Integration of trusted operating system from open source

An operating system (OS) can be viewed as the collection progress of required directives before a computer system can run. Thus, OS is the most important software in any computer system. If OS is risky, then the computer system could be in danger. So, information security has become a critical issue for computer systems, it is necessary to develop a trusted operating system. As the result, in order to improve system security, there are many enhancements, which are developed. Some of them are open source. We can integrate appropriate software to construct a trusted system. The paper first gives a discussion covered the current security problems and the difficulty in solving those problems. Then, we study security function requirements from "protection profile for multilevel operating systems in environments requiring medium robustness", to find important secure features. Next, we demonstrate important security enhancement projects of OS with these corresponding security features. Finally, we give an idea about how to combine some of well-done open source secure software, and satisfy the secure features.