Data security cube

I was going through some stuff in my basement and I came across my Computer Science 464 notes from my alma mater. I didn’t even realize that even back then, we covered a little bit of information security. I had the following depiction in my notes, courtesy of Dr. Arch Harris: (click to expand)

It is a 4×4×4 cube, with areas where data might be exposed on the X axis, security risks on the Z axis, and risk mitigations on the Y axis. So, what’s missing from the cube? How have the last 15 or so years changed our thinking, and what is the correct way of visualizing this today? Please comment below!