Method of cleaning data is a special method by which a data destruction program or file shredder to overwrite the data on the hard disk or other storage device to the stored data securely destroyed without possibility of recovery.
Technically, there are other methods of destroying data that are not based on overwriting sectors to media, such as destroying media in shredders, demagnetizing hard drives, or burning hard drives and SSDS. As a rule, the term “data cleaning” refers to software methods of information removal.
List of data cleaning methods
Here are some popular data cleaning methods used by data destruction programs:
- Secure Erase (industry standard)
- DoD 5220.22-M (US Department of defense)
- NCSC-TG-025 (us Department of security)
- AFSSI-5020 (US AIR FORCE)
- AR 380-19 (US Troops)
- NAVSO P-5239-26 (US Navy)
- RCMP TSSIT OPS-II (Canada)
- CSEC ITSG-06 (Canada)
- HMG IS5 (United Kingdom)
- ISM 6.2.92 (Australia)
- NZSIT 402 (New Zealand)
- VSITR (Germany)
- GOST R 50739-95 (Russia)
- Gutmann (Peter Guttman)
- Schneider (Bruce Schneier)
- Pfitzner (Roy fitzner)
- Filling in random data
Most data destruction programs also allow you to customize your own data cleaning method with any overwrite pattern and as many passes as you want. For example, a program might allow data to be overwritten with zeros during the first pass, ones in the second pass, and then random characters for eight more passes.
What is the best method of data cleaning?
Overwriting one or more files or the entire hard drive just once with a single character (one or zero) should prevent data recovery from the hard drive by any file recovery software - this has been proven by research laboratories, which means most data cleaning methods are overkill.
Most experts agree that the best way to safely erase is to overwrite the entire hard drive in a single pass. The very simple Write Zero method does pretty much the same thing, albeit much slower.
Using any cleanup method to delete data actually just comes down to writing other data on top of your previous ones – this happens both when you safely delete one file and when you clean up the entire hard drive or disk array.
If one overwrite is enough, why are there so many methods to clean up data?
Some researchers believe that there are, or may be, methods for extracting information from hard drives that use residual plate magnetization, which will allow data to be recovered even after each sector on the drive has been completely overwritten. Therefore, independently of each other, different organizations have developed their own standards that guarantee the impossibility of recovery, not only existing methods, but also those that will appear in the future. In simple terms, everyone is trying to make a name for themselves on what is unclear and inaccessible to others.
What do you mean, “record check”?
Most of the methods to securely erase the device using the test recording sector, to ensure that his content really has changed. Some data cleaning programs allow you to change the number of such checks: once at the very end of the process (after all passes have been completed), or after each pass.