): Complete documentation index.