“What’s that, Turing? Oh yes! It seems we picked up a test message from a German operator who must have been all thumbs. I was just looking over the message when it occurred to me that there wasn’t a single instance of the letter L in the whole damn message!”
Turing knew immediately what that meant! Any time an Enigma machine key was depressed, it would return any letter of the alphabet except the one letter labeled on the key being used. If there were no instances of the letter L in the message, then it was a clear tip that the key labeled L had indeed been used, and most likely multiple times.
“On a hunch I assumed this operator had gotten very lazy and just kept using that single key. Well we broke that whole message, and sure enough, I was correct. It just read LLLLL.” Dilly smiled. “I’m calling it my L crib, Alan. Make a note of it. It will likely go down in history!” Knox laughed and was on his way.
Turing did not laugh.
Apparently I did make a note of it, he thought darkly. Right on the back of that bloody photo. And yet I’ve heard this from Knox for the very first time, and just this minute.
Just this minute…
His hand fell on the watch in his pocket now.
Yes! It was all about time!