So what does NIS 800-88 say? It says “a single overwrite pass with a fixed pattern such as binary zeros typically hinders recovery of data even if state of the art laboratory techniques are applied to attempt to retrieve the data.” Great, that’s in line with NISPOM. Instead of three passes, it now suggests a single pass is fine, writing a character (e.g. Instead, it directs you to NISPOM, which has a different clearing suggestion for “non-removable rigid disks” (gotta love that modern terminology). Interestingly, the DoD published an instruction that cancelled directive 5220.22M. And that’s without considering that SSDs now store data much differently in order to extend the life of the drive by ensuring all bits of the SSD are written an equal number of times (separating logical sectors from their physical storage). The first is still a real issue, but the second is probably no longer an issue. This three-pass erasing of the drive was designed to address two problems: (1) there could be deleted-but-not-erased files present on currently-unused portions of the disk, and (2) there could be magnetic “echoes” that could still be used to determine recent bit values even if they were overwritten by new data. 0xFF), and then a random character, for a total of three write passes across the whole drive. Obviously physical destruction of the drive (incinerate, pulverize, melt, etc.) is acceptable, but if you want to use the drive again, the basic clearing method is to write over each byte of the drive with a character (e.g. It’s a big document, but we can focus on one specific portion of it: sanitation (erasing) of data from hard drives (non-removable rigid disks). Let’s look at those one at a time, starting with the DoD directive 5220.22M. US Department of Defense (DoD) directive 5220.22M.“Can you tell me how to properly wipe a disk before we dispose of or return this PC, following standard X?” where “X” can be one of a few different standards: This is one of those topics that I’ve been in the middle of for years.
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