Root of Trust implementation – Connected devices with authentication requirements need a root of trust in the system architecture. This is particularly important for devices that can be updated over the air. In a system with TrustZone technology, code for firmware-update support and associated authentication can be placed in secure memory space and hence protected. Even if a device is compromised at the application level it cannot be wiped out and replaced with spurious firmware.
Security management in IoT devices – Many IoT devices need to handle security sensitive information such as user information and security keys. TrustZone technology allows this information and associated firmware (that can have direct access to this data) to be stored in protected secure memory space. The architecture design enables the application code running in non-Secure state access to the secure information via predefined APIs only and (if provided in the secure software) via an authentication process.
Firmware protection – Firmware shipped with the device includes valuable IP which needs to be protected. TrustZone technology enables such protection by allowing the supplier to put their firmware in protected, secure memory space, while still allowing users to use the firmware via predefined API calls.
Sandboxing for devices with certified software – Many ASSPs, such as a Bluetooth chipset, contain preloaded software while also allowing developers to add their own software components. Using TrustZone technology, the preloaded firmware can be placed in the secure side and its behaviour prevented from being altered by applications running on the non-Secure side. This helps in ensuring that certified firmware remains in its certified state. In addition, placing the firmware in the secure side helps protect it from being reverse engineered.
Consolidation of multiple helper processors in complex SoCs – Complex application processor SoCs often contain Cortex-M processors for off-load or for managing system functions. Sometimes multiple Cortex-M processors are used to isolate secure software from non-secure software. TrustZone for ARMv8-M makes it possible to merge secure and non-secure processors to reduce system cost and software development complexity.
what else?