Abstract: A lighting system (100) and a method of protecting a lighting device of a lighting system against theft are provided. The lighting system comprises a lighting device (110) and at least one other device (170). Both the lighting device and the at least one other device comprises a data storage (116, 176), a controller (114, 174) and a network interface (112, 172). The lighting device additionally comprises a light emitter (118). When the lighting device powers up, the other device transmits a verification value stored in its data storage to lighting device. The lighting device assesses the verification value in relation to a unique value stored in its data storage to check whether the lighting system knows the lighting device. In dependence of the assessment, the lighting device is controlled to operate in a first or in a second operational mode. In a commissioning procedure the other device may receive the verification value for storage in its data storage.