TrustZone Explained: Architectural Features and Use Cases

ARM TrustZone is a hardware security extension technology, which aims to provide secure execution environment by splitting computer resources between two execution worlds, namely normal world and secure world. TrustZone is supported on different flavors of ARM architectures, that include architecture deployed on targets running regular applications, such as mobile devices and architecture for micro-controllers. As ARM is widely deployed on the majority of mobile and micro-controller devices, TrustZone's goal is to provide security for those platforms. In this paper, we will discuss details of different ARM architectures that support TrustZone technology. Then, we will review how TrustZone is implemented in the hardware and software of ARM products. We will also compare TrustZone with other implementations of trusted execution environments on the market.