[StillBored]

Thanks for that, I was going to point out its the public key, and cert validation that is going to be the problem more than the actual data encryption. I had this problem a couple years back with a project on a esp8266, which was taking on the order of 5 seconds at 160Mhz to setup a TLS connection. And it got worse with longer key lengths, and validating a cert chain.

So, ballpark it probably takes multiple minutes, and probably consumes most of the RAM for the intermediate steps with longer keys.

OTOH, I switched to an ESP32 because it has RSA offload, and something like that could be attached to an apple ][ fairly easily, to provide a connection offload accelerator.