[ale] [Fwd: Re: [ale] encryption/obfuscation (Was: No, wait- Leonard...)]

[Jeff Hubbs]

-- BEGIN included message

To: Kevin Krumwiede <krum at smyrnacable.net>
Subject: Re: [ale] encryption/obfuscation (Was:  No, wait- Leonard ...)
From: Jeff Hubbs <hbbs at attbi.com>
To: ale at ale.org
Date: 09 Jul 2002 23:01:51 -0400
In-Reply-To: <1026263972.1144.21.camel at aphrodite>
References: <20020709131856.52048.qmail at web12805.mail.yahoo.com><1026240517.28933.11.camel at localhost.atl.ipsvc.net><1026237212.14167.17.camel at localhost.localdomain> <200207091509.30146.kilpatms at mindspring.com> <1026263972.1144.21.camel at aphrodite>

On Tue, 2002-07-09 at 21:19, Kevin Krumwiede wrote:
> On Tue, 2002-07-09 at 15:09, Sean Kilpatrick wrote:
>  
> > I _think_ steganography is the technique of hiding a simple text message
> > within a standard graphics format, such as .JPG.  That is, the attachment
> > <foopix.jpg> can be opened within a graphics viewer and, indeed, foopix is
> > displayed, but when opened with different software, the encrypted message
> > is revealed.
> 
> That's right, though I don't know if it's been done with JPEG files.  I
> know it can be done with lossless image formats and even sound or video
> files.  And you can encode not just text, but any type of data.
> 

I think you're kind of under-generalizing.  "[H]iding a simple text
message > > within a standard graphics format" is a *kind* of
steganography but I think the term refers to any hiding of data within
otherwise innocuous data.  It seems to me that even given a particular
type of carrier data (say, a .JPG), there are many, many ways to encode
data for later retrieval and I think that they rely on some kind of
out-of-band understanding of the encode/decode process.

Just to cite a ridiculously simple example, suppose I tell a buddy that
I'm going to pass him a signal via Usenet messages but I won't tell him
exactly when, from what address, or exactly what newsgroup (I might
narrow it down a bit for him, though).  Let's say that I've already
given my buddy a task but I need him to do it at a certain time that
even I do not yet know.  Suppose I have one of those nonsense generators
make me 999 newsgroup messages and then I have it make one more and I
take its md5sum (the exact algorithm isn't important as long as I know
what it is any my buddy knows what it is (or, to be more exact, as long
as I can perform it and so can he).  I set then set that message aside
and send my buddy away with just the md5sum.  Then, every day, I post
from my list of 999 generated messages and keep the 1000th one to
myself, and when I need to signal my buddy to execute the task, I slip
the 1000th message into the posting stream.

Meanwhile, my buddy's got a machine set up somewhere that does nothing
but scroll newsgroups and taking the md5sum of the messages.  One day,
the md5sum of a message matches the one I gave him however long ago, and
he carries out the task I gave him.

What did the outside world see?  Nothing but senseless babbling.  It was
the OUT-OF-BAND communication - where and how to look for the signal,
the md5sum to match, and a task to complete when the signal arrives -
that turns my daily stream of meaningless crap into a signaling device
and a control-at-a-distance mechanism.  I could synchronize the work of
a whole lot of people that way.

This was the kind of thing that was going through my head in the weeks
after 9/11. 

That study that purported to do a steganographical analysis of all the
images on eBay and foud nothing proves nothing but that if there WERE
hidden messages in the images, they didn't know how to recover them.  Of
COURSE they didn't know how to recover them; they didn't have the
out-of-band information if any secret messages existed!!

- Jeff



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