That technology must have came from either one of 3 places.
1. China has been secretly and actively helping North Korea with their Nuclear Weapons program right under our noses.
2. Iran has also have been secretly been helping North Korea with their Nuclear Weapons program right under our noses.
3. China and other countries have been stealing our nuclear weapons techknowlogies with the help of Bill Clinton selling them missile technology.
4. All of the above.
With any of these, why did those folks think the Norkies would be any kind of loyal friend once they had the magic destruction apparatus in their hands?