[Cryptography] Pearl Harbor and Crypto (was Re: ISIS has ‘help desk’ to ai d would-be terrorists with encryption)

[Perry E. Metzger]

On Sun, 22 Nov 2015 10:04:48 -0500 Arnold Reinhold <agr at me.com> wrote:
> On Saturday 21 Nov 2015 Perry E. Metzger wrote:
> > The actual events were a bit more complicated. A better
> > explanation is given in the opening section of "The Codebreakers"
> > by Kahn. (The chapter is entitled "One Day of Magic", "MAGIC"
> > having been the codename for the decrypted Japanese intercepts.)
> 
> The “Codebreakers” chapter is an essential read for anyone
> interested in cryptography, but doesn’t materially change the
> conclusion.

There are a number of important details, however, such as the
dramatic difference in the speed with which the US could break things
in the PURPLE cipher vs. other Japanese codes, and even the speed
with which the Japanese themselves could process messages in the more
manually intensive systems.

Perry
-- 
Perry E. Metzger		perry at piermont.com