Code number input device for PIN or password in cash machine or access control system, randomly assigns symbols of keypad to individual keys, and resets after input process

摘要

The input device has a keypad with numbers, characters or symbols. The device does not allow unauthorized observers to determine the input number- or symbol sequence. At the start of each input process, control circuitry randomly assigns symbols to the individual keys of the keypad, and resets them to a standard layout after the input process. An independent claim is included for a method of inputting code numbers.