Grace H. Nibaldi describe a safety system design based on safety of nuclear [11] presented the definition of trusted computing base (Trusted Computing Base, TCB), this method identify requirements of all functions Related to computer systems and security protection, and make them left the other functions in the system, and then separate them to prevent them from being undermined, so the results that is independent is called TCB. In standard of ‘protecting computer information system security classification criteria’, the TCB as a general mechanism for the protection of the computer information system security is given the following definition: TCB is a ‘computer system’s overall protection devices, including hardware, firmware, software and the combination of the thing that is Responsible for the implementation of security strategy. It established a basic protected environment and provides the additional customer service required by reliable computing systems.