Information embedding apparatus and method, tampering detecting apparatus and method, and recording medium

The present invention relates to an information embedding device for embedding information for detecting falsification in moving image data and related technology.

Conventionally, recording and reproduction have been performed by analog image processing technology. Examples of the medium include films, VHS video tapes, and the like. In such analog image processing, when tampering is applied, unnatural evidence remains at the joints and the like, and it is said that a skilled person can see whether or not the moving image has been tampered with. Therefore, if an expert determines that a VHS videotape has not been tampered with, it will be able to prove that the VHS videotape is authentic.

In recent years, digital image input devices such as digital cameras and digital recording devices such as hard disk recorders have rapidly become widespread in place of analog image processing technology.

Digital moving image data can be easily and easily tampered with (edited, processed, etc.) using commercially available image processing software. Moreover, it is possible to falsify the digital moving image data without leaving any trace. Therefore, it is almost impossible for even an expert to distinguish whether or not certain digital moving image data has been tampered with.

Digital moving image data has come to be used in fields such as monitoring and recording devices, and there is a demand for establishment of a detection technique capable of determining whether or not digital moving image data has been tampered with.

The digital moving image data includes a data unit configured so that a plurality of frame images can be sequentially arranged on the time axis, and a header unit for holding information about the data unit. This time axis may be a time axis for reproducing a plurality of frame images, or may be a time axis for accumulating a plurality of frame images on a recording medium (for example, a disk, tape, memory, etc.). The "time axis" referred to in the present specification may be any of these time axes.

In the present specification, the "frame image" may be a one-frame image in the moving image data adopting the frame structure, or a one-frame image created based on the field image in the moving image data adopting the field structure. It may be an image.

The falsification of moving image data, which is the subject of this specification, can be roughly classified into the following two types.

(First tampering) One of them is to process the frame image itself. For example, in order to hide his / her crime, the criminal deletes his / her own image (partial image of the frame image) from the frame image or replaces it with another image.

(Second falsification) The other is falsification in which a plurality of frame images are sequentially arranged on the time axis by the data part of the moving image data. For example, the criminal extracts the frame image of the scene in which he / she is shown (inconvenient frame image) in frame image units, or the extracted part is taken in frame image units by the frame image of the scene in which he / she is not shown. It is a case of replacement.

Of course, it is possible that both the first and second tampering will be performed. In order to prove that the moving image data is genuine and has not been tampered with, it must be able to cope with not only the first tampering but also the second tampering.

Conventionally, a falsification detection method using a digital watermarking technique has been known for the first falsification. Digital watermarking is a technology for embedding digital information inside digital moving image data in a form that cannot be perceived by humans.

For example, Japanese Patent Application Laid-Open No. 2002-271609 (Patent Document 1) discloses a method for verifying falsification of digital image data.

Hereinafter, this falsification verification method will be described with reference to FIG. FIG. 15 is a block diagram of a conventional falsification verification device.

In FIG. 15, the control unit 804 controls each element 801 to 803 and 805 to 813. The key input unit 801 inputs key information, and the pseudo-random number generator 810 generates pseudo-random numbers. The image data is input from the image data input unit 809 and stored in the memory 812.

The block division unit 807 divides the image data stored in the memory 812 into blocks of a specific size, and the frequency conversion unit 802 converts the divided image data into the frequency space. The tampering verification data embedding unit 803 generates tampering verification data from the generated frequency component, and the tampering verification data embedding unit 803 embeds the generated tampering verification data in a part of the generated frequency component. Thereby, the presence or absence of falsification can be determined based on the falsification verification data. The Huffman coding unit 808 encodes the frequency component in which the falsification verification data is embedded.

Further, Japanese Patent Application Laid-Open No. 11-341268 (Patent Document 2) discloses the following falsification detection method. That is, the digital watermark is embedded in the digital image by embedding the digital signature bit of the hash function of the digital image in the frequency function of the digital image. On the other hand, embed when watermarking the Mareta fragile watermark is extracted from the digital image, the hash function of the digital image, calculated in the same manner as in the digital watermarking, using the public key, effective extracted watermark is the hash value Tampering is detected by verifying whether it is a signature. If the signature is valid, it is determined that the digital image has not been tampered with, and if it is not valid, it is determined that the digital image has been tampered with.

