* Andy Lutomirski: >> I _believe_ there are also things like AES-NI that can get strong >> protection from stuff like this. They load encryption keys into (AVX) >> registers and then can do encrypt/decrypt operations without the keys >> leaving the registers. If the key was loaded from a secret memory area >> right into the registers, I think the protection from cache attacks >> would be pretty strong. > > Except for context switches :) An rseq sequence could request that the AVX registers should be cleared on context switch. (I'm mostly kidding.) I think the main issue is that we do not have a good established programming model to actually use such features and completely avoid making copies of secret data.