Patent ID: 7673138

Claim:
A method for switching a folder to be accessed based on a confidential mode for use in a computer, said computer executing a kernel and an application program as a process, said kernel having a file system for controlling file access of a disk device, said application program executing file access to the disk device via the file system, the process comprising a plurality of processes including a process in a confidential mode and a process in a normal mode, both of which are different in security level from each other, the computer maintaining security by restricting communication among the plurality of processes based on the security level, said method comprising: setting a directory structure in the disk device such that: a confidential root directory is located below a normal root directory; at least one normal folder is located below the normal root directory with a directory structure and is configured to store a normal file comprising non-confidential information; at least one confidential folder is located below the confidential root directory with a directory structure and is configured to store a confidential file comprising confidential information; and a directory structure comprising the at least one confidential folder other than the confidential root directory is the same as that comprising the at least one normal folder other than the normal root directory; specifying a security level expressing whether the application program should be operated as a process in a confidential mode capable of accessing the confidential file or as a process in a normal mode incapable of accessing the confidential file when the application program is started up by the computer; determining whether the application program is operating as the process in the confidential mode or as the process in the normal mode based on the security level specified when a file access request for file access to the disk device with a specified file path name is received from the application program; rewriting the specified file path name with a file path name of the confidential folder below the confidential root directory and allowing file access to the confidential file specified by the file path name to be executed via the kernel when the application program is operating as the process in the confidential mode; and not permitting file access to the confidential file in the confidential folder when the application program is operating as the process in the normal mode.