The WebSIM − Clever Smartcards Listen to Port 80

We describe the WebSIM, an approach that integrates GSM SIMs into the Internet. The underlying idea is to implement a Web Server inside a SIM, and to allow for transparent access to it from the Internet. The contribution of our approach is that a SIM, which is currently a security module (smartcard) fitted in a GSM mobile phone, becomes also a personal security server in the Internet. Like any other server in the Internet, it speaks TCP/IP and processes HTTP requests, e.g. for accessing certain SIM services (e.g. authentication) via CGI scripts. The Internet connectivity of a SIM inside a mobile phone can be achieved either by turning mobile phones into IP routers, or by having a proxy host tunnel IP packets to the SIM over SMS. The latter approach, which is explained in detail, can be easily implemented with today’s networks and mobile phones. 1 The opinions expressed in this paper are those of the author, and do not necessarily reflect the views of Deutsche Telekom AG. Draft − Comments are Welcome Version of 15.12.99 19:21 h p. 2/16 Table of