How does evidence eliminating software that permanently erases files
on hard drive work?
How can anyone prove a particular product has worked?  Which is the
best one to use. What are the moral arguments against using it, could
the software be legally banned? Are there any statistics on how many
Paedophiles use it? How can we stop it being used for immoral
purposes? Have you any other comment on this subject?

Hello Camdenflat,

Software to "erase" disks or files is readily available depending on
the system. I will assume you want answers related to Windows PC's so
I will provide answers based on that. Similar products exist for other
systems - the methods are pretty similar.

Q: How does software that permanently erases files work?

A: Generally by overwriting the contents one or more times. The DoD
had a rule to overwrite files with zeros, then ones; three cycles. The
idea was to make the remaining energy on the disk to be below the
detection of sensitive instruments. For more sensitive data, the media
had to be destroyed (e.g., burnt, acid wash, sand blasted, chopped to
bits).

For a *few* references, check..
  http://pcprivacycentral.com/pc_priv_et2002.htm
  http://www.cyberscrub.info/overview.htm
  http://www.powerquest.com/datagone/
  http://www.sellshareware.com/ProgramInfo.asp?AfID=8687&PrID=35432
the last one has a "view" option to help answer your next question.
There are a *lot* of such products available - for sale and for free.

Search with phrases such as
  erase files destroy contents 
to get more references, I got over 19000 hits for these phrases.

Q: How can anyone prove that a particular product has worked?

A: Most people assume that it works OK. However if you don't trust the
software, you view (or automatically check) the region that the files
used to occupy with a disk utility. If the results are "all zeros" (or
whatever pattern was supposed to be there) the "erasure" took place.
The sector viewer of DiskSanitizer is an example of that.

Q: Which is the best one to use?

A: Hmm. A trite answer might be "the one you have". I don't think I
(or anyone else) could provide a definitive answer - it depends on
your needs. Any of the products I referred to above can do a thorough
job of erasing data on the disk. The DoD has pretty high standards - I
suggest using a product that meets those standards as a reasonable
approach to determine a "best one". One that works automatically on
all files thrown away in the Windows trash can might be "good" because
you don't have to remember to run it.

Q: What are the moral arguments against using it [disk erasing
software], could the software be legally banned?

A: There are plenty of laws on the books (depending on the
jurisdiction) that apply to tools to aid the comission of a crime.
However, as far as I am aware, there are no US laws that apply to the
use of disk erasing software. Is there a particular jurisdiction you
are interested in that I could research more fully? I can't comment on
the moral implications - adding moral to the search phrases above did
not find any moral commentary on this topic.

Q: Are there any statistics on how many paedophiles [pedophiles?] use
it [disk erasing software]?

A: Hmm. As far as I can tell, most pedophiles do not use such
software. There are plenty of hits on google with the phrase
  erase files destroy contents pedophile
and a quick perusal of the first few indicate over and over again that
the computer forensic people got information off of the computer to
aid in prosecution. Relatively recent busts of groups such as
"Wonderland" and similar cases point out this as well. As another
reference, try the following at
  http://news.google.com/
enter
  pedophile computer
as the search phrase and find over 100 recent articles about computers
being used (or seized) in busts of pedophiles.

Q: How can we stop it [file erasing software] being used for immoral
purposes?

A: Since it is not illegal to own or use such software in the US, I do
not see any "real way" to do that. This also gets in to a whole set of
privacy issues as well.

Q: Have you any other comment on this subject?

A: I don't think it would be particularly relevant.

If you want some more references or have me dig deeper into a specific
question, don't hesitate to use the clarification request.

  --Maniac

The moral arguments against allowing consumers to completely erase
their files are most likely outweighed by the need to protect the
sensitive personal data stored on their hard disks.

Since the majority of arrests in cases involving children and
sexuality over the internet are on the unsuspecting, permanently
erasing the contents of the drive is not typically an option for those
accused.  The computer becomes confiscated by the athorities before
the opportunity arises.  I suspect this is why there is little
information as to the morality of the software.

Systems runnning Windows XP or Windows 2000, using NTFS as their
filesystem, and enabling encryption are impossible to crack with
current technology (aside from the 'brute-force' password-guessing)
whether or not the drive has been 'wiped' with ones and zeroes. 
Combining this encryption with a strong password (e.g. a ten-plus
letter password including no words and many high characters such as
ƒ,á,², etc.) will render the drive undecryptable by even the most
advanced algorythms available to the US government.  The encryption is
transparent to the user.  The amount of data on the drive is not a
large enough pool to look for data patterns to decrypt.  All that
could be removed from the drive is information from the File
Allocation Table (FAT), including file names and sizes.  Third-party
applications can offer similar security for users of other operating
systems.

I could not find any case of pedophilia where the perpetrator had used
such a configuration, but this may be due to the fact that if he or
she had, there would be no significant evidence of crime, unless the
prosecution could prove their case using only the data available in
the FAT.