However, in the prior art, when the moving image data conforms to a format that utilizes frame-to-frame prediction (for example, MPEG, etc.), it is not possible to embed a digital watermark used for falsification detection in the predicted coded image.

For example, if the moving image data records a scene with little movement and almost a still image, the difference between the frame images will be almost zero, and the predicted coded image (P picture or B picture in MPEG). ), There are virtually no encoded blocks. In this case, since both Patent Documents 1 and 2 presuppose the existence of the encoded block to be embedded in the digital watermark, the information itself cannot be embedded. Therefore, in the prior art, falsification cannot be detected for the predicted coded image.

Further, the conventional technique is insufficient because it can cope with the first tampering but cannot cope with the second tampering.

Regarding the second tampering, it is conceivable to use a technique of adding a time display (visible) in the frame image and recording it. However, in this case, a human checks the time display one by one in order to detect the presence or absence of tampering. This is not realistic because it takes a lot of labor to check the moving image data for a long time.

More importantly, if the tamperer creates a frame image with a time display added so that it makes sense, the fraud cannot be revealed and the credibility of the moving image data can be increased. Can not. After all, conventional technology cannot take sufficient measures against falsification of moving image data.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2002-271609</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 11-341268</text></patcit><patcit num="3"><text>Japanese Unexamined Patent Publication No. 2000-165248</text></patcit><patcit num="4"><text>U.S. Pat. No. 6064764</text></patcit>

<p> A first object of the present invention is to provide a technique capable of detecting falsification on the time axis in digital moving image data.</p><p> A second object of the present invention is to provide a technique capable of detecting falsification of the predicted coded image itself.</p>

<p> The information embedding device according to claim 1 embeds information in moving image data including a data unit configured so that a plurality of frame images can be sequentially arranged on the time axis and a header unit that holds information about the data unit. An information embedding unit that is a device and embeds an order information input unit that generates order information of a plurality of frame images and an order information generated by the order information input unit in moving image data so that they cannot be visually recognized in a plurality of frame images. And.</p><p> The tampering detection device according to claim 5 is the presence or absence of tampering with moving image data including a data unit configured so that a plurality of frame images can be sequentially arranged on the time axis and a header unit for holding information about the data unit. An input unit that inputs moving image data with embedded order information, a detection unit that detects order information from the moving image data input to the input unit, and an order detected by the detection unit. It is provided with a tampering determination unit that determines whether or not the moving image data has been tampered with based on the information.</p><p> In these configurations, the order information enables detection of falsification on the time axis and automatic detection thereof. Moreover, since the order information is embedded in the moving image data in an invisible manner in the frame image, the order information can be protected from malicious rewriting.</p><p> In the information embedding device according to claim 2, the information embedding unit embeds order information in a plurality of frame images as a digital watermark.</p><p> With this configuration, order information can be extracted from the frame image, and deterioration in image quality of the frame image can be reduced. Furthermore, an important partial image of the frame image (for example, a partial image of the criminal's face) is not hidden behind the order information and becomes unclear.</p><p> In the information embedding device according to claim 3, the information embedding unit embeds order information in the header unit.</p><p> With this configuration, order information can be embedded in the moving image data without any processing on the frame image.</p><p> In the information embedding device according to claim 4, the order information is a number indicating the order of a plurality of frame images.</p><p> In the falsification detection device according to claim 6, the order information is a number indicating the order of a plurality of frame images.</p><p> With these configurations, the order can be easily defined and interpreted by number.</p><p> In the falsification detection device according to claim 7, the falsification determination unit determines that the moving image data has been tampered with when the order of a plurality of frame images is changed, dropped or added.</p><p> With this configuration, various aspects of tampering on the time axis can be detected.</p><p> The information embedding device according to claim 8 embeds information in moving image data including a data unit configured so that a plurality of frame images can be sequentially arranged on the time axis and a header unit that holds information about the data unit. A device, which is a single or a plurality of different frame images having a certain relationship on the time axis with respect to a specific frame image among a plurality of frame images included in the moving image data, and is a plurality of frame images. It is provided with a unique information calculation unit that calculates unique information about what is included in the image, and an information embedding unit that embeds the calculated unique information in a specific frame image.</p><p> The tampering detection device according to claim 13 has presence or absence of tampering with moving image data including a data unit configured so that a plurality of frame images can be sequentially arranged on the time axis and a header unit for holding information about the data unit. In the input unit for inputting the moving image data in which the order information is embedded and the moving image data input in the input unit, the device is embedded in a specific frame image among a plurality of frame images. Regarding a single or a plurality of different frame images having a certain relationship on the time axis with respect to a specific frame image, which are included in the plurality of frame images, while detecting the unique information and obtaining the first unique information. Based on the comparison result of the unique information calculation unit that calculates the unique information and obtains the second unique information, the comparison unit that compares the first unique information and the second unique information, and the comparison unit, the moving image data It is provided with a tampering determination unit that determines the presence or absence of tampering.</p><p> Since unique information is used in these configurations, it is possible to associate a specific frame image with another frame image, and if the association is broken, it can be determined that there is falsification on the time axis. Furthermore, when the frame image itself is tampered with, this association is cut off, so that the first tampering can also be dealt with at the same time.</p><p> In the information embedding device of claim 9, the unique information is a hash value for another frame image.</p><p> With this configuration, unique information can be accurately expressed using hash values.</p><p> In the information embedding device according to claim 10, another frame image is a frame image adjacent to a specific frame image on the time axis.</p><p> With this configuration, adjacent frame images can be associated with each other to counter tampering on the time axis.</p><p> In the information embedding device according to claim 11, the moving image data is MPEG compressed moving image data, the specific frame image is an intra-coded image, and the single or multiple different frame images are single or plural. It is a predictive coded image.</p><p> With this configuration, even when the data of the predicted coded image is small, it can be dealt with.</p><p> In the information embedding device according to claim 12, the intra-encoded image and the single or a plurality of predicted-encoded images belong to one GOP (group of pictures).</p><p> With this configuration, processing can be performed in a unit by using the correlation.</p>

