I always feel uneasy to connect a device with private key directly to an untrusted online computer
I hope something like a audio modem could be implemented but seems it's too slow to be practically used?
https://bitcointalk.org/index.php?topic=135423.0It is already implemented in Electrum, just not easy to setup and use...
Be it slow or fast it seems a nice and secure idea, I think...
We have just the solution for this problem - firewall between the crypto controller and the interface, implemented directly in silicon: