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Thread Starter 
[quote]Originally posted by Artman @_@:
<strong>I've heard too that there are apps that'll do a clean sweep of all data if needed...there's an application for everything. Just as the FBI has them to find and recover deleted files and data.</strong><hr></blockquote>

Worst secure: Emptying the trash.

The files are still there in your computer, only the directory entries have been deleted. A quick sweep with Norton or other utilities can quickly recover complete files.

More secure: Zeroing data.

Many utilities erase files by writing zeroes (or another series) to the space occupied by the file, or to all empty space on the drive. This means no software can possible recover the file, but as a slight magnetic resonance is still left on the drive, this leaves the possibility of recovery with special magnetically sensitive equipment.

The zeroing process can be repeated, but this just means the recovery hardware needs to be more sensitive.

Incidentally, wiping the disk with a strong magnetic field such as using a bulk eraser does basically the same thing as zeroing. The stronger the magnet, the more difficult the recovery.

Better: Random overwrite.

Rather that writing zeroes to the drive, random data is written over the file to scramble the data. Totally secure? No. If the randomization algorithm is known, or can be detected, the resonance can be read.

Best: Multiple random overwrites.

Writing random data several times over the original data can make detection almost impossible. I don't think the FBI can recover data erased this way, unless the exact algorithm can be found.

Note: these are my simple observations as a layman. If anyone has anything to add/correct, please do so.