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MANUAL.TXT
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1994-03-08
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╔═════════════════════╗
║ S-Tools for Windows ║
╟─────────────────────╢
║ Version 1.00 ║
║ (c) 1994 Andy Brown ║
╚═════════════════════╝
What is steganography ?
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Steganography is the ancient art of hiding information in some otherwise
inconspicuous information. Many years ago people used to use illustrations
to conceal messages. The idea being that one party could send the
illustration to the other in reasonable confidence that if the messenger
was questioned then the illustration would not arouse any interest from his
enemies.
Since the advent of computers there has been a vast dissemination of
information, some of which needs to be kept private, some of which does
not. S-Tools brings you the capability of `hiding' files within Windows
sound wave (.WAV) files. The modified .WAV file that contains your hidden
file will not sound any different to the human ear than the original file.
The modified file does not increase or decrease in size, it remains the
same. I suppose you could look at this as a kind of infinite compressor for
the file that you are hiding, since you can quite happily delete it after
you've hidden it, extracting it from the WAV file whenever you need it.
Shareware
─────────
S-Tools is shareware. That means that if you find it useful and would
like to continue to use it after a reasonable trial period, which I
consider to be about one calendar month, then you should register your copy
of the program with me.
The registration fee for S-Tools is 15 UK pounds sterling. To register
S-Tools, send a cheque drawn against a UK bank, International Money Order,
International Postal Order or Sterling travellers cheques for 15 pounds to
the address below:
Andy Brown
28 Ashburn Drive
Wetherby
West Yorkshire
LS22 5RD
United Kingdom
For your registration fee you will receive a printed manual, a personalised
copy of the program, and a copy of the `C' source code.
I can be reached by e-mail at <asb@cs.nott.ac.uk> until June 1994.
Using S-Tools
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S-Tools comes with a Windows help file that you can activate by pressing
F1 or by selecting the appropriate option from the Help menu. This help
file documents every command and option that is available within S-Tools.
As such, there is little point in duplicating all that information here.
Instead, the rest of this manual will consist of how-to sessions that walk
you through the process of hiding and retrieving files. I would recommend
that you read the appendices at the end of this document so that you are
familiar with the limitations of, and the techniques employed by S-Tools.
How to hide a file
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In order to hide a file you need to be in possession of three pieces of
information. These are:
1. The name of the file that you want to hide.
2. The name of the WAV file that you want to hide it in.
3. A name for the new WAV file that contains the hidden file.
If you are experimenting with S-Tools for the first time then you might
like to try hiding something inside the ORIGINAL.WAV file that is supplied
with S-Tools.
When you've figured out the above three pieces of information you need
to follow the following steps.
1. Select the `Open WAV file' option from the `File' menu. Use the Windows
file selection box to choose the name of the WAV file that you want to
hide your file in. If the WAV file is one that S-Tools understands then
you will see a representation of the sound wave in the main window area.
In addition to this, you will see a few extra pieces of information
about the file in the status bar at the bottom of the screen. This tells
you some miscellaneous things like the playback frequency of the file,
the number of bits per sample and, more importantly, the maximum size
file that you hide within this WAV file.
2. Assuming step 1 went ahead without any trouble, you can now choose the
file that you want to hide. Select the `Hide file' option from the
`File' menu. Now use the Windows standard file selector to choose the
name of the file that you want to hide. Assuming that the file is not
too large to hide in the WAV file that you loaded, there will be a short
delay and then the waveform display will change. The areas marked in red
on the waveform are areas of the sound wave that were altered by the
concealment process. The areas in black just happened to not have to be
altered in order to conceal the file.
3. Naturally you will now want to save your modified wave file so that you
can send it to the person that you are exchanging secret information
with (!). To do this, simply select the `Save wave file as' option from
the `File' menu. Use the Windows standard file selection box to choose
the name of the new WAV file.
4. Well that's just about all there is to it. Except perhaps one thing.
After you've hidden a file inside a wave, you might like to compare the
sound of the original file to the sound of the modified one. The two
`Play' options under the `Options' menu will do this for you. See if you
can spot the difference between the original and the modified version !
Do you think you could spot a concealed file if you didn't have the
original to compare to ? No way !
Revealing a hidden file
───────────────────────
If you are experimenting with S-Tools for the first time then you might
like to try extracting the hidden message within the file HIDDEN.WAV. The
hidden file is comprised only of text, so you can use the `Screen' option
to display the message.
Revealing a hidden file is even easier than hiding a file. All you need
to do is to follow these steps.
1. Select the `Open WAV file' from the `File' menu. Use the Windows
standard file selector to choose the name of the WAV file that contains
the information that you want to extract. The main Window will change to
display information about the WAV file, and a representation of its wave
form.
2. Now choose the `Reveal file' option from the `File' menu. S-Tools will
now try and guess whether the sound wave has a hidden file within it.
It is quite possible that S-Tools will tell you that a there could be a
hidden file in a wave when there isn't one, but never the other way
around. It will never tell you there is no hidden file when there is one.
If it thinks the wave might have a concealed file then you will be shown
a dialogue box with the length of the file in it, together with two
buttons that allow you to either save the concealed file to disk or to
show it in a window. Naturally, the latter option is only relevant if
the file consists only of text. If you choose to save the concealed file
to disk then you should use the Windows standard file selector to select
a name for the extracted file. Please note that it is not possible to
reconstruct the original sound wave, but then you couldn't hear the
difference anyway could you ?
Limitations
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The WAV file format is quite complex and is extensible. S-Tools supports
the most common subset of the WAV format, known as Microsoft PCM format.
S-Tools supports 8 and 16 bit samples, in mono or stereo. It does not
support files that contain extra information other than the wave data
itself. Luckily nearly all WAV files (including those supplied with Windows
3.1) are of this limited form.
You should never use any `lossy' compressor programs on WAV files that
have files hidden within them, this will result in your hidden file being
corrupted.
Extra information
─────────────────
If you intend to use S-Tools for h