Such an illustrious academic as yourself deserves an equally illustrious answer: http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html
The lazy among us, however, should skip to Dr. Gutmann's conclusion: "Data overwritten once or twice may be recovered by subtracting what is expected to be read from a storage location from what is actually read. Data which is overwritten an arbitrarily large number of times can still be recovered provided that the new data isn't written to the same location as the original data (for magnetic media), or that the recovery attempt is carried out fairly soon after the new data was written (for RAM). For this reason it is effectively impossible to sanitise storage locations by simple overwriting them, no matter how many overwrite passes are made or what data patterns are written. However by using the relatively simple methods presented in this paper the task of an attacker can be made significantly more difficult, if not prohibitively expensive." Would NSA invest large sums of money to read deleted stuff off hard drives if they knew it could always work? Methinks yes. -DMZ On Wed, 2005-11-02 at 17:16 -0500, Rob wrote: > On Wed, Nov 02, 2005 at 12:28:34PM -0500, David Zakar wrote: > > Yes. There was a discussion on bugtraq (or focus-linux?) a while back, I > > believe. Essentially, the best way to delete your data is to never store > > it unencrypted, and make sure to use a good crypto algorithm. You could > > always piece together a shattered hard drive and then read that, whereas > > brute forcing the encrypted data is mathematically just not going to > > happen. > > > > Of course, they could still conceivably read your RAM, so you'll need to > > physically destroy/hide that, too. And your crypto key! Breaking into > > your house and stealing that hidden USB key is a serious issue... > > I've always taken it as a question of your faith in voodoo: > > Does the NSA have stronger voodoo in making lost bits coming back to > life or by breaking strong encryption? Lots of smart people can talk, > but no one really nows.. > > > - Rob > . > > -- David Zakar <[EMAIL PROTECTED]>
