WO2019112185A1

WO2019112185A1 - Video security transmission system

Info

Publication number: WO2019112185A1
Application number: PCT/KR2018/013274
Authority: WO
Inventors: 백기영
Original assignee: 주식회사 명광
Priority date: 2017-12-08
Filing date: 2018-11-02
Publication date: 2019-06-13
Also published as: KR101899554B1

Abstract

In transmitting and receiving a video having an I frame, a P frame, and a B frame by compression and coding, the video, in which the I frame is encrypted by an image puzzling method, is transmitted, and a receiving side decodes the I frame to restore the video, in which the degree of the image puzzling flexibly varies depending on the number of pixels of the I frame, the frame rate of the video, or a data amount of the P frame and the B frame.

Description

Video Security Transport System

In transmitting and receiving a moving picture having an I frame, a P frame, and a B frame by compression coding, a moving picture in which an I frame is encrypted by an image puzzling method is transmitted. On the receiving side, a moving picture is decoded by decoding an I frame, The present invention relates to a video security transmission system capable of flexibly adjusting the degree of encryption and the time required for encryption according to the number of frame pixels, the frame rate, or the amount of unencrypted frame data.

A method of encrypting data of various formats including images is divided into a plurality of subblocks by rearranging the data rearranged so as to have an array of a matrix or an array of a matrix, .

The inventor of the present invention invented a technique for enhancing security by allowing a user to arbitrarily change the size of a sub-block and the number of times of changing the position of a free block (i.e., the number of shuffling) in order to improve the encryption technique of the puzzling method, Patent No. 10-1112157.

However, this encryption technique can secure security by appropriately selecting the size of the sub-block and the number of shuffling times. When applied to moving picture data (i.e., video data) implemented by continuous connection of image frames, This can be a time consuming problem.

That is, for different moving picture data having different resolutions such as HD, FULL HD, UHD, and different frame rates such as 15, 20, 30, and 60, And the number of shuffling is used as a uniform value or arbitrarily selected and used, it is delayed by the time required for encryption to process a moving image, and it may be a problem in providing a real-time streaming service, for example.

On the other hand, the moving image data is typically compressed and coded using an I frame, a P frame, and a B frame, and at this time, only the I frame has a full image.

According to the registration number 10-0732056, only the I frame is encrypted in consideration of this compression coding structure. Thus, the time required for encryption can be shortened and the overhead can be reduced.

However, the time required for the encryption varies greatly depending on the difference in image quality supported by the moving image data, it is difficult to ensure proper encryption, and the moving image processing can not be stably handled.

[Prior Art Literature]

[Patent Literature]

(Patent Document 1) KR 10-1112157 B1 2012.01.27.

(Patent Document 2) KR 10-0732056 B1 2007.06.19.

Therefore, it is an object of the present invention to provide a video security transmission system that can adaptively control the encryption process and the degree of encryption by flexibly operating the encryption process even for moving images having different supported image quality.

In order to accomplish the above object, the present invention provides a moving picture security transmission system, comprising: a shuffling process of randomly selecting two image fragments in a state where an I frame of a moving picture is divided into a plurality of image fragments, An encryption unit 11 for replacing an I frame of the moving picture with an encrypted I frame after generating an encrypted I frame, and an encrypting unit 11 for encrypting the encryption condition including the image fragment size and the number of shuffling to be used by the encrypting unit 11, A transmission side security module 10 installed in the transmission terminal 1 for transmitting moving pictures and for transmitting a moving picture encrypted with an I frame, ; And a receiving terminal 2 that receives the moving picture and divides the I frame of the moving picture to be received into the image fragment size of the encryption condition and repeats the shuffling in the reverse order of the number of shuffling of the encryption condition, And a receiving side security module 20 for replacing an I frame of a moving image to be decrypted with a decrypted I frame and restoring the decrypted I frame to a moving image before encryption.

According to the embodiment of the present invention, the transmitting-side security module 10 and the receiving-side security module 20 use a random number generator that generates the same random number according to a seed value, 10 allows a decryption by transmitting the encrypted image data to the receiving side security module 20 by including a seed value applied to randomly select two image fragments by the number of shuffling times.

According to the embodiment of the present invention, the transmission side security module 10 adjusts the encryption condition according to the frame rate of the moving image and uses the encryption condition.

