🚀 go-pugleaf

>>>>> styri@hal.nta.no (Haakon Styri) (HS) writes:

HS> In the light of the Registered Keys thread I believe there is a good reason
HS> to discuss steganography.  How can the govt. tell that there's an encrypted
HS> message if I hide it? How can I prove there is no such message if the govt.
HS> says there is?

A very simple way to hide a message is the following:

Suppose your favorate Mafioso wants to send you a secret message. He
encrypts it with a non-registered key. Now he takes a digital picture of
his nice family (say with 8 bits per pixel) and replaces each low-order bit
with one bit of the message. If the color palette is suitably chosen or it
is a grey-scale picture or a 24 bit true color picture or similar, this
will not change the picture much, but just add a bit of noise. How is the
government to prove that the picture contains an encrypted message?

(NOTE: this method is an adaption of something that was published earlier
in sci.crypt)

Of course this method is difficult to use for encrypted telephone communication.
-- 
Piet* van Oostrum, Dept of Computer Science, Utrecht University,
Padualaan 14, P.O. Box 80.089, 3508 TB Utrecht, The Netherlands.
Telephone: +31 30 531806   Uucp:   uunet!mcsun!ruuinf!piet
Telefax:   +31 30 513791   Internet:  piet@cs.ruu.nl   (*`Pete')