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Possible Duplicate:
How to wipe a USB hard drive

[Author edit] Actually I think the duplicate is this one: Permanently delete files from a flash drive [/edit]

I have a USB stick returned to me by someone else. To maintain confidentiality of what it was used for I want to perform a secure erase on it so that data recovery tools cannot retrieve the contents - I don't know whether the same tools that are used for HDD's can be used on USB sticks, or whether a format will actually overwrite the existing (and deleted contents).

Is there a simple app that can perform this task? Freeware preferably.

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marked as duplicate by Tom Wijsman, music2myear, haimg, Ƭᴇcʜιᴇ007, Nifle Mar 6 '12 at 11:35

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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check this thread and this thread –  Raystafarian Mar 5 '12 at 20:58
    
@Raystafarian, those questions don't really address the specific requirement of flash memory very well. However, I just found this question, which is very similar to mine: superuser.com/questions/371785/… My question is a little different, being Windows specific. –  Highly Irregular Mar 6 '12 at 1:26

4 Answers 4

up vote 4 down vote accepted

CCleaner has an option to wipe free space on a drive.

Then there is also the free open source Eraser.

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I ended up using Eraser, thanks. To prevent wear and tear I told it to only do 2 passes writing over the card, rather than the default (which was something much higher like 8 or 15). Note that, from memory, it's important to use the setting which overwrites blank space, otherwise it may be possible to recover files from that part of the card/disk. –  Highly Irregular Mar 30 '12 at 2:00

I use DBAN or Eraser as mentioned above. Both are free and relatively easy to use.

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All of the other answers do provide ways to prevent the drive from being read using OS based recovery tools, however if the drive swapped out sectors due to bad sector errors/wear leveling (I doubt low end USB keys will do this but it is possible) the data could be recoverable by reading the flash memory chip directly and bypassing the controller.

See this answer from the security SE site for more details and read the Inaccessible media areas section on Wikipedia's "Data remanence" article. Once something has been written on any drive (flash/SSD/Spinning Disk) if you can not bypass the controller and write directly to the media (Even DBAN can not overwrite bad sectors) then you can not trust that the data is ever "gone".

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Dummy File creator, then a quick format. Similar to a wipe, A dummy file creator can be used for other things too :-) Tight, tiny, easy fast, one shot, one write , because it is writing a standard file, there is no thought to the file system. This one for example is 23k without installer, and the installer is very unnessisary. http://www.mynikko.com/dummy/

Assuming you use the above utility, you could just Quick format (if needed) Check the properties for about how much space. Run the dummy, type in the size of the file you want, Browse to put it direct on the flash drive, push the button, and ignore it until it is done.

Just like a dummy :-) if I screw it up, all it does is put a big file somewhere :-) instead of wipe the wrong disk .

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