New vulnerabilities are continually uncovered, and systems are configured or used in ways that make them open to attack.

While many hackers have the knowledge, skills, and tools to attack computer systems, they generally lack the motivation to cause violence or severe economic or social harm.

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.

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.

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.

We have never really had absolute privacy with our records or our electronic communications - government agencies have always been able to gain access with appropriate court orders.