Current Issue

Uncle Dick
and other Horrors of the Enigma
by HEINZ ULBRICHT -- abstract

The main parts of the Enigma cipher machine were the keyboard for input of the plain-text, the 'Stecker'-board, the scrambling unit consisting of the three cipher-wheels (Schlüsselwalzen) and the reflector (Umkehrwalze), and the lampfield for reading out the ciphertext. The reflector was the central part of the array of scrambling elements, a number of them was used in Enigma, the most commonly being ‘Bravo.’ Bletchley Park was quite effective in solving the German keys until in January 1944 some messages resisted the usual treatment. This was due to an additional reflector, ‘Dora’, which was soon nicknamed ‘Uncle Dick,’ and which was giving cryptanalysts a bad headache. Fortunately, different key nets used either one or the other reflector and even committed the sin of re-enciphering messages on a large scale, which made way for Bletchley Park solutions. Another new contraption designed to improve the security of the Enigma in 1944 was the “Enigma-Uhr.” It was the only alteration by the Germans in the course of the war that had been introduced without any warning to Bletchley Park and received bitter curses. In the worst case, a message had been encoded with both ‘Dora’ and the ‘Uhr.’ These and other measures confirm that the Enigma, if handled properly, was indeed unbreakable by any known method.