OPTZ: a Hardware Isolation Architecture of Multi-Tasks Based on TrustZone Support

Abstract

In order to improve the safety of existing embedded system, make user data more secure, we propose an implementation of multitasking hardware isolation based on TrustZone named OPTZ (Open TrustZone). ARM TrustZone technology can implement the hardware isolation to improve the security of the software without additional hardware chips outside. In this paper we designed a complete trusted execution environment (TEE) and implemented the multitasking hardware isolation between normal world and secure world. Moreover, the multitasks in the secure memory are also separated from each other. Our architecture includes a secure operating system running in secure world, an normal operating system from normal world, secure services and communication mechanism. At last, we have done some experiments of physical memory access to test and verify the correctness of our architecture. Client application(CA) runs in normal world cannot access the secure world's physical address. The trusted application(TA) can communicate with each other but not access. The experiment results show that multitasking hardware isolation worked well, and the memory isolation can reach the hardware level.