Athenz is an open source system for role-based access control (RBAC) that uses two token types - principal tokens (N-Tokens) that identify users or services, and role tokens (Z-Tokens) that represent roles a principal can assume. It provides advantages like service-based security profiles, dynamic provisioning, and single source of truth for access management. Athenz works using a centralized authorization server (ZMS) that issues tokens, and decentralized token servers (ZTS) that verify tokens. Services are assigned identities and roles via tokens to control access in a decentralized manner according to policies managed in Athenz domains.