What is the difference between authentication and authorization?

Authentication and authorization are two distinct concepts in the context of security in software systems.

Authentication is the process of verifying the identity of a user or system. In other words, it is a mechanism that confirms the validity of a user's claimed identity, such as a username and password, or a digital certificate. The main goal of authentication is to ensure that a user is who they claim to be before granting access to a resource or service.

Authorization, on the other hand, is the process of determining whether a user or system has the necessary permissions to access a particular resource or perform a specific action. Authorization involves checking whether a user or system has the required rights, roles, or privileges to perform an operation or access a resource. The goal of authorization is to ensure that only authorized users have access to the appropriate resources and actions.

In summary, authentication is about verifying the identity of a user or system, while authorization is about determining whether that user or system has the necessary permissions to perform a specific action or access a resource. These two concepts are closely related and often used together to provide secure access to software systems.