KR20150135652A - Device and method for preventing information from being leakage by screen capture in video output apparatus - Google Patents

Abstract

The present invention relates to a security device and method for a video output apparatus. More particularly, the present invention relates to a device and a method for preventing information from being leaked by screen capture in video output apparatus. A screen of a part where security information is displayed is divided. The divided screens are allocated to each frame. After that, the security information is displayed to prevent the leakage of security information by capturing the screen.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device and method for preventing leakage of information by screen capture of a video output device,

The present invention relates to a security apparatus and method for a video output apparatus, and more particularly, to an apparatus and method for preventing information leakage by capturing a screen of a video output apparatus that prevents leakage of security information by capturing a screen displaying security information .

With the spread and popularization of high-speed Internet, and the combination of wireless communication and mobile communication technologies, a cloud computing environment has been established to provide various services by accessing the Internet anytime and anywhere.

And mobile computers such as notebook computers, tablet computers, smart devices such as smart phones and smart pads as well as fixed computers such as desktop computers are becoming popular.

The dissemination of such computers and the establishment of a cloud computing environment assist people in facilitating their work, provide enjoyment, and provide convenience in various fields. Particularly, as the cloud computing environment is established, various services for displaying and inputting important information (hereinafter referred to as "security information") for using the service such as settlement and transfer service are spreading. The security information may include a resident registration number, a telephone number, a one-time password (OTP), a personal identification number, and automatic input prevention information.

As described above, the cloud computing environment provides convenience to the user because the computer can be connected to the Internet anytime and anywhere, and provides an environment in which a third party such as a hacker can access the computer anytime and anywhere. In such a cloud computing environment, various methods are used to extract personal and corporate security information.

One of the methods of hacking information from third parties is to capture the screen of user's computer using hacking program and to extract important information.

Therefore, various methods for preventing leakage of security information by a third party in a cloud computing environment are being studied.

For example, Japanese Unexamined Patent Application Publication No. 10-2013-0084727 (hereinafter referred to as Patent Document 1) and Japanese Patent Laid-Open Publication No. 10-2014-0003353 (hereinafter referred to as Patent Document 2) Discloses a method in which the number of digits to be used among the digits of the authentication number of the authentication message is selected in advance and only the number corresponding to the number of digits previously selected by the user is inputted so that the security can be improved by encrypting the digits.

However, the above-mentioned prior art documents can not prevent leakage of security information because it does not block the leakage of the security information by capturing or enhancing the security of the displayed security information.

Patent Publication No. 10-2013-0084727 Patent Publication No. 10-2014-0003353

Accordingly, an object of the present invention is to divide security information and security information into a proper number that can be normally displayed by an optical illusion of a user, allocate divided security information to a frame, And an apparatus and method for preventing information leakage by screen capture of a video output apparatus that prevents leakage of security information by capturing a screen.

It is another object of the present invention to provide an information leakage preventing device by screen capturing of a video output device which randomly inserts an obfuscated image among divided displays of security information to prevent information leakage by continuous screen capture And a method.

Another object of the present invention is to monitor the occurrence of an overload exceeding a preset reference value among divided displays of security information to be displayed and to perform black screen processing on an area including the security information display part in case of overload, And an apparatus and method for preventing information leakage by screen capturing of a video output apparatus that prevents an outflow.

According to another aspect of the present invention, there is provided an apparatus for preventing information leakage caused by a screen capture of a video output apparatus, the apparatus comprising: a screen security event detection unit detecting at least one of display and input of security information as a screen security event; A security information processing unit for hooking the security information displayed on the screen upon detecting the screen security event, and then dividing and outputting the hooked security information; An image synthesizer for allocating the divided security information to an image frame, combining the divided security information and the frame, and outputting a secure frame; And an image output unit for displaying the secure frame through a display device.

Wherein the security information processing unit comprises: a security information obtaining unit for obtaining and acquiring security information to be displayed for a screen security event when a screen security event is detected; And a security information division unit for dividing and outputting the obtained security information.

The security information is information composed of one of a segment, a pixel and an image.

Wherein the apparatus further comprises: an obfuscation unit for randomly generating a first pseudo noise during display of the secure frame and outputting the generated first pseudo noise to the video synthesis unit, wherein the video synthesis unit combines the first pseudo noise And outputs the synthesized signal.

