Robert,

It's my understanding that there has been no documented case of data
recovered from a hard disk that has been erased by completely
overwriting the contents 3 or more times with your choice of 0s, 1s,
alternating bits, random bits, or whatever, outside of a lab
environment using magnetic electron microscopy. Is that no longer
true?  I had thought that one didn't need a particularly good RNG for
it, since anything will do. Or, is that just what the NSA *wants* me
to think?

~~James
_____________________
http://www.turtlezero.com


On 7/22/07, Robert Howard <[EMAIL PROTECTED]> wrote:
> How about deleting confidential data from hard disks!
>
> The solution today is to overwrite it many times with random data.
>
> But modern mathematics and technology makes it possible to recover the much
> of the original text given the original random sequence used to delete the
> data. Given a long sequence of deleted white space (or zeros on the disk),
> then it becomes possible to recover the original pseudo-random sequence (for
> example, one based on linear congruence) – even if a many passes are
> performed.
>
> With a true random number generator, only one pass is needed.
>
> I'm sure hardware random number generators based on quantum effects, which
> have been around for decades, would be used instead of hitting a web site,
> which compromises the who shebang.
>
>
>
> Robert Howard
>
> Phoenix, Arizona

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