I recently sold my digital camera online, and because I was including the memory card, I wanted to be sure that there was no recoverable data on it. A quick search turned up Eraser, a free, multi talented hard drive eraser program. Eraser works by overwriting the disk with various flavours of data-destroying mayhem that prevents retrieval using undelete software or forensic analysis software.
After installation, Eraser gives you a bunch of options, including a scheduler which lets you setup a collection of hard drives or folders to wipe, letting them run overnight. I just used the right-click option allowing me to delete drives via My Computer. Any drive you can mount with Windows can be seen by Eraser; memory cards, flash drives, external hard drives and internal drives.
Probably the most useful (and unintuitive) bit of Eraser is that it allows you to partially delete disks. So as well as being able to delete an entire drive, you can also delete just the empty part of a disk or just a specific folder. If you’ve still got photos on your memory card, but you want to remove anything else that may be lurking, Eraser will only write over the unused portion. It does this by default, so if you want to erase an entire disk, you’ll need to delete/format it first, then sick Eraser on to it to finish it off.
There are 5 options for overwriting, from the exhaustive Gutmann process which overwrites the disc 35 times with a special pattern that resists almost all types of recovery, to the much quicker method of overwriting once with pseudo random data.
To test the effectiveness of Eraser I first tried Recuva on the camera-formatted memory card in deep scan mode, and sure enough, it found hundreds of “deleted” pictures. So I set Eraser to wipe the card using the DOD method of overwriting 3 times. It took about 12 minutes to do a 4GB SDHC card that was plugged in via a USB SD card adapter. I then scanned the Erasered card with Recuva and it couldn’t find anything to recover. Sure, this wasn’t an exhaustive test, it was good enough for me and probably more than most people do when they sell equipment with memory cards.
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Eraser is currently up to version 5.8 and it’s source code has been released under the GNU General Public License so you can be pretty sure it’s safe. Version 6 is around the corner and has major improvements so keep an eye out. Eraser runs with Windows 9x/2k/XP/Vista/Server 2003/Server 2008. There’s also a portable version of Eraser that can be run from USB flash drives. A very useful little application.
Eraser is an advanced security tool for Windows which allows you to completely remove sensitive data from your hard drive by overwriting it several times with carefully selected patterns.