TrustZone is basically the name for the ring -1/hypervisor access level for ARM CPUs, not a separate "engine" or product. It can be used to run and isolate code

TrustZone is basically the name for the ring -1/hypervisor access level for ARM CPUs, not a separate "engine" or product. It can be used to run and isolate code at a higher privilege level than an operating system eg. for DRM.