Indeed they had penetrated Purple , the diplomatic cipher
and a number of other codes, but not JN-25

But Mr.Churchill clearly stated "..military and diplomatic.." which includes
JN25 too.


Quite so , an attack of the Phillipines and Malaya
was expected and all Pacific commands had been
issued a war warning.

So called War Warning was designed not to warn Pearl Harbor but to draw
attention away from Pearl Harbor,even though US learned on Nov.25 that the
Pearl Harbor was the target.
That was the reason why Naval Court of Inqury exonarated Kimmel.