I was having my electrical panel reworked during Hurricane Sandy to allow more of the house to be powered via generator (last year when we lost power during Irene, we discovered the thermostat wasn't powered, so we had no heat, even though the boiler/water pump were powered).
Anyway, the electrician got a call from one of his other clients, and mentioned something about a military grade RJ-45 setup (RJ-45 is the cat 5/6 cables used for ethernet cables). I asked him what was a military grade RJ-45, and he said you could pick up your whole computer while it was dangling on the RJ-45 cable. I would imagine that is secure.