A method and system as disclosed for use in a virus-free certificate proxy (107, 801), of retrieving from one or a plurality of virus-free certificate authorities (104, 804) a virus-free certificate (200) certifying that a file is virus-free. The method includes the steps of: receiving (1001) virus-free certificate request for a file; selecting a virus-free certificate authority (104, 804) having authority to generate a virus-free certificate (200) for the file; requesting (1003 . . . 1007) the virus-free certificate to the selected virus-free certificate authority (104, 804); receiving (1003 . . . 1007) from the selected virus-free certificate authority the generated virus-free certificate; sending back (1005) in response to the virus-free certificate request the received virus-free certificate.