WO2013042843A1 - Method for authenticating images on the basis of block units using a reversible watermarking based on a progressive differential histogram - Google Patents

Abstract

According to the present invention, a method for authenticating images on the basis of block units using a reversible watermarking based on a progressive differential histogram involves splitting original image data on the basis of block units and inserting an authentication code into each block using a DCT coefficient to verify the integrity of image data, thereby providing the effect of enabling authentication of whether or not damage has been caused by an attacker.

Description

Block-based image authentication method using progressive histogram-based reversible watermarking

The present invention relates to a block-based image authentication method using reversible watermarking based on a difference value histogram, and more specifically, to detect which region is forged rather than forging the entire image data upon integrity authentication of the image data. Since it is more useful in practical applications, it is possible to divide the image data into smaller blocks and insert a watermark into each block to perform integrity authentication, thereby verifying the integrity of the image data and detecting the forgery and tampering areas. The present invention relates to a block-based image authentication method using reversible watermarking based on difference value histogram for enabling high speed.

Due to the rapid development of information processing capability and communication technology of hardware and software, many services using digital contents such as music, images, videos, electronic documents, educational materials and animations have been developed and become a common everyday life.

However, due to the characteristics of digital data that can be easily copied and reproduced after modification, many problems have arisen due to illegal distribution and forgery of contents. In particular, many services that use image data, such as the medical service field dealing with medical images of patients, the management of surveillance camera image data, military and satellite imagery, works of art, and remote telemetry, are not necessarily forged. Video is required.

If forged image data is used in these services, it can cause a lot of human and material damage, and can also lose its function as legal evidence. Accordingly, the demand for various security technologies has been increased to prevent the distribution of forged contents.

In order to authenticate the integrity of the video data, it must be able to prove that the received video data has not been forged, and the authentication process must be processed in real time so as not to disturb the huge amount of multimedia flow.

In addition, security conditions must be satisfied so that an attacker cannot easily infer or replicate. Early authentication techniques used encryption to ensure that only legitimate recipients could view the video.

However, encryption technology only guarantees protection in the content distribution process, and once decrypted content can no longer be protected, it is insufficient to provide sufficient means for verifying the integrity of the content.

Digital watermarking technology as a post-security technology for original content is a technique for invisibly inserting confidential information into digital content, and is used for various purposes such as proof of ownership, copyright protection, broadcast monitoring, and content authentication.

In particular, digital watermarking technology can be used as a means to protect contents after distribution because it can satisfy the requirements of various insertion capacities, perceptual transparency, robustness, confidentiality and computational complexity depending on the application. It can be a means.

Digital watermarking can invisibly embed watermark information such as metadata or original information for authentication code and copyright for the verification of the original content, and according to the application point of view, robust watermarking and fragile ) Are classified as watermarking.

Robust watermarking is designed to protect the content of the watermark from all possible distortion attempts while maintaining the visual quality of the content. Soft watermarking, on the other hand, can easily be applied to verify or authenticate the integrity of the content forgery and tampering, as the watermark is easily damaged by even a small modification.

In order to conceal the data in the content to prove its integrity and forgery certification, modification of the original content is inevitably inevitable, and any damage in applications such as medical imaging, military imaging, legal evidence, telemetry and artwork is inevitable. No original footage required.

This is because the degree of change is minimal and human perceptions may not be recognized at all, which can affect the right decision and become a legal issue.

Existing studies for the authentication of contents have focused on the robustness of the inserted watermark, so that the restoration of the original after removal of the watermark is not possible, and the accuracy of forgery is not high.

Reversible watermarking, which is part of flexible watermarking, removes messages from watermarked content and can be fully restored to the original content, so that not only the integrity verification of the content, but also proof of tampering and good use for copyright protection. Can be used as

Accordingly, in the technical field, there is a demand for technology development for authenticating the integrity of image data and detecting forgery region using watermarking, particularly soft watermarking.

[Related Technical Documents]

1. Data amount generation limiting device in block encoding for video compression (Patent Application No. 10-1997-0081256)

The present invention is to solve the above problems, in order to verify the integrity of the image data by dividing the original-image data by block unit by inserting the authentication code using the DCT coefficient in each block, to authenticate the damage by the attacker The purpose of the present invention is to provide a block-based image authentication method using a difference value histogram-based reversible watermarking.

