I watched the presentation and am still processing the information. I was not so terribly impressed as the data is from 2003. I was more looking for what they have done since then.

The general principles of how to construct implosion weapons are generally available. What remains the hardest part of a nuclear weapon is to produce enough enriched uranium to build the core.

Centrifuges get you only so far, then you need to put the uranium into a reactor and enrich it.

I spent a lot of time in physics and reading about nukes since the 80's. Have a friend who is a Navy nuke operator to ask. Will report back.