Before the US National Security Agency's secret internet and phone spying programs were revealed this summer, the head of the NSA assured lawmakers that the US had the best cyber attack capabilities in the world. "We believe our offense is the best in the world," General Keith Alexander, the NSA's director, said in response to written questions from the House of Representatives submitted after a March hearing. Alexander's answers were just published by the government late last month. Alexander also warned in his responses that "potential adversaries are demonstrating a rapidly increasing level of sophistication in their offensive cyber capabilities and tactics."

The comments add to Alexander's growing list of remarks indicating the US boasts a formidable cyber arsenal. Under Alexander's tenure, the NSA, for example, reportedly worked with Israeli intelligence agencies on the creation of the Stuxnet and Flame viruses, in an effort to sabotage and spy on Iran's nuclear program. Aside from leading the NSA, Alexander has been in charge of US cyber command since 2010, overseeing the expansion of hiring and development of cyber espionage tools and weaponry.