# Authentication and Authorization
This section mainly explores the concepts of authentication and authorization and how to ensure the security of MQTT messaging systems through authentication mechanisms.
Authentication refers to the process of verifying the identity of a client when connecting to an MQTT broker. Authorization, on the other hand, involves granting the appropriate access levels and permissions to authenticated clients. By employing authentication mechanisms and fine-grained authorization, you can ensure that only authorized clients can connect to your MQTT broker and perform specific operations.
To learn how authentication and authorization are implemented in EMQX and how to configure the access control functions, refer to Access Control.