But NSA is.....
U.S. NSA recently released a security-enhanced version of Linux -- code and all -- to the open source community.
From NSA Security-enhanced Linux Team:
As part of its Information Assurance mission, the National Security Agency has long been involved with the computer security research community in investigating a wide range of computer security topics including operating system security. Recognizing the critical role of operating system security mechanisms in supporting security at higher levels, researchers from NSA's National Information Assurance Research Laboratory have been investigating an architecture that can provide the necessary security functionality in a manner that can meet the security needs of a wide range of computing environments.
End systems must be able to enforce the separation of information based on confidentiality and integrity requirements to provide system security. Operating system security mechanisms are the foundation for ensuring such separation. Unfortunately, existing mainstream operating systems lack the critical security feature required for enforcing separation: mandatory access control. As a consequence, application security mechanisms are vulnerable to tampering and bypass, and malicious or flawed applications can easily cause failures in system security.
The results of several previous research projects in this area have yielded a strong, flexible mandatory access control architecture called Flask. A reference implementation of this architecture was first integrated into a security-enhanced Linux® prototype system in order to demonstrate the value of flexible mandatory access controls and how such controls could be added to an operating system. The architecture has been subsequently mainstreamed into Linux and ported to several other systems, including the Solaris™ operating system, the FreeBSD® operating system, and the Darwin kernel, spawning a wide range of related work..
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
FreeBSD® is a registered trademark of the FreeBSD Foundation.
Solaris™ is a trademark or registered trademark of Sun Microsystems, Inc. in the United States and other countries.
If NSA need a secure OS internally, and that is the Linux
we can take to be relatively secure in Linux as home desktop users.
SELinux is now available in Hardy Heron.
See that page for installation instructions: