Working Principles

Figure 1 Working principle of the ARM TrustZone

TrustZone provides an additional secure execution environment through hardware security extension.

• Extends a secure execution environment by using the time-multiplexed sharing mechanism of CPUs.
• Provides isolated hardware resources for the secure world based on hardware expansion.
• Marks the resources and access sources of the two worlds. The hardware filter controls the resource access permissions.
• Uses the monitor to switch between the running modes of CPUs.
• Deploys their own systems in the two worlds.