Only trusted applications running in a tee have access to the full power of a devices main processor, peripherals and memory, while hardware isolation protects these from. Api was formed in 1919 as a standardssetting organization and is the global leader in convening subject matter experts across segments to establish, maintain, and distribute consensus standards for the oil and gas industry. For information about the trusty api, see the api reference. Virtualization for cortex a9, arm11 cortex a9 and arm11 are the most popular arm cores that are found in todays socs.
Mixed criticality environment with rt requirements security and trustworthiness of the software. On some devices, the soc boot code switches to normal world automatically, but. Previously phil has held a number of senior software engineering roles in the. Arm also welcomes general suggestions for additions and improvements. The processor supports the main recommendations from the platform security architecture psa, which is a framework providing a common approach to security. Enabling dynamic analysis of realworld trustzone software using. Second, we report on the advantages and limitations of optee 26, an opensource framework that supports trustzone. Instead it would use a highlevel api that is provided by a userspace library. In addition, the actual api dll or code where can i download. Arm have produced a standardized software api, called the trustzone api tzapi. Trustframe, a software development framework for trustzone enabled hardware. On arm systems, trusty uses arms trustzone to virtualize the main.
Trustzone trusted application development questions. Sometimes, the cou pling between two components is so tight. Finally we explore the linux memory management, a topic that contains useful information for this work, since this os is used in the overall system 2. The trusted kernel in secure state hosts services, like key management or drm. This required us to implement lowlevel driver support for basic peripherals such as. Security ip arm provides an expanding portfolio of secure ip, firmware and software, collaborating with the ecosystem to provide the right countermeasures for the variety. We cover the features that trustzone adds to the processor architecture, the memory system support for trustzone, and typical software architectures. Arm security technology building a secure system using. Third, we provide a methodology to extend the kernel of optee in order to offer new. Trusted computing building blocks for embedded linux. The spm is a psacompliant software hypervisor that creates and manages. In this section we will explore the arm trustzone technology.
Trustzone offers an efficient, systemwide approach to security with hardwareenforced isolation built into the cpu. Api availability recognizing that development of a security software ecosystem has been hindered by the lack of common standards for software development, arm has released the trustzone api as a public specification that can be downloaded and used free of charge by any software developer as an. Designing requirements for an api goes like any software design goes. The open virtualization project offers developers of embedded devices the ability to rapidly integrate open source trustzone software. For more technical details on arm trustzone, please refer to our blog. Trustzone is a hardware security extension provided by recent arm processors to enable trusted computing 12. The security extensions are an open component of the arm architecture, so any developer can create a custom secure world software environment to meet their requirements. Arm trustzone technology has been around for almost a decade. The gadget2008 design will include a 128kb sram, and use a trustzone memory adapter to allow the bottom 96kb to be made secure.
User interface hmi solutions for mixed safetycritical. Today we will talk about trusted os tee and its applications. This document assumes that you are familia r with the arm proce ssor architecture and. The mbed implementation of psa apis mbed os 5 documentation.
Pdf the trustzone technology, available in the vast majority of. The security of a tee is especially challenging, as the tee needs to protect itself and its trusted applications against attacks using only the resources on the device. In previous articles we looked at the trustzone hardware and the operation of the secure monitor mechanism. Trusted computing building blocks for embedded linuxbased arm trustzone platforms johannes winter institute for applied information processing and communications iaik graz, university of technology inffeldgasse 16a, 8010 graz, austria johannes. Arm trustzone technology is exploited to implement the root of trust of a virtualizationbased architecture that allows the execution of a general purpose operating system gpos sidebyside with a realtime operating system rtos. It goes without saying that this concept is vastly more flexible than tpm chips because the functionality of the secure world is defined by system software instead of being hardwired. The training includes architecting the software, configuring the secure side, accessing secure apis from the nonsecure side and dealing with exceptions. The reason is that secure is privileged, so code unware of trustzone will still run without any modification ie, linux kernel, vxworks, etc. Trustzone technology, whether they are writing security requirements, designing a soc, developing software, or auditing a design for security. In order to host a normal world, you need something in the secure world to host it. However, emulating the required software component apis is not always more practically feasible. Arm security technology building a secure system using trustzone.
