A technique is provided for authentication of a user accessing an access control device. The technique includes an application server that receives a request from a communication device associated with the user or the access control device. The request contains an identifier of the communication device, an identifier of the access control device and presence data indicating that the communication device is associated with the access control device. The application server checks a database for the user's subscription, sends a response to the access control device to request the user to enter a secret code via an interface of the access control device, receives a temporary secret code generated by a service provider server if the entered secret code is correct, and sends a message containing the temporary secret code to the communication device to request the user to enter the secret code via the interface of the access control device.