Dieppe - I’m not convenced that the raid was solely to acquire the German codes based upon this article; but having it as one of several reasons for the mission does make sense. I think the need to draw German forces from the Eastern Front is the major reason.
I don’t know what the real purpose was, but in order to draw German forces from their Eastern Front, the Dieppe raid would have had to establish a perimeter and hold it for some considerable time.
From what I have read....The Nazi war machine, was all over Europe, and no one was capable of opposing, the media continued to report the advances of the Nazi hoard....and so Churchill and others, needed to redirect the media....hence the attacking force, was thrown together; with a logical result....I haven’t read: did they secure the code machine?