Erase data from PC is not a simple exercise to make room for the hard drive. Whether because we want to sell, return or give away a computer, or simply a matter of security, we must bear in mind that drag a file to the recycle bin and emptied press we are not eliminating anything.
At a time when security is increasingly important, let’s take a look at the world of ones and zeros, what they call low-level format and methods of ultra-cleared.
Today Ray Bradbury wrote: “A data in the hands of a neighbor is a loaded gun.”
What’s that low-level formatting?
Look at the top graph. When you run a delete, we write zeros on one. But where there was always a residual data magnetism, which can be read by specialized equipment.
Depending on the intensity of this wave can deduce the content that was in the past. Hence, the more rewrites and reads on the same sector, the harder it is to recover the information: is buried, literally crushed on the new data.
- One Pass Zeros: Classic recycling bin. Deletes the information by overwriting the data 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 popular system that has endured over time, where running erased from 7 passes by sector.
- Gutmann Method: A similar method combining overwriting with random values, until 35 passes.
- Custom settings: Most erasure software allows you to specify a particular number of overwrites, even define the size of the buffer. Professional companies choose this handy tool. They are extremely slow formatting: to certify a memory reset can spend whole days.
- US DoD 5220.22-M: Method introduced by the United States Department of Defense, similar to that Gutmann of 35 passes. It is to overwrite with a fixed value on the first pass, with its complementary value in the next, and a third rewrite with random values.
Indeed, a low-level format not only overwritten, is also able to repair problems related to poor magnetization of the disc, so that helps extend the life of HD and can, in part, fix those errors read / write they end up leaving entire sectors unusable.
No, not necessary formatter 35
Surely you’ve heard of a compromised computer on which 35 took formatting.Refers to antiquated methods , as has already given way to more modern protocols deleted. Specifically the Gutmann Method. In 1996, Drs Computer Peter Gutmann and Colin Plumb presented a method of erasing data virtually foolproof.
This was to write about the original data from 35 different patterns, to eradicate any trace of the original content and that no examination of the detected computer forensics. This algorithm flighty friend treasurers was structured as follows: 4 deleted disk full and immediately, 27 random overwrites.
|SENDING THE FILE TO THE TRASH||Nothing. It’s like changing from one folder to another.|
|EMPTYING TRASH||Same. The operating system moves the files to a folder invisible. It will overwrite each other.|
|WITH A FORMAT||It is reduced to 70% of the magnetization. Some parts of file are lost.|
|TWO FORMATTER||It is reduced to 80% of the magnetization. Rebuilding files depends on the randomness of formatting.|
|THREE FORMATTER||It is reduced to 90% of the magnetization. It is very difficult to recover files because some parties are corrupt.|
Now comes the hard reality: today or information is encoded with the MFM / RLL system or our hard drives leave many holes to detect ancient footprints. By having greater data density on the surface of the disk platters, with just two or three deleted we will have cleaned those files forever. It also plays a role the time factor, since the magnetism of hard drives is no stranger as time passed.
Any file is fragmented in turn in different pieces scattered across the hard drive.The defragmentation process brings together all those pieces and board in contiguous sectors, so that they are arranged on the disk.
Use defragmentation as a tool to clean the hard drive is ideal: reorganizes the memory and leaves all those empty sectors on your site. But in no case it is a complementary tool for erasing. So no, a foolproof deletion requires formatting.According certifications NSA (National Security Agency US) and taking into account the current interfaces, with 3 complete passes we can give our data missing.
However, it still recommend seven formatting. Using a tool such as Blancco 5 we can choose between specific configurations to meet the highest security protocols.
The refiner’s fire
Yeah, maybe it sounds extreme, but it is one of the safest methods. And even with all, some companies have managed to rescue PC information after a fire. The physical destruction is the foolproof method, if a user does not usually walk disassemble each separate plate, then sand them or throw them some form of acid. And, as we noted in this article, an industrial drill can also be a good enemy of those data that do not want anyone to find.
Another way is physically destroy data by magnetizing. Since data is written that way, why not reverse the process to delete? HDs carcasses are becoming safer, but removing a disc and dragging on it a magnet, most data will be completely useless. And yes, sell magnets both online and in hardware stores.
Speed and security concern
One of the reasons that the SSDs are a trend, compared to the old HD mechanics, is offer the added speed. But also they represent a leap in security, because it is more difficult to recover data. When we delete a file, the operating system uses the TRIM, reporting that block can be erased and grouping the data to remove one last command.
So solid discs are so effective: do random reads. By reducing the number of readings, optimize speed. The SSD housed in its previous NAND memory, similar to the RAM just is not volatile, remains until the lees. After formatting, on computers that use this command the recovery rate is reduced to 27%. If you look at the ASUS ZenBook UX305LA, it has flash – a high – speed storage up to 512 GB SSD up to 6 times faster than a conventionally HD reduces reading times to a minimum.
The other reason is switching to SSD mobility. Said ZenBook UX305LA, thanks to its low weight and a kilogram of thickness of 1.49 cm, mounted up to 512 GB of space. And that space would have to add another 100 GB WebStorage ASUS gives each new customer. Formatting time to time to download those files, never hurts and keeps the hard drive clean and efficient.
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