Secure inspection of web transactions

Web transactions are vulnerable for attacks where malicious software has infected a browser or where a root certifier has been compromised. As a countermeasure, we intercept HTTPS traffic in order to authorise certifiers as well as to inspect, verify and complement transactions securely. The interception and inspection is done in a trusted device, outside potentially compromised PC and browser. We propose a novel and flexible mechanism for controlling interception dynamically with directives embedded into HTML documents. We limit the authority of root certifiers over critical services with site-specific certification rules. We propose different models for realising the interceptor concept. The feasibility of the proposals is demonstrated by implementing and deploying interception into a USB gadget and a mobile phone.