From: rarachel@prism.poly.edu (Arsen Ray Arachelian)
Date: Sun, 28 Aug 94 12:22:58 PDT
To: CCGARY@MIZZOU1.missouri.edu (Gary Jeffers)
Subject: Re: CEB 8 - WNSTORM Info
In-Reply-To: <9408240134.AA26527@toad.com>
Message-ID: <9408281909.AA00358@prism.poly.edu>
MIME-Version: 1.0
Content-Type: text


WNSTORM is available from:
ftp.wimsey.bc.ca:/pub/crypto/software/dist/US_or_Canada_only_XXXXXXX/Steg

Usual routine to get it. i.e. cd /pub/crypto/software, get the README
file, and if you agree to the terms then follow the instructions.

Short description off the top of my head (I wrote the beastie)  Another
info scrap should be in the same directory as WNSTORM.


WNSTORM is a data encryption/steganography utility which is pretty secure for
most uses.  Unlike some stego systems WNSTORM is expandible, all you have to
do is write your own LSB injector/extractor for whatever data format you wish
to hide information into.

WNSTORM doesn't require the recipient of the host picture, sound, movie, etc.
to have the original un-stormed picture.  Unlike primitive stego programs,
WNSTORM doesn't compare an stormed picture with an unstormed picture.

WNSTORM will cover its tracks statistically.  If it changes a 0 bit in the
LSB data stream to a zero, or a 1 bit to a 1, it does nothing.  If it changes
a 1 bit to a zero, it will balance itself by changing an unused adjacent 0
bit to a 1.  Ditto for a 0->1 transform.

WNSTORM will NOT change every bit of the LSB in order to prevent detection.
It will use a passkey along with a probabilistic algorithm to decide which
bits it will change.  The algorithm for picking bits depends on the previous
succesfully encoded/decoded cyphertext AND the passkey.

Internally WNSTORM works by picking "windows" or "packets" of bytes out of
either a random number stream or an LSB stream extracted from a picture,
sound, movie, etc.  It then injects eight bits of cyphertext into this window.
Each window is of variable size.  The bit locations where the bits are inserted
are randomly exchanged for each pass.  The bit values are also randomly 
exchanged for each pass.

WNSTORM includes an injector/extractor for PCX images, however I will write
more injecotr/extractor programs for it in the future, and OTHERS can do so
as well.