Teachers

Teaching With Documents:
The Zimmermann Telegram

Decoding a Message

In substitution codes, the letters of the plaintext (message to be put into secret form) are replaced by other letters, numbers, or symbols. In this code system, each letter of the alphabet and each of the numbers from 1 to 9 appears in the matrix of the grid. Each letter in the grid is replaced by two letters in the coded message. The first letter in the message is from the vertical axis of the grid, and the second letter is from its horizontal axis. For example, if "DG" were the first two letters to decipher in a cryptogram, you would find the letter "D" on the vertical axis and the letter "G" on the horizontal axis. Trace them across the grid to their intersection at the letter "A" in the plaintext.

To decode the fictitious message in the cryptogram, begin by grouping each set of two letters starting with the first two letters (FG) and continuing through the message. The code letters are arbitrarily arranged in groups of five letters. Some letter pairs will carry over from one line to the next. As you locate each letter in the grid, you should write that letter above the pair of code letters to which it corresponds. There are no punctuation marks in the telegram, so your teacher may need to help you in clarifying the message.

Cryptogram
FGAFA AAVXA DGAVX VADAD DVDDD VGA      
VXVDX DVDDF AFDXG XGDDG AVFDV X      
VAAFX GDADX VDDXD AVXXV          
AAAVD AVXDA VVGDD XAVDG DXGXV XVDVF VVAFD XAVAF  
VXDXV DFDAF XAVVV FAVAF VVVVV ADGXV AXAFD GGXFX AFAVV
ADGDF VFAXV DVXXF DAVXG DVAAF XGDAD XVDVF AVAFV FDGAV
AFVXV DAXAF DGXDA FAFVA AADGV VVVXV VDDFV VGDVD AVVXD
FVDVX DADXA F            
AAAFA VDFVV VXVDA VFGFG XFDGV VGDDA DFFXV    
XVDDF FDDX              
Grid
       A      D      F      G      V      X

A

     B

     2

     E

     5

     R

     L

D

     I

     9

     N

     A

     1

     C

F

     3

     D

     4

     F

     6

     G

G

     7

     H

     8

     J

     0

     K

V

     M

     O

     P

     Q

     S

     T

X

     U

     V

     W

     X

     Y

     Z

Teachers: Should your Web browser not display the above material correctly, you may access a JPEG image of the Crytogram and Grid.

Read the Decoded Message!

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