In addition, the present invention uses a method of correcting the progressive difference histogram when inserting the authentication code, and by performing authentication for each of the R, G and B color channels of the color image, the difference value histogram based to increase the accuracy of authentication To provide a block-by-block video authentication method using reversible watermarking.

In addition, the present invention is to provide a block-based image authentication method using a gradual difference histogram-based reversible watermarking that can insert, detect / authenticate the authentication code at high speed while maintaining visual quality.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a block-based image authentication method using gradual difference histogram-based reversible watermarking according to an embodiment of the present invention, the original-image data Red (hereinafter, R), Green (hereinafter, G) And a first step of separating into Blue (hereinafter, B) channels; A second step of dividing original-image data separated into R, G, and B channels in units of blocks; A third step of extracting feature values through discrete cosine transform (DCT) and quantization for each divided block on the R, G, and B channels; A fourth step of performing an exclusive OR (XOR) operation on each extracted feature value to generate an authentication code by matching each divided block; A fifth step of constructing a progressive difference histogram for inserting each authentication code for each divided block and inserting the matching generated authentication code to generate a modified progressive difference histogram; A sixth step of performing pixel value update of each of the divided blocks for each of the R, G, and B channels using the modified incremental difference histogram; And a seventh step of re-merging the R, G, and B channels whose pixel values have been updated to obtain watermarking-image data having a watermark embedded in the original-image data.

At this time, in the second step, it is preferable to divide the block unit at the time of division into block units of 16 × 16 size.

In addition, the fifth step is to adjust the capacity of the message constituting the authentication code, and the quality of the watermarking-image data at the insertion level L (L is 0 and natural number) when the authentication code in the block unit is inserted. It features.

In the fifth step, the bin used to insert the message in the gradual difference value histogram is preferably set to {( -L -1) to (+ L )} around the 0th bin. Do.

In addition, the fifth step includes shifting bins not used for insertion to secure a message insertion space constituting the authentication code on the progressive difference histogram (a); And (b) modifying the progressive difference histogram by changing the message to be inserted into a bit value.

In the fourth step, the secret key may be any one of a key issued through an authentication authority, a user-specific unique ID, a password, an organization code, an image generating device ID, and a time code.

In order to achieve the above object, a block-based image authentication method using gradual difference histogram-based reversible watermarking according to another embodiment of the present invention includes separating watermarking-image data into channels of R, G, and B colors. First step; Dividing the watermarking-image data separated into the R, G, and B channels in units of blocks; A third step of constructing a progressive difference histogram for each divided block on the R, G, and B channels, and detecting an inserted authentication code by matching the divided block; A fourth step of detecting each of the authentication codes and then performing a correction to remove a watermark constituted by the authentication code from the progressive difference value histogram; And restoring original-image data of each of the R, G, and B channels using each of the progressive difference histograms from which the watermark has been removed, and then, original of each of the R, G, and B channels. And a fifth step of reconstructing the original original-image data by merging a gradual difference histogram corresponding to the image data.

At this time, in the second step, it is preferable to divide the block unit at the time of division into block units of 16 × 16 size.

On the other hand, the present invention is carried out after the fifth step, in order to determine whether the forgery of the reconstructed original-image data, separated by the R, G and B channels for the reconstructed original-image data, and blocks After extracting feature values through block-based DCT and quantization process, the authentication code for the partitioned block in the restored original-image data is performed by performing XOR operation on the extracted feature values. Extracting the sixth step; And a seventh step of determining as forgery when it is found that the extracted authentication code corresponding to each of the divided blocks of the detected authentication code does not match.

In addition, the fourth step may include: constructing the progressive difference histogram with respect to the watermarking-image data, and then scanning the message insertion space to detect an embedded message constituting the authentication code; And restoring the progressive difference histogram that has been modified to insert the message, and restoring bins that have been shifted to secure space.

In the sixth step, the secret key may be any one of a key issued through an authentication authority, a user-specific unique ID, a password, an organization code, an image generating device ID, and a time code.

