Thursday, 12th May 2016V205, Mathematics Building
John Mack(The University of Sydney)
The breaking of Japanese Army and Navy codes during WW2
In 2000, after investigating the published literature(for which I had reason then), I realised that there was clearly confusion surrounding the question of how WW2 Japanese army and navy codes had been broken by the Allies.
Fourteen years later, my academic colleague Peter Donovan and I understood why that was so: the archival documents needed to perform this task, plus the mathematical understanding needed to interpret correctly these documents, had only exposed themselves through our combined researches over this long period. The result, apart from a number of research publications in journals, is our book, "Code Breaking in the Pacific", published by Springer International in 2014.
Both the Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN) used an encryption system involving a code book and then a second stage encipherment, a system which we call an additive cipher system, for their major codes – not a machine cipher such as the Enigma machines used widely by German forces in ww2 or the Typex/Sigaba/ECM machines used by the Allies. Thus, the type of attack needed to crack such a system is very different to those described in books about Bletchley Park and its successes against Enigma ciphers.
However, there is a singular difference: while the IJN’s main coding system, known to us as JN-25, was broken from its inception and throughout the Pacific War, yielding for example the intelligence information that enabled the battles of the Coral Sea and Midway to occur, or the shooting down of Admiral Yamamoto to be planned, the many IJA coding systems in use were, with one exception, never broken!
I will describe the general structure of additive systems, the rational way developed to attack them and its usual failure in practice, and the "miracle" that enabled JN-25 to be broken - probably the best-kept secret of the entire Pacific War: multiples of three! Good maths, but not highly technical!
Winter of Disconnectedness (MATRIX Workshop)
Monday, 27th Jun 2016 — Friday, 8th Jul 2016[The University of Melbourne]
For details please visit the workshop website and the Special Programme website for "Winter of Disconnectedness".
Mathematical Optimisation Down Under 2016
Monday, 18th Jul 2016 — Friday, 22nd Jul 2016Radisson Hotel [Melbourne]
The workshop is designed to bring together researchers working in various areas of modern mathematical optimisation, to prompt an exchange of ideas between Australian and overseas researchers. The workshop is focussed on the modern aspects of optimisation that involve deep interplay between computational problems and pure mathematical questions. We especially encourage participation of students and early career researchers. Visit the workshop website at www.modu2016.org.
Winter of Disconnectedness (AMSI Workshop)
Monday, 25th Jul 2016 — Friday, 5th Aug 2016(Location to be decided)
For details please visit the the Special Programme website for "Winter of Disconnectedness".