Trusted World Systems

One way in which modern trusted execution environments are built is using a ‘world’ that executes with hardware-enforced separation. Secure worlds are built such that not even root-level adversaries within the ‘main’ operating system can gain access to its assets. The secure world runs largely in parallel, protecting applications that are deemed too sensitive to use operating system-only controls. Crucially, the rest of the system is relatively untouched, which contains the ‘main’ operating system and the everyday user applications we are familiar with using. This chapter discusses technologies that follow this paradigm, including the GlobalPlatform TEE specifications, ARM TrustZone, and the ARM Confidential Compute Architecture. We also present two case studies, showing how trusted world TEEs are used to underpin key management and biometric authentication on Android devices.