Abstract: Provided is a kernel program and so on capable of enhancing the confidentiality of data memorized in a storage device without using a file system on an OS kernel level. The kernel program is mounted on a computer operable to input and output data between an application program and a storage device, and causes the computer to function as: a socket establisher establishing a socket for connecting with the application program; a relational database operable to input and output data from/to the storage device through a device driver; and an access controller inputting a command from the application program through a message structure of the socket then to output the command to the relational database and inputting an execution result from the relational database then to output the execution result through a message structure of the socket to the application program.