Gutmann Method

The Gutmann method is an algorithm for securely erasing the contents of computer hard drives, such as files. Devised by Peter Gutmann and Colin Plumb, it does so by writing a series of 35 patterns over the region to be erased.

The selection of patterns assumes that the user does not know the encoding mechanism used by the drive, so it includes patterns designed specifically for three types of drives. A user who knows which type of encoding the drive uses can choose only those patterns intended for their drive. A drive with a different encoding mechanism would need different patterns.

Most of the patterns in the Gutmann method were designed for older MFM/RLL encoded disks. Relatively modern drives no longer use these older encoding techniques, making many of the patterns specified by Gutmann superfluous. Moreover, since about 2001, ATA IDE and SATA hard drive manufacturer designs include support for the “Secure Erase” standard, obviating the need to apply the Gutmann method when erasing an entire drive.

The method was first presented in the paper Secure Deletion of Data from Magnetic and Solid-State Memory, in July 1996.

Read more about Gutmann Method:  Technical Overview, Method, Criticism, Software Implementations

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