But in cryptography, you have a security claim that is based on the hardness of a well known mathematical probelm. So you know that breaking a certain scheme is as hard as solving that problem. If someone finds out how to solve such a problem efficiently the scheme is broken, but as long as no one has a solution the scheme is safe. Here it is not clear to me what is the hard problem that makes this scheme secure. Yes, you have light scattering in a random way, but they also showed that it is possible to train a neural network to get the data back. Why can't an attacker do the same?