This is Confidential Computing https://en.m.wikipedia.org/wiki/Confidential_computing
with another name. Intel, AMD and Nvidia have been working for years on this. OpenAI released a blog some time ago where they mentioned this as the "next step". Exciting that Apple went ahead and deployed first, it will motivate the rest as well.
Apple's Private Cloud Compute seems to be conceptually equivalent with System Transparency - an open-source software project my colleagues and I started six years ago.
I'm very much looking forward to more technical details. Should anyone at Apple see this, please feel free to reach out to me at stromberg@mullvad.net. I'd be more than happy to discuss our design, your design, and/or give you feedback.
Relevant links:
- https://mullvad.net/en/blog/system-transparency-future
- http://system-transparency.org (somewhat outdated)
- http://sigsum.org
This is what they are doing. Search implementations of this to understand more technical details.