Am 12.07.2015 um 23:10 schrieb Rich Freeman: > On Sun, Jul 12, 2015 at 4:43 PM, Volker Armin Hemmann > <volkerar...@googlemail.com> wrote: >> Unlike you, I read some stuff before posting. This is OLD NEWS: > No need to be rude. > >> http://www.howtogeek.com/115573/htg-explains-why-you-only-have-to-wipe-a-disk-once-to-erase-it/ >> >> http://www.vidarholen.net/~vidar/overwriting_hard_drive_data.pdf >> >> to quote: >> >> " >> Resultantly, if there is less than a 1% chance of determining each >> character to be >> recovered correctly, the chance of a complete 5-character word being >> recovered drops >> exponentially to 8.463E-11 (or less on a used drive and who uses a new >> raw drive >> format). This results in a probability of less than 1 chance in 10Exp50 >> of recovering >> any useful data. So close to zero for all intents and definitely not >> within the realm of >> use for forensic presentation to a court. >> " >> >> 10^50. Think about that for a moment. And that is not 'all the data' but >> 'any useful data'. >> > This really looks like a pragmatic argument, and not a theoretical > one. I see no arguments based on hard laws of physics. This argument > basically says that because this lab couldn't read the data with their > equipment/methods, it is impossible for anybody to do it at any time > in the future using any equipment. > > I'd say Schneier's Law applies. >
read the second link I provided. And then google for yourself. All that 'overwritte many times' crap came from people who never read Guttman's original paper closely. Back then it was very hard. Today it is impossible. You toss a coin for every bit. And that is your chance to extract anything. There are better chances to extract the key you used to encrypt your data from RAM than to extract any useful data from a harddisk that was overwritten once.
