>input latency feels high because redrawing the screen is slow (along with all the encryption, which is also slow)

Is modern encryption a challenge to those old machines? Is it because of specialized encryption hardware or sheer brute force?

Or is it just this implementation that's slow?

I used telnet back in the 68k days.

It's the encryption. For Crypto Ancienne, it may take 20 or more seconds for a cacheless 25MHz '030 to do a local TLS 1.2 transaction, and that's with skipping a whole bunch of steps. Pretty much anything under 40MHz will have timeouts because most servers won't wait.

https://github.com/classilla/cryanc