Whitepaper by OpenBSD developers Niels Provos and David Mazières discussing ways of building systems in which password security keeps up with hardware speeds. http://www.usenix.org/events/usenix99/provos.html
Outline notes for the half-day tutorial presented at the O'Reilly Open Source Conference in Monterey, California on July 17, 2000. http://www.openbsd.org/papers/oreilly2000/
This paper from Usenix 2002 describes the design of the new OpenBSD packet filter (pf) and compares performance of stateful vs. stateless filtering. http://www.benzedrine.cx/pf-paper.html