Abstract: Structural protection of operating system is currently a difficult problem in security field. This paper studied a process execution environment model based on hierarchy isolation, and gave definition and conditions of process environment security. Then we formalized structural requirements of process environment, and proved that a secure process environment can be available by structured method proposed. Finally combined with classic non-interference theory, the security model was extended from process environment to the whole system.

Key words: Operating system, Structural protection, Non-interference, Process environment