While the vast majority of hackers may be disinclined towards violence, it would only take a few to turn cyber terrorism into reality.

If we take as given that critical infrastructures are vulnerable to a cyber terrorist attack, then the question becomes whether there are actors with the capability and motivation to carry out such an operation.

Systems are complex, so controlling an attack and achieving a desired level of damage may be harder than using physical weapons.

I don't have a particular recommendation other than that we base decisions on as much hard data as possible. We need to carefully look at all the options and all their ramifications in making our decisions.

However, leaving everything to the market is not necessarily good for society.

Further, the next generation of terrorists will grow up in a digital world, with ever more powerful and easy-to-use hacking tools at their disposal.

Although cyber attacks have caused billions of dollars in damage and affected the lives of millions, few if any can be characterised as acts of terrorism.