Access control systems are a type of security system used to control access to areas, assets, and resources. These systems are used to grant or deny access to specific areas and resources, and can be either physical or electronic. Physical access control systems, such as locks and keypads, are used to control access to physical locations, and electronic access control systems use credentials, such as passwords and cards, to control access to digital resources. Access control systems are used to protect sensitive areas and resources, as well as to provide accountability for who is accessing what and when.