A luminaire (10) is disclosed comprising a wireless communication module (13) for configuring the luminaire; an optical signal detector (11) for detecting a directional optical signal (31) comprising source information included in the directional signal by a signal source (20) of the directional signal; and a controller (15) for controlling the wireless communication module. The controller is adapted to decode the source information of the coded directional optical signal to extract an identification code and a cryptographic key; to enable the wireless communication module such as to establish a wireless communication link (33) between the wireless communication module and the signal source if the extracted code matches a reference code; and to encrypt data sent over the wireless communication link (33) in accordance with said cryptographic key. A method for communicating with such a luminaire, a computer program product for implementing such a method and a mobile communications device comprising the computer program product are also disclosed.