System and method for data security

• US 5,629,984 A
• Filed: 03/10/1995
• Issued: 05/13/1997
• Est. Priority Date: 03/10/1995
• Status: Expired due to Fees

• Current Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: McManis, Charles E.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/402,485
• Time in Patent Office: 795 Days
• Field of Search: 380/3, 380/4, 380/5, 380/6, 380/7, 380/8, 380/9, 380/10, 380/54, 380/59, 348/56
• US Class Current: 380/54
• CPC Class Codes: G06F 1/1616 with folding flat displays, e.g. laptop computers or notebooks having a clamshell configuration, with body parts pivoting to an open position around an axis parallel to the plane they define in closed position
• CPC Class Codes: G06F 1/1637 Details related to the display arrangement, including those related to the mounting of the display in the housing
• CPC Class Codes: G06F 21/84 output devices, e.g. displays or monitors
• CPC Class Codes: G09G 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T

Abstract

A system and method for substantially reducing accidental disclosure of confidential information by interleaving video data frames with video flash frames. These video flash frames preclude an unauthorized person not wearing an appropriate shutter device from intelligibly reading video data frames by influencing the unauthorized person'"'"'s eye prior to transmission of the video data frame.

Claims

1. An apparatus for preventing an unauthorized person from intelligibly viewing a video data frame, comprising:

a select device that alternatively outputs the video data frame with a video flash frame being a video frame being a video frame having a majority of its pixels illuminated; and

a display device coupled to said select device, said display device displays one of the video data frame and said video flash frame.

2. The apparatus according to claim 1 further comprising a shutter device coupled to and controlled by said select device, said shutter device is placed in a transparent state upon displaying the video data frame and is placed in an opaque state upon displaying said video flash frame.

3. The apparatus according to claim 2, wherein said select device comprises:

a select element that receives the video data frame and said video flash frame and to selectively output one of the video data frame and said video flash frame;

a counter element coupled to said select element through a select line, said counter element controls said select element; and

a signal conversion element coupled to said select element, said signal conversion element converts said one of the video data frame and said video flash frame, output from said select element, into video signals used by said display device.

4. The apparatus according to claim 3 further comprising a first storage element coupled to said select element, said first storage element temporarily contains the video data frame prior to the video data frame being transferred into said select element.

5. The apparatus according to claim 4 further comprising a second storage element coupled to said select element, said second storage element temporarily contains said video flash frame prior to said video flash frame being transferred into said select element.

6. The apparatus according to claim 5 further comprising:

a timer element that generates a pixel clock, a horizontal synchronous pulse and a vertical synchronous pulse through corresponding dedicated lines; and

an address element coupled to said timer element via said corresponding dedicated lines, said address element selects, said address element is configured to select the video data frame temporarily stored in said first storage element.

7. The apparatus according to claim 6, wherein said counter element is loaded with a predetermined count value and is decremented by said vertical synchronous pulse.

8. The apparatus according to claim 7, wherein said counter element selects said video flash frame to be output from said select element by asserting said select line when said counter element is greater than zero and selects the video data frame to be output from said select element by de-asserting said select line when said counter element is equal to zero.

9. The apparatus according to claim 8, wherein said counter element includes a plurality of counters being loaded with different count values in order to provide different clearance levels.

10. The apparatus according to claim 2 further comprising a transmitter coupled to said select device through a transmission line, said transmitter indicates that the video data frame is being transmitted for display on said display device.

11. The apparatus according to claim 10, wherein said select element asserts said transmission line to indicate that the video data frame is being transmitted for display on said display device, causing said transmitter to transmit a control signal to said shutter device to appropriately de-activate said shutter device, said control signal being in synchronism with the video data frame.

12. A system for preventing an unauthorized person from intelligibly viewing a video data frame displayed on a display device, comprising;

a shutter device;

a transmitter coupled to said shutter device, said transmitter activates said shutter device to become opaque when the display device is displaying a video flash frame being a video frame having a majority of its pixels illuminated and to become transparent when the display device is displaying said video data frame; and

a data processing system coupled to the display device and said transmitter, including;

a memory bus,

a central processing unit coupled to said memory bus, said central processing unit processes said video data frame,

a communication bus,

a main memory element coupled to said communication bus, said main memory element contains said video data frame,

a memory controller coupled to said memory bus and said communication bus, said memory controller enables said video data frame to propagate from said central processing unit to said main memory element, and

a video display interface coupled to said communication bus, said transmitter and the display device, said video display interface alternatively displays said video data frame and said video flash frame and to output control signals to said transmitter in order to place said shutter device in a transparent state upon displaying said video data frame via the display device and to place said shutter device in an opaque state upon displaying said video flash frame via the display device.

13. The system according to claim 12, wherein said video display interface comprises:

a first storage element that contains said video data frame;

a second storage element that contains said video flash frame;

a select element coupled to said first and second storage elements, said select element receives said video data frame and said video flash frame and selectively outputs one of said video data frame and said video flash frame;

a counter element coupled to said select element through a select line and said transmitter through a transmission line, said counter element controls said select element and indicates when said video data frame is being transmitted to said display device; and

a signal conversion element coupled to said select element, said conversion element converts said one of said video data frame and said video flash frame, output from said select element, into video signals used by the display device.

14. The system according to claim 13, wherein said video display interface further comprises:

a timer element generating a pixel clock, a horizontal synchronous pulse and a vertical synchronous pulse through corresponding dedicated lines; and

an address element, coupled to said timer element via said dedicated lines, selecting said video data frame temporarily stored in said first storage element.

15. The system according to claim 14, wherein said counter element is loaded with a predetermined count value and is decremented by said vertical synchronous pulse.

16. The system according to claim 15, wherein said counter element selects said video flash frame to be output from said select element by asserting said select line when said counter element is greater than zero and selects said video data frame to be output from said select element by de-asserting said select line when said counter element is equal to zero.

17. The system according to claim 16, wherein said counter element includes a plurality of counters being loaded with different count values in order to provide different clearance levels.

18. The system according to claim 12, wherein said video display interface comprises:

an output port coupled between said communication bus and said transmitter, said output port propagates said control signals from said communication bus into said transmitter; and

a software driver stored in said main memory element, said software driver controls the alternative display of video flash frames and video data frames based on an interrupt scheme.

19. A method for preventing an unauthorized person from intelligibly viewing a video data frame and for enabling an authorized person wearing a shutter device to intelligibly view the video data frame, comprising the steps of:

a) displaying a video data frame alternatively with at least one video flash frame being a video frame having a majority of its pixels illuminated; and

b) controlling the shutter device in synchronism with step a) in order to place the shutter device in a transparent state upon displaying the video data frame and placing the shutter device in an opaque state upon displaying said at least one video flash frame.

20. The method according to claim 19, wherein said controlling step includes the steps of:

b1) determining a clearance level associated with said video data frame; and

b2) transmitting a control signal to the shutter device to place the shutter device into said transparent state, provided the shutter device associated with the authorized person is able to support video data frames of said clearance level.