I've heard people with more paranoida than sense claim that recovery labs (like, say, in the NSA) can 'peel' off passes. Effectively they can view he state of

I've heard people with more paranoida than sense claim that recovery labs (like, say, in the NSA) can 'peel' off passes. Effectively they can view he state of a given drive sector after N writes. If you do complete passes of writing zeroes (or even random numbers), the theory is the spooks can still view your stuff. To counter this people have written disk cleaning utilities that will write random values to a random subset of the disk each pass. After a few passes of writing randoms to a random subset (say 50% of the sectors) it becomes REALLY hard to know what was on the disk because there is no way to 'peel' off a layer. Practical speaking... if you're defending yourself against someone with the ability and motivation to do more than a simple Norton undelete there are better options. I believe the standard practice for Defense contractors is to pass a magnetizing wand over the drives then throw them into a massive shredder. All of this is way overkill for a person who wants to erase their online passwords and letters to mistresses.