Bruce Schneier has an interesting take on
Security and Function Creep.
He raises a lot of great points about security systems taking on new tasks they weren't originally designed for. This is quite natural in the evolution of things. Not all evolution make sense. The six armed monkey never caught on, as poop flinging wasn't a historically desirable trait until the creation of the modern zoo.
I can't help but wonder about how Open Source fits into this though. Bruce has a quote in his article
... and the same operating systems that run our businesses are suitable for military uses.
SELinux makes me wonder about this. SELinux was born from the NSA, a government group which does nothing without security in mind (or at least I hope so). I will agree that most operating systems aren't suitable for military use, but something like Open Source can change the game. If the square peg doesn't fit in the round hole, what happens if it can be turned into a round peg? Open Source can allow this to happen. The group actually running the software can make changes as needed so the software fits their task at hand.
More thought and discussion needs to go into this idea, but Open Source is very powerful, more powerful than most of can even imagine. The old saying "all of us are smarter than one of us", while corny, is very true. Security folks are generally bad UI designers, and UI designers are generally bad at security. Open Source can make it easy for these two groups to work together and accomplish great things.