A separate area inside a processorA computer chip that does computing work for a computer. It may do general work (like in your home computer) or it may do specialized work (like some of the processors in your smartphone). where trusted softwareIn this context, "software" refers to functions in an IoT device that are implemented by running instructions through some kind of processor. It's distinct from "hardware," where functions are built into a silicon chip or some other component. can run, with access to all resources. Software running outside that area has to access resources through the trusted area; it can’t do so directly.
Inside the Internet of Things - Bryon Moyer Blog