Part of the World War II Cryptographic Simulation

Japanese Point of View: Ciphers similar to the one used by our military have been used for hundreds of years; however, we have adapted ours and change it often enough for it to be reasonably secure. Each transmitter is issued three books, one with a dictionary of words and their corresponding five digit groups. The second and third books are comprised of 50,000 five digit additives that are used to further encipher the message. In order to encipher the phrase "I have the honor to inform your excellency" a clerk would first look up each word in the code book:

I = 78130
have = 63450
the = 94025
honor = 57346
to inform = 37694
your = 43791
excellency = 90940

The clerk then looks up a set position in one of the additive books, and using non-carrying addition, adds the additives to the original message. So if the additives for this day were "61349, 78024, 94613, 75164, 00573, 80861, 17643"

78130 63450 94025 57346 37694 43791 90940 
61349 78024 94613 75164 00573 80861 17643 
39479 31474 88638 22400 37167 23552 07583 
Given sufficient time and a high number of transmissions, such as our military present, this code can be cracked eventually. To prevent this we change the additives books and codebooks on a fairly regular basis.

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