Erasing PC data is not a
simple exercise to make space on your hard drive. Either because we want
to sell, return or give away a computer, or for simple security reasons, we
must bear in mind that by
dragging a file to the recycle bin and pressing empty we are not deleting anything.
At a time when security is increasingly important, let's take a look at that
world of ones and zeros, what they call low-level wiping and ultra-secure
erasure methods. Today Ray Bradbury would write: "A piece of information in the
hands of a neighbor is a loaded gun."
What is that low
level Data Wiping?
Look at the
graph above. When we execute an erasure, we write zeros over the
ones. But where there was data, there is always a residual magnetism,
which can be read by specialized equipment.
Depending on
the intensity of that wave, the content that existed in the past can be
deduced. Hence, the more rewrites and reads of the same sector, the more
difficult it is to retrieve the information: it is buried, literally crushed,
on the new data.
These are the
main erasure methods:
·
One Pass Zeros: the classic recycle bin. Delete the information by
overwriting the information with zeros.
·
One Pass Random: Exactly the same but using random characters.
·
Russian GOST
P50739-95: the same but with 5 passes.
·
German VSITR: a very popular system that has endured over time, where
erasures of 7 passes per sector are executed.
·
Gutmann method: a similar method, combining overwrites with random
values, up to 35 passes.
·
Custom configuration: most eraser software allows you to specify a
specific number of overwrites, including defining the size of the buffer. Professional
companies opt for this practical tool. They are extremely slow wiping:
whole days can take to certify a total Data wiping.
·
US DoD 5220.22-M: method introduced by the United States Department of
Defense, similar to the aforementioned Gutmann from the past 35. It
consists of overwriting with a fixed value in the first pass, with its
complementary value in the next, and a third rewriting with random values.
·
By
the way, a low-level format not only overwrites, it is also capable of repairing
problems related to a bad magnetization of the disk, in a way that helps to
extend the useful life of the HD and can, in part, fix those read / write
failures that end up leaving entire sectors unusable.
·
No, 35 formats are not necessary
·
Surely
you have heard of a certain compromised computer that took 35 formats. It refers to outdated methods,
as it has already given way to more modern erasure protocols. Specifically
to the Gutmann Method. In 1996, DDS Peter Gutmann and Colin Plumb
introduced a virtually foolproof data erasure method.
·
This
consisted of writing on the original data of 35 different patterns, to
eradicate any trace of the original content and that no forensic computer exam
detected them. This elusive treasurer friendly algorithm was structured as
follows: 4 full disk erasures, followed by 27 random overwrite.
Now comes the harsh reality: at present,
neither information is encoded with the MFM / RLL system nor our hard drives
leave so many holes to detect old fingerprints. By having a higher data
density on the surface of the disk plates, with just two or three erasures we
will have cleaned those files forever. The time factor also plays a determining role,
since the magnetism of hard drives is not alien to the passage of time.
What about defragmentation?
Any file is in turn fragmented into different
pieces scattered throughout the hard drive. The defragmentation process
groups all these pieces together and puts them together in contiguous sectors,
so that they are arranged on the disk.
Using defragmentation as a tool to clean your
hard drive is ideal: it reorganizes memory and leaves all those empty sectors
in place. But in no case is it a complementary tool for erasure. So
no, a foolproof erase requires wiping. According to the certifications of
the NSA (US National Security Agency) and taking into account the current
interfaces, with 3 complete passes we can give our data as missing.
However, seven formats are still recommended. Using
a tool such as Blancco 5, we can choose between specific
configurations to comply with the maximum security protocols.
The purifying fire
Yes, it may sound extreme, but it is one of
the safest methods. And still, some companies have managed to rescue PC
information after a fire. Physical destruction is the infallible method,
although an ordinary user does not usually disassemble each independent plate,
and then sand them or throw some form of acid. And, as we pointed out
in this article, an industrial drill can also be a good enemy of that data that
we do not want anyone to find.
Another
way to physically destroy data is through magnetization. Since data is
written that way, why not reverse the process to erase it? HD enclosures
are becoming more secure, but by unmounting a disk and dragging a magnet over
it, most data will be completely useless. And yes, they sell magnets
both online and in any hardware store.
World-class speed and security
One
reason SSDs are trending over old mechanical HDs is because of the added speed
they offer. But they also represent a leap in security, because it is more difficult to recover the data. When
we want to delete a file, the operating system uses the TRIM command, informing
which block can be deleted and grouping the data to eliminate them in a single
pass.
That's why solid discs are so effective: they
don't do random reads. By reducing the number of readings, they optimize
their speed. SSDs have NAND memory in their old memory, similar to RAM
only that it is not volatile; it remains until you delete it. After a
format, in the computers that use this command the recovery average is reduced to 27%. If
you look at the ASUS ZenBook UX305LA, it has high-speed flash storage - an
SSD of up to 512GB up to 6 times faster than a conventional HD - which reduces
read times to a minimum.
The
other reason to move to SSD is mobility. The aforementioned ZenBook
UX305LA, thanks to its low kilogram of weight and a thickness of 1.49 cm,
mounts up to 512 GB of space. And to that space we would have to add another 100 GB in Web
Storage that ASUS gives to each new client. A wiping
every so often, to download these files, never hurts and keeps the hard drive
clean and efficient.
Although if what we are looking for is
maximum speed, the Tytan series is our goal. The G20AJ has
been considered the most powerful compact desktop in the world. A safe and
agile system that offers better performance in any type of task and includes
one-click wiping tools, restoration tools - with Total Recovery Pro, within the
'Backup & Recovery' menu - and always clean and fast.
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