This Christmas, New York is in Sandy Recovery mode. With the holiday season approaching, the race has been on to get the lights on - or, more specifically, as much of the city's infrastructure restored as possible. The Big Apple has succeeded to an impressive degree: subway lines are working, tunnels are drained and, yes, for the most part the electricity grid is back.

However, as those recovery efforts continue, there is a decidedly un-festive question haunting some public officials: namely, could all those lights go out again? For quite apart from the threats posed by hurricanes or other weather shocks, there is another, more unnerving spectre haunting the city: the threat of a cyber-attack.

Think about it. In the past few months, it has become crystal-clear that places such as New York are apt to face severe disruption if the electricity grid or other key infrastructure suddenly get suspended. It is also clear that cyber-hackers and terrorists are becoming increasingly bold in their efforts to infiltrate the computer systems that run that critical infrastructure.