Deletion confirmation tool

Hi All,

We are writing one Shredder which will shredd all unwanted info on
users request.

I am in search of tool which tests that the shredder has done the
intended job sucessfully.

Basicall, i am in search of a tool which confirms that "if a user has
shredded all files and folders" then all files and folders are really
deleted from system.

Can someone recommend me any such tool or technique?

Thanks in Advance.

Mehul D

Re: Deletion confirmation tool

mehul.dave@gmail.com wrote:
> Hi All,
>
> We are writing one Shredder which will shredd all unwanted info on
> users request.
>
> I am in search of tool which tests that the shredder has done the
> intended job sucessfully.
>
> Basicall, i am in search of a tool which confirms that "if a user has
> shredded all files and folders" then all files and folders are really
> deleted from system.
>
> Can someone recommend me any such tool or technique?

Forgive me if I misunderstand, but you're writing this shredder, and you
don't know how to tell if a file has been completely deleted?

Scary.

Re: Deletion confirmation tool

On Mon, 30 Jul 2007 16:44:55 GMT, Colin B. wrote:

> mehul.dave@gmail.com wrote:
>> Hi All,
>>
>> We are writing one Shredder which will shredd all unwanted info on
>> users request.
>>
>> I am in search of tool which tests that the shredder has done the
>> intended job sucessfully.
>>
>> Basicall, i am in search of a tool which confirms that "if a user has
>> shredded all files and folders" then all files and folders are really
>> deleted from system.
>>
>> Can someone recommend me any such tool or technique?
>
> Forgive me if I misunderstand, but you're writing this shredder, and you
> don't know how to tell if a file has been completely deleted?
>
> Scary.

Relevant point.

Poster: You have to define your potential adversary.
--
"You can't trust code that you did not totally create yourself"
Ken Thompson "Reflections on Trusting Trust"
http://www.acm.org/classics/sep95/

Re: Deletion confirmation tool

On Mon, 30 Jul 2007, in the Usenet newsgroup comp.security.misc, in article
<1185812023.275047.119450@q75g2000hsh.googlegroups.com>, mehul.dave@gmail.com
wrote:

>We are writing one Shredder which will shredd all unwanted info on
>users request.

And the reason you feel the Eleventy-Zillion existing tools need
another competitor is...

>I am in search of tool which tests that the shredder has done the
>intended job sucessfully.

Any standard disk editor should allow you to inspect the sectors
where the files/directory-listing/etc. had resided. Of course, this
assumes you have a clue as to how such data is placed so that you
know _where_ to look. But this won't check on the reserved and/or
bad-blocks that the operating system (never mind your application)
has no access to. It probably also won't look at temporary files
or swap-space on the drive that _could_ have said unwanted info.

>Basicall, i am in search of a tool which confirms that "if a user has
>shredded all files and folders" then all files and folders are really
>deleted from system.

You _REALLY_ need to learn exactly how those bits are put onto the disk,
AND how the operating system can access those bits. You also want to
learn how the disk-controller operates - specifically with respect to
bad-block re-mapping. You may also want to learn about disk caching, as
this often catches the ones who aren't aware that it exists.

>Can someone recommend me any such tool or technique?

If you are just building a tool so that Mommy won't see that you've
been surfing the pr0n sites, a raw disk editor should suffice. If Mommy
works for a Three Letter Agency, or is more technically competent than
you are, then it's probably not adequate - but then, neither is any
application you can create. That's why people in the security business
know about physical means of destroying the media that held the data.

Old guy