A method for verifying the identity of a user of an online service, characterized by the steps of: - when a user terminal is connected to an online service by means of a communication over an Internet protocol, sending from a server of said online service to said user terminal an IP address of an authentication server; - connecting said user terminal to said IP address and downloading from said authentication server at least one application, said at least one application being for taking photos with the webcam of the user terminal; - taking a photo with the webcam of the user terminal, said taking the photo being controlled by said application; - sending said photo and associated metadata to a management unit, said metadata comprising at least a user ID of the user using said user terminal and the time of capture of said photo; - storing said photo and associated metadata in a data base; - at an automatic facial recognition module, automatically extracting one set of biometrical parameters per each face which appears in said photo; - at said automatic facial recognition module, comparing said set or sets of biometrical parameters extracted from said photo with a reference biometrical model of the user to which said user ID belongs, said reference biometrical model being stored in said data base; - if the result of said comparison unequivocally matches the person in the photo with the user to which said user ID belongs, said management unit adds to the result a flag indicating that no manual validation is needed; - otherwise, if the result of said comparison does not unequivocally match the person in the photo with the user to which said user ID belongs, the management unit adds to the result a flag indicating that manual validation is needed; then: either informing the online service provider of this or sending said photo to a manual recognition unit for manual validation of the photo; - repeating the step of taking a photo with the webcam of the user terminal and the subsequent steps, thus continuously verifying the identity of the user connected to the online service through said user terminal. - when a user terminal is connected to an online service by means of a communication over an Internet protocol, sending from a server of said online service to said user terminal an IP address of an authentication server; - connecting said user terminal to said IP address and downloading from said authentication server at least one application, said at least one application being for taking photos with the webcam of the user terminal; - taking a photo with the webcam of the user terminal, said taking the photo being controlled by said application; - sending said photo and associated metadata to a management unit, said metadata comprising at least a user ID of the user using said user terminal and the time of capture of said photo; - storing said photo and associated metadata in a data base; - at an automatic facial recognition module, automatically extracting one set of biometrical parameters per each face which appears in said photo; - at said automatic facial recognition module, comparing said set or sets of biometrical parameters extracted from said photo with a reference biometrical model of the user to which said user ID belongs, said reference biometrical model being stored in said data base; - if the result of said comparison unequivocally matches the person in the photo with the user to which said user ID belongs, said management unit adds to the result a flag indicating that no manual validation is needed; - otherwise, if the result of said comparison does not unequivocally match the person in the photo with the user to which said user ID belongs, the management unit adds to the result a flag indicating that manual validation is needed; then: either informing the online service provider of this or sending said photo to a manual recognition unit for manual validation of the photo; - repeating the step of taking a photo with the webcam of the user terminal and the subsequent steps, thus continuously verifying the identity of the user connected to the online service through said user terminal.