The weapon is the easy part. Doable by most countries nowadays given enough enriched U235. The only slightly difficult thing is the trigger system, for which yo

The weapon is the easy part. Doable by most countries nowadays given enough enriched U235. The only slightly difficult thing is the trigger system, for which you can find measurements and designs online. But the deliver system is a whole different story. Missiles and jet engines are much more difficult to develop from scratch. That’s why non-proliferation focuses on preventing countries from enriching Uranium and preventing countries from developing rocket booster technology.