JP2005165664A - Information terminal, control method of information terminal, program and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information terminal that can prevent unauthorized reading of information from the outside through a network, and to provide a control method of the information terminal, program and storage medium therefor. <P>SOLUTION: In a step S401, the information terminal accesses structure data of events that are acquired, and looks for data to be displayed. After finding out the data to be displayed in the step S401, a display module is made to display the data on the basis of display lists of the found data, in a step S402. Then, with respect to an object displayed, "true" is written in a "drawing is completed" member of the data structure to show that the drawing is completed. When the drawing of the data to be displayed is terminated, the data of the displayed object on a memory are erased in a step S403. Specifically, the display lists are followed once again from the beginning, and the memory area is erased concerning the object whose "drawing is completed" member has become "true". <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an information terminal, an information terminal control method, a program, and a storage medium that improve information security.

  2. Description of the Related Art Conventionally, there are information terminals such as tablet PCs that include a display unit and display information via a network. A method for erasing data on a memory in such an information terminal is described in, for example, Japanese Patent Application Laid-Open No. 2003-76354.

  As a thin display device, the structure of an electrophoretic display device is described in, for example, Patent Document 2 (Japanese Patent Laid-Open No. 9-185087).

  However, the invention described in Patent Document 1 has been made for the purpose of efficient use of memory, and information security is not sufficient. That is, in the information terminal that receives information via the network and displays the information, since the information is obtained via the network, a malicious cracker illegally accesses the information terminal via the network. There is a possibility that the information is illegally obtained by illegally intruding into the terminal by such means and reading the information of the hard disk or the memory. In addition, the data stored in the memory described in Patent Document 1 is also configured to delete data after a predetermined time has elapsed after data reception. During the period before deleting, the risk of malicious data being stolen via the network by a malicious cracker cannot be completely eliminated. A similar problem exists in the display device described in Patent Document 2.

JP 2003-76354 A JP-A-9-185087

  An object of the present invention is to provide an information terminal, an information terminal control method, a program, and a storage medium that can prevent unauthorized reading of information from the outside via a network.

  As a result of intensive studies to solve the above problems, the present inventor has come up with various aspects of the invention described below.

  An information terminal according to the present invention is an information terminal for displaying information acquired from a network on a screen, and a display means having a memory property for retaining an image once displayed as it is, and the above-mentioned acquired from the network Temporary storage means for storing image data displayed on the display means, and when the image is displayed on the display means, the image data is temporarily stored before a predetermined time elapses after the image is displayed. Data erasing means for erasing from the storage means.

  The information terminal control method according to the present invention is a method for controlling an information terminal that displays information acquired from a network on a screen of a display means having a memory property that retains an image once displayed as it is. A storage step of storing data of an image displayed on the display means acquired from the network in a temporary storage means; and when the image is displayed on the display means, a predetermined time after the image is displayed. A data erasing step of erasing the data of the image from the temporary storage means before elapses.

  According to the present invention, even if a malicious cracker attempts an unauthorized intrusion into an information terminal and succeeds in the intrusion, the information can be prevented from being read out.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a network configured using information terminals according to an embodiment of the present invention. In this network, information terminals (PLD (paper-like display) devices) 101, 102, and 103 according to an embodiment of the present invention and a file server 120 are connected to each other via a network cable 110. Note that the information terminals 101, 102, and 103 and the file server 120 may be capable of communicating via wireless.

  FIG. 2 is a diagram illustrating an internal configuration of the information terminals 101, 102, and 103. However, in FIG. 2, the information terminals 101, 102, and 103 are collectively referred to as the information terminal 200. The information terminal 200 is provided with a CPU 201 that executes software stored in the ROM 202, and the CPU 201 comprehensively controls each device connected to the system bus 204. In addition to the CPU 201 and the ROM 202, the system bus 204 includes a RAM 203 that functions as a main memory and a work area for the CPU 201, a button controller (BTN C) 205 that controls input from various buttons 209, and a display module (DISPLAY). A display controller (DISP C) 206 that controls the display of 210 and a network interface card (NIC) 208 are connected. A LAN (network) 110 is connected to the NIC 208, and the information terminal 200 exchanges data bidirectionally with other network devices or file servers via the LAN (network) 110.

