Hardware data destruction on the hard disk

Live to the full

It's no secret that to completely and permanently delete information from digital media, simply select a file and press the del key or use the rm command is not enough. It’s not so easy to make smart and meticulous guys recover deleted files from your media, and sometimes requires elegant solutions.

Today we will try to figure out how to destroy the data not only definitively, but also with a sense of style during the time that good FSB officers, slandered businessmen and people just insulted by your sense of humor are testing your front door for strength.
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What can be done in order not to wake up in the middle of the night in a cold sweat, worrying about the safety of personal or corporate information - right under the cat.

"Traditional" way. Coercive force

This method is simple as an ax, and also reliable. To completely and permanently erase all data, it is necessary to create a magnetic field of such intensity at which the ferromagnet will simply demagnetize.

The value of magnetic field strength necessary for complete demagnetization of a ferromagnet is called the coercive force.


So, what do we need to use this method?

We already have a ferromagnet - this is your favorite disk with very important data, or rather a thin layer of chromium dioxide deposited on pancake plates. It is this thin layer that is responsible for storing information that should not fall into the hands of rogues and enemies of the people.

It remains the case for small - to get a magnetic field of the desired intensity.

The magnetic field created by the wire with current is directly proportional to the current flowing in the conductor. Therefore, in order to get more current, demagnetizing a hard disk will require more voltage and a wire with a larger section.

Although the domains of the ferromagnet are relatively lazy, a short current pulse should be enough to demagnetize the disk. Therefore, for the accumulation of the required amount of energy is quite suitable battery capacitors. Capacitors are connected in parallel to increase capacity. And for simplicity of construction, we include them directly into the network through a diode bridge. Perhaps not the most elegant solution, but very simple. On the other hand to the capacitors solder wire, entwined around the hard drive. And do not forget about the power button.

True, I did not have time to run to the radio parts store and put it all together.

It turns out that such a scheme has already been implemented and is fully described in the journal “Hacker” as far back as 2006. And the author of this article writes this article. This device was assembled from the remains of the power supply, the red button and the mysterious part called the "shovel conder."

The schematic diagram of the device is not much different from my efforts. The resulting design destroyed the discs with a loud pop, defiantly splashing metal when the wires were closed.

Well, it turns out that this method cannot be called the safest either. But after the operation of this device, the disks, although they had no visible damage, refused to be detected in BIOS.

And here is a link to this creation of human hands .

The article begins on the 20th page.

Since the article recommended that the device be disconnected from the network when the capacitors were discharged, I added a second switch to my circuit. As a result, she acquired the following form:



Schematic diagram of the device in 3D:

1. Diode bridge
2. Battery capacitor
3. Sacrificial disc
4. Light switches

In fairness it should be said that this method is very effectively used in industrial solutions. For example, here are the contents of the Impuls-9V disk shredder.



The same coil, a block of capacitors, which is charged from its rectifier (not in the photo) and the controller.

However, our homemade is dangerous, somewhere difficult to manufacture. But there is a more reliable way. Do you want to burn? I have them!

Destroy at any cost

As Ecclesiastes wrote, “Everything has its time, and the time of every thing under the sky: ... time to scatter stones, and time to collect stones."

There is a time to accumulate information, and there is a time when it is necessary to permanently destroy it. Sometimes the circumstances are such that some data must be quickly and safely get rid of. This modest opus is dedicated to how to get rid of information on the HDD, and at the same time from the hard drive itself.

If I were suddenly offered to destroy the hard drive with all its contents, then the consciousness would instantly give the answer: “burn!”, And the hands themselves would stretch the propane-butane burner. From a physical point of view there is a certain reason for this, since the maximum temperature of the flame can reach 1300 degrees Celsius, and the aluminum plates of the hard disk will begin to melt already at a temperature of about 660 degrees Celsius. It is worth noting that in practice this method will cause a lot of inconvenience, and it will take a lot of time.

However, I still could not refuse myself the pleasure of melting the disc and decided to proceed with the auto-de-fe. For this, I needed the following:

• A disk that will suffer for our sins;
• Gas burner and gas cylinder for it;
• Good acquaintance Greenbastad aka sevasat , who agreed to be an operator.
• It was decided to burn a disc with a stopwatch on to at least roughly estimate the time during which it is possible to destroy the disc in this way.

