From: uri@watson.ibm.com
Date: Thu, 11 Mar 93 09:33:35 PST
To: thug@phantom.com (Murdering Thug)
Subject: Re: Hiding Encrypted Messages
In-Reply-To: <m0nWpAZ-000jozC@phantom.com>
Message-ID: <9303111731.AA20272@buoy.watson.ibm.com>
MIME-Version: 1.0
Content-Type: text/plain


Murdering Thug says:
> I think it would be quite easy to hide encrypted text in music/sound or
> graphics files.
> 1.  Use a SoundBlaster-type card to sample a given amount of music from a
> radio/tape/cd/whatever using 8-bit samples at some low sampling rate
> like 11,000 samples/second. This would give you a lot of music for the
> space used.
> 2. Then take an encrypted PGP file and dispurse it bit-by-bit into the
> LSB (least-significant-bit) of each sample.  This wouldn't distort the
> sound sample to any extent noticable by the human ear.  Thus each byte
> of PGP file would be dispursed into 8 bytes of sound file.  Thus if
> you wanted to send a 20k PGP file, you would have to put it into a
> 160k music file.
> If you're ever forced to explain what that file contains (unlikely, since
> you can always take the Fifth Ammendment) you can just play it on your
> computer and have the NSA/SS/FBI/Whatever listen to James Brown go
> "Hyeeeah... I feel good!"

a) This method has essentially the same complexity, as one-time pad,
   but without it's strength.

b) If it's played and recognized - one can trace your source (a CD, a
   tape of radio broadcast, whatever) and do a comparison. Then the
   file containing of all the LSBs is cryptanalyzed...

I might be wrong IF those nice LSBs are too hard to track... But then
again, you're facing the need to communicate that one-time pad...

> +---------------+     +-------------------------------------------------+
>                       |  *****       ___\!/_   *         *     *     *  |
>  Murdering Thug       |    *      __/_  /|\    * *       *      *   *   |
>                       |    *     /    \        *   *     *       * *    |
> thug@phantom.com      |    *    |      |       *     *   *        *     |
>                       |    *     \____/        *       * *        *     |
>                       |  *****                 *         *        *     |
> +---------------+     +-------------------------------------------------+

Oh yes, and I'm sure LOTS of people would join! (:-)
--
Regards,
Uri         uri@watson.ibm.com      scifi!angmar!uri 	N2RIU
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<Disclamer>