aTypical Joe: a gay New Yorker living in the rural South

Thursday, June 30, 2005

It never goes away

The explainer on deleting files from your computer:

When you delete a file, all you’ve really done is tell the computer that it can reuse the clusters assigned to that file for something new. The data in those clusters remains intact, until the computer reassigns and overwrites those chunks of disk space with new files. Experts say that the original data can remain intact for weeks or months, depending on the particulars of the system.

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But even if you do wipe your disk successfully-and overwrite each of your deleted files-traces of the original data remain. Writing to a magnetic disk is not as precise as one might think; when you overwrite a file, the new version doesn’t completely cover up the old. The leftover data can be read out with certain imaging techniques, like magnetic-force microscopy and magnetic-force scanning tunneling microscopy. Computer forensics experts say it’s possible to recover data beneath dozens of layers of overwriting, and privacy fanatics talk about wiping their disks up to 35 times over to be absolutely safe.

I wonder. Computer forensics seems like a black hole to me. Where are the Barry Sheck and Peter Neufelds of the computer forensics world? Those who look for innocence, not just guilt.

I hear a lot of people being found guilty for what’s on their computer, but I’m also aware that machines are shared, and that things go on on computers that the user has little or no understanding of. There’s url spoofing and spoofing attacks and adware and spyware and…

Again, I’m just a wee bit wary of certainty; reasonable doubt is a good thing.