Re: FileCopy overwrites the existing file

if you refer US
Department of Defence they, depends on how documents are classified
recommends up to 7 times rewriting with random data (if I remember well).

Three times is the actual standard. Indeed, there was a *SUGGESTION*
that overwriting data up to 7 times may be needed, but, again, this is
just a speculation.
Concerning classification, AFAIK, top-secret data is still destoyed
only by disk incineration.....

Recovering overwritten data is NOT a speculation, it can be done and any
good software recovering company will do it without problems if the data
was overwritten only once (we're talking about magnetic data storage
disk here).

AFAIK, they deal only with such things as disaster (i.e mechanical or
electrical damage to the disk) recovery, formatted disks, accidentally
deleted files, etc, and still they never guarantee that absolutely all
data will be recovered - when it comes to recovering data that has been
actually overwritten, they are out of luck (unless they are able to
find a copy of it somewhere on the disk, which happens quite
often).....


Anton Bassov

Grzegorz Wróbel wrote:
anton bassov wrote:
The most naive believe here is that "the old data disappears for good"
in case of overwriting the same sectors.

Why is it naive???? There is a speculation that *THEORETICALLY* it may
be possible to retrieve overwritten data with microscope, but this is
just a speculation - no one has *EVER* demonstrated that it can get
done in practice. Just to give you an idea, ovewriting data 3 times
(once with all 0s, once with all1s and once with a random sequence) is
the technique, approved by US Department of Defence for destroying *
CLASSIFIED* data.....

Hah, why so many question marks? There are many standards of destroying
classified data, each country has it's own, but if you refer US
Department of Defence they, depends on how documents are classified
recommends up to 7 times rewriting with random data (if I remember well).

Recovering overwritten data is NOT a speculation, it can be done and any
good software recovering company will do it without problems if the data
was overwritten only once (we're talking about magnetic data storage
disk here). Upon what your claims that "no one has *EVER* demonstrated
that" are based?



--
Grzegorz Wróbel
http://www.4neurons.com/
677265676F727940346E6575726F6E732E636F6D

.

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