  In the present embodiment, the display module 210 has a memory property for holding an image once displayed, such as a cholesteric liquid crystal display device, a particle movement display device, an electrophoretic display device, and a dry toner movement display device. Things are used.

  Next, the operation of the information terminal 200 will be described with reference to a flowchart. FIG. 3 is a flowchart showing the operation of the information terminal 200. The operation of the information terminal 200 is controlled and executed by the CPU 201. Hereinafter, the software for controlling the information terminal 200 will be described as being built on a real-time OS such as VxWorks, but is not limited thereto. In the present embodiment, the control program for the information terminal 200 is created in an event-driven manner.

  When the program starts, first, in step S301, the CPU 201 enters an event waiting state and waits until an event occurs. When an event occurs, the event is acquired and the process proceeds to step S302.

  In step S302, the CPU 201 determines whether the event acquired in step S301 is a screen display request event. If it is determined that the event is a screen display request event, the process proceeds to step S303. If it is determined that the event is not a screen display request event, the process proceeds to step S304.

  In step S303, the CPU 201 accesses the event data acquired in step S301 and performs screen display processing. This screen display process will be described in detail later with reference to FIG. On the other hand, in step S304, other processing than the response to the screen display event is performed.

  After the process of step S303 or step S304, the CPU 201 returns to step S301 and waits until the next event occurs.

  Next, screen display processing will be described. FIG. 4 is a flowchart showing the screen display process in step S303 of FIG. 3 in more detail.

  In the screen display process, first, in step S401, the CPU 201 accesses the acquired event structure data to search for data to be displayed. Data to be displayed is stored in the RAM 203. An example of a specific data structure of the RAM 203 is a structure as shown in FIG.

  In the example shown in FIG. 5, four types of objects 501 to 504 are included in the data structure as objects to be displayed, and the type of each object and specific data are also included in the data structure. Note that the data structure shown in FIG. 5 is merely an example, and the data structure of the display data is not limited to this.

  When the CPU 201 finds data to be displayed in step S401, in step S402, the CPU 201 operates the display controller 206 based on the found data display list to cause the display module 210 to display the data. For the displayed object, true is written in the “drawn” member of the data structure to indicate that it has been drawn.

  When the drawing of the data to be displayed is completed, the CPU 201 erases the data of the displayed object on the memory in step S403. Specifically, the display area is traced again from the beginning, and the memory area of the object whose “drawn” member is true is deleted. At this time, it is preferable to release the memory after overwriting the memory area to be erased with random data.

  In this embodiment, since the display module 210 itself has a memory property to hold the displayed image as it is, even if the memory area for display is erased and released, the display image is displayed as it is. Subsequently, the display image is not erased.

  Note that the displayed image data need not be erased at the same time as the completion of the image display, and may be erased before a predetermined time elapses after the image is displayed.

  Note that the program used in the information terminal according to the present embodiment described above does not need to be stored in the ROM 202, and may be executed by each of the information terminals 101 to 103 by a program installed from the outside. In that case, the program stores an information group including the program from an external storage medium by a storage medium such as a CD-ROM, flash memory, or flexible disk, or via a network such as e-mail or personal computer communication. The present invention is applied even when the information is loaded on the information terminal 101 to 103 by being loaded on the information terminal 103.

  FIG. 6 is a diagram showing a memory map of a CD-ROM which is an example of a storage medium. An area 9999 in which directory information is stored indicates positions of an area 9998 in which an installation program is stored and an area 9997 in which a device control program is stored.

  When the above-described device control program is installed in each of the information terminals 101 to 103, first, the installation program stored in the area 9998 storing the installation program is loaded into the system and executed by the CPU 201. Next, the installation program executed by the CPU 201 reads the device control program from the area 9997 where the device control program is stored, and rewrites the contents of the ROM 202. In this case, the ROM 202 is not a simple mask ROM, but must be a rewritable ROM such as a flash ROM.

  Note that the present invention may be applied to a system or an integrated device including a plurality of devices (for example, a host computer, an interface device, a reader, etc.) or an apparatus including a single device.

