From: Niall O Broin (niall at domain linux.ie)
Date: Thu 20 Sep 2001 - 14:11:49 IST
On Thu, Sep 20, 2001 at 10:08:09AM +0100, Gerard J Keating wrote:
> or a nice way to hide a copyright notice on a photo or image on your web
> site....
Except that most (no, make that all) image steganographic systems break when
you apply certain filters to the image e.g Gaussian blur, or scale and
recompress as JPEG. I bluntly say all systems, because for any particular
kind of steganography, you can come up with some kind of filter which will
kill it without making much more visible difference to the image than the
original steganography did.
Niall
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