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→Operational Procedures: Not true. The wheel start position for each message was unique, chosen by the operator.
The Nazis used word salad, but they also made a costly mistake. They routinely ended each message with "HH", for "Heil Hitler". This foolish bit of vanity was helpful to the British.
The Nazis used word salad, but they also made a costly mistake. They routinely ended each message with "HH", for "Heil Hitler". This foolish bit of vanity was helpful to the British.
There is another problem. The movement of the rotors meant that simple letter frequency analysis, which plays an important part in solving cryptograms in magazines ("This message has a lot of m's; let's guess that m corresponds to e.") won't work. But one can still do frequency analysis on the letters in a corresponding position in the messages, since they all used the same key. That is, if today's messages often have m appearing in the 15<sup>th</sup> position, one could guess that those were e's in the 15<sup>th</sup> position, since everyone's rotors would have been in the same position at that point. While utilizing this information would have been much harder than ordinary substitution ciphers, it was still a weakness.
There is another problem. The movement of the rotors meant that simple letter frequency analysis, which plays an important part in solving cryptograms in magazines ("This message has a lot of m's; let's guess that m corresponds to e.") won't work.
To avoid this weakness, an extra trick was developed. Instead of just setting the rotors and plugboard according to that day's instructions in the code book, the procedure was this:
To avoid this weakness, an extra trick was developed. Instead of just setting the rotors and plugboard according to that day's instructions in the code book, the procedure was this: