wipe

On destroying data

The Known Plaintext blog has a pretty interesting high-level article called Ten Commandments of Data Destruction, which gives some advice on how to handle destruction of data on hard drives or USB thumb drives (e.g. if you want to sell them on eBay)...

While most of the stuff is good advice, there's one thing in there which is certainly not a good idea: "format your hard drive before giving it to the recycler"! That will usually not help at all! Don't ever think that formatting will really erase your data! Using simple, and widely-available tools everybody could restore data from such a formatted drive, even without requiring any costly equipment.

If you absolutely must sell or give away an old hard drive (physical destruction is always better!), wipe it with a Gutmann-style tool, such as wipe(1), or shred(1). Oh, and apply the tools to the raw partitions (e.g. /dev/hda) after booting from a live CD. Wiping single files on a mounted file system might not yield the expected results on some (journalled) file systems, because they are caching stuff etc...

The follow-up article presents some further ideas, e.g. an acid bath for your hard drive. It also mentions that simply breaking the read/write head or the motor of the disk might not suffice, forensics labs could replace those parts successfully...

David Bianco makes a very good point about data on company laptops (especially so if you consider the alarmingly high rate of "laptop theft, xxx million data records lost"-type news stories): "don't put the freakin' data on the laptop in the first place!".

(via Jesse Kornblum)

Syndicate content