<p> According to the present invention, falsification on the time axis can be detected in digital moving image data by order information. In addition, falsification of the predicted coded image itself can be detected.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram of an information embedding device according to the first embodiment of the present invention.

As shown in FIG. 1, the information embedding device in the present embodiment includes an order information input unit 101, a unique information calculation unit 102, a unique information holding unit 103, and an information embedding unit 104.

Here, as shown in FIG. 10, the moving image data includes a data unit 20 configured so that a plurality of frame images F1 to F5 can be sequentially arranged on the time axis, and a header unit that holds information about the data unit 20. Including 10 and.

Further, in FIG. 1, the order information input unit 101 generates order information of a plurality of frame images F1 to F5. The information embedding unit 104 embeds the order information generated by the order information input unit 101 in the moving image data so that it cannot be visually recognized in the plurality of frame images F1 to F5.

The information embedding unit 104 of the present embodiment can embed the order information in a plurality of frame images as a digital watermark, or can embed the order information in the extension area 10a of the header unit 10. Further, the order information of this embodiment is a number indicating the order of a plurality of frame images F1 to F5.

The unique information calculation unit 102 is a single or a plurality of different frame images having a certain relationship on the time axis with respect to a specific frame image among the plurality of frame images F1 to F5, and is included in the plurality of frame images. The unique information regarding the image is calculated, and the unique information holding unit 103 holds the calculated unique information and outputs the calculated unique information to the information embedding unit 104. Further, the information embedding unit 104 embeds the unique information held by the unique information holding unit 103 in a specific frame image.

Hereinafter, the information embedding device of this embodiment will be described with reference to FIG. FIG. 2 is a flowchart of the information embedding device of FIG. In this embodiment, the moving image data for embedding the tampering detection information is composed of an intra-coded image (I picture), a forward-directed predictive coded image (P picture), and a bidirectional predictive coded image (B picture). Use MPEG compressed moving image data.

First, the unique information calculation unit 102 calculates the unique information based on the frame image of the input moving image data (step 201).

