Secure access control method with short range and medium or long-range modes of operation

A secure access control method using a reader, of the secure access control reader type, and at least one radiocommunication mobile terminal carried by a user, the reader comprising a control module in connection with a remote processing unit, a first radiocommunication module having a first range, and a second radiocommunication module having a second range less than the first range, said secure access control method comprising:

• implementing a first mode of operation when the mobile terminal is located at a distance from the reader less than the first range and greater than the second range, wherein in the first mode, a first radiocommunication chip of the mobile terminal establishes a radiocommunication in a first radiocommunication channel with the first radiocommunication module of the reader to exchange identification data by way of the first radiocommunication channel between the mobile terminal and the control module of the reader during or subsequent to an authentication phase;
• and
• implementing a second mode of operation when the mobile terminal is located at a distance from the reader less than the second range, wherein in the second mode, a second radiocommunication chip of the mobile terminal establishes a radiocommunication in a second radiocommunication channel with the second radiocommunication module of the reader to exchange identification data by way of the second radiocommunication channel between the mobile terminal and the control module of the reader during or subsequent to the authentication phase, wherein the second radiocommunication channel is selected automatically and as a priority over the first radiocommunication channel,
• wherein, during the authentication phase, the mobile terminal communicates authenticated identification data specific to said mobile terminal and towards the remote processing unit.