The conventional wisdom is that the successful US cryptanalytic efforts against Japanese naval codes was a closely-held secret. I've just stumbled on a source that disputes that. In "The Unknown Battle of Midway: The Destruction of the American Torpedo Squadrons" (Alvin Kernan, Yale University Press, 2005), the author states:
Rumors began to circulate that the Japanese were planning to invade little Midway Atoll and draw our ships out to fight the great sea battle their strategy had long anticipated. Our information, we heard, at the scuttlebutt, came from code breakers... Unbelievably, the Japanese never tumbled throughout the entire war to the fact that their codes had been broken, and the U.S. Navy, equally blindly, continued to believe that its ability to read one after another of the Japanese codes remained a deep, dark secret from its own sailors. But when the American carriers sailed from Pearl Harbor to the Battle of Midway everyone aboard knew what was in the wind and how we knew it. The source for this statement isn't clear. The author himself was an enlisted sailor on one of the American carriers (he was an ordnanceman for a torpedo squadron), so it may be first person knowledge. Later in the second paragraph, there's a footnote to Prange et al's "Miracle at Midway", but I don't have that reference. --Steven M. Bellovin, http://www.cs.columbia.edu/~smb --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]