Security Enhanced Linux (SELinux) is a security enhancement to Linux implementing mandatory access control (MAC). Users and processes can be granted their least required privileges in a much more granular way than with traditional Unix access control. For example, you can define a policy to prevent your web browser from reading your SSH keys. The security model of SELinux has been ported to other operating systems; see SEBSD for FreeBSD and Project fmac for OpenSolaris.