While the world's attention focuses on North Korea's cyberwar with Sony Pictures, the Hermit Kingdom is rapidly increasing its stockpile of nuclear weapons material, with real little pushback from the United States.

A new analysis of North Korea's nuclear program by a group of top U.S. experts, led by David Albright, president of the Institute for Science and International Security, estimates that North Korea could have enough material for 79 nuclear weapons by 2020.

The analysis, part of a larger project called "North Korea's Nuclear Futures" being run by the U.S.-Korea Institute at the Johns Hopkins School of Advanced and International Studies, has not been previously published.