Actually, there are solutions to store the keys in CPU privileged registers (eg: hw debug registers), and when combined with AES-NI don't even cause much overhe

Actually, there are solutions to store the keys in CPU privileged registers (eg: hw debug registers), and when combined with AES-NI don't even cause much overhead: http://en.m.wikipedia.org/wiki/TRESOR http://en.m.wikipedia.org/wiki/TRESOR Not sure why these techniques aren't mainstream yet.