Reply #18: Seven times is definitely excessive.

[Akoto]

If I understand correctly, they overwrote the free space. That is not, in itself, an illegal act. As you delete something, the area it occupies on the hard drive becomes 'free' space. Later, stuff that you download or install fills that 'free' space and overwrites what was previously there. So, overwriting happens naturally in the life of a hard drive. It's the bane of many computer users who delete things they later want to recover, but can't. :)

Deliberately washing your free space is wise if you're doing something like selling your PC with the hard drive, because somebody can easily recover your deleted info at home with programs. In this case, however, it's possible (and likely, knowing Rove) that it was used to cover up questionable data. May be outright illegal if the law forbids them to conduct this procedure on computers used for government business. I don't know enough about that to say.

Seven times would leave almost no trace of information. I'm not an expert in this area, but I think you could picture your hard drive like this ...

1 1 1 0 1 1 0

0 1 0 0 1 0 1

1 1 0 1 0 1 1

The above represents how data looks. If you did one overwrite pass, that would be sufficient for most users unless you were holding really secure stuff. The Department of Defense standard is three passes. After you did a wipe, it'd be more like this ...

0 0 0 0 0 0 0

0 0 0 0 0 0 0

0 0 0 0 0 0 0

In other words, lots of nothing. A frequently used computer does not look like this, so unless the hard drive is brand new with nothing on it, it's pretty obvious that it has been washed. Each pass finds more and more refuse data, and makes it that much harder to recover. It comes down to who's looking and what tools they have.

If they were using an algorithm that randomly overwrote the free space, instead of overwriting it with zeroes, I'd call that even more suspicious. As I understand it from reading, that would make it appear as though there's data present, but it's really just gibberish. So, maybe trying to hide that they did it?

Seven times wouldn't just delete a virus in your free space. It would take plenty of other stuff with it. Theoretically, it could still be recovered, but it would be extremely difficult for anyone to do after a point.