According to the embodiment of the present invention, the transmission side security module 10 may reset the number of shuffling according to the amount of data of the P frame and the B frame depending on the I frame to make the number of shuffling different for each I frame have.

According to the embodiment of the present invention, the transmission side security module 10 records the number of shuffling before resetting according to the data amount of the P frame and the B frame in the header of the moving image together with the image fragment size, The receiving side security module 20 decrypts the I frame according to the image fragment size and the shuffling count recorded in the video header, and the shuffling The number of times of shuffling is used only as the value recorded in the I frame header for the I frame in which the number of times is recorded in the header.

According to an aspect of the present invention, there is provided a security module including a transmitting terminal (1) for encrypting a moving picture and transmitting the moving picture through a communication module (1a), and a moving picture received through the communication module And a receiving terminal (2) for decrypting a video signal transmitted from the transmitting side security module (10) and the receiving side security module (20), the transmitting side security module and the receiving side security module being constituted by the transmitting side security module (10) and the receiving side security module (20).

According to the present invention as described above, by encrypting only the I frame and varying the size of the divided image fragment and the number of shuffling operations that control the encryption time, according to the number of pixels of the I frame image, So that it is possible to appropriately adjust the time required for encryption on the transmission side and the time required for decoding on the reception side, thereby enhancing transmission and reception security.

According to one embodiment of the present invention, by resiliently resizing the image fragment size or the number of shuffling of the I frame according to the amount of data of the frame rate or unencrypted frame (P frame and B frame), the average of the decoding time is Security can be further enhanced without significantly increasing.

1 is a block diagram of a moving picture security transmission system according to an embodiment of the present invention;

FIG. 2 is a flowchart of a secure transmission step S100 performed by a transmitting-end security module 10 in a moving picture security transmission system according to an embodiment of the present invention.

FIG. 3 schematically illustrates the secure transmission step S100 shown in FIG. 2; FIG.

Fig. 4 is a view showing a fluctuating image as the shuffling is repeated; Fig.

FIG. 5 is a flowchart of a security receiving step (S200) performed by a receiving security module 20 in a moving picture security transmission system according to an embodiment of the present invention.

The moving picture security transmission system according to the present invention transmits a moving picture coded with an I frame, a P frame and a B frame after replacing only an I frame with an encrypted I frame on the transmitting side, Decoded I frame and restored.

The encryption I frame is a shuffling process in which two images are randomly selected and the positions of two image pieces are exchanged in a state where the image in the data area of the I frame is divided into a plurality of image fragments The puzzle image is obtained by repeating a predetermined number of times. Thus, the original image can be restored only on the receiving side, which allows the user to know the image fragment size, the random sequence, and the shuffling count, which are encryption conditions.

Further, by using the image fragment size and the shuffling number that determine the required time for encryption to be variable according to the number of pixels of the I frame, it is possible to prevent the difference in the time required for encryption for the videos having different resolutions from being different, And it is also possible to reduce the difference in the time required for decoding on the receiving side or to reduce the difference.

According to an embodiment of the present invention, it is possible to re-use the size of the image fragment and the number of shuffling according to the frame rate of the moving image. Also, according to the sum data amount of the P frame and the B frame, By increasing or decreasing the number of times of ringing, the security of a group of pictures (GOP) having a large amount of information is enhanced.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the embodiments of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a configuration diagram of a video security transmission system according to an embodiment of the present invention.

2 is a flowchart of a secure transmission step S100 performed by the transmitting-side security module 10. As shown in FIG.

FIG. 3 is a diagram showing a security transmission step (S100) shown in FIG. 2, and FIG. 4 is a view showing a fluctuating image as repeating shuffling.

5 is a flowchart of a security reception step S200 performed by the receiving security module 20. [

1 and 2, a moving picture security transmission system according to an embodiment of the present invention includes a coded (coded) frame having an I (Intra) frame, a P (Predictive) frame, and a B A transmitting side security module 10 for encrypting and transmitting a moving image by installing and operating a moving image in a transmitting terminal 1 to be transmitted through the communication module 1a; And a receiving side security module 20 for decrypting and obtaining the encrypted moving image by installing and operating the encrypted moving image via the communication module 2a in the receiving terminal 2.

Here, the I frame, the P frame, and the B frame are obtained by compressing the continuous moving picture data before the coding of each continuous frame of moving picture data in units of GOP (Group of Picture), and are obtained by a known compression coding technique , A detailed description will be omitted and a coding structure of moving picture data shown in FIG. 3 will be briefly described for the understanding of the present invention.

