The Internet has evolved significantly over time, and people have come to depend on it for a number of activities such as voice and video communications, social networking, online banking, e-government and shopping. Trust is the core of social and economic activity in the Internet, and is the basis of economic transactions, social connections, and communication between people and organisations. As we increasingly rely on broadband networks, it is extremely important to make them more secure and trustworthy and protect them against any kind of accidental or deliberate failure. Over the past decade we have witnessed an ever-increasing amount of cyber attacks on the Internet. Ranging in style from large-scale worms to phishing attempts, cyber attacks have evolved to unprecedented levels of sophistication. To counter these phenomena, defenders are (mostly) developing safeguards after the attacks are made. In the meantime, while defenders are busy with mending the fences, attackers have already developed and planned their next strike. We are facing an asymmetrical threat; unless addressed, this asymmetrical threat will have the defenders locked into a vicious cycle: chasing after attackers without ever being able to catch up.