* Mandatory Access Controls (MACs) - these are access controls that are applied across the entire system in a uniform way, and cannot be individually overridden by the users or administrators. An example of a Mandatory Access Control system is SELinux (security-enhanced Linux), a system originally developed by the National Security Agency of the US Federal Government and now part of the Linux Kernel (via KSM - Kernel Security Models). SELinux uses type enforcement and labelling of both resources (files, network connections) and processes to determine whether a specific process should have access to a specific resource, and to deny access when it does not. SELinux is used in several operating systems, including Android, Fedora, CentOS, and Red Hat Enterprise Linux, and Android.