Abstract: TrustZone technology has been widely used in the security protection of various smart systems, such as data encryption, fingerprint login, DRM protection, electronic payment and so on.  TrustZone technology provides programs with a trusted execution environment (TEE) that is isolated from the host environment to provide the runtime protection for important code and data. Therefore, the calling process of the security application based on TrustZone has changed, then the application adds processes such as data sharing and messaging between the secure and non-secure worlds, which causes additional performance overhead. This paper locates four key elements that affect the performance of the security application: world switch, interrupt, shared memory management, and data copy. On this base, four corresponding performance optimization methods are proposed. Through the AES encryption ser- vice based on TrustZone technology, the proposed performance optimization methods were compared and tested to verify their effectiveness. Experimental results show that: 1. Setting parameters reasonably can improve the performance by 31% at most. 2. Masking external interrupts can improve the perfor- mance by 4.5% at most. 3. Memory reusing can improve the performance by 37% at most. 4. Reducing memory copy can improve the performance by 39% at most.

Key words: TrustZone, trusted execution environment, performance, optimization