MULTIWINDOW SYSTEM, SECURITY PROTECTION METHOD, AND SECURITY PROTECTION PROGRAM FOR MULTIWINDOW SYSTEM

摘要

Security levels and positional information in the Z-axis direction (Z-order) of windows on the screen with a limitation. A program that is assigned a low security level cannot become higher than a program that is assigned a high security level in the Z-axis direction. In addition, a restriction is imposed on information flow via a clipboard and a window message from a higher program to a lower program in the Z-axis direction. The security levels are managed on the window basis according to attributes of files to be accessed or documents to be displayed. The display state of each window in the desktop is dynamically controlled depending on the security level of the window on which a user actually performs operation. The visual states of system resources such as printers and drives are controlled in accordance with the assigned security level.