The apparatus further includes an attack detection unit for monitoring an external attack during the display of the secure frame, generating a second pseudo noise when an external attack is detected, and outputting the generated second pseudo noise to the image composition unit, Synthesizes the second pseudo noise in a combined security frame and outputs the combined result.

The attack detection unit includes an occupancy rate detection unit for obtaining a occupancy rate of at least one of a CPU and an I / O of the video output apparatus; An attack determining unit for determining whether at least one of the detected CPU occupation rate and the I / O occupancy rate exceeds each reference value and determining whether the attack is outside; And a pseudo noise generator for generating a second pseudo noise during the attack detection of the video output apparatus through the attack determination unit and outputting the generated second pseudo noise to the video synthesis unit.

And the second pseudo noise is a black screen.

The apparatus includes: a screen security policy storage unit for storing security application information including information on at least one of security information for at least one or more security applications to be monitored for occurrence of the screen security event, ; And an installed application. When a registration request is generated from a user for a screen security application detected upon detection of installation of an arbitrary application, the security application information for the application is stored in the screen security policy storage unit, And a screen security application registration unit for registering the security application as a security application, wherein the screen security event detection unit determines whether an application driven when an arbitrary application is driven is a security application stored in the screen security policy storage unit, And monitors whether a screen security event has occurred or not.

The screen security application registration unit may include an application installation detecting unit that monitors whether an arbitrary application is installed and detects an arbitrary application installation; A registration confirmation unit for displaying a message asking the user to register the application when the installation of an arbitrary application is detected through the application installation detection unit and determining whether the application is registered with the screen security application; A handle information acquisition unit for acquiring application information including location information on a security information display and input part of the installed application from the application installation module when the security application registration request of the installed application is requested through the registration confirmation unit; And a registration processor for storing the application information in the screen security policy storage unit and registering the application information when the application information of the installed application is acquired.

According to another aspect of the present invention, there is provided a method of preventing information leakage by capturing a screen of a video output apparatus, the method comprising: detecting whether a screen security event is generated by at least one of display and input of security information; A screen security event detection process; A security information processing step of, after the security information processing unit hooks the security information displayed on the screen upon detection of the screen security event, dividing and outputting the hooked security information; A video synthesizing unit dividing the divided security information into frames of a predetermined unit of time, combining the divided security information and the frames, and outputting a security frame; And a video outputting step in which the video output unit displays the secure frame through a display device.

Wherein the security information processing step comprises: obtaining security information by hooking security information to be displayed for a screen security event upon detecting a screen security event; And a security information division step of dividing and outputting the obtained security information.

The security information is information composed of one of a segment, a pixel and an image.

The method may further include: an obfuscation process of randomly combining the first pseudo noise into the security frame during the display of the secure frame generated through the obfuscation unit, and outputting the combined first pseudo noise to the secure frame.

The method includes the steps of: the video synthesis unit monitors an external attack through an attack detection unit during the display of the secure frame, synthesizes the second pseudo noise generated by the attack detection unit when an external attack is detected, And an attack detection process.

The attack detection process includes: an occupancy rate detection step of obtaining a occupancy rate of at least one of a CPU and an I / O of the video output apparatus; Determining whether an attack is detected by detecting whether at least one of the detected CPU occupation rate and I / O occupancy rate exceeds a preset reference value; And a second pseudo noise synthesis step of generating a second pseudo noise when the apparatus detects an attack through the occupancy rate detection unit and composing the second pseudo noise to the secure frame.

Since security information is divided and security information is divided and displayed in different frames, the security information can be normally viewed by the user who directly sees the screen. However, the image captured per frame is divided into divided security It is possible to prevent leakage of the security information.

In addition, the present invention has the effect of preventing security information from being leaked by continuous capturing of a third party by inserting a pseudo noise at the time of an attack detection at a random or video output device.

In addition, according to the present invention, at least one application in which security information is displayed or security information must be input is registered, and the security information displayed and input to the registered application is divided and displayed, so that it can be applied to various applications And has an effect of improving usability.

