The OpenBSD project produces a multi-platform 4.4BSD-based UNIX-like operating system. OpenBSD's efforts emphasize portability, standardization, correctness, proactive security and integrated cryptography. OpenBSD supports binary emulation of most programs from SVR4 (Solaris), FreeBSD, Linux, BSD/OS, SunOS and HP-UX.
OpenBSD believes in strong security. Our aspiration is to be NUMBER ONE in the industry for security (if we are not already there). Our open software development model permits us to take a more uncompromising view towards increased security than most vendors are able to. We can make changes the vendors would not make. Also, since OpenBSD is exported with cryptography, we are able to take cryptographic approaches towards fixing security problems.
"Secure by Default"
To ensure that novice users of OpenBSD do not need to become security experts overnight (a viewpoint which other vendors seem to have), we ship the operating system in a Secure by Default mode. All non-essential services are disabled. As the user/administrator becomes more familiar with the system, he will discover that he has to enable daemons and other parts of the system. During the process of learning how to enable a new service, the novice is more likely to learn of security considerations.
This is in stark contrast to the increasing number of systems that ship with NFS, mountd, web servers, and various other services enabled by default, creating instantaneous security problems for their users within minutes after their first install.