What is the DoD 7-Pass Wipe Standard?
DOD Standard 5220.28 STD is the data sanitization method that was developed by the US Department of Defence and is usually used to wipe sensitive data from a hard drive or any other storage device.
Why is it Important?
The DoD 7-Pass Wipe Standard is one of the most effective data-wiping procedures to exist. It is able to protect highly sensitive information by making data with drive unrecoverable to prevent data leaks. It is also a highly efficient method that takes less time when compared to other data-wiping methods.
How does DoD 5220.28 STD work?
DoD Standard 5220.28 STD recommends overwriting all the locations with a character, its complement, and then a random character and then verifying. So as to clear and sanitize the information stored on the media. The process is as explained below:
- It overwrites all addressable locations with 0x35.
- Then the hard dive locations will be overwritten by 0xCA.
- It overwrites the drive or any storage device with a random character.
- Now, all addressable locations on the hard disk are verified in hardware using the Verify Sectors command to the disk.
In order to perform this, it requires 7 passes (hence, it is slower) matching the U.S. Department of Defense standards (DOD 5220.28).
The method first overwrites with 01010101. The second overwrite is performed with 10101010. This cycle is repeated three times. The final overwrite is made using random characters. The Department of Defense (DoD) hard disk wipe standard requires the data to be destroyed and rewritten multiple times to ensure proper data protection.
Pass number |
Write Action |
|---|---|
|
PASS 1 |
0x56 |
PASS 2 |
0xAA |
PASS 3 |
0x56 |
PASS 4 |
0xAA |
PASS 5 |
0x56 |
PASS 6 |
0xAA |
PASS 6 |
Random |
Note: If you have an SSD or any flash-based storage device it is better to avoid the DoD 7-Pass Wipe Standard as it may shorten the lifespan of your drive.
Is it still Relevant?
The DoD 7-Pass Wipe Standard has been around since the early 2000s. With new technologies such as SSDs and flash-based drives, The DoD 7-Pass Wipe Standard is still relevant but is no longer an industry standard.
Today, there is no requirement to overwrite data 3 to 7 times as today's storage devices make use of advanced writing technologies that are highly precise and can securely wipe data within 1 overwriting pass.
While the DoD 7-Pass Wipe Standard is not followed religiously it is still used and proven to be highly effective on older hardware.
