Stego worm

[Major Variola (ret)]

At 08:09 PM 12/11/03 -0500, Tyler Durden wrote:
>
>As for Variola's comment, you might be right. I just assumed there's
some
>kind of relationship between LSB and those spatial freuencies wherein
image
>information might be stored. Actually, I would still think there's a
>relationship, in which case an Echelon-like approach based on ffts and
>"noise templates" might be going on (hence the usefulness of jamming).

I'm not saying that you could never use FT to detect weaker kinds of
stego.
But if information is encoded as say the parity of 3 LSBits from
different
regions of the image, good luck.

>Anyone got a TLA Operative Handbook? ANy mention in there of what kind
of
>photos are best for Stego? How about cloud photos? (particularly where
there
>are clouds of many different shapes and sizes present in the photo
>simultaneously.)

The most important thing is not to put too much cargo in your carrier.
Think in terms of signal to noise if you wish.

Obviously a picture with truly uniform color fields ---like a digital
cartoon--
won't be useful.  But scanning a piece of paper does not have this
problem,
for say 8 bits per grayscale pixel.   Because each analog scan of the
same piece
of paper gives different bits.

TD, you surely have the background to look into this stuff (and stego
detection) if you want.  BTW Stego ~aka watermarking.  And stego
can be done in music, movies, ascii text, etc.

Or you could work from first principles, if you are able to mentally
switch between
steganographer and stego-detecter.  (This same
playing-chess-with-yourself is
vital to security analysis, crypto, etc.)