For a physicist, studying cryptography feels like learning actual magic.
Discussion
Boomshakalaka
Wait until you start playing with quantum computing and qubits where they can be any state at any time - makes your brain start to hurt.
Never forget my college advisor telling me "I'm better off as an enginner instead of a physicist" because I wanted to actually apply the connected circle instead of discussing Pi
The deeper you go the more magical the entire universe becomes. I’ve written about this. 
Any book recommendations?
As a mechanical engineer, that's how I felt learning to code. Macros that can do weeks worth of work in an afternoon... 🤯 And I think some coworkers thought a jupytern notebook that I used to perform a design study was witchcraft 😁
Some helpful sources to explore the matter further?
I'm pretty sure physics is way better magic.