This is a list of operating systems specifically focused on security. Operating systems for general-purpose usage may be secure without having a specific focus on security.[1]
Similar concepts include security-evaluated operating systems that have achieved certification from an auditing organization, and trusted operating systems that provide sufficient support for multilevel security and evidence of correctness to meet a particular set of requirements.
Security-Enhanced Linux (SELinux) is a module that may be incorporated into a Linux distribution. SELinux gives administrators more control over access of the system. SELinux has been integrated with the Linux kernel by default since 2003.[16]
These operating systems are all engineered around the object-capabilities security paradigm. Instead of the system deciding if an access request should be granted, the bundling authority and designation decides.