So, first of all it is necessary to remove the lid, because to warm the body is useless. It took me about 2 minutes, half of which went to tear off the sticker under which the last screw was sitting.


The disk is completely ready for the procedure.

Then, to heighten the fun, we feed to the disk. Damn starts defiantly spinning. I bring the burner, and the blue flame licks the shiny surface of the pancake. In the first second the disk is covered with condensate, but after a moment it becomes smooth and shiny like a mirror again.


The very beginning of the process.

After some time, the pancake expands, and the rocker begins to cut circles on the surface of the disk.



After 5 minutes, the disk stops - it seems that the spindle motor could not stand it. At this point, we pull out the power from the disk so that the wires do not interfere at hand.


Went the seventh minute of the experiment, it seems that the disc began to give up.

And here I see a completely unexpected phenomenon. Aluminum pancake coatings withstand hellish heat much better than the plate itself. The place of heating becomes rippled, begins to gush, but completely refuses to lose shape completely and turn into a puddle of metal. That's so bad luck.


The surface of the pancake gums, but continues to keep its shape.

But it’s too late to retreat, so we continue to shamelessly warm everything that comes to hand: spindle, damn, actuator - nothing escapes a terrible fate. Soon the disk gets warm and the board located on the back side starts to smoke. Then she flashes a yellow flame.


Fire as it is.

“We'll make a fire like this,” the operator says.
- Already arranged! - He laughs in response.

The room begins to fill with acrid smoke, with a piquant aftertaste of phenolic resins.
Meanwhile on the stopwatch 15:52. The experiment could have been completed, but instead, in the 17th minute, we go all-in and light a burner under the disc.



Further events can be described with one single phrase: "wild frenzy".

At the 20th minute, the operator’s patience ends, and he checks the strength of the pancake with a knife. Under the pressure of physical and thermal influences, the disk begins to crumble and crumble, but only where the knife has been, the disk still tries to retain its original shape in other places.


Combined way to destroy information.

Throwing away the knife, my companion is also armed with a torch. We remove one by one, holding the burner in one hand and the camera in the other.



The final moments of madness look surprisingly beautiful - the disc looks like a flower with blue-green petals.



28 minutes - "experiment" is over.

The disk lies motionless and shows no signs of life. It looks very unimportant.


The hard drive is a bit out of shape.


On the back surface of the case turned out to be a rather entertaining pattern, vaguely reminiscent of a frosty pattern on the windows.

Honestly, it is not necessary to melt a hard disk to such a state. Suffice it to reach the Curie point. This is the temperature at which thermal motion will destroy the orderly arrangement of the domains of the ferromagnet. At the same time, the information stored on the disk should disappear (But this is not accurate). For chromium dioxide, whose film is most often used to store data on hard disks, the Curie temperature is 386 ° K. But I am a dark man, so I melted everything to the ground. Moreover, this approach ensures the impossibility of data recovery. But it does not guarantee that molten aluminum will not manage to drip into your sneakers.

However, it is worth noting that after the collapse of the shuttle Columbia, the disk, which descended on a fiery chariot and struck the earth, still contained information that was almost completely recovered.


Drive from the shuttle.

Therefore, perhaps, our zeal was not so vain.

True, we killed the hard drive was only one pancake. He was chosen randomly from several failed HDDs, and this fact came as a complete surprise to us. Therefore, no matter how much the pancakes roasted hiding near the wall, we will not know.

In fact, a little imagination and knowledge of the laws of physics will help you find a whole bunch of ways to destroy discs, but after the experiment, I would have thought three times before putting them into practice. Do not forget that it is always possible to erase the data, and then write new ones on top of them, or just a random set of zeros and ones. This method of data destruction, despite the fact that it is terribly slow, ensures the safety of your hard disk.

Conclusion

So what do we have at the end?

You can always destroy the disk with your own hands with the help of uncomplicated improvised means. However, this option is suitable only if you have a supply of unnecessary disks, and also want to spend your time unusually and try a new kind of leisure. In practice, this method is more than useless, and moreover, it can be dangerous to your health.

A self-made destroyer, like the first one, is more suitable for shorting dark winter evenings than for use for its intended purpose.

The third and perhaps the only worthy option is the purchase of a finished device with great functionality and a design that has been tested by tests. Although this, of course, is not our method.

The article was published on April 1 :). Created in collaboration with Alexandr_1101 (the main idea and its text).