An I frame is a frame obtained from a GOP before coding, and is an independent frame that has all the image data in the pre-coding frame as it is, like a general image, and becomes a reference frame in a GOP. Such an I frame can be compressed and used as a still image, for example, by DCT conversion.

The P frame and the B frame are frames having a conversion value called a motion vector obtained by referring to the I frame, and are dependent on the I frame.

In other words, a P frame is a frame that is coded so as to be reproduced by supplementing only the difference from a reference I frame, and may be a reference of a P frame to be reproduced next.

The B frame is a frame coded with reference to the previous frame, the latter frame, or both of the front and back frames, and is disposed between the I frame and the P frame, or between the P frame and the next P frame.

The I, P, and B frames have a header for recording a code for identifying at least a frame type.

Therefore, even if only I frames are encrypted for security reasons, I frame, P frame and B frame, which are dependent on the I frame, can restore almost all of the videos impossible.

For this reason, it is possible to shorten the time required for encryption and effectively operate the transmission side security module 10 by encrypting I frames only after I, P, and B frames are identified by distinguishing them by a header. Of course, a moving image in I, P, and B frames also has a header, so that it is possible to record moving-related header information.

As shown in Fig. 1, the transmitting-side security module 10, which is installed and operated in the transmitting terminal 1 to encrypt an I-frame, includes an encryption condition setting unit 12 for setting an encryption condition to be applied when encrypting, And an encryption unit 11 for encrypting the I frame of the moving picture according to the condition.

The encryption unit 11 extracts an I frame image from the I, P, and B frames of the moving image and divides the I frame image into a plurality of image fragments, and performs shuffling in which two image fragments are randomly selected and exchanged Thereby generating an encrypted I frame image of the image puzzling method and then outputting an encrypted video obtained by replacing the I frame of the moving image with the encrypted I frame image. Thus, the transmitting terminal 1 encrypts the I frame, and the P frame and the B frame are transmitted in the same manner as before the encryption, through the communication module 1a.

At this time, in order to encrypt the I frame image by the puzzling method, the image fragment size and the number of shuffling should be set to an appropriate value according to the number of pixels of the I frame image.

As an example of real-time encryption of a moving picture, the larger the frame rate of a moving picture, the larger the number of I frames to be encrypted per unit time, and the longer the time required for encryption per unit time, It is recommended to adjust the size and the number of shuffling according to the frame rate.

Since the number of I frame image pixels and the frame rate are applied in the same way throughout the moving picture, the moving picture to be transmitted is fixed, but the moving picture is used without change.

When the I frame is decoded, the entire frame in the GOP to which the I frame belongs can be obtained by using the P frame and the B frame depending on the I frame. The larger the amount of data of the P frame and the B frame, It is preferable to adjust the image fragment size and the number of shuffling according to the data amount of the P frame and the B frame.

Since the amount of data of the P frame and the B frame is a variable value that varies according to each GOP of the moving picture, it is preferable to change only the number of shuffling rather than changing both the image fragment size and the shuffling number in accordance with the variable value.

Accordingly, the encryption condition setting unit 12 acquires the number of I frame pixels, the frame rate, and the P frame and B frame data amount as encryption conditions, and sets the encryption condition according to the encryption condition, An initial setting unit (12a) that variably sets the image fragment size and the number of shuffling according to the number of I frame image pixels and the frame rate before starting encryption, and an initial setting unit And an instant re-setting unit (12b) for variably setting and changing the number of shuffling to be applied for each I frame in accordance with the data amount of the P frame and the B frame.

The encryption unit 11 records the image fragment size and the number of shuffling set by the initial setting unit 12a in the moving picture header and the number of shuffling set by the instant resetting unit 12b corresponds to the number of shuffling of the corresponding I frame Header. That is, the number of shuffling applied to each I frame is recorded in the corresponding I frame header, thereby enabling the receiving security module 20 to recognize that the number of times of shuffling that has been reset only for the corresponding I frame is used.

The transmission side security module 10 will be described in more detail with reference to FIGS. 2 to 4. FIG.

The initial setting unit 12a of the encryption condition setting unit 12 obtains the number of pixels of the I frame image indicating the resolution of the moving image and the frame rate indicating the number of frames per second as the initial encryption condition from the moving image (S111), an initial encryption condition setting step (S110) for initially setting an image piece size and a shuffling number as an encryption condition (S112) is performed before moving picture encryption.