1 is a block diagram of a device for preventing information leakage according to an embodiment of the present invention.
2 is a block diagram illustrating a configuration of an apparatus for preventing information leakage according to a second embodiment of the present invention.
3 is a diagram illustrating the configuration of a screen security application registration unit of an information leakage prevention apparatus according to a second embodiment of the present invention.
4 is a flowchart illustrating a method of preventing information leakage by screen capturing of a video output apparatus according to an exemplary embodiment of the present invention.
5 is a flowchart illustrating a method of registering a screen security application in a method of preventing information leakage by screen capture of a video output apparatus according to a second embodiment of the present invention.
6 is a diagram illustrating an example of partitioning of 7-segment OTP security information according to an embodiment of the present invention.
FIG. 7 is a diagram illustrating an example of partitioning of image-type automatic input prevention security information according to an embodiment of the present invention.
FIG. 8 is a view showing another example of partitioning of automatic image entry prevention security information according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a configuration and operation of an information leakage prevention apparatus by screen capturing of a video output apparatus according to the present invention will be described with reference to the accompanying drawings, and a method for preventing information leakage in the apparatus will be described.

The information leakage prevention device by the screen capture of the video output device according to the present invention may be configured to be constituted by one security application or firmware requiring screen security according to the first embodiment and may be configured to operate in the second embodiment And a separate information leakage preventing application that can register and delete at least one or more security applications according to the security information.

FIG. 1 is a block diagram illustrating a configuration of an apparatus for preventing information leakage according to an embodiment of the present invention, which is applied to both the first embodiment and the second embodiment. 6 is a diagram illustrating an example of partitioning the 7-segment OTP security information according to the embodiment of the present invention. FIG. 7 is a diagram illustrating an example of partitioning the automatic input prevention security information in the form of image according to the embodiment of the present invention And FIG. 8 is a diagram illustrating another example of partitioning of the image-type automatic input prevention security information according to the embodiment of the present invention. This will be described below with reference to Figs. 1 and 6 to 8. Fig.

The video output device of the present invention may be a smart device such as a personal computer (PC), a notebook, a tablet PC, a smart phone, and a smart pad.

Referring to FIG. 1, an apparatus for preventing information leakage by screen capture of a video output apparatus includes a screen security event detection unit 10, a security information processing unit 20, an attack detection unit 30, an obfuscation unit 40, (50) and an image output unit (60).

The screen security event detection unit 10 detects a screen security event generated by at least one of display and input of security information according to the first embodiment through an upper system such as an operating system (OS) Is inspected. That is, the screen security event detecting unit 10 detects a screen security event such as an OTP, an automatic input prevention number, etc., a display request of security information, a display request of a security information input means such as an account number, a telephone number, a resident registration number, , Start of input of security information, and the like as the screen security event.

According to the second embodiment, the screen security event detecting unit 10 monitors the execution of the application, determines whether the application executed when the application is executed is a screen security application registered in advance, , It is checked whether a screen security event occurs as in the first embodiment.

The security information processing unit 20 includes a security information obtaining unit 21 for hooking and obtaining one of the security information to be displayed and the security information to be displayed when a screen security event is detected through the screen security event detecting unit 10, And a security information division unit 22 for dividing the obtained security information and outputting the divided security information to the image synthesis unit 50. The security information may be segment-type data displayed in an OTP generator or the like as shown in (A) of FIG. 6, or it may be a segment type that displays numerals in a segment form, such as a graphic liquid crystal display And may be data in the form of a pixel that displays a number in pixel units, or may be data in the form of an image such as an automatic input preventing image as shown in FIGS. 7 and 8 (A). The security information obtaining unit 21 of the security information processing unit 20 according to the second embodiment loads location information on a portion where security information is displayed or input from security application information for a screen security application set in advance, And acquires the security information by hooking based on the loaded location information. The security information division unit 22 divides the security information into three or more pieces as shown in (b) to (d) of FIG. 6 when the security information is in a 7-segment form, Or may be output horizontally as shown in FIG. 8 (a) to FIG. 8 (b) to FIG. 8 (e). In the case of the image format, the division information may be divided into various forms in addition to FIGS. 7 to 8. FIG. The location information may be coordinate information of the security information display of the screen security application and / or the portion where the security information is displayed and / or input by the input means, and may be the name of the edit box and the coordinate information of the edit box It might be.

