the idea is new and I wonder how the OP came up with such a good business story...

OP, if you are really a beginner in all of this and you have to ask here about the legality of the exchanger business, I'm afraid it's not for you. maybe you should think about what your abilities and knowledge are, and based on that you should make investments.
you will certainly be on very slippery ice, but it is a great advantage if you know how to slide.