The size of the image fragment and the number of shuffling are not only correlated with each other but also determine the time required for encrypting the I frame. In order to appropriately adjust the time required for encryption, the number of I frame image pixels and the frame rate ).

Referring to the I frame image shown in FIG. 3, an I frame image extracted from a moving image is divided into image fragments having a size of a X b pixel, and then a process of randomly selecting two image fragments and shuffling is repeated At the time of shuffling, the number of shuffling must be sufficiently large to make it impossible to visually recognize any image and make it difficult to restore original image data as data.

However, the smaller the size of the image fragment, the larger the number of image fragments obtained by division, and the larger the number of image fragments, the larger the number of shuffling.

The inventor of the present invention could obtain the result of the following equation (1) showing the correlation between the number of images and the appropriate shuffling number by using a mathematical theory on probability, and by puzzling the number N of divided image pieces The correlation of equation (1) was verified from the obtained image. The appropriate shuffling frequency can be set according to the image size by providing a rule or a data table for appropriately adding and subtracting the result of Equation 1 and increasing the number of shuffling as the number of image pieces increases.

In Equation 1, k is an appropriate shuffling number, N is the number of divided image fragments, and? Is a probability that a specific image fragment is stochastically present at uniform probability regardless of the dividing position as the shuffling process is repeated Which represents the convergence rate to a stationary distribution.

In addition, when the execution time of the program is created for the implementation of the encryption unit 11, the larger the size of the image fragment, the smaller the number of the divided image fragments. Thus, the time required for the one-time shuffling becomes longer, The number of rings can be reduced, and time savings can be achieved by reducing the number of shuffling.

That is, the execution time according to the image fragment size is not only an increase factor but also a reduction factor.

However, since the size of the divided image fragment is made small so that the execution time of the one-time shuffling becomes relatively short and the corresponding number of times of the shuffling is relatively increased, the size of the divided image fragment becomes large, It is possible to reduce the time required for puzzling (encryption), rather than making relatively long and relatively few shuffling times.

This means that execution of the program code required to exchange positions of a relatively large divided image fragment has a greater influence on the time required for puzzling, and the inventor of the present invention creates an encryption program to vary the size of the image fragment As a result of executing the encryption program by applying the appropriate shuffling frequency to the size of the image fragment, it is confirmed that the smaller the image size, the smaller the time required to encrypt the I frame image, that is, the encryption time.

Of course, as a result of writing a puzzling program, if the size of image fragments is increased to reduce the number of times of shuffling, the size of the image fragments can be increased to reduce the time required for encryption, However, according to the puzzling program identified by the applicant of the present invention, the smaller the size of the image fragment, the shorter the time required for encryption.

Accordingly, in the embodiment of the present invention, in order to reduce the time required for the encryption (puzzling) to increase as the number of pixels of the I frame image increases, a rule or a lookup table for setting the size of the image fragment having a smaller number of pixels Respectively. As an example of a rule, the size of a segmented image fragment can use a rule that is inversely proportional to the number of I frame pixels.

However, if the number of divided image fragments is excessively large, the necessary pseudo random number becomes too large, which is greatly influenced by the performance and operation time of the pseudo random number generator. If the size of the image fragment is too large, reverse puzzling may be possible even when the puzzling process is not known.

The maximum value of the image fragment size is determined according to the degree of difficulty of reverse puzzling, and the size of the image fragment is set within a predetermined range. Or a lookup table.

In addition, the initial setting unit 12a changes the size of the image fragment set according to the number of pixels of the I frame image according to the frame rate.

For example, the larger the frame rate, the smaller the size of the image fragments. Therefore, even when the frame rates are different, the difference in the time required for encryption can be reduced.

Of course, if the image fragment size is changed, the number of divided image fragments corresponding to the changed image fragment size also changes, so the number of shuffling is also changed accordingly.

On the other hand, according to a commonly used moving picture, since the total number of pixels (or the number of pixels) of the I frame image and the frame rate are limited, the total number of pixels of the I frame image and the image fragment size and the number of shuffling A lookup table may be used.

