Stream ciphers typically encrypt plaintext a bit or byte at a time, and are most commonly used to encipher real-time communications, such as audio and video information.
Like many machines of the era it used an electromechanical system of rotors in order to encipher messages, but with a number of security improvements over previous designs.
To encipher a message, the inner disk was turned until the desired letter was at the top position, with the number of turns required for the result transmitted as ciphertext.
