Jefferson disk

The Jefferson - roller is a tool to encrypt and decode messages. It was developed by Thomas Jefferson in 1790.

The " Chiffrenrad " is a 4.8 inches thick and 14.4 inches long cylinders made ​​of wood. This cylinder consists of 36 numbered discs are 0.4 centimeters wide, and the edge areas are divided into 26 equal sections for 26 letters. The order of the wafers is critical for the encryption and decryption, and must be equal at the transmitter and receiver. The text set in a row and locks the roller. The discs show 25 encrypted lines, from which the sender can select one for transmission. The receiver provides the windows of his cylinder so that it receives the same sequence of letters as the message in one line. Among the other 25 lines then is also the clear message.

Using different locations of the 26 letters of the alphabet, there are

Possible different slices. If an unauthorized person is in possession of the same 36 discs to be like the transmitter, so also exist

Ways to arrange these.

The Jefferson - roll was ahead of its time, but has been used either by itself or Jefferson of the armed forces or the diplomatic corps at that time. It was not until about 120 years later, a variant of the device was introduced in the U.S. armed forces.