I feel as though I should revive this post with some additional information... I am sure it's most likely been written elseware as suggested but here it is again none-the-less.
Image removed by moderator as it goes against forum size rules
Deletions: whats secure and when?
1-pass deletions are good for SSD's this is considered secure due to the nature of most modern SSD Drives. 2-passes is considered Super-secure for SSD's
For HDD Drive (spinning disks) - the information never really goes away forever, there are ways of making it so garbled it can never be recovered to anything intelligible, such as Magnetic Under-writting of a HDD (this writes information directly to the un-used 3rd (or last) platter of a Disk-Stack).
In addition DoD 7-pass is mostly safe... even though DoD standards are to erase it 7-times all 0's, all 1's and random 1's and 0's with the final sequence being all 0's, then a "low-level format" is applied and finally the disk is shattered by fireing a pin through it and incenerating it afterwards.
NSA usually follows the same procedures as above with HDD's however if the disk must be re-used then a 9-pass random, 1's, 0's is applied 3x (resulting in 9 passes). afterwards the disk is sent to a De-gausing facility where a large magnet is used to "purge and sanatize" the disk(s).
gutmann is useless and dead... let it die already.
(please note that without degausing or using magnetic underwritting some data can still be retrieved from the last-layer of the disk; such a program to recover this information is expensive and not available to the public sector at large. IE: Fluke Forensics Disk Discovery). and that only has a 40-50% recovery rate after more then 3 passes... at 7-passes it is 10% recovery, at 9-passes of an HDD it is 0%. So if there is a reason that someone would want to take your HDD and submit it to a Data Forensics Speciallist (such as myself) who charges an average of $50,000 - $150,000 PER GB of recovered information then you might want to buy a Drive degauser and have at it... lets just say that with the cost of the software I have used to recovered Drives for several "high-profile" cases, has not paid for the software.
I hope this helps, some people might be scared but seriously; noone is going to waste the time/effort unless it's a top-secret government drive you stole and have hidden in your basement and are publishing monthly articles online from; and even then they'd just employ you or kill you outright and pay your family a cool mill (if they are lucky) to stay quiet.
