On Mon, Apr 14, 2014 at 10:09:14PM +0000, Matthew Black wrote: > IIRC, the message was sent via courier instead of cable or telephone to > prevent interception. Did the military not even trust its own cryptographic > methods? Or did they not think withdrawal of the Japanese ambassador was not > very critical?
The message was sent by Western Union. There being no cable between the Hawaiian Islands and the mainland at the time, the message went by commercial radio, in plaintext, and thence by civilian bicycle messenger (of Japanese ancestry, as it happened) to Fort Shafter, where it was read while the attack was in progress. David Kahn's fine book, _The Codebreakers_, discusses this in rather more detail. I recommend the original version; the paperback and later hardback editions contain rather less meat. -- Mike Andrews, W5EGO mi...@mikea.ath.cx Tired old sysadmin
