HTTPS stands for HyperText Transfer Protocol Secure. This communication protocol is used on the World Wide Web to transmit data securely.
If you call up a page with HTTPS, whose SSL server certificate has not been supplied in the browser (client) or has already been permanently stored, a corresponding notice is made. Here you have the possibility not to visit the page (“Leave this page” on Firefox or “Click here to leave this page”) or to examine and accept the certificate and, if necessary, save it.
If the user accepts the SSL server certificate, the secure connection is usually indicated by an icon (padlock). By clicking on the icon, information about the server can be queried.