The initial encryption condition thus set is recorded in the header of the moving image, and then the moving image encryption is performed by the encryption unit 11. [

In the moving image encryption, the I frame extracting step (S120), the encrypting step (S130), and the I frame replacing step (S140) are sequentially performed for each I frame of the moving image, and the encrypted moving image data is output according to the result of the performing.

As shown in FIGS. 2 and 3, the I frame extracting step (S120) extracts an I frame, which is dependent on the extracted I frame, by the instantaneous resetting unit 12b of the encryption condition setting unit 12, (S121), and the number of shuffling to be applied only to the extracted I frame can be reset (S122).

For this purpose, the instantaneous resetting unit 12b extracts the data amount of the P frame and the B frame depending on the I frame to be extracted, and then obtains the sum data amount of the P frame and the B frame (S121) And the number of times of shuffling is reset (S122).

3 illustrates a closed GOP in which I, P, and B frames are generated by compressing only a frame within a GOP. Thus, the amount of data of P and B frames existing in the GOP is extracted following the extracted I frame. However, to support open GOP, the range is adjusted to include the frame appearing before the extracted I frame, but it is limited to the P and B frames existing in the open GOP.

Here, the re-setting of the number of shuffling is a method of increasing the number of times of increasing the number of shuffling as the amount of data to be summed in the P and B frames is larger, and is to be reset in accordance with each GOP of the screening.

This is because, even if the number of shuffling is set by the initial setting unit 12a as described above, the amount of increase in the number of shuffling increases as the data amount of the P and B frames becomes larger, thereby enhancing the security for the I frame .

Of course, since the number of times of shuffling is directly controlled, the size of the set divided image piece is not modified.

On the other hand, as the number of shuffling times increases, the time required for encryption becomes longer. Therefore, the number of times of increasing shuffling times is limited so as not to exceed a predetermined upper limit.

In addition, since the number of shuffling is increased at the time of encrypting the I frame, the delay time (encryption required time) is increased by the number of times of increase in the number of times of increase. The shuffling number set by the initial setting unit 12a is preferably set to a value slightly lower than a value determined according to Equation 1 in consideration of the resetting of the shuffling number of times.

As shown in FIG. 2, the encrypting step (S130) is a step of generating a puzzled I frame obtained by encrypting the extracted I frame by the puzzle method. The I frame image in the data area of the extracted I frame is obtained, An image dividing step of dividing each image piece into a grid shape according to the size of the piece and then numbering the image pieces (S131), randomly selecting a random number to generate a random number sequence, selecting a seed, A random number generation step (S132) of generating a random number sequence of two times of the number of shuffling using a pseudo random number generator in which a random number sequence is determined (S132); a random number generation step A purging step (step S133) of repeating a shuffling process of exchanging the numbered image fragments by a shuffling number, and a purging step (step S133) The encrypted I frame image obtained by the image puzzling method is inserted into the data area of the I frame to replace the I frame image before encryption and the number of times of shading and the number of shuffling are recorded in the header of the I frame, And an encrypted I-frame generation step (S134).

Here, it is preferable that the number of shuffles and the number of shuffling to be recorded in the header of the I frame are recorded in a code encrypted in accordance with the pre-established agreement with the receiving security module 20 provided in the receiving terminal 2 .

The puzzling step S133 will now be described with reference to FIG. 4, which is an exemplary illustration of the case where the number of image fragments is set to 63. If the pre-encryption I frame image A is divided into 63 image fragments Then, shuffling is performed repeatedly after assigning order numbers a01, a02, ..., a63 to each image fragment.

When shuffling is performed, two pieces of image are randomly selected and then the positions are exchanged. Accordingly, as the number of times of shuffling increases, the number of image pieces moving from one position to another increases.

Since the image fragments are randomly selected every time shuffling is performed, the probability distribution that each image fragment or any one specific image fragment can exist at each divided position by repeating shuffling is a uniform probability And converge to a stationary distribution that may exist as a whole. Accordingly, the degree of convergence of Equation (1) is appropriately selected and the appropriate shuffling number corresponding to the number of divided image pieces is set in advance, thereby repeating shuffling to such an extent as to puzzle appropriately. Of course, rather than applying Equation 1 as it is, it is preferable to change the image size, the number of divisions, etc., and modify the puzzle to have a proper number of shuffling.

The I frame replacing step S140 encrypts the I frame by inserting the generated encrypted I frame into the moving image data and replacing the I frame before encryption, and outputs the video data that has been kept in the non-encrypted state in the P and B frames .

