An Allied cryptanalyst intercepts the message, “JDNTOENVIPDJ,” during World War II and attempts to decrypt it. He assumes it was encrypted using the German Enigma machine and performs the standard cryptanalysis, resulting in the message “PQNXLATIDNW.” He is completely baffled…the Allies had already broken the Enigma, so why was this message indecipherable?
The Germans had invented a new cryptographic weapon.
The Germans’ new cipher, the Rasterschlüssel 44, was introduced in 1944. Ironically, the origins of this new German cipher can be traced to British cryptography (Rijmenants). The cipher was used in the field, mainly by police forces and the army (Cowan 2004) instead of by diplomatic officials. The Rasterschlüssel 44 (RS 44) was a hand cipher, meaning that it could be implemented with pencil and paper, unlike the German Enigma, which required a machine to encipher and decipher a message. Like all hand ciphers, the RS 44 needed to balance security strength and convenience. The cipher had to be complicated enough to withstand decryption efforts, but not so complicated as to be difficult to use.
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