Re: Steganography -- Tell Tale Signs?

["Mark M." <markm@voicenet.com>]

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On Wed, 4 Sep 1996, makofi wrote:

> 1) If I hide some PGP encrypted data in a
> gif, jpg or wav file will there be any tell tale 
> signs to the naked eye of an expert? If yes,
> what are they?

I don't think so.  Especially for jpg which uses a lossy compression scheme.
Any random noise could be attributed to the compression.  There is already
enough noise in wav files that inverting one bit won't make much of a
difference.

> 3) Are there any tools at the moment 
> to expose (not crack) the hidden encrypted 
> data? If none. are there tools in development?

The whole point of steganography is plausible denial.  The data that someone
could de-stego from a file should just be random garbage, in which case there
would be no way of telling whether there was an encrypted file stegoed in the
data file.  If PGP files are used, a utility like Stealth is a must.

- -- Mark

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Key fingerprint = d61734f2800486ae6f79bfeb70f95348
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