19.3

1. Aside from quantum anything, the most difficult part for me is the Fourier transform. I know that it transforms things from the time or spatial domain to the frequency domain, but despite my continued readings on the subject, I just can't grasp it.

2. Quantum computing changes the game, but I think it is not the panacea that many make it out to be (and the author agrees with me on this point). If I'm not mistaken, there are provably secure encryption models based on the behavior of quantum systems. Of course it is in the best interest of governments and institutions to keep their information secure, but do we expect that overcoming the physical limitations of quantum computing will allow us to use an arbitrarily large number of qubits (or maybe a practically large)? If not, we can always stay ahead of the tech with longer and longer keys, right?