The AFSSI-5020 data sanitization method is usually implemented in the following way:
- Pass 1: Writes a zero
- Pass 2: Writes a one
- Pass 3: Writes a random character and verifies the write
You might also see iterations of the AFSSI-5020 data sanitization method that write a one for the first pass and a zero for the second. I've also seen this method implemented with verifications after each pass, not just the last one.
Erasing a hard drive using the AFSSI-5020 data sanitization method will prevent all software based file recovery methods from lifting information from the drive and is also likely to prevent most hardware based recovery methods from extracting information.
The AFSSI-5020 sanitization method was originally defined in the Air Force System Security Instruction 5020 by the United States Air Force (USAF). It's unclear if the USAF still uses this data sanitization as its standard.
Most data destruction programs support multiple data sanitization methods in addition to AFSSI-5020.