Overwriting is a method where a random pattern of usually “1” and “0” is written to every part of the drive, frequently three times, to obliterate the underlying data. The advantage of this method is the drive can be re-used. However, there are several disadvantages with Overwriting:
- Only adds layers to existing data, the underlying data still remains and is susceptible to forensic recovery
- Requires a skilled operator to ensure the overwriting is done correctly
- Non-functioning sectors of the hard drive cannot be overwritten allowing data to remain on the drive
- Because Overwriting is not regarded as fail-safe, it is not permitted for the highest data security standards such as the NSA or DoD
- Nearly five times the cost of degaussing because it requires a considerable amount of time (hours) and electricity