Then, the process goes to the I frame extracting step (S120) to encrypt the next I frame in the moving image data.

The moving image encrypted and output by the transmission side security module 10 installed and operated in the transmission terminal 1 encrypts only the I frame and stores the image fragment size and the shuffling frequency set by the initial setting section 12a And transmits it to the communication path 3 of the communication network via the communication module 1a as a moving image in which the number of shuffling times and the number of shuffles set for each I frame by the instantaneous resetting unit 12b is recorded in the I frame header So that the receiving side security module 20 installed in the receiving module 2 can obtain the video before encryption by utilizing the recording information of the video header and the I frame header.

The receiving side security module 20 includes an encryption condition acquisition unit 22 for acquiring an encryption condition in an encrypted moving image transmitted through the communication path 3 and received by the communication module 2a, And a decoding unit 21 for decoding the moving picture.

Here, the encryption condition acquisition unit 22 may include an initial condition acquisition unit 22a that acquires an image fragment size and a shuffling count recorded in the video header at the beginning of the moving image, and an I frame And an instantaneous condition acquisition unit 22b for acquiring the number of times of shading and shuffling recorded in the header of the I frame.

The receiving security module 20 will be described in detail with reference to the security receiving step (S200) shown in FIG.

The initial condition acquisition unit 22a of the encryption condition acquisition unit 22 reads the image fragment size and the shuffling count recorded in the video header at the initial stage of reception when the moving image is received, (S210).

Thereafter, the decoding unit 21 performs an I frame extraction step (S220), a decoding step (S230), and an I frame replacement step (S240) for the I frame sequentially appearing in the moving image, .

When the I frame extracting step S220 is performed, the instant condition acquisition unit 22b of the encryption condition acquiring unit 22 acquires the number of times of shades and shuffling recorded in the header of the I frame to be extracted Decryption unit 21, as shown in FIG. That is, if the number of shuffling is recorded in the I frame header, the number of shuffling of the I frame header is temporarily used only for the I frame instead of the number of shuffling set by the initial condition obtaining unit 22a, The number of times of shuffling recorded in the I frame header is given priority.

The decryption step S230 follows the procedure of the encrypting step S130 by the encrypting unit 11, but there is a difference in that iterative shuffling is performed in reverse order to change the position of the image fragment.

The decrypting step S230 will be described in more detail. After dividing the extracted I frame image into the set image fragment size, a number is assigned to each image fragment in the same manner as the image fragmenting step S131 of the encrypting step 130 The same pseudo random number generator as the pseudo random number generator used in the image segmenting step S231 and the random number generating step S132 of the encrypting step S130 are operated to generate a 2-fold random number sequence of shuffling times according to the seed A random number generating step S232 for generating the same random number sequence as the random number generating step S132 of the encrypting step S130; a random number generating step S232 for generating random numbers in reverse order in the random number sequence; An inverse puzzling step S233 of obtaining a decoded I frame image obtained by inverting the shuffling process by the number of times of shuffling, To obtain the decoded I frame is decoded into a data area of an I frame the I frame generating step includes a (S234).

That is, in the decoding step S230, the I frame image is divided into the image fragment size recorded in the moving picture header, thereby performing image division in the same manner as in the encrypting step (S130), and in accordance with the sequence recorded in the header of the I frame, S130) can be generated for each I frame.

Also, the pseudo-random number generated according to the seed is generated with a length twice as many as the number of shuffling recorded in the video header, and only the I frame in which the number of shuffling is recorded in the header is used as the value recorded in the I frame header And for the I frame in which the number of shuffling is not recorded in the header, the number of shuffling obtained in the initial condition acquiring unit 22a is used so that a random number sequence equal to the random number sequence generated for each I frame in the encrypting step (S130) .

Then, for each I frame, the same random number sequence as the encryption step (S130) is generated, but two pseudo-random numbers are selected in reverse order from the random number sequence, and shuffling is repeated in the reverse order of the shuffling performed in the encryption step (S130) , An I frame before encryption can be obtained. That is, it is possible to restore the I frame image by performing the shuffling in the order shown in Fig. 4 in the reverse order.

The I frame replacement step (S240) replaces the I frame of the encrypted moving image with the decrypted I frame generated in the decrypting step (S230) to recover the moving image.

