Abstract: A method and system for securing an electronic communications session between a mobile device and a network server is provided. The method includes requesting, from the mobile device, a unique session identifier from an authentication server. The authentication server in turn requesting the session identifier from the network server on behalf of the mobile device and, upon receipt thereof, communicating it to the mobile device over a secure communication channel between the mobile device and the authentication server, established using a unique digital certificate on the mobile device which was previously issued to it by a trusted certification authority. The session identifier being useable by the mobile device and network server to secure, mutually validate and authenticate the electronic communication session between them conducted by means of a conventional electronic communications protocol.