Aauth
Authorization, Authentication and User Management library
...Despite its ease of use, it has also very advanced features like private messages, grouping, access management, and public access. User management and operations (login, logout, register, verification via e-mail, forgotten password, user ban, login DDoS protection) Group operations. Admin and public group support (public permissions). Permission management (creating/deleting permissions, allow/deny groups, public permissions, permission checking) Group permissions, user permissions, user and system variables.