The attack detection unit 30 detects an occupancy rate of a CPU (not shown) and an I / O (not shown) occupancy rate from an operating system (Windows, Linux, Android, 31), an attack determining unit (32) for determining whether one of the obtained CPU and I / O occupation rate exceeds a preset reference value, and then determining whether an external attack has occurred based on whether the occupancy rate exceeds a reference value, And a black screen generating unit 33 for generating a black screen, which is a second pseudo noise, and outputting the black screen to the image synthesizer 50 if it is determined that there is an external attack.

The obfuscation unit 40 generates an obfuscated image, which is the first pseudo noise, when the obfuscation event is detected through the obfuscation event detection unit 41 for detecting the occurrence of the obfuscation event and the obfuscation event detection unit 41, And an obfuscated image generation unit 42 for outputting the obfuscated image to the unit 50. The obfuscation event may be generated at a random time period or may be generated at regular intervals. However, the obfuscation event may be generated at random intervals in order to prevent the security information divided by continuous capture from being leaked as one piece of security information. .

The image synthesizing unit 50 divides the divided security information (hereinafter referred to as "divided security information") output from the security information processing unit 20 into frames of a predetermined time unit (30 frames per second (FPS) ), Or sequentially allocates frames to the frames irrespective of time units to generate a security frame. At least one of the black screen and the obfuscated image, which are pseudo noise from the attack detection unit 30 and the obfuscation unit 40, And outputs the black screen and the obfuscated image to the image output unit 60. The black screen and the obfuscated image are combined to the security frame.

The video output unit 60 outputs display data, which is composite video output from the video composition unit 50, to a display device and displays the display data.

2 is a block diagram illustrating a configuration of an apparatus for preventing information leakage according to a second embodiment of the present invention.

The apparatus for preventing information leakage by screen capture according to the second embodiment includes a screen security application registration unit 100, a screen security control unit 200 and a screen security policy storage unit 300.

The screen security application registration unit 100 detects the installation of the application and inquires the user whether or not to register the application as a screen security application when the application is installed. If the user wants to register the screen security application, The window handle information including the information display and / or the security information display on the input means and / or the location information of the input portion is acquired and stored in the screen security policy storage unit 300 and registered as the screen security application.

The screen security policy storage unit 300 stores security application information including policy information such as window handle information of at least one registered screen security application and screen security activation for the security application. The screen security activation information indicates whether to activate the screen security function for the registered screen security application.

1, the screen security control unit 200 includes a screen security event detection unit 10, a security information processing unit 20, an attack detection unit 30, an obfuscation unit 40, an image synthesis unit 50, Monitors the execution of an arbitrary application in the video output apparatus including the application 60 and refers to the screen security policy storage unit 300 when executing an arbitrary application, 1, the security information is divided and allocated to a frame per predetermined time period, as described above with reference to FIG. 1, when the executed application is a screen security application. do.

3 is a diagram illustrating the configuration of a screen security application registration unit 100 of an information leakage prevention apparatus according to a second embodiment of the present invention.

3, the screen security application registration unit 100 includes an application installation detection unit 110, a registration confirmation unit 120, a handle information acquisition unit 130, and a registration processing unit 140.

The application installation detecting unit 110 detects whether an application is installed through an operating system (not shown) of the video output apparatus.

When the installation of the application is detected through the application installation detecting unit 110, the registration confirmation unit 120 displays on the display device of the video output device a message asking whether to register the installed application as a screen security application, And outputs it to the handle information acquiring unit 130. [0033]

If the response information of the user is input from the registration confirmation unit 120 and the response information is registered, the handle information acquisition unit 130 requests the operating system of the video output device to obtain the window handle information of the installed application And outputs it to the post-registration processing unit 140. [

The registration processing unit 140 receives the window handle information from the handle information obtaining unit 130 and receives a screen security policy setting such as security activation setting and security activation time zone information of the application to be registered in the display device, And stores the policy information and the window handle information input through the screen security policy setting means for the application in the screen security policy storage unit 300 and registers the application as a screen security application.

4 is a flowchart illustrating a method of preventing information leakage by screen capturing of a video output apparatus according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the screen security event detecting unit 10 displays a screen of security interface means including at least one of security information display means and security information input means according to the first embodiment, And / or whether a screen security event due to the start of input of security information or the like occurs. According to the second embodiment, the screen security event detection unit 10 monitors whether the screen security application registered in the screen security policy storage unit 300 is executed and whether a screen security event is generated by the executed security application (S111).

