Deleting data from a computer It is a sensitive job. U.S. Decided to withdraw from Afghanistan, The Department of Defense issued a report Guidelines to prevent information from falling into the hands of the Taliban. The withdrawal of troops from the Asian country is a very serious and heroic situation. This is a source that is sometimes used to destroy evidence of crime or to compromise photos. Most of the procedures used by companies and individuals before recycling or disposing of a computer. In all these cases, deleting the data alone is not enough, says Juan Jose Galen, Head of Business Strategy at All4Sec, who says expert hands can recover information without problems.

“Formatting a hard drive is not enough,” Gallon explains. If we reformat a computer’s hard drive, we think it will be configured in its original factory installation and all information will be erased. However, nothing more than the truth. “Reformatting a computer’s disk can lead to the disappearance of file index tables, but not their contents, the expert explains. “This is practically the same as deleting a file and forgetting it in the recycle bin.” Therefore, content can be retrieved and accessed immediately with the appropriate tools.

That is, when we delete a file and free the memory, the computer marks that piece of memory as available, but the file is actually still available. What is the correct standard procedure? First of all, you need to go to the classic hard drive formatting. But it is also necessary to rewrite it several times. When a user saves a file, the system does not archive it into a single piece, but divides it into several pieces, so with a single overwrite, pieces of a file remain intact. This option cannot be used on damaged or unedited CDs and DVDs.

An example: If we have a 500GB internal hard drive, we will format it first. After that, we have to copy and paste a large file (for example 5gb movie) 100 times to fill the capacity. After that, we must not forget to empty the recycle bin. “It’s better to reformat the disk a second time,” says Galen.

There is a second option, which involves decomposing the hard drive. Those who watched the series breaking Bad They remember the first chapter of the fifth season, in which Walter White and Jesse Pinkman used a giant magnet to demagnetize the criminal content of a computer guarded by police. Something similar can be done on a small scale. Demonization is the process of exposing the media to a strong magnetic field, erasing the data stored on the device. For each device, depending on its size, shape, and type of magnetic support, a specific force is required to ensure complete polarization of all particles, National Institute of Cyber ​​Security (InCB).

Neither of these two procedures, the editing, and Degas’ destruction of the media. The fastest way to delete information is to destroy the media. In fact, “on optical and electronic disks, such as DVDs, CDs, or solid hard drives (SSDs), physical destruction only guarantees the destruction of stored content,” explains Juanjo Galen. “But there are conditions even for destruction. Criteria UNE-EN 15713: 2010, Secure destruction of confidential objects, code of good conduct, It can be crushed or shattered to eight levels, ”says the expert igs. There are formulas such as decomposition, dust, melting or burning, all of which completely destroy the storage medium. “These methods are usually carried out on a metal shredder or at an approved incineration plant,” the InCB warns. Shredders can be used to destroy flexible storage media, such as obsolete floppy disks. Optical storage media (CD, DVD, magneto-optics) should be crushed and destroyed by cross-cutting shredding or burning.

And what about mobiles? These tools are a special case, Gallon explains. Its contents are encrypted, so a factory reset is usually sufficient. In any case, this only applies to the terminal’s internal memory. If the phone has a SIM card, it will need to be overwritten so that the content is not available to third parties. “It is important to remember that technological obsolescence is an irreversible process. Sooner or later the equipment will become obsolete and we can all make mistakes when we discard them. “

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