Peter Mount wrote:
> The only way I can think this could be done is with the data being
> stored in one of the frames (GIF's can have multiple frames, which is
> used in animation).
>
> However, for this to work, you would need some external app to read the
> frame.
>
> The only other part of a GIF file, is the comment string, but this is
> only 255 bytes AFAIK.
>
> Peter
>
>
>
> -----Original Message-----
> From: Phillips, Steven W (Steve), GOVMK [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, May 27, 1999 1:20 AM
> To: [EMAIL PROTECTED]
> Subject: Hide and Seek Programs
>
> Does anyone have information on programs that can be used to hide files
> in
> GIF images? I have never seen this done, but have been told that they
> are
> call Hide and Seek programs. If anyone knows how this is done and
> whether
> or not the presence of a file in a GIF image can be detected using some
> sort
> of file scanner, please let me know.
>
I'm not an expert in this area, but I belive that it is done by storing
information in the lowest bits of the color values. If every pixel is
represented by a byte, then changing the least significant bit is not
going to modify the image to much. This way you can store a bit in every
byte.. As for detection, I think it may be difficult unless you know
something about the format of the hidden information, and the ways it is
hidden (maybe it is in the second bit position). You can try to extract
the lowest bits of data and see whether it makes up a text message or a
file header of some sort, and go on from there..
http://129.105.116.5/fravia/stego.htm
You may use www.fravia.org when it is reopened. As for general info and
programs it shouldn't be to difficult to find by searching for
'steganography' in any search engine..
-
[To unsubscribe, send mail to [EMAIL PROTECTED] with
"unsubscribe firewalls" in the body of the message.]