Key manager client, provides apis for accessing the secure repository and. The integration of complementary technologies like puf and trustzone further boosts the security credentials of these lowpower, lowcost microcontrollers as iot security requirements increase. Trustzone for armv8m for cortexm profile the security extension, marketed as trustzone for armv8m technology, was introduced in the armv8m architecture. The cortexm33 processor brings trustzone security to demanding and lowpowered devices, enabling programmers to use a familiar programming model to make software isolation more achievable. At least two of those will require hardware modification or device drivers. On top of that, reference designs and development boards further simplify the security equation by employing multiple levels of embedded protection in a. Implementation report of the logical trustzone tpm integration 1. The role of the monitor mode software in a design is to provide a robust gatekeeper which manages the switches between the secure and nonsecure processor states. Trustframe, a software development framework for trustzone. The implementation of a secure world in the soc hardware needs some secure software to run within it and to make use of the sensitive assets stored there. Integrated hardware and software security tech paper. This fourpage laminated guide is designed to help consumers understand the api engine oil quality marksthe api certification mark starburst and service symbol donutand the api service categories.
Unblock websites, overcome censorship and surf anonymously with a trust. A client can specify simple access rules when storing data in key. A hardware software codesign framework for easing the economy of meeting the new generation of embedded systems requirements. Become familiar with trustzone ecosystem target audience hardware and software system architects who need to understand the issues in developing trusted systems using arm trustzone. User interface hmi solutions for mixed safetycritical industrial automation systems with arm trustzone technology. Unfortunately, the software figure 3, left provided by the unit manufacturer. Techonline is a leading source for reliable tech papers.
The code is designed to be portable and reusable across hardware platforms and software models that are based on the armv8a and armv7a architectures. Trustzone trusted application development questions offline lee noonan over 4 years ago i want to develop a trusted application running on the tee trustzone. However, they advertise their support of a certain development. Trustzone tee is a hybrid approach that utilizes both hardware and software to protect data. The aim of trustzone technology is to provide two execution environments. If applicable, the page numbers to which your comments refer. Arm trustzone and kvm coexistence with rtos for automotive automotivegrade linux summit, 20150601, tokyo, japan. In theory if we believe brooks mythical man month you design the documentation and make sure theres a matching implementation. No support for virtualization only two levels of privilege. Implementing puf key and trustzone security digikey. Access blocked content, prevent isp from tracking your online activity. Mobile payment specification arm information center.
To support security requirements, the lpc55s6x also offers support for secure boot, hash, aes, rsa, uuid, dynamic encrypt and decrypt, debug. It was introduced at a time when the controversial discussion about trusted platformmodules tpm on x86 platforms was in full swing tcpa, palladium. There are a wide variety of possible software architectures for the secure world, and the implementation of these is almost totally dependent on the application the user is targeting. The interrupt model outlined in secure interrupts, in which irq is configured as a normal world interrupt and fiq is configured as a secure world interrupt, requires some core configuration by the monitor software on world switch. Download arm trustzone software from open virtualization. Generation of arm processors featuring trustzonem architecture. Trustzone technology can help support such techniques, as certain crypto software and hardware can be configured to only be accessible within the secure state. Software running in nonsecure state needs to have controlled accesses to those services. Trustzone api android forum open source software and. In collaboration with interested parties, we will continue to enhance tfa with reference implementations of arm standards to benefit developers working with armv7a and armv8a trustzone. The trustzone api to encourage the development of security solutions arm have produced a standardized software api, called the trustzone api tzapi, which defines a software interface which client applications running in the rich operating environment can use to interact with a security environment. As of armv6, the arm architecture supports noexecute page protection, which is referred to as xn, for execute never. It simplifies the design and software development of digital signal control systems with the integrated digital signal processing dsp instructions.
A userspace application is unlikely to be directly aware of trustzone. Integrated hardware and software security abstract for details on the trustzone. Understand what is secure debug and how to implement it. To encourage the development of security solutions arm have produced a standardized software api, called the trustzone api tzapi, which defines a. To allow for some flexibility in the design we will use a trustzone protection controller to provide the inputs to the trustzone memory adapter, enabling the.
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