Iran has the know-how to produce a nuclear bomb
This isn\’t rare know-how nor is it tough to get. TGive me enough highly enriched uranium (or, better still, give me half a dozen people you don\’t mind dying and I\’ll tell them what to do from afar with the HEU) and we could get a bomb together in a few days.
It\’s a little more complex than simply dropping one large piece of HEU onto another but not much. Good old black gunpowder would do the trick of getting the plates to hit each other fast enough.
The difficulty is in making the HEU: something we know Iran can indeed do. The others are all about making a bomb small enough, efficient enough, that you can put it on a missile and so on. Those are tough, yes.
But if all you want is a low yield bomb that fits on the back of a truck then if you\’ve enough HEU it\’s pretty trivial.