1. Re: Why We Must Fight UCITA
On Thu, 3 Feb 2000 15:12:30 -0800, neksys <i.shoot at REDNECKS.COM> wrote:
>Kat wrote:
>
>>
>> Norton Utilities for dos (circa 1983?) has a NSA certified eraser (or it
>> *was* certified in it's day) for data on floppies and hardrives. NSA spec at
>> the time called for a spec'd number of writeovers of specified patterns. The
>> amount of time to execute went way up the higher one would set the security
>> required.
>>
>> Kat
>
>The NSA standard was (and still is) 7 writeovers of random data.
>Unfortunately,
>nowadays, even after 7 writeovers, data can still be extracted. I believe a
>private data recovery service proved that it would take in the range of 15
>writeovers of non-random data to leave no trace of previous things on the
>drive.
>
>Greg
Because of low level encoding to prevent too many consecutive 1's or 0's
from being written, the pattern necessary to clear previous patterns is not
immediately obvious. The only way that I know to be sure of clearing a
drive would be to write zeros over the whole drive, use a utility like
old Norton Diskedit to mark all sectors as bad, and then use a utility
like Steven Gibson's SpinRite on maximum to recover all the "bad" sectors.
I believe that that particular item reads and writes over 40 "worst case"
patterns over the sector to test it after recovering the primary data written
on the sector...which in this case would be zeros. There are still some
areas of the drive that could have been written too deliberately that would
not be erased by this technique...maintenance sectors...that would have to
be written to by directly instructing the controller to read and write to the
maintenance sectors. This technique varies from manufacturer to
manufacturer and without examining their code, one could not be sure
that everything had been gotten. The bottom line is that the only way
to truly erase a drive is to melt it to a completely molten state or completely
oxidize it...that is burn it up.
Everett L.(Rett) Williams
rett at gvtc.com
