Research And Implementation Of Application Integrity Protection Based On TrustZone

It is a perpetual topic about the confrontation between security threats and information security which is an important part of the development of information technology in our country of which level is directly restricted by the state of information security.In order to construct the protection system of information security,the nationalization of the basic software and hardware of information system should be accelerating replaced to avoid the recurrence of such as Microsoft Windows Black Screen and Prism Door Event,while the protection system about the security of operation system,application program and network should be actively constructed for the purpose that the “footstone” about the domestic basic software and hardware can be able to resist various forms of attack and threat.Application program is the gateway and window of the interaction among information systems and is extremely important to information system of which the illegal operation of malicious applications and the illegal tampering of legal application may lead to the functionality paralysis.From the point of the security of application,this paper studies the two basic methods of application security,the protection method based on software or hardware.Through the comparative analysis between the two methods,concluding that the latter is more safety and time-effective.What's more,considering the high efficiency of Trust Zone security mechanism and the integration of domestic desktop CPU chip FT1500 A,this paper decides to use the Trust Zone as the basis for the realization of the protection of application program integrity in many hardware based protection methods.Based on the deep analysis of the mechanism of Trust Zone hardware isolation,the following work in this paper is carried out.Above all,this paper not only implements the KL-TEE including the trusted operation system providing with the function about thread processing,memory management,security interrupt,security system call and monitor mode software which is responsible for the switching between Normal Environment and Trusted Environment according to the Global Platform standard,but also achieves the mechanism of communication between the dual system and the method of construction in trusted application,so as to establish the basic operating environment for the method of integrity protection of application program.In the next place,the integrity protection method is designed based on the operating environment.Add SMC switching instructions to the execve system call by the methods configuring the hook function in LSM framework in order to enter the Trusted Environment through the monitor mode and establish a session with Trusted Application using its UUID.Then the shared memory region will be created to accomplish the authentication to the executable files.After that,the application security management module,certificate authentication module and integrity check module are called by the Trusted Execution Environment to determine whether the “identity factor” of executable file——the X.509 certificate issued by security operation system OEM is legal and integrated and prevent the application programs which have no certificate and are tampered from running.In addition,in order to form the completed method of protection,the cryptographic algorithm service module,key management module and security storage module are designed and implemented to achieve the function of providing cryptographic operations,key authorization service and security key storage.Then,the listing security mechanism and function modules are developed using the Hikey development board.For the purpose to proves the feasibility of the scheme,the developed method of protection is used to authenticate and check the identity and integrity of the user security login program which is provided with security storage function designed according to the Trust Zone security mechanism.Finally,the background,principle and implementation method of this thesis are summarized.Besides,the shortcomings of current design scheme and the specific direction of research work in future is put forward.