Michael Chertoff, Former US Secretary of Homeland Security

Most of us have embedded the internet and smart technology in our lives. We might like to believe we're autonomous digital citizens, but what if our behaviours are now being monitored, and modified by private and state actors over which we have no control? Stephen Sackur speaks to Michael Chertoff, director of homeland security in the Bush administration and a leading thinker on cyber security. Has the internet left every one of us dangerously exposed?