Cyclometer
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The cyclometer was a cryptologic device designed, "probably in 1934 or 1935," by Marian Rejewski of the Polish Cipher Bureau's German section, to catalog the cycle structure of Enigma permutations, th
Cyclometer, devised in the mid-1930s by Rejewski to catalog the cycle structure of Enigma permutations. At top are the two rotor banks, one with lid open; below is the rheostat at left, and at right the array of lamps and switches labelled with corresponding letters.
Enigma, an electro-mechanical rotor machine with scrambler comprising entry drum, three rotors, and reflector. This military model also has a plugboard.
Marian Rejewski, ca. 1932
Bombe
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The Bombe was an electro-mechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted secret messages during World War II. The British Bombe was developed from the
Cyclometer
…thereby facilitating the decryption of German Enigma ciphertext. With Rejewski's later cryptologic bomb, it can be viewed as a predecessor to the Bombe that was to help break Enigma ciphers later in the war at Bletchley Park in England. Using drawings made by Rejewski, Hal Evans and Tim Flack at the…
A wartime picture of a Bletchley Park Bombe
The plugboard of an Enigma machine, showing two pairs of letters swapped: S–O and A–J. During World War II, ten plugboard connections were made.
A German Enigma key list with machine settings for each day of one month