ARM TrustZone. It controls access to various hardware. Other software, including the kernel and baseband isn't supposed to be able to even observe its state. Th

ARM TrustZone. It controls access to various hardware. Other software, including the kernel and baseband isn't supposed to be able to even observe its state. There's a base set of functions which handset vendors can add to. Of course, it has vulnerabilities too. I haven't heard of any process hardening going on though. Do you have a source for that? I want to learn more about it.