Data Erasure

A

angyatnumbers

New Member
So I was having a bit of a debate with a friend and decided that a place like this would be a good spot to find some more knowledgeable thoughts. So here it is:
Is it possible to completely and utterly wipe a hard drive of all information and data to make it IMPOSSIBLE (not just difficult) for anybody to recover the data? I understand the formatting process doesn't delete the info from the drive, but what about "military wipe" sorts of things? Is overwriting info traceable? Can you figure out how info has been changed in order to work backwards using equations and logic and such and find out what was there?

As much info on all technical aspects of this question would be much appreciated. A lot of words were thrown around and I'd like to get some outside sources.
Thanks.
 
Firstly, welcome to CF! I hope you enjoy your stay!

I don't believe you can erase the data to the point where you could be 100% certain that none of it is every going to be recovered. When doing a more secure wipe (what the DoD, etc, does) is write over the data with zeroes, so that you need to uncover more layers to get to the base data (what was originally deleted). So I suppose if you wiped it with enough layers, it would be very highly improbably that anything incriminating, or otherwise, could be pulled from the drive. The person would, however, be able to tell that something had been erased and written over many times.


Of course, a sure fire way to wipe the drive is to use a magent. That, or a baseball bat. :P
 
The best way to make it impossible to recover data from a hard drive is: get software that overwrites the entire hard drive 35+ times. Then drill holes or otherwise damage the platters inside the hard drive. The next step would be to burn or crush the platters into ash/dust.
 
i worked for a DoD contrator that built ships for the navy and we used BcWipe to wipe hard drives on end of lease workstations we would have to run it 8 times on each HD before we could send the workstations back to IBM.
 
Deepblue said:
i worked for a DoD contrator that built ships for the navy and we used BcWipe to wipe hard drives on end of lease workstations we would have to run it 8 times on each HD before we could send the workstations back to IBM.
Click to expand...

Wow, thats very thorough :)
 
A usual format will only 'wipe' once, but the best kind of wiping is the Guttmann method, 'wiping' 35 times using a complex algorithm. This is obviously more secure and pretty much absolutely ensures no data can be re-traced.
 
The thing to understand is even when hard drives are wiped and then wiped again, whether with the Guttmann method or others, there are residual magnetic traces, nomatter how feint, that could help the FBI etc recover the data. I found this in a google cache page...

"There are very few techniques that, with an unlimited amount of time and resources, would not let us recover data," says Paulynn Schaff, special agent for the FBI, National Infrastructure Protection Center Squad. "To the best of my knowledge, there's never been a situation where I couldn't call one of the national laboratories or a private industry forensics organization we work with and had them say, ‘Pff, we can't do it.'"

The FBI, however, would not comment on the technologies it uses to recover wiped data. Neither would it indicate which commercially available software solutions are best at wiping data, although special agent Schaff says, "Some are much better than others. You could do one pass with some software that might be more effective than several passes with another."
Click to expand...

I would say, for the purposes of selling second hand hard drives to a second party, a good couple of wipes would be fine.
 
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