In the block-based image authentication method using gradual difference histogram-based reversible watermarking according to an embodiment of the present invention, in order to verify the integrity of the image data, original-image data is divided into block units, and DCT coefficients are used for each block. By inserting the authentication code, it provides an effect that can authenticate whether the attacker is damaged.

In addition, according to another embodiment of the present invention, a block-based image authentication method using gradual difference histogram-based reversible watermarking uses a method of correcting a gradual difference histogram when an authentication code is inserted and R, G of a color image. And by performing authentication for each of the B color channel, it provides an effect that can increase the accuracy of the authentication.

In addition, the block-based image authentication method using gradual difference histogram-based reversible watermarking according to another embodiment of the present invention provides an effect of inserting, detecting, and authenticating authentication codes at high speed while maintaining visual quality. .

1 is a flowchart illustrating a process of inserting an authentication code in a block unit video authentication method using a progressive histogram-based reversible watermarking according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a process of generating a watermarking-image data in which a watermark is inserted into the original-image data by inserting the authentication code of FIG. 1. FIG.

3 is a flowchart illustrating a process of detecting an authentication code in a block-based image authentication method using reversible watermarking based on difference values according to an embodiment of the present invention.

4 is a diagram illustrating an authentication code detection process in the watermarking-image data of FIG. 3.

5 is a view for explaining the process of generating the authentication code in Figures 1 and 2.

6 to 8 are diagrams for explaining a process of inserting and detecting an authentication code in units of blocks in FIGS. 1 to 4.

9 to 13 are diagrams for explaining an experiment and performance evaluation according to the block-based image authentication method using the difference value histogram-based reversible watermarking according to an embodiment of the present invention.

Hereinafter, the detailed description of the preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted when it is deemed that they may unnecessarily obscure the subject matter of the present invention.

In the present specification, when one component 'transmits' data or a signal to another component, the component may directly transmit the data or signal to another component, and through at least one other component. This means that data or signals can be transmitted to other components.

1 is a flowchart illustrating a process of inserting an authentication code in a block unit video authentication method using a progressive histogram-based reversible watermarking according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a process of generating watermarking-image data in which a watermark is inserted into original-image data by inserting the authentication code of FIG. 1.

1 and 2, in the insertion process, an authentication code must be inserted into each block by a watermarking technique in order to perform block-by-block authentication for forgery of original-image data.

Accordingly, the original image data is separated into channels classified into red (hereinafter, R), green (hereinafter, G), and blue (hereinafter, B) colors (S1).

After step S1, original-image data divided into respective channels are divided into block units of 16 × 16 size (S2).

According to step S2, a discrete cosine transform (DCT) for each divided block on each of R, G, and B channels is extracted, and a feature value extracted through a quantization process is extracted (S3).

By performing an exclusive OR (XOR) operation on each feature value extracted according to step S3, an authentication code for each partitioned block is generated (S4).

After step S4, a progressive difference value histogram is constructed to insert each authentication code for each divided block by step S2, and then, by inserting each authentication code, a modified incremental difference histogram is generated ( S5).

The pixel value updating process of each divided block is performed for each R, G, and B channel by using the progressive difference histogram modified in step S5 (S6).

After step S6, the R, G, and B channels with updated pixel values are re-merged to obtain watermarking-image data, which is an image in which a watermark is inserted into the original-image data (S7).

3 is a flowchart illustrating a process of detecting an authentication code in a block-based image authentication method using reversible watermarking based on difference values according to an embodiment of the present invention. 4 is a diagram illustrating an authentication code detection process in the watermarking-image data of FIG. 3.

3 and 4, in the authentication code detection process, after the image in which the authentication code is inserted by the watermark technique is distributed, an authentication process is required to determine whether the attacker or an external factor is damaged.

The watermarking-image data is separated into channels of R, G, and B colors (S11).

In step S11, the watermarking-image data separated into respective channels of R, G, and B is divided into blocks of 16 × 16 size (S12).

In step S12, a progressive difference value histogram for each divided block is constructed, and an authentication code inserted in this process is detected (S13).

