Access control is an essential element of security that determines who is allowed to access certain data, apps, and resources—and in what circumstances. In the same way that keys and preapproved guest lists protect physical spaces, access control policies protect digital spaces. In other words, they let the right people in and keep the wrong people out. Access control policies rely heavily on techniques like authentication and authorization, which allow organizations to explicitly verify both that users are who they say they are and that these users are granted the appropriate level of access based on context such as device, location, role, and much more.