When a screen security event is generated during monitoring whether or not the screen security event is generated, the security information acquisition unit 21 of the security information processing unit 20 receives the security information or the security information input through the security information display means of the security interface means, (Step S113).

When the security information is hooked, the security information division unit 22 divides the security information into the security information as shown in FIG. 6 to FIG. 8 and outputs the divided information (S115).

When the security information is divided, the image combining unit 50 divides the divided security information into a plurality of consecutive frames within a predetermined period of time, as shown in (B) through (D) of FIG. 6, (S117), and generates a secure frame by combining the allocated divided security information with the corresponding frame, and outputs the secure frame to the video output unit 60 (S119).

When the secure frame is generated, the video output unit 60 outputs the secure frames to the display unit and displays the secure frames (S121).

If the screen security event is detected, the obfuscation unit 40 checks whether a first pseudo noise insertion event is generated (S123), and the attack detection unit 30 determines whether an attack from the outside is detected (S125) . In FIG. 4, although the first pseudo noise insertion event and the attack detection are performed after the display of the security frame is started, the first pseudo noise insertion event and the attack detection may be performed immediately after the occurrence of the screen security event is detected.

When the first pseudo noise insertion event is generated, the obfuscation unit 40 outputs the first pseudo noise, which is an obfuscated image, to the image synthesis unit 50, and the image synthesis unit 50 inputs the input first pseudo noise And outputs the combined frame to the video output unit 60. The video output unit 60 outputs the combined video signal to the video output unit 60. [

When the attack is detected, the attack detection unit 30 outputs the second pseudo noise, which is a black screen, to the video composition unit 50 until the attack detection is canceled, and the video composition unit 50 outputs the input black screen to the frame And outputs the synthesized image to the video output unit 60.

5 is a flowchart illustrating a method of registering a security application in a method for preventing information leakage by screen capture of a video output apparatus according to a second embodiment of the present invention.

Referring to FIG. 5, the screen security application registration unit 100 checks whether an application installation event is detected through an operating system (OS) of a video output apparatus (S211).

When the application installation event is detected, the screen security application registration unit 100 acquires application information for the installed application (S213), and then checks whether the installed application has stored the screen security policy based on the acquired application information (S215) .

If the application is not registered, the screen security application registration unit 100 displays a screen security application registration confirmation unit and asks the user whether to register the installed application as a screen security application (S217, S219).

When the user requests registration, the screen security application registration unit 100 displays the screen security policy setting means on the display device, and displays policy information such as whether the registered screen security application registered through the displayed screen security policy setting means, (S221).

When the policy information is set by the user, the screen security application registration unit 100 stores the security policy information including the set policy information and the application information in the screen security policy storage unit 300 and completes the registration (S223).

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It will be easily understood. It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, it is intended to cover various modifications within the scope of the appended claims.

10: screen security event detection unit 20: security information processing unit
21: security information acquisition unit 22: security information division unit
30: attack detection unit 31: occupancy rate detection unit
32: Attack judging unit 33: Black screen generating unit
40:
41: Obfuscation event detection unit 42: Obfuscated image generation unit
50: video synthesizer 60: video output unit
100: screen security application registration unit 110: application installation detection unit
120: registration confirmation unit 130: handle information acquisition unit
140: registration processing unit 200: screen security control unit
300: Screen security policy storage unit

Claims (15)

