There were 4 main parts in the enigma: the keyboard, the lampboard, the rotors and the plugboard.
Keyboard and Lampboard
This is where the operator would had imputed the message to be encrypted and also get the output. A built-in typewriter was featured in the earlier commercial enigmas however, as it was less portable, later versions had a lampboard and relied on the operator to record the letters himself.
The Plugboard
The plugboard (Steckerbrett in German) permitted the operator to substitute a pair of letters. It was introduced to German Army versions in the 1930's, and was soon adopted by the Navy. The plugboard contributed more cryptographic strength than an extra rotor. Enigmas without a plugboard could be solved relatively easily.
A cable placed onto the plugboard connected letters in pairs; for example, E and Q might be a steckered pair. The effect was to swap those letters before and after the rotors. For example, when an operator presses E, the signal was diverted to Q before entering the rotors. Up to 13 steckered pairs might be used at one time, although only 10 were normally used.
Keyboard and Lampboard
This is where the operator would had imputed the message to be encrypted and also get the output. A built-in typewriter was featured in the earlier commercial enigmas however, as it was less portable, later versions had a lampboard and relied on the operator to record the letters himself.
The Plugboard
The plugboard (Steckerbrett in German) permitted the operator to substitute a pair of letters. It was introduced to German Army versions in the 1930's, and was soon adopted by the Navy. The plugboard contributed more cryptographic strength than an extra rotor. Enigmas without a plugboard could be solved relatively easily.
A cable placed onto the plugboard connected letters in pairs; for example, E and Q might be a steckered pair. The effect was to swap those letters before and after the rotors. For example, when an operator presses E, the signal was diverted to Q before entering the rotors. Up to 13 steckered pairs might be used at one time, although only 10 were normally used.
The Rotors
The rotors were the heart of the machine, located at the top part of the machine. They measured about 10 cm in diameter and were placed on the shaft. The three/four installed movable rotors were sandwiched between two fixed wheels: the entry wheel, on the right, and the reflector on the left. The electrical contacts on both sides represented the 26 letters of the alphabet so when the rotors are resting side by side, it forms an electrical connection. By itself, a rotor performs only a very simple type of encryption—a substitution cipher. For example, the pin corresponding to the letter E might be wired to the contact for letter T on the opposite face, and so on. Enigma's security came from using several rotors in series (usually three or four). Also, the regular stepping movement of the rotors ensured that a letter encoded twice or more would always be different. Every time a key is pressed, the rotor on the first rotor moves one step; When the first rotor finishes a full rotation, it would kick the second rotor. When the second rotor finishes a full rotation. Because of this, every time you press a letter, it would be a different letter every single time. This is why the Germans thought they had an unbreakable code. |
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