Even computer security itself is a metaphor (at least in its inception). I often wonder what if instead of using terms like access, key, illegal operation, firewall, etc. we'd instead chosen metaphors from a different domain, for example plumbing. I'm sure a plumbing metaphor could also be found for every computer security concern. Would be so quick to romanticize as well as militarize a field dealing with "leaks," "blockages," "illegal taps," and "water quality"?