Learn about the method of clearing DoD 5220.22-M data

DoD 5220.22-M is a software-based data sanitization method, used in various file shredder and data shredder programs to overwrite existing information on hard drives or other storage devices.

Deleting a hard drive using the DoD 5220.22-M method will prevent all software-based file recovery methods from getting the information from the hard drive and also prevent most hardware-based recovery methods.

What is DoD 5220.22-M?

The DoD 5220.22-M method was originally defined by the National Industrial Security Program of the United States and is one of the most common methods used for data destruction software.

Most data destruction programs support a number of data sanitization methods in addition to DoD 5220.22-M, such as Secure Erase, Write Zero, Random Data and Schneier.

How to delete DoD 5220.22-M

The data sanitization method of DoD 5220.22-M is usually performed in the following way:

1. 1st time : Override number 0 and verify the writing.
2. 2nd : Override number 1 and verify the writing.
3. 3rd : Overwrite a random character and verify the writing.

You may also come across different versions of DoD 5220.22-M including: DoD 5220.22-M (E), DoD 5220.22-M (ECE), etc. Each version may use a single lettering. override and different verification frequency.

Although less common, there is another version of DoD 5220.22-M that overrides 97 for the last time instead of a random character.

The software uses the DoD 5220.22-M erasing method

Some free programs use the standard DoD 5220.22-M to erase all information from the hard drive.

A popular tool is DBAN. Similar software includes CBL Data Shredder.

Examples of some free file shredder software that have the option to delete files based on DoD 5220.22-M include Eraser, Securely File Shredder and Freeraser.

Is DoD 5220.22-M better than other methods?

It doesn't matter which method you delete data from. Because most of us just wipe our hard drive before selling or installing a new operating system, there's nothing to worry about how many random characters are written to the drive.

However, when choosing the data sanitization method, you need to consider how long it will take to wipe the drive. If you have a really large hard drive, Write Zero will take less time to complete than the DoD 5220.22-M, (but the DoD 5220.22-M will be much faster than Gutmann, the method can be done more. 30 overrides).

Also, consider whether verification is done after overwriting. Because some software can implement the DoD 5220.22-M method in a way that verifies each write, the whole process will take longer than using another erase method without verification (like Secure Erase), or wait until the last turn is completed to verify that the data has been overwritten.

Another factor that can determine the method you use is the actual data used to overwrite the hard drive. Some delete methods, like Write Zero, only use zeros instead of random characters. The use of random characters will make the probability of data recoverable lower.