As a result, more data breach are reported when files are sent to recycling centers, transferred elsewhere, or when a device is lost compared to attempting to hack or breach security.
We often hear a controversy that performing multiple disk overwrite passes, regardless if it eats up our time is a safest method of software data destruction. These methods are effective 10 years before where development of how the hard disk reads and write are not as advance as it is today. The question is, will we still need to overwrite the data several times or is one pass enough to make it unrecoverable?
Why Overwrite Data
When a file gets deleted it goes to the trash, right? If you don't want anyone to restore these files, emptying the recycle bin seems to be the best way to make it unrecoverable. This is not the end of your file yet. Because what actually happens when you empty your trash, is it just removes the index of the file.
The index is like the computer's table of contents. Every file has its own index, so the computer can locate whatever file you wish to show faster. If the index is gone, the computer won't be able to view the file, but the actual file itself resides somewhere in the computer's free space, waiting to be overwritten. The computer's overwriting process will take into action when a new file is created. Moreover, overwriting starts from the oldest file that was removed up to the newest.
It is possible to recover data permanently deleted using a file recovery software.
That is why we need to overwrite data because you can choose to select the file to be overridden or entirely overwrite the contents of the disk, so it won't be recovered.
How Multi-Pass Overwrite Started
The common controversy is when people claimed that two overwriting passes is not enough because it can be recovered by using advanced tool or advanced data recovery software. Moreover, popular claims define that a secure software data destruction method should take not two but ten to 35 passes. It is because Magnetic Force Microscopy can read overwritten tracks that are below 35 passes according to Peter Guttman, the creator of the Guttman Method.
What is Magnetic Force Microscopy?
Magnetic Force Microscopy is a technique used in viewing overwritten data on the drive. It uses imaging for magnetization patterns with high-resolution and minimal sample preparation.
How MFM works?
This technique is derived from Scanning Probe Microscopy (SPM) and uses a sharp magnetic tip that is fastened to a flexible cantilever placed close to the surface to be analyzed where it interacts to the stray field coming out from the disk.
Disadvantage of MFM
Although you can recover overwritten files with MFM, the MFM microscope is extremely expensive. You are also required to have exact knowledge on how to perform MFM successfully. One sector can take minutes to perform, and if there is even a slight mistake, recovery won't be successful. Unless the file is extremely valuable, MFM is an expensive method to try. No identity thief will spend half the day scanning one drive only to find out that there is nothing of importance in that drive.
Which means there is 0.80% chance that anyone scavenging for broken hard disks in the dumpster or buying your used drive can recover sensitive information out of overwritten drives even if it is only one pass.
Software Data Recovery
Software data recovery works by scanning the files index focusing on the deleted files. Anything that is removed is shown in the recovery software, and with just one click, deleted files can be recovered.
Although overwritten files cannot be recovered, most file recovery software claims that they can recover files from overwritten media, and this claim is not true.
It is possible to recover overwritten data but, the recovered file is not usable.
Conclusion
Today's modern drives are equipped with features 10-year-old hard drives don't have. Moreover, multi-pass data was implemented when floppy disks were popular. Which means, during that time, Run Length Limited (RLL) and Modified Frequency Modulation (MFM) was the encoding used in hard disk drives and these encoding methods are not being used in hard disk drives for more than a decade now.
Although there are no known cases about a hard disk drive being used to gather sensitive information and sell it, preventing something to happen can save you a lot of money and resources, as opposed to fixing the problem.
Arnel Colar is a freelance writer that writes anything that can provide knowledge to the readers around the world. He writes articles ranging from environment preservation, social education, finance and loans, money, and anything that he can think of. With good research, convincing details, and creative insights added with passion, articles can become a masterpiece.
On his free time, he writes blogs about his experiences on the freelance industry. You can visit his blog at http://freelanceadvise.blogspot.com/ to know more about what a freelance is. Do you have a computer with a reliable internet connection? Then jobs are just a click away.
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