Underrated explanation, you held it finally click for me. I consider myself a fairly educated person but just couldn’t wrap my head around what made it so special. Correct me if i’m wrong but my understanding is the server uses the public key to encrypt a challenge code that can only be decrypted by your private key. You get an on device prompt to approve the process and the rest is done under the hood.

To go further on this, is the public/private key a mathematical relationship? What ties the two together to make them useful as a pair?