At 04:23 PM 01/25/2000 -0600, Rick Smith <[EMAIL PROTECTED]>
wrote:
>The basic notion of stego is that one replaces 'noise' in a document with
>the stego'ed information. Thus, a 'good' stego system must use a crypto
>strategy whose statistical properties mimic the noise properties of the
>carrying document. Our favorite off the shelf crypto algorithms do *not*
>have this property -- they are designed to generate output that looks
>statistically random. So, can't we detect the presence of stego'ed data by
>looking for 'noise' in the document that's *too* random?
It depends on how much work you want to do and how well you can
model the properties of the noise you're replacing.
If you _really_ don't care, just hide the unencrypted data in the cover
text :-)
If you care a lot, build an invertable mapping from the
random-noise space of the low bits to the space of the cyphertext,
so you can expand the cyphertext into something that looks plausible.
If your cyphertext is only readable by someone with the key,
and you're using a stealthy crypto system rather than something with
big markers at the beginning like PGP, you should be ok.
Thanks!
Bill
Bill Stewart, [EMAIL PROTECTED]
PGP Fingerprint D454 E202 CBC8 40BF 3C85 B884 0ABE 4639
