An online verification method comprising the steps of: a) generating, by a module at a server, a random code (S_COD1) associated with a subject to be identified; b) recognizing the operating system of a mobile electronic device of the subject and sending, from said module to a mobile electronic device of the subject to be identified, a text message (S_TXT) including the random code (S_COD1) or a hypertext link for selecting the random code (S_COD1); c) receiving, at the mobile electronic device, said text message (S_TXT) including the random code (S_COD2) or the hypertext link; d) acquiring, by means of the at least one electronic image-taking device of the mobile electronic device, at least one first image representing the subject; e) detecting, by a second acquisition module of a processing unit of the mobile electronic device, the random code (S_COD2) in the body of the text message (S_TXT) and displaying it in a field of a graphical interface represented on the mobile electronic device of the subject, or selecting the hypertext link contained within the body of the text message and displaying the random code in said field of the graphical interface; f) generating, by the second acquisition module of the processing unit of the mobile electronic device, a second image representing the random code (S_COD2) received at the mobile electronic device within said text message (S_TXT) or selected with the hypertext link of the text message; g) processing in a single composite screen page comprising at least two images, the at least one first image representing the subject and the second image representing the random code (S_COD2); h) performing, at the server (9a, 9b), a check between the random code (S_COD2) represented in the second image of the single composite screen page and the random code (S_COD1) generated by the server. a) generating, by a module at a server, a random code (S_COD1) associated with a subject to be identified; b) recognizing the operating system of a mobile electronic device of the subject and sending, from said module to a mobile electronic device of the subject to be identified, a text message (S_TXT) including the random code (S_COD1) or a hypertext link for selecting the random code (S_COD1); c) receiving, at the mobile electronic device, said text message (S_TXT) including the random code (S_COD2) or the hypertext link; d) acquiring, by means of the at least one electronic image-taking device of the mobile electronic device, at least one first image representing the subject; e) detecting, by a second acquisition module of a processing unit of the mobile electronic device, the random code (S_COD2) in the body of the text message (S_TXT) and displaying it in a field of a graphical interface represented on the mobile electronic device of the subject, or selecting the hypertext link contained within the body of the text message and displaying the random code in said field of the graphical interface; f) generating, by the second acquisition module of the processing unit of the mobile electronic device, a second image representing the random code (S_COD2) received at the mobile electronic device within said text message (S_TXT) or selected with the hypertext link of the text message; g) processing in a single composite screen page comprising at least two images, the at least one first image representing the subject and the second image representing the random code (S_COD2); h) performing, at the server (9a, 9b), a check between the random code (S_COD2) represented in the second image of the single composite screen page and the random code (S_COD1) generated by the server.