CYPHER.1.0  (c) March 1990 by Frank Roberts

Following decrompression, you should have the following programs:

CYPHER10   --- The main program
CY.info    --- The info file (rename it CYPHER10.info)
TEST       --- An encoded text for test (use keyword THINKQUICK)
READ.ME    --- This text file (da!)
ZPAD.FOO   --- A bunch of words for arc and zoo padding

CYPHER10 is a modification of an old Atari 800 (8K BASIC) program that
I wrote several years ago and published in one the computer magezines.
It served no purpose except as an exercise in string manipulation on
a "bare-bones" BASIC language.  Having nothing to do one Saturday, I
decided to rewrite it for the Amiga in AmigaBasic.  It turned out to
be a long, and slow program.  I offer it just for fun.  It may appeal
to any who may have, at one time in their very young life, wanted to
own a Captain Midnight Secret Decoder Ring.  You know, the kind of
stuff us old guys used to save our cereal boxtops for.  I sent for one
many, many years ago but, for some postal reason, it never came so I
borrowed my dad's slide rule (before calculators) and made my own.
From the age of 10 to 12 I pursued a rather "cloaked" carreer as the
neighborhood crypto specialist.  Then, alas, interest in the girls
ended such goofy stuff.  It was fun reliving pre-pubescence through
the Amiga while translating this program.  I hope you (whoeveryouare)
have as much fun playing with it.

The program encyphers and decyphers your text messages using a simple
technique known as polyalphabetic substitution.  This means that the
alphabet when translated into cypher and back is offset by a series of
of numbers known only to the person coding the message and his or her
intended correspondent. The series of numbers can be any length and
the longer the length of key numbers, the harder the code is to break
-- escpecially with short messages.  In this program the key numbers
are extrtacted from a keyword which is supplied by the user.  A keyword
is much easier to remember than a series of numbers (it's sort of like
a password).  I suggest the user makes his or her keyword one that is
easy to remember, such as a real word or phrase (no spaces between words
in phrases), i.e., THINKQUICK (not THINK QUICK).  The longer the word
or phrase, the harder the cypher is to break.

The program allows the user to code and decode from Keyboard entry or
Disk File (files must be in ASCII format and can be supplied by any
text processor that files in ASCII).  Output from either coded or decoded
messages can be to Screen, Disk file or to a printer.

As I said, this program is just for exercise in string manipulation with
AmigaBasic. If you have fun with it drop me a line. For 5 bucks and a
blank disk I'll send the source code.

This program is Copyright (c) March 1990 by Frank Roberts. ALL rights
are reserved.  Permission to pass it along to others is granted provided
no money, tender or barter is charged, and provided this text file is
included with the program.  Have fun, all.

Frank Roberts
4507 Lafayette Esplanade
Fort Wayne, IN 46806
(219) 456-1401

E mail Compuserve 70357,376

Genie

THE-BBS (219) 482-4117