After detecting the authentication code according to step S13, in order to restore the original-image data, a correction process of removing the watermark constituted by the authentication code from each of the incremental histograms configured in step S13 is performed. (S14).

In step S14, a process of restoring original-image data of each channel of R, G, and B is performed by using the progressive histogram of each watermark from which the watermark is removed, and corresponding to the original-image data of each channel. Merging the progressive difference histogram restores the entire original-image data (S15).

After step S15, in order to check whether there is a forgery, the DCT and quantization process of the block unit according to the division into 16 x 16 block units for each of R, G, and B channels for the original-image data of step S15 After extracting the feature values through the extracted feature value, each extracted feature value by performing a secret key and XOR operation, and extracts the authentication code for each divided block (S16).

Subsequently, if it is found that the match does not match through comparing with each of the authentication code detected in step S13 and the authentication code extracted in step S16 matched with it is determined as forgery (S17).

FIG. 5 is a diagram for describing a process of generating an authentication code in FIGS. 1 and 2. 1, 2 and 5, in order to achieve a high performance authentication rate, an authentication code having a sufficient length to minimize the probability of false detection should be used, so that DCT upper coefficients for each block are selected for authentication. Used as feature value.

The experimentally obtained optimal authentication code length is 8 Bytes and its probability of false positive detection is 1 / (2 ⁶⁴ ), that is, 1 / (1.84467E + 19) = 5.42101E-20. You can say no.

The length of the authentication code for each block to be inserted is 64 bits, so it is necessary to check whether the block has enough insertable capacity.

Experiments have found that when the image is divided into 8 x 8 blocks, the insertion space is insufficient and not appropriate.

Therefore, referring to FIG. 5, the present invention divides the original-image data into blocks having a size of 16 × 16, averages each block to a size of 8 × 8, and performs DCT and quantization to perform the upper 8 Bytes. Select the coefficient to generate the authentication code.

At this time, if the attacker attacked by completely cutting out the area of the size larger than the block instead of partially changing the color information of the image, it is detected in the block when authentication is performed using the authentication code inserted in FIGS. 1 and 2. One authentication code and the calculated authentication code are equal to 0, so that proper authentication cannot be performed.

In order to prevent this problem, a final authentication code is generated by performing an XOR operation with the secret key shared with the receiver of the image data.

The "secret key" may use a key issued through a certification authority, or user-specific code, i.e., a user-specific code, a unique ID, a password, an organization code, an image generating device ID, and a time code. It can be used flexibly.

6 to 8 are diagrams for describing a process of inserting and detecting an authentication code in a block unit in FIGS. 1 to 4. Referring to FIGS. 1 to 4 and 6 to 8, a process of generating a reversible watermark using incremental histogram shifting for inserting and detecting the authentication code generated in the process of FIG. 1 into each block will be described. Describe the algorithm.

Conventionally, for grayscale images, only authentication for the entire image data is performed, but the present invention performs block-by-block authentication for R, G, and B color images.

First, referring to any gradual difference histogram of 6, when the block verification code insertion, the capacity of the messages that make up the verification code, and the watermark-quality image data is inserted according to the needs of the application level L Adjustable with

Depending on the value of L starting from 0, the bin used for message insertion in the progressive difference histogram is from {( -L -1) to (+ L )} around the 0th bin.

FIG. 7 illustrates a procedure in which a progressive difference histogram is corrected in a process of inserting a message when the insertion level L is 1 in step S5 of FIG. 1.

First, a progressive difference histogram is constructed with respect to the original-image data (Fig. 7 (a)), and then bins not used for insertion are shifted to secure a message insertion space (Fig. 7 (b)).

Next, by modifying the progressive difference histogram (FIG. 7 (c) and FIG. 7 (d)) by changing the message to be inserted into a bit value, the step S6 of FIG. 1 is reflected to reflect the corrected progressive difference histogram. And watermarking-image data through step S7.

FIG. 8 illustrates a procedure in which a progressive difference histogram is corrected in a process of recovering original-image data by detecting a message when the insertion level L is 1 in step S14 of FIG. 3.

First, a progressive difference histogram is constructed for the watermarking-image data (Fig. 8 (a)), and then the inserted message constituting the authentication code is detected by scanning the message insertion space (Fig. 8 (b)).

