DoD 5220.22-M

It appears as an option in almost every erasure software, and many tenders demand it: the DoD 5220.22-M standard. But where does it come from, what exactly is behind it, and how does it fit today's data carriers such as SSDs? This entry puts the method into perspective.

What is DoD 5220.22-M?

The manual regulates how companies working for the US government handle classified information. The versions from the 1990s contained a table on clearing and sanitizing data carriers ("Clearing and Sanitization Matrix"). This is the origin of the overwriting method that is still known today under the name DoD 5220.22-M.

Later versions of the manual no longer contain this table and refer to the respective competent authorities. Since 2021, the rules of the program have been set out as a US federal regulation (32 CFR Part 117). However, the name DoD 5220.22-M lives on as an established designation for a proven overwriting method.

How the method works

Variant	Sequence
DoD 5220.22-M (3 passes)	1. Overwrite with one character, 2. with its complement, 3. with random values, then verification
DoD 5220.22-M ECE (7 passes)	Extended variant: two 3-pass runs with a random pass in between

The verification at the end is decisive. It ensures that all addressable areas have actually been overwritten. More on the principle at Overwriting.

Context: HDD, SSD and other standards

With classic magnetic hard drives (HDD), the method overwrites all sectors that the operating system can address. Hidden areas such as Host Protected Area and Device Configuration Overlay must be detected and released beforehand. Good erasure software does this automatically.

With SSDs the situation is different. A flash controller distributes write operations internally and keeps spare blocks that cannot be reached directly from outside. Here, commands executed by the data carrier itself, such as Sanitize or cryptographic erasure, are used in addition or as an alternative. How this works together is explained in the guide Securely erasing hard drives and SSDs.

Newer guidelines such as NIST SP 800-88 therefore distinguish by data carrier type rather than by number of passes. Similarly well known are the Gutmann method with 35 passes and the German method VSITR with seven passes.

DoD 5220.22-M at Second IT

Second IT erases with the Blancco software and is a Blancco ITAD Gold Partner. The certified erasure methods meet international standards such as DoD 5220.22-M and NIST. Hidden areas such as HPA and DCO are also erased. Every erasure is logged, and you receive a digitally signed erasure certificate per device. More on certified data deletion.

Frequently asked questions about DoD 5220.22-M

How many passes does DoD 5220.22-M have?

The well-known standard variant has three passes followed by verification. The extended ECE variant works with seven passes.

Is DoD 5220.22-M suitable for SSDs?

Overwriting alone does not reliably reach all internal storage areas on SSDs. Firmware-based methods such as Sanitize or Crypto Erase are therefore used for SSDs, often in combination with an overwriting pass and verification.

Is DoD 5220.22-M still an official standard?

The current versions of the US manual no longer prescribe a specific overwriting method. As a designation for the method, however, DoD 5220.22-M remains widespread in erasure software, tenders and erasure certificates.

Where does the name DoD 5220.22-M come from?

It is the designation of the "National Industrial Security Program Operating Manual" of the US Department of Defense. Earlier versions contained a table on clearing and sanitizing data carriers. This is the origin of the overwriting method that still bears this name today.

What is the difference between DoD 5220.22-M and the Gutmann method?

Both are overwriting methods. DoD 5220.22-M works with three passes followed by verification, the Gutmann method with 35 passes. Newer guidelines such as NIST SP 800-88 distinguish by data carrier type rather than by number of passes.