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Data erasure (sometimes referred to as data clearing, data wiping, or data destruction) is a software-based method of data sanitization that aims to completely destroy all electronic data residing on a hard disk drive or other digital media by overwriting data onto all sectors of the device in an irreversible process. By overwriting the data on the storage device, the data is rendered irrecoverable.
Ideally, software designed for data erasure should:
Permanent data erasure goes beyond basic file deletion commands, which only remove direct pointers to the data disk sectors and make the data recovery possible with common software tools. Unlike degaussing and physical destruction, which render the storage media unusable, data erasure removes all information while leaving the disk operable. New flash memory-based media implementations, such as solid-state drives or USB flash drives, can cause data erasure techniques to fail allowing remnant data to be recoverable.[1]
Software-based overwriting uses a software application to write a stream of zeros, ones or meaningless pseudorandom data onto all sectors of a hard disk drive. There are key differentiators between data erasure and other overwriting methods, which can leave data intact and raise the risk of data breach, identity theft or failure to achieve regulatory compliance. Many data eradication programs also provide multiple overwrites so that they support recognized government and industry standards, though a single-pass overwrite is widely considered to be sufficient for modern hard disk drives. Good software should provide verification of data removal, which is necessary for meeting certain standards.
To protect the data on lost or stolen media, some data erasure applications remotely destroy the data if the password is incorrectly entered. Data erasure tools can also target specific data on a disk for routine erasure, providing a hacking protection method that is less time-consuming than software encryption. Hardware/firmware encryption built into the drive itself or integrated controllers is a popular solution with no degradation in performance at all.
For sanitizing entire disks, built-in sanitize commands are effective when implemented correctly, and software techniques work most, but not all, of the time. We found that none of the available software techniques for sanitizing individual files were effective.