To render secure a connection between an access point of a short-range network and a mobile terminal within a cellular network while precluding acquisition of a PIN code, a platform transmits a confirming message, including a secret code and the access point address retrieved from a terminal request, to the terminal through the cellular network and a connection request message including the secret code and the mobile terminal address to the access point. The access point authenticates the terminal, or the terminals authenticate each other as a function of a session key determined as a function of the secret code retrieved from the connection request message and from the confirming message.