I always wondered why Britain was so keen to keep the efforts at Bletchley Park so secret after the war had been won - it turns out we were selling encryption machines very similar to Enigma to lots of countries and organizations and we didn't want anyone to know that we could break the codes.
From a German perspective, this is uncomfortably close to deceit.
IMO, this is one of the reasons the Germans lost the war. The English speakers are by nature sneakier.
http://en.wikipedia.org/wiki/V-1_(flying_bomb)#Deception
http://www.suite101.com/content/allied-misdirection-fooled-g...