  In addition, a storage medium in which a program code of software for realizing the functions of the above-described embodiments is recorded is supplied to a system or apparatus, and a computer (conceptually including a CPU and MPU) of the system or apparatus is stored in the storage medium. The object of the present invention can also be achieved by reading and executing the stored program code.

  In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium storing the program code constitutes the present invention.

  As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  In addition to executing the program code read by the computer, the functions of the above-described embodiments are realized, and an OS or the like running on the computer is part of the actual processing based on an instruction of the program code. Alternatively, the functions of the above-described embodiment can be realized by performing all of the processes and performing the processing.

  Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. The CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments can be realized by the processing.

  The present invention is also applicable to a case where the program is distributed to a requester via a communication line such as personal computer communication from a storage medium in which the program code of the software realizing the functions of the above-described embodiments is recorded. it can.

It is a figure which shows the network comprised using the information terminal which concerns on embodiment of this invention. It is a figure which shows the internal structure of the information terminals 101, 102, and 103. FIG. 3 is a flowchart showing an operation of the information terminal 200. It is a flowchart which shows the screen display process in step S303 of FIG. 3 in detail. 3 is a diagram illustrating an example of a specific data structure of a RAM 203. FIG. It is a figure which shows the memory map of CD-ROM which is an example of a storage medium.

Explanation of symbols

101-103, 200: Information terminal (PDL device)
110: Network 120: File server 201: CPU
202: ROM
203: RAM
204: System bus 205: Button controller 206: Display controller 208: Network interface card 209: Button 210: Display module 501-504: Object 9997-9999: Area

Claims (14)

An information terminal that displays information obtained from the network on the screen,
A display means having a memory property to hold an image once displayed as it is,
Temporary storage means for storing image data displayed on the display means acquired from the network;
When an image is displayed on the display means, data erasure means for erasing data of the image from the temporary storage means before a predetermined time has elapsed since the image was displayed;
An information terminal comprising:   2. The information terminal according to claim 1, wherein the data erasing unit erases the data of the image simultaneously with the completion of the display of the image.   3. The display device according to claim 1, wherein the display means is a display device selected from the group consisting of a cholesteric liquid crystal display device, a particle movement display device, an electrophoretic display device, and a dry toner movement display device. The described information terminal. The data erasing means is
Random data overwriting means to overwrite the memory area of the displayed object with random data,
Memory area releasing means for releasing the memory area;
The information terminal according to any one of claims 1 to 3, wherein the information terminal is provided.   5. The information terminal according to claim 1, further comprising a network connection unit for acquiring information from the file server via the network.   6. The information terminal according to claim 5, wherein the network connection unit includes an identification unit for identifying an individual information terminal using IPv6.   The information terminal according to claim 5 or 6, wherein the network connection means performs encrypted communication using IPv6. A method of controlling an information terminal that displays information acquired from a network on a screen of a display means having a memory property that retains an image once displayed as it is,
A storage step of storing, in a temporary storage unit, data of an image displayed on the display unit acquired from the network;
When an image is displayed on the display means, a data erasure step of erasing data of the image from the temporary storage means before a predetermined time has elapsed since the image was displayed;
A method for controlling an information terminal, comprising:   9. The method of controlling an information terminal according to claim 8, wherein in the data erasing step, the data of the image is erased simultaneously with completion of display of the image. The data erasing step includes:
A random data overwriting step of overwriting the memory area of the displayed object with random data;
A memory area releasing step for releasing the memory area;
10. The information terminal control method according to claim 8 or 9, characterized by comprising: A program that causes a computer to execute control of an information terminal that displays information acquired from a network on a screen of a display unit having a memory function that holds an image once displayed as it is,
On the computer,
A storage procedure for storing data of an image displayed on the display unit acquired from the network in a temporary storage unit;
When an image is displayed on the display means, a data erasing procedure for erasing data of the image from the temporary storage means before a predetermined time has elapsed since the image was displayed;
A program characterized by having executed.   12. The program according to claim 11, wherein in the data erasing procedure, the computer erases the image data simultaneously with the completion of the display of the image. The data erasing procedure is:
Random data overwrite procedure to overwrite the memory area of the displayed object with random data,
A memory area release procedure for releasing the memory area;
The program according to claim 11 or 12, characterized by comprising:   A computer-readable storage medium storing the program according to any one of claims 11 to 13.

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