On the other hand, only the image fragment size is recorded in the moving picture header, and the number of shuffling and the number of shuffles may be recorded in the header of the I frame. In this case, the number of shuffling set by the initial setting unit 12a is When the instant re-setting unit 12b resets the number of times of shuffling, the number of times of shuffling recorded in the I frame is changed to the reset value.

Alternatively, both the image fragment size, the number of shuffling times, and the seed value may be recorded in the header of the I frame.

As another alternative, the image fragment size, the number of shuffling times, and the seed value may be transmitted in separate data packets instead of being recorded in the header of the moving image and the header of the I frame.

On the other hand, when a single seed value is set for a whole moving image, there is no need to record a seed for each I frame, and an initial seed value is input to a pseudo-random number generator, Sequentially take in the sequence of frames.

Meanwhile, the video security transmission system according to the present invention can embed the transmission side security module 10 in the transmission terminal 1 and embed the reception side security module 20 in the reception terminal 2 However, it can also be configured as a system composed of a transmitting terminal 1 having the transmitting side security module 10 as a component and a receiving terminal 2 having the receiving side security module 20 as a component.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, . &Lt; / RTI > Accordingly, such modifications are deemed to be within the scope of the present invention, and the scope of the present invention should be determined by the following claims.

[Description of Symbols]

1: transmitting terminal 1a: communication module

2: receiving terminal 2a: communication module

3: Communication path

10: Transmission-side security module

11:

12: Encryption condition setting unit

12a: initial setting unit 12b: instantaneous resetting unit

20: Receiver security module

21:

22: Encryption condition acquisition unit

22a: Initial condition obtaining unit 22b: Instant condition obtaining unit

Claims

After an encrypted I frame is generated by repeating shuffling in which two image fragments are randomly selected and exchanged in a state where an I frame of the moving image is divided into a plurality of image fragments, An encryption unit 11 for replacing the encryption unit 11 with a frame and an encryption condition including an image fragment size and a shuffling frequency to be used in the encryption unit 11 in a variable manner according to the number of pixels of the I frame and the frame rate of the moving image A transmission side security module 10 configured to include an encryption condition setting unit 12 and installed in a transmission terminal 1 for transmitting moving pictures to transmit a moving picture encrypted with an I frame; And

A shuffling process is repeated in the reverse order of shuffling times of the encryption conditions in a state in which the I frame of the moving image to be received is divided into the image fragment size of the encryption condition and the decryption I frame is generated A receiving side security module 20 for replacing an I frame of a moving image with a decrypted I frame and restoring the moving image as a moving image before encryption;

&Lt; / RTI >

The encryption condition setting unit 12

The number of shuffling is set to be increased as the number of image fragments according to the size of the set image fragments is increased,

The size of the set image fragment is reset so as to become smaller as the frame rate is larger, and the number of shuffling is reset in accordance with the number of image fragments corresponding to the size of the reset image fragment

Video secure transmission system.
The method according to claim 1,

The transmitting side security module 10 and the receiving side security module 20 use a random number generator that generates the same random number according to a seed value,

The transmitting side security module 10 may include a seed value applied to randomly select two image fragments by the number of shuffling in the encryption condition and transmit the encrypted image data to the receiving side security module 20 so as to decrypt doing

Video secure transmission system.
The method according to claim 1,

The transmission side security module 10 may reset the shuffling times according to the data amount of the P frame and the B frame depending on the I frame so that the shuffling times can be different for each I frame

Video secure transmission system.
The method of claim 3,

The transmitting side security module 10 records the number of times of shuffling before resetting according to the data amount of the P frame and the B frame in the header of the moving picture together with the image fragment size and is reset according to the data amount of the P frame and the B frame The number of times of shuffling is recorded as the header of the I frame,

The receiving side security module 20 decrypts the I frame according to the image fragment size and the shuffling count recorded in the moving picture header, and stores the number of shuffling only for the I frame in which the number of shuffling is recorded in the header in the I frame header Use as a value

Video secure transmission system.
A transmitting terminal 1 for encrypting a moving image with the transmitting side security module 10 and transmitting the encrypted moving image via the communication module 1a and a receiving terminal 1 for decrypting a moving image received through the communication module 2a to the receiving side security module 20, (2)

The transmitting side security module 10 and the receiving side security module 20 are constituted by the transmitting side security module 10 and the receiving side security module 20 described in any one of claims 1 to 5, Secure transmission system.