Elliptic curve cryptography
I'm reading the Ethereum Yellow Paper, and got up to the reference to Appendix F, so jumped to reading that, which requires an understanding of SECP-256k1, an elliptic curve cryptography technique. Learning about elliptic curve cryptography has thrown me down the rabbit hole of maths. Trying to understand one topic leads me to need to understand other concepts, each of which in turn may require me to need to learn other concepts, and so on.
I think I will skip over continuing to learn elliptic curve cryptography for now, maybe I'll learn it later.