As I work on TLS for lwIP and research the necessary requirements for TLS 1.3 I have found that there are 2 algorithms that I have need for and will need to be fast. Like VERY fast. Fast enough that they should probably be done by someone who can code assembly so optimized it bends space and time, and that isn't me. Thus, I'm putting these here for anyone who is willing to help out.

bigint powmod for 2048-4096 bits (for RSA signature verification)
https://github.com/cagstech/lwip-ce/issues/14

secp256r1 (for ECDSA and ECHDE)
https://github.com/cagstech/lwip-ce/issues/15

We can also optionally add SHA-384. It's not necessary.
https://github.com/cagstech/lwip-ce/issues/12