The exposure of the United States' Internet surveillance program by former National Security Agency contractor Edward Snowden has once again highlighted the issue of responsible state behavior in cyberspace, a subject Washington has been raising at bilateral and multilateral forums without accounting for its own illicit activities.

So what makes responsible state behavior? How should a responsible state behave when it comes to cyberspace?

First, a responsible state should abide by some basic but important canons in its international relations. Good faith is one of these canons. As the Permanent Court of Arbitration categorically said more than a century ago, the principle of good faith "ought to govern international relations". Good faith is not only a rule of international law, but also one of "the general principles of law recognized by civilized nations", and a common heritage of all civilizations.