When the frame image is an I picture (intra-encoded image), the unique information calculation unit 102 hashes from all the component values except the component that embeds the digital watermark among the frequency components in all the blocks constituting the frame image. Calculate unique information (unique information I) using a function.

When the frame image is a P picture or a B picture (predicted coded image), the unique information calculation unit 102 calculates a hash function from the frequency components of all the blocks in all the P pictures or B pictures included in the unit interval. Use to calculate unique information (unique information BP).

In this embodiment, the unit interval on the time axis is the interval from the I picture to the immediately preceding image of the next I picture in the order of accumulation. Of course, a section of a frame image belonging to one GOP (group of pictures) may be used as a unit interval.

Further, the unique information I and the unique information BP are 128-bit data, respectively. FIG. 3 shows the relationship between the unique information and the target picture for calculating the unique information.

Next, the unique information holding unit 103 holds the unique information calculated in step 201 (step 202).

Next, the order information input unit 101 determines whether or not the processing of the unit interval is completed (step 203), and if so, the order information input unit 101 inputs the order information according to a predetermined rule. (Step 204). In this embodiment, the order information uses numbers that increase by "1" in the order of "0", "1", and "2". The order information is 16-bit data.

Next, as shown in FIG. 3, the information embedding unit 104 uses the unique information I and the unique information BP held in step 202 and the number input in step 204 as the falsification detection information, and uses the falsification detection information as a unit interval. Embed it as a watermark in the first I picture of (step 205).

Next, the embedding method will be described with reference to FIG. FIG. 4 shows a method of allocating falsification detection information in block units. The rectangles in the frame to be embedded in FIG. 4 indicate blocks of 8 pixels × 8 pixels, respectively.

The falsification detection information in this embodiment is simply a combination of the unique information I, the unique information BP, and the number, and the total number of bits is 272 bits.

The information embedding unit 104 selects a block having several bits of falsification detection information information, and sets the selected block as an embedding target block. In FIG. 4, the block to be embedded is indicated by a shaded rectangle. The information embedding unit 104 allocates one bit of falsification detection information to each of the selected blocks.

FIG. 5 shows each frequency component of the block to be embedded. The information embedding unit 104 selects one component of the constituent frequency components in the embedding target block, and embeds the assigned bits. In this embodiment, the information embedding unit 104 selects the frequency component AC3 in FIG. When the assigned bit is "0", the information embedding unit 104 changes the value of the frequency component AC3 to an even number, and when the assigned bit is "1", the information embedding unit 104 changes the value of the frequency component AC3 to an odd number. change.

Finally, the information embedding unit 104 determines whether or not the moving image data input is completed (step 206), ends the process when the input is completed, and returns to step 201 if not.

(Embodiment 2) In the second embodiment, the falsification detection information is detected from the moving image data in which the falsification detection information is embedded as a digital watermark in the first embodiment, and the presence or absence of falsification is determined.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram of the falsification detection device according to the second embodiment of the present invention.

As shown in FIG. 6, the falsification detection device includes the input unit 501, the unique information calculation unit 502, the unique information holding unit 503, the detection unit 504, the detection information holding unit 505, the comparison unit 506, the continuity determination unit 507, and the falsification determination. It has a part 508.

The input unit 501 inputs moving image data in which order information is embedded. The detection unit 504 detects order information from the moving image data input to the input unit 501. The detection information holding unit 505 holds the order information detected by the detection unit 504.

The continuity determination unit 507 determines whether or not the continuity of the frame image is maintained based on the order information held by the detection information holding unit 505. More specifically, the continuity determination unit 507 determines that there is no continuity when the order of the frame images is changed, dropped or added, and determines that there is continuity otherwise.

The falsification determination unit 508 determines whether or not the moving image data has been tampered with based on the determination result of the continuity determination unit 507.

The unique information calculation unit 502 detects the unique information embedded in a specific frame image among the plurality of frame images in the moving image data input to the input unit 501, and obtains the first unique information. Further, the unique information calculation unit 502 calculates unique information about a single or a plurality of different frame images having a certain relationship on the time axis and included in the plurality of frame images with respect to the specific frame image. Get a second unique piece of information. These first and second unique information are held in the unique information holding unit 503.