A screen security event detecting unit detecting at least one of display and input of security information as a screen security event;
A security information processing unit for hooking the security information displayed on the screen upon detecting the screen security event, and then dividing and outputting the hooked security information;
An image synthesizer for allocating the divided security information to an image frame, combining the divided security information and the frame, and outputting a secure frame; And
And an image output unit for displaying the secure frame through a display device.
The method according to claim 1,
The security information processing unit,
A security information acquisition unit for acquiring security information to be displayed for a screen security event by hooking up when a screen security event is detected; And
And a security information division unit for dividing and outputting the obtained security information.
3. The method of claim 2,
Wherein the security information is information in the form of one of a segment, a pixel, and an image.
The method according to claim 1,
Further comprising an obfuscation section for randomly generating a first pseudo noise during the display of the secure frame and outputting the first pseudo noise to the image synthesis section,
Wherein the image synthesizer comprises:
And combining the first pseudo noise and the first pseudo noise in a security frame in which the divided security information is synthesized, and outputting the synthesized first pseudo noise.
3. The method according to claim 1 or 2,
Further comprising an attack detection unit for monitoring an external attack during the display of the secure frame, generating a second pseudo noise when an external attack is detected, and outputting the generated second pseudo noise to the image composition unit,
Wherein the image synthesizer comprises:
And the second pseudo noise is synthesized with the security frame in which the divided security information is synthesized, and outputs the synthesized second pseudo noise.
6. The method of claim 5,
The attack detection unit detects,
An occupancy rate detector for obtaining a occupancy rate of at least one of a CPU and an I / O of the video output apparatus;
An attack determining unit for determining whether at least one of the detected CPU occupation rate and the I / O occupation rate exceeds an individual reference value to determine whether an attack is outside; And
And a pseudo noise generator for generating a second pseudo noise when an attack of the video output device is detected through the attack determiner and outputting the generated second pseudo noise to the video synthesizer.
The method according to claim 6,
Wherein the second pseudo noise is a black screen.
The method according to claim 6,
A screen security policy storage unit for storing security application information including information on at least one of security information for at least one or more security applications to be monitored for occurrence of the screen security event; And
Monitors an installed application and stores security application information for the application in a screen security policy storage unit when a registration request is generated from a user for a screen security application detected upon detection of installation of an arbitrary application, And a screen security application registration unit for registering the screen security application as an application,
Wherein the screen security event detection unit comprises:
Wherein the monitoring unit monitors whether an application that is activated when an arbitrary application is activated is a security application stored in the screen security policy storage unit and then generates a screen security event if the application is a security application. Information leakage prevention device.
9. The method of claim 8,
The screen security application registration unit may include:
An application installation detecting unit that monitors whether an arbitrary application is installed and detects an arbitrary application installation;
A registration confirmation unit for displaying a message asking the user whether or not to register the application when the installation of an arbitrary application is detected through the application installation detecting unit and determining whether the application is registered with the screen security application;
A handle information acquisition unit for acquiring application information including location information on a security information display and input part of the installed application from the application installation module when the security application registration request of the installed application is requested through the registration confirmation unit; And
And a registration processor for storing the application information in the screen security policy storage when the application information of the installed application is acquired, and registering the application information in the screen security policy storage.
A screen security event detecting step of checking whether a screen security event detecting unit generates a screen security event by at least one of display and input of security information;
A security information processing step of, after the security information processing unit hooks the security information displayed on the screen upon detection of the screen security event, dividing and outputting the hooked security information;
A video synthesizing unit dividing the divided security information into frames of a predetermined unit of time, combining the divided security information and the frames, and outputting a security frame; And
And a video output step of causing the video output unit to display the secure frame through a display device.
11. The method of claim 10,
The security information processing step includes:
A security information acquiring step of acquiring by hooking security information to be displayed for a screen security event upon detecting a screen security event; And
And dividing the obtained security information and outputting the divided security information. The method of preventing information leakage by screen capture of a video output apparatus,
12. The method of claim 11,
Wherein the security information is information in the form of one of a segment, a pixel, and an image.
11. The method of claim 10,
Wherein the image synthesis unit further comprises an obfuscation step of synthesizing the first pseudo noise randomly in the security frame during the display of the secure frame generated through the obfuscation unit and outputting the synthesized first pseudo noise to the security frame. Prevention device.
The method according to claim 10 or 11,
An image combining unit monitors an external attack through an attack detection unit during the display of the secure frame, and combines the second pseudo noise generated by the attack detection unit in a security frame at the time when an external attack is detected, Wherein the information output apparatus further comprises a display unit for displaying the information.
15. The method of claim 14,
The attack detection process,
An occupancy rate detecting step of obtaining a occupancy rate of at least one of a CPU and an I / O of the video output apparatus;
Determining whether an attack is detected by detecting whether at least one of the detected CPU occupation rate and I / O occupancy rate exceeds a preset reference value; And
And a second pseudo noise synthesis step of generating a second pseudo noise when the attack of the device is detected through the occupancy rate detection unit and composing the second pseudo noise to the secure frame.

Images