An electric bicycle has an electric motor and an electric energy store for supplying energy to the electric motor. Accordingly, the bicycle has a first controller coupled to the electric motor and is configured to store a first keycode. The bicycle has a second controller coupled to the energy store and is configured to store a second keycode. The controllers are connected or can be connected to a data transmission system, which is a bus. The first and second controllers are configured such that at least one specified controller of the controllers receives the keycode of the other controller. The specified controller is configured to determine whether its keycode matches the received keycode of the other controller using specified criteria. An immobilizer for an electric bicycle can be formed from these components.