Rotor

Rotor

His name was Lothar,

(Music)

So in this picture, you see that rotor four is spinning faster and rotor two is spinning slower.

They were happy because the story survived, and that the world would keep on spinning.

So we were able to associate the small digital warhead with the rotor control.

And the other way around, if you increase the speed of rotor three and decrease the speed of rotor one, then the robot pitches forward.

This man refused to fold to the conventions of normalcy and just decided to fold.

When it ticks forward, a new shift could be generated by adding up each number on the rotors.

So let me give you just a very quick tutorial on how these robots work.

Lothar Meggendorfer.

First, we choose from 1 of 6 possible rotor orderings.

Now, the state of the art technology of the time was called a rotor encryption machine.

This is equivalent to having a list of shifts 17,576 numbers long.

Let's visualize the key space at this point.

The rotor is that moving part within the centrifuge, that black object that you see.

If you spin these rotors at the same speed, the robot hovers.

Give away the key setting, and you give away the entire sequence.

So at each rotor position, there's an electrical path from every input letter to every output letter.

The small warhead is taking one cascade, and spinning up the rotors and slowing them down, and the big warhead is talking to six cascades and manipulating valves.

For example, some changes they made were to add a fourth rotor wheel, and increase the number of possible rotors you could put into the machine to 60.

Notice how a new shift is used at each position in the message.

During World War Il, one of the most important encryption technologies used by the German military was known as the Enigma.

It was an electromechanical rotor machine invented by a German engineer at the end of the World War I.

Each rotor wheel had electrical contacts on either side with a maze of wirings within.

During the war, they continually tried to increase the key space of the Enigma, in order to make it stronger.

For a given messaging crypt, the Bombe could scan through all possible rotor positions and orders, in order to find possible key settings in a matter of minutes.

And then finally, if you spin opposite pairs of rotors faster than the other pair, then the robot yaws about the vertical axis.

This destroyed the uniform distribution of the initial rotor position, and after repeated observations, it allowed the allies to reverse engineer the rotor wirings completely.

This key space increases if the number of ways to initially configure the machine increases.

This would have prevented the reverse engineering of the rotor wirings, and if the Enigma allows the letters to be encrypted to themselves, the Bombe couldn't have taken advantage of crypts, and this would require the allies to check the entire key space, which was impossible even with the fastest computer.

Each day, the operator would cut off the daily settings, and this would tell them the daily configuration of their machine, such as what rotors to use and the order of the rotors.

So you can take this thing over here and move it around, and what you actually see of the object depends on the angle of the rotors.

One fact remains, this initial attempts at automating the one time pad failed.

What we're interested in is developing robots like this and here are two other pictures of robots that you can buy off the shelf.

And if you manipulate the speed of this rotor, you are actually able to crack the rotor and eventually even have the centrifuge explode.