An Australian mathematician has revealed that a fatal flaw in the Japanese navy war code helped the Allies win World War II.

JN-25 is the name used by Western cryptography organizations for the main secure command and control communications scheme used by the Imperial Japanese Navy (JIN) during and before World War II (it was the 25th Japanese Navy system identified).

Dr Peter Donovan of the University of New South Wales found out that the code used groups of numbers that were multiples of three. "Having multiples of three in the code book was a flawed process", he says.

Recognising that pattern and finally cracking the secret code was critical in helping the Allies win the Battle of Midway, one of the turning points of the Pacific War.


Donovan reported his finding in a paper published in the journal Cryptologia, "a unique scholarly journal devoted to all aspects of cryptology".

Source:

Judy Skatssoon, News in science