Near-field communication method implemented within a vehicle

A method for near-field communication implemented within a motor vehicle, in a near-field communication device, called NFC reader, connected to control means configured to control a function of said vehicle, said method comprising the steps, executed by said NFC reader, of:

• transmitting a presence request for detecting at least one portable device comprising a predetermined type of near-field communication means;
• receiving a presence message from each predetermined type of portable device that is present;
• said method being wherein it comprises the following steps, executed by said NFC reader, implemented when multiple portable devices of the predetermined type are present:
• for each of said predetermined type of portable devices;
• transmitting at least one request for collecting a data pair comprising a device identifier and an application identifier of the portable device;
• and
• receiving said data pair from said portable device;
• storing, as it is received and in a memory of said NFC reader, each data pair having an application identifier corresponding to a predetermined authorized application identifier;
• transmitting, when the data pairs of each of the predetermined type of portable devices present have been received, all the received and stored data pairs to the control means;
• receiving, from said control means, a request for an authentication key associated with a data pair selected by said control means;
• transmitting at least one request for collecting an authentication key to the portable device associated with the selected data pair;
• receiving said authentication key;
• and
• transmitting said received authentication key to said control means, for comparison with at least one authorized authentication key and for controlling said function of the vehicle when said transmitted authentication key corresponds to an authorized authentication key.