some technical steganography
jim at bilbo.suite.com
Sun Mar 6 16:17:41 PST 1994
>> I assert that an "unrecognizable encrypted message" will be a
>> random sequence of bits. Is my assertion correct?
> It's neither correct or incorrect because the specific
> notion of randomness hasn't been specified.
I don't understand what you mean by "specific notion of randomness
hasn't been specified". How many different "notions of randomness"
> Your statement is falsifiable, however, since
> sometimes a non-random string of bits is what you want to
> get out, if what you would expect to get out normally was
> also non-random. And you want them to be non-random in the
> same way.
I agree. The output of the reverse stego process should produce
similar results, regardless of the presence of a hidden message.
That's the point I've been trying to make. I've been attempting to
make that point by describing a hypothetical stego system that, when
run in reverse, produces a random sequence of bits. I suppose there
could be other hypothetical stego systems that produce non-random
output, but then you would need a decryption system that could
understand and decrypted that non-random output. I prefer random bit
sequences. Or perhaps I should say - bit sequences with no apparent
> > Of course, this assumes there is no other way to detect a
> > hidden message besides reversing the stego process and
> > testing the result.
> Don't count on it. Statistical tests can find
> correlations you hadn't suspected were there. In fact,
> for some message types, _not_ finding the correlations
> may indicate dithering, or maybe a steganographic
I agree completely. This is a large part of what makes effective
steganography so difficult to achieve.
Jim_Miller at suite.com
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