Cyber-attacks should be subject to the same laws, treaties and international conventions as in the physical world. So said UK defence minister Nick Harvey, in a Chatham House speech that laid down an important new marker in government attitudes.
Harvey's speech sounded a warning that as far as the UK is concerned the gloves are about to come off. Countries will not be allowed to get away with overtly or covertly sponsoring cyber-warfare without the fear of a political response.
In Harvey's view, the UK and its allies should find ways to apply principles such as NATO's mutual defence pact, Article V, to acts of aggression in cyberspace. This would apply the concept of deterrence, something that was currently almost non-existent in internet policy.
"I would argue that the established laws governing the use of force and the conduct of hostilities are equally applicable to cyberspace as they are to traditional domains," said Harvey.
"Of course the issue of attribution in cyberspace will be difficult. As will the issue of intent. But as I said earlier, just because it will be difficult, doesn't mean it will be impossible."
A second layer of threat arose from terrorist and other ideological organisations, which would seek to exploit the internet's potential for asymmetric warfare. To counter this, the UK and its allies would need to develop tools and expertise to enable defenders to quickly work out which asset was being attacked and by which entity.
"It can only be a matter of time before terrorists begin to use cyberspace more systematically, not just as a tool for their own organisation, but as a method of attack," said Harvey.
Harvey's speech will be seen as an intelligent acknowledgement that the task of cyber-defence will not be easy for the UK or any other government. There is no clear perimeter to defend, attackers have the ability to obscure their real targets while hiding, and accountability is low to non-existent. Just throwing money and brains at the problem will not be enough.
But external parties will notice the underlined references to deterrence in his words, and to NATO's clause V defence agreement, which is still seen as having helped stop Stalin from calling the USA's nuclear bluff by picking off smaller territories one by one in the 1950s.
If put into effect, such a policy would force countries attacking a NATO state in cyberspace to factor in the detection capabilities and wider response from that country's allies.
"As Clausewitz showed, while the essential nature of conflict is unchanging, its character moves with the times," concluded Harvey.