I don't believe we had broken the Naval operational code by then, only the diplomatic code. We could read the “East Wind Rain” message, but couldn't put a location of where the attack would be.
To the day he died, he maintained that someone at the top knew something bad was about to happen in Hawaii. He was transferred to the ETO in 1944.
I'll try to find the book, thanks.
Diplomatic code and Purple (operational)code were not the same. Also, as in Germany, our intel was always reluctant to indicate to the enemy that we did have their code, ie. “Enigma” machine, we had to appear lucky.