Abstract: The present invention offers a solution to the problem of the “strong” authentication of a user who intends to access an IT platform to benefit from a generic service. The invention finds its main application (and this is the industrial context in which it was conceived) in the “strong” identification of the subjects wishing to make economic transactions on a generic IT platform, but it is certainly applicable with a wide generality and effectiveness in all contexts in which it is advisable to identify in a “strong” way an operator who accesses an IT platform for the most varied reasons. In extreme synthesis, the present invention combines two existing systems (and therefore, in general, known systems) which are therefore modified with the addition of new functionalities so that they can be integrated in such a way as to cooperate, in a manner that, de-facto, they become a new combined system.