Next, restore the progressive difference histogram that was modified to insert the message (Figs. 8 (c) and 8 (d)), and then restore the bins that were shifted to secure the space (Fig. 8 (e)). ), The original-data image is restored by using the restored progressive difference histogram.

9 to 13 are diagrams for explaining the experiment and the performance evaluation according to the block-based image authentication method using the difference value histogram-based reversible watermarking according to an embodiment of the present invention.

The original-image data used in the experiments of the present invention is an 8-Bits color 512x512 image from the University of Southern California-Signal & Image Processing Institute (USC-SIPI) image database Airplane, baboon, House, Lena, Peppers, Sailboat, Splash, And eight of Tiffany are shown in FIG. 9, and watermarking-image data is shown in FIG.

The quality of original-image data and watermarking-image data were measured by PSNR (dB) calculated through Equations 1 and 2 below.

[Revision under Rule 26 08.03.2012]
Equation 1

[Revision under Rule 26 08.03.2012]
Equation 2

Where M and N are the horizontal and vertical sizes of the image, respectively, P (i, j) is the pixel value of the original-image data, and P '(i, j) is the pixel of the watermarking-image data with the watermark embedded therein. Value, and n is the number of bits (Bit Depth) needed to represent one pixel.

For the performance evaluation, the typical attack methods “Brightness”, “Darkness”, “Manipulating”, “Blurring” and “Copy & Paste” of FIG. 10 were tested. Performance was measured using Visual Studio C ++ 6.0 on an Intel i5-450M microprocessor and MS Windows 7 personal computer.

As can be seen from FIG. 11 representing the watermarking-image data in which the entire authentication code is inserted, the change of the image cannot be detected by human visual ability. Watermarking the authentication code for the experimental image is shown in Table 1 below. PSNR, the visual quality, is in good condition with an average of 36 dB.

Table 1 video PSNR (dB) Payload (bpp) Insert execution time (seconds) Authentication execution time (seconds) Certification rate (%) Airplane 38.08 0.75 0.671 0.640 97.38 Baboon 28.56 0.75 0.733 0.640 98.68 House 34.80 0.75 0.686 0.639 96.04 Lena 34.45 0.75 0.687 0.656 97.89 Peppers 36.19 0.75 0.682 0.655 98.12 Sailboat 34.17 0.75 0.686 0.640 97.60 Splash 42.71 0.75 0.655 0.640 97.84 Tiffany 37.04 0.75 0.686 0.640 98.07 Average 35.88 0.75 0.69 0.64 97.70

As can be seen from this result, the performance of the block-based image authentication method using incremental histogram-based reversible watermarking by the proposed image authentication reversible watermarking algorithm is slightly different depending on the image characteristics.

For example, an image containing more low frequency components such as "Splash" can obtain a high insertion capacity while maintaining good quality, but an image having a lot of high frequency components such as "Baboon" is relatively low in quality. .

The insertion capacity is the same as 0.75 bits per pixel (ppb), and the insertion capacity for a single channel is 0.25 bpp since 8 Bytes are inserted into each of 16 channels by 16 Bytes.

Looking at the average value in Table 1, the insertion process took 0.69 seconds on average, and the authentication code detection and authentication took 0.64 seconds on average. The authentication rate was 97.7%, which detected most of the compromised blocks.

FIG. 12 is an experimental result of detecting forgery by a block unit image authentication method using incremental histogram-based reversible watermarking according to the present invention when an actual attack is performed on the House image of FIG. 9. FIG. Represents authentication-video data.

On the other hand, Figure 13 detects the forgery by the block-based image authentication method using a gradual difference value histogram-based reversible watermarking according to the present invention when the actual attack on the Airplane image of FIG. 9 It is a figure which shows enlarged authentication | video image data.

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system.

Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, which are also implemented in the form of carrier waves (eg, transmission over the Internet). It also includes.

