Security-focused operating system

This is a list of operating systems specifically focused on security. 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.

Linux

Android-based

• GrapheneOS is a privacy and security-focused mobile operating system for selected Google Pixel smartphones and tablets.

Debian-based

• Tails is aimed at preserving privacy and anonymity.
• Whonix consists of two virtual machines. All communications are forced through Tor.
• Linux Kodachi is a security-focused operating system.

Other Linux distributions

• Alpine Linux is designed to be small, simple, and secure. It uses musl, BusyBox, and OpenRC instead of the more commonly used glibc, GNU Core Utilities, and systemd.
• Owl - Openwall GNU/Linux, a security-enhanced Linux distribution for servers.

BSD

• OpenBSD is a Unix-like operating system that emphasizes portability, standardization, correctness, proactive security, and integrated cryptography.

Xen

• Qubes OS aims to provide security through isolation. Isolation is provided through the use of virtualization technology. This allows the segmentation of applications into secure virtual machines.