Best Practices/Ways for Data Wiping

 

Best Practices/Ways for Data Wiping

In our last blog, we talked about the importance of being able to safely and permanently erase data at the end of its useful life. Whether you are working for a company that has a legal obligation to destroy customers' personal information after a certain period of time, or you are considering selling your old Smartphone on eBay and you want to make sure that no one digs up your selfies, it pays to know how to get the job done right. And yet this is often a source of confusion: many consumers and businesses have misconceptions about what secure data shredding is and what it is not.

Formatting a disk, for example, will not actually erase it, but will only delete the existing file system and generate a new one, somewhat similar to throwing out a library catalog when you really want to check out the books from the library. What's more, breaking hard drives with a hammer is also no guarantee - unlikely as it may be - that someone with enough time on their hands won't be able to reassemble the platters and transcribe the data.

So how can consumers and businesses achieve peace of mind that their confidential information is not used against them after it has been erased? In fact, there are some failsafe data destruction methods that are endorsed by governments and international standards bodies, and that vary widely in cost, each with particular advantages and disadvantages. Here are three of the most important.

Method 1: Data Erasure Software

One of the easiest ways to permanently erase data is through the use of software. Hard drives, flash storage devices and virtual environments can be removed without the need for specialized hardware, and the necessary software ranges from free - like the 'shred' command included in most Unix-like operating systems - to commercial products like Unistal’s Data Wipe, Blancco 5 .

Although different data destruction applications use different techniques, they all adhere to a single principle: overwrite the information stored in the medium with something else. Therefore, a program could go through the hard disk sector by sector and replace each bit with a zero or with randomly generated data. In order to ensure that no trace of the original magnetic pattern is preserved, this is typically done several times: the most common algorithms include the seven-pass Scheier and the even more rigorous 35-pass Gutmann method.

Unfortunately there are some drawbacks with software-based data erasure. First of all, it takes a long time. Also, and perhaps most importantly, is the fact that if some sectors of the hard drive become inaccessible by normal means, the application will not be able to write to them. However, someone with the right tools could recover data from a bad sector.

Obviously software-based data erasure also runs into a problem when you want to destroy information stored on media that can only be written once, such as most optical discs.

 

Method 2: Degausser (degaussing)

The days of cathode ray tubes may be far in the past, but you probably remember what happened when you placed a powerful magnet next to an old television or computer monitor: electrons shooting towards the back of the screen. screen going off course and resulting in distorted colors. To avoid this, those devices contained degaussing coils - components designed to reduce or eliminate undesirable magnetic fields.

This process is also used to render data on retired hard drives and other magnetic media irrecoverable. A modern degausser, like the Ontrack Eraser Degausser 3.0 , is basically a giant box that generates a powerful magnetic field, causing the existing magnetic domains in the magnetic medium to fall into disarray. This is usually extremely reliable, but there could be a problem in that state-of-the-art hard drives are denser than their ancestors and therefore require more magnetic force to be fully degaussed. But the current generation of degaussers should still be fit for use for quite some time.

Unfortunately, degaussing has a couple of drawbacks. For starters, it is effective on magnetic media, but only on magnetic media. One degausser may be enough to clean a 100-terabyte hard drive, but inserting a flash storage device into it will come out of the process unscathed.

Second, degaussed hard drives cannot be reused, so it is not an ideal solution for companies looking to recycle or sell their hardware.

Method 3: Physical Destruction

Finally, physical destruction of the media is an option, although, as discussed above, it is not as foolproof as it sounds. As Kroll On track has shown on YouTube, a hard drive can suffer significant damage before the data on it becomes irretrievable. In fact, even if the interior turntables were smashed, it is theoretically possible that someone could put the pieces together and retrieve the contents.

In reality, simply breaking a hard drive into two pieces is not a suitable technique to permanently erase data at the end of its useful life. If a business goes down the path of physical destruction, it must ensure that the media is smashed into as many pieces as possible - most professionals recommend using a special hard drive shredder.

For devices that use flash memory, the process is a bit different. If the memory chip itself is destroyed, the data cannot be recovered. But if they survive, they can be transplanted onto another printed circuit with a new controller chip and the information can be accessed without great difficulty.

Bottom line: it's easy to assume that physical destruction of media is a guaranteed way to safely erase data, but that's not always the case. Getting it right is often as slow a process as any other method and requires no less rigor.