Proof of Elgamal's semantic security using a reduction to DDH

Happy New Year.

I like drawing, and I haven't drawn in a long time. I figured I could use crypto as an excuse to draw something and start this year in a more creative way :)

(by the way, here is the talk I'm talking about)

Here I glance over a lot of the concepts. I don't explain what is Elgamal or how it works, I don't explain proofs based on games and what semantic security is (and why it is considered insufficient), I don't even explain what I mean by an adversary's advantage. I'm expecting that you will read that on your own and then head here to understand how you can use all of that to prove Elgamal's semantic security.