Sender: "T. Bruce Tober" <•••@••.•••>
In your message dated Thursday 28, September 1995, Karl Long
<•••@••.•••> wrote :
> When a magnetic record such as on a hard disk is overwritten with new
> data, a residual trace of the previous data still exists. With the
Correct.
> right equipment and skill in its use, one can extract the previous
> data. Each subsequent overwriting reduces the likelyhood of being
> able to retrieve the target data.
Correct.
> I don't know how many overwrites the current state-of-the-art
> equipment can recover, but it was at least three, ten years ago.
And version 7 of NU did it to US Govt Security Stds (DOD 5220 22M) which:
1. Overwrites the area first with Zeros and then with ones, at least three
times.
2. Overwrites the area with a random value.
3. Verifies the last write. If this verification fails for some reason, a
warning msg appears to say you should not consider the disk completely
wiped.
That ultra secure wipe is user definable, ie the user can choose a less
secure (faster) wipe.
Norton continues to warn that the file, or parts of it may also exist in
backup files (be they extant or erased) and in RAM and those files also
need to be found and wiped (the RAM file by switching off the machine).
> In order to make data unrecoverable, you must overwrite it several
> times (ideally with random data). Utilities such as Norton can make
> it difficult to recover deleted data, but not impossible.
Er, I believe, if you follow the above guidelines as quoted from the
manual, it is completely gone (again beware the proviso about RAM and
backup files).
tbt
|Bruce Tober - •••@••.••• - B'ham, Eng|
| Publisher/Editor of The Write Byte monthly newsletter |
| WebSite address to come shortly |
| TWB - The computer newsletter specifically for Writers |
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Sender: "Steve Eppley" <•••@••.•••>
Karl Long <•••@••.•••> wrote:
>>>Short of reformatting the drive, there is no way to actually
>>>erase a file from disk.
[snip]
>In order to make data unrecoverable, you must overwrite it several
>times (ideally with random data). Utilities such as Norton can make
>it difficult to recover deleted data, but not impossible.
If memory serves, Norton's WIPEFILE utility offers to overwrite the
disk sectors many times. I haven't looked at modern utilities which
make deletions secure automatically, though.
What would the presence of a deleted "illegal" file indicate,
anyway? That the computer's owner may have violated the law in the
past? No need to shut down a currently proper operation... Or could
it indicate that the conscientious owner deleted a file that someone
else (perhaps an overzealous cybercop) wrongfully uploaded?
---Steve (Steve Eppley •••@••.•••)
~=-=-=-=-=-=-=-=~=-=-=-=-=-=-=-=-=~-~=-=-=-=-=-=-=-=~=-=-=-=-=-=-=-=-=~
Posted by -- Andrew Oram -- •••@••.••• -- Cambridge, Mass., USA
Moderator: CYBER-RIGHTS (CPSR)
World Wide Web:
http://jasper.ora.com/andyo/cyber-rights/cyber-rights.html
http://www.cs.virginia.edu/~hwh6k/public/cyber-rights.html
FTP:
ftp://jasper.ora.com/pub/andyo/cyber-rights
You are encouraged to forward and cross-post messages and online materials,
pursuant to any contained copyright & redistribution restrictions.
~=-=-=-=-=-=-=-=~=-=-=-=-=-=-=-=-=~-~=-=-=-=-=-=-=-=~=-=-=-=-=-=-=-=-=~
