Ask HN: Video camera and microphone encryption at the driver or hardware level?

In *nix, are there any examples of microphone and video drivers or do microphone and video camera hardware exist that implement real-time encryption, so that all applications using streaming microphone and video data have to implement decryption of sound and video data to be useful? I know this would place a greater computational burden on the system, but it would ensure that any software on your device installed without your awareness is incapable of eavesdropping on you.