Date: Mon, 09 Jan 1995 21:08:32 -0600 (MDT) From: "Alan A. Hodson" Subject: [MM] Challenge # 13: Mother dear! To: mathmagic-k-3@mathforum.org, mathmagic-4-6@mathforum.org Cc: mathmagic-7-9@mathforum.org, mathmagic-10-12@mathforum.org (1/9/95) *************************************** MathMagic Cycle 13: All Levels a.k.a. Challenge # 13: The mother of all codes *************************************** Happy new year to all MathMagicians! Like in most activities, there will be times when teams participating in challenges are stump and need some fuel (help) to get them to their destination. What I thought we do is revive and old coding scheme that I believe has been around for a few hundred years and was even used during the American Civil war called the VISIONAIRE CODE. I am doing this out of memory, and must confess I am having a hard time finding references to it, so any help with the name and source will be appreciated. I will be coding some hints when the challenges are too difficult, so we must familiarize ourselves with how the code works. It goes like this: (If you use a Word Processor to write this out, make sure your font is a proportional one such as Courier) Using a 55X55 grid, and starting from left to right at the top, leave one blank space and then write the alphabet in order. For MM purposes we are going to add numbers 1 through 0 and these characters: !@#$%^&*()+-/=<> There should be 53 spaces, including the first blank. Under the black space write now the first letter (A) and all others, basically shifting all characters one space to the left. The last character should now be an A. Under the letter A write the second letter (B) shifting to the left. The last two characters should now be AB. Under the letter B write the third letter (C) shifting to the left. Continue this process until you have a 53X53 grid: ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()+-/=<> (Remember to ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()+-/=<>A use proportion- BCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()+-/=<>AB al fonts when CDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()+-/=<>ABC viewing/using DEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()+-/=<>ABCD this file) The way this coding/decoding devise works is by using a control word that "selects" one letter at a time the column you are going to match with a given row. For our learning purposes we are going to select MATHMAGICINTERNET as our control word. When I am ready to send a message, I write (and repeat) my control word. Say I want to send the message BAD CAB. Even though they are two words, I may want to join them (to make it more difficult to decode) so the message is BADCAB. My control word tells me that my message's first letter is going to come from the M column, my 2nd from the A column, my third from the T column, my fourth from the H column, my 5th from the M, and my 6th from the A column (you continue this pattern for longer messages, starting over after the last T with the first M.) The first letter of my message is B, so I go to the B row and look across until I am under the M column: the letter O is my first coded letter. The second letter of my message is A, so I go across until I am under the A : my second coded letter is B. The third letter I want to code is D, so I go across and look under the T: the letter is X. Continue this process until you code it all: OBXKNC. It is helpful to have the message written below the control word: M A T H M A G This process is called encoding. You are creating ------------- a coded message, that later will be decoded by the B A D C A B other party receiving your message. To decode, you proceed backwards: knowing what the control word is, you line up M A T H M A G I C I N your control word and the coded message ---------------------- and you look across to the left for the O B X K N C real message: on the M column, the O is to the right of the (first) letter B; the B on the A column corresponds to A: the X on the T column corresponds to D, an so forth. In case you are wondering what connection is there between math and codes, I encourage you to read about codes and cryptography. Due to the mathematical prowess of the US government, German and Japanese codes during the Second World War were broken and their secret messages intercepted, contributing greatly to the success of the Allies and saving many lives. With the advent of the computer, very sophisticated codes have been developed, but many of them still use variations of the VISIONAIRE CODE. The widely available ROT13 is a code that moves your characters 13 spaces down the ASCII table, a baby scheme compared to the power of our code. Without knowing what the control word is, this code is almost uncrackable. Give the message below a try: UF@MVTOXSR21$/WX(2V@JRT18HJ6 This one has IMPORTANT info and may avoid headaches: R/7IVMMRON17AU3IY With your NTP decode the above messages and practice sending a few mes- sages back and forth. You may have in the case of 0 and O to try both zero and letter O. I find it helpful to have two papers on top of my code to join the rows and the columns accurately. Be good and well MrH