I agree that the author is arguing you can do that. But he's wrong, you can't, it's monstrously difficult for a human to do what the machine does easily (yes I'

I agree that the author is arguing you can do that. But he's wrong, you can't, it's monstrously difficult for a human to do what the machine does easily (yes I'm aware there's a flawed modern attempt described in the novel Cryptonomicon) and given the human propensity to fuck things up it's just futile. The War provided an excellent proof by fire, it's more obvious for Japan because they weren't using machines at the start at all, and so we broke literally everything. All "secret" radio communication by the Japanese was decoded, translated and handled as intelligence up until Purple (a machine) was introduced and then it got harder.