I Once Had to Implement U2F/FIDO2 Auth With X509 Certs

I just recently remembered that when working with some proprietary IOT 
devices I realized I needed to build a monitoring system for them that 
involved fetching alarm data via their embedded web server (they didn't 
have SNMP or *ANY* other network daemon running on their machine) which 
required me to implement U2F/FIDO2 entirely with RSA X509 certificates.

This maddness really distrubed me at a core level as I would imagine that 
using crypto in this way would warrant using a simpler crypto 
serialization method. 

Just to clarify the x509 wrapper around the crypto was simply discarded to 
grab the private and public keys to create and respond to challenges made 
with them. It was really gross over all.