The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. And functional programs, codes and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

As described above, the present specification and drawings have been described with respect to preferred embodiments of the present invention, although specific terms are used, it is only used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention. It is not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

Claims (11)

A first step of separating original-image data into Red (hereinafter R), Green (hereinafter G) and Blue (hereinafter B) channels; A second step of dividing original-image data separated into R, G, and B channels in units of blocks; A third step of extracting feature values through discrete cosine transform (DCT) and quantization for each divided block on the R, G, and B channels; A fourth step of performing an exclusive OR (XOR) operation on each extracted feature value to generate an authentication code by matching each divided block; A fifth step of constructing a progressive difference histogram for inserting each authentication code for each divided block and inserting the matching generated authentication code to generate a modified progressive difference histogram; A sixth step of performing pixel value update of each of the divided blocks for each of the R, G, and B channels using the modified incremental difference histogram; And A seventh step of re-merging the R, G, and B channels whose pixel values have been updated to obtain watermarking-image data having a watermark embedded in the original-image data; Block-based image authentication method using a progressive difference histogram-based reversible watermarking comprising a. The method according to claim 1, wherein in the second step, The block unit image authentication method using incremental histogram-based reversible watermarking, characterized in that the block unit at the time of division is divided into block units of 16 x 16 size. The method according to claim 1, wherein the fifth step, Progressive difference histogram, characterized in that when the authentication code is inserted in the block unit, the capacity of the message constituting the authentication code and the quality of the watermarking-image data are adjusted to an insertion level L (L is 0 and a natural number). Block-based image authentication method based on reversible watermarking. The method according to claim 3, wherein in the fifth step, The bin used to insert the message in the progressive difference histogram is set to {( -L -1) to (+ L )} around the 0th bin. Block-based image authentication method using watermarking. The method of claim 3, wherein the fifth step, Shifting bins on the progressive difference histogram that are not used for insertion to secure the message insertion space constituting the authentication code; And Modifying the progressive difference histogram by changing a message to be inserted into a bit value; Block-based image authentication method using a progressive difference histogram-based reversible watermarking comprising a. The method according to claim 1, wherein in the fourth step, The secret key is one of a key issued through an authentication authority, a user-specific unique ID, a password, an organization code, an image generating device ID, and a time code, using a progressive difference histogram-based reversible watermarking. Block unit video authentication method. Watermarking-a first step of separating the image data into channels of R, G and B colors; Dividing the watermarking-image data separated into the R, G, and B channels in units of blocks; A third step of constructing a progressive difference histogram for each divided block on the R, G, and B channels, and detecting an inserted authentication code by matching the divided block; A fourth step of detecting each of the authentication codes and then performing a correction to remove a watermark constituted by the authentication code from the progressive difference value histogram; And Restoring the original-image data of each of the R, G, and B channels using each of the progressive difference histograms from which the watermark has been removed, and then, the original-image of each of the R, G, and B channels. A fifth step of reconstructing the original original-image data by merging a progressive difference histogram corresponding to the data; Block-based image authentication method using a progressive difference histogram-based reversible watermarking comprising a. The method of claim 7, wherein in the second step, The block unit image authentication method using incremental histogram-based reversible watermarking, characterized in that the block unit at the time of division is divided into block units of 16 x 16 size. The method according to claim 7, which is performed after the fifth step, In order to check whether the restored original-image data is forged or modified, the R, G, and B channels of the restored original-image data are separated, and the block-by-block DCT and quantization process are performed. Extracting feature values, and performing a XOR operation on the extracted feature values to extract an authentication code for the partitioned block from the restored original-image data; And A seventh step of determining as forgery when it is found that the extracted authentication code corresponding to each of the divided blocks of the detected authentication code does not match; Block-based image authentication method using a progressive histogram-based reversible watermarking, characterized in that it further comprises. The method of claim 7, wherein the fourth step, Constructing the progressive difference histogram with respect to the watermarking-image data, and then scanning the message insertion space to detect an inserted message constituting the authentication code; And Restoring the progressive difference histogram that has been modified to insert the message and restoring bins that have been shifted to secure space; Block-based image authentication method using a progressive difference histogram-based reversible watermarking comprising a. The method according to claim 9, wherein in the sixth step, The secret key is one of a key issued through an authentication authority, a user-specific unique ID, a password, an organization code, an image generating device ID, and a time code, using a progressive difference histogram-based reversible watermarking. Block unit video authentication method.

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