The comparison unit 506 compares the first unique information held in the unique information holding unit 503 with the second unique information. The falsification determination unit 508 determines whether or not the moving image data has been tampered with based on the comparison result of the comparison unit 506.

Here, the falsification determination unit 508 determines that the moving image data has not been tampered with when the comparison result that the first unique information and the second unique information are equal is input from the comparison unit 506.

Hereinafter, the falsification detection device of this embodiment will be described with reference to FIG. 7. FIG. 7 is a flowchart of the falsification detection device of FIG.

First, the input unit 501 inputs a frame image constituting the moving image data in which the falsification detection information is embedded (step 601).

Next, the unique information calculation unit 502 calculates the unique information from the input frame image (step 602). Since the process of this step is the same process as step 201 (see FIG. 2) in the first embodiment, the description thereof will be omitted.

Next, the unique information holding unit 503 holds the unique information calculated in step 201 (step 603).

Next, the unique information calculation unit 502 determines whether or not the processing of the unit interval is completed (step 604), and when it is completed, the detection unit 504 inputs the information embedded from the I picture at the beginning of the unit interval. Detect (step 605). Here, the unique information calculation unit 502 first selects the embedding target block by the same selection method as at the time of embedding.

Next, in the selected block, the unique information calculation unit 502 embeds the bit value as "0" when the value of the frequency component selected at the time of embedding is even, and as "1" when the value is odd. Detected information. That is, the unique information calculation unit 502 performs the reverse processing of step 205 in the first embodiment.

Next, the detection information holding unit 505 holds the information detected in step 605 (step 606).

Next, the continuity determination unit 507 collates the bit string corresponding to the number in the detection information held in step 606 with a predetermined rule indicating continuity, and determines whether the detection information is continuous or not (step 607). ). Here, the rule indicating continuity is the same as that at the time of embedding. For example, if the number to be continuous, which is detected from the I picture of the unit interval, is always increased by "1" in the order of "0", "1", "2", the continuity determination unit 507 will perform continuity. It is determined that there is, and if not, it is determined that there is no continuity.

Next, the comparison unit 506 compares and collates the unique information I and the unique information BP held in step 603 with the bit strings corresponding to the unique information I and the unique information BP among the detected information held in step 606. And output the difference (step 608).

Next, the tampering determination unit 508 determines that there is no tampering when it is determined in step 607 that there is continuity and the difference output in step 608 is "0", and if not, tampering is not performed. Determined to be present (step 609).

Finally, the falsification determination unit 508 determines whether or not the moving image data input is completed (step 610), ends the process when the input is completed, and returns to step 601 if not.

As described above, according to the information embedding device according to the first embodiment and the falsification detection device according to the second embodiment, the embedded order information is detected and collated with the rule showing the same continuity as at the time of embedding. Therefore, tampering on the time axis can be detected.

Furthermore, when embedding information, the unique information BP of P picture and B picture is embedded in another image, I picture, and when the digital watermark is detected, the unique information BP calculated by the same method as when embedding is compared with the detected information. Therefore, it is possible to detect the spatial tampering of the P picture and the B picture. Even if there are almost no blocks encoded in the P picture and the B picture, spatial tampering of the P picture and the B picture can be detected by embedding all the blocks in the encoded I picture. ..

Further, by embedding the unique information of all the P pictures and the B pictures included in the unit interval in the I picture which is another image, it is possible to detect the falsification of the P picture and the B picture on the time axis. For example, when several P pictures and B pictures are removed, the detected information and the unique information BP calculated at this time are different at the time of digital watermark detection, and falsification can be detected.

Furthermore, by embedding the unique information I of the I picture itself, which is the image to be embedded, in the I picture, and comparing and collating the unique information I calculated by the same method as when embedding the digital watermark with the detected information, I It is possible to detect tampering in the space of the image itself from a single picture.

In the present embodiment, MPEG encoded data is used as the moving image data, but the present invention is not limited to this, and for example, motion JPEG and the like can be similarly applied.

Further, in the information embedding device according to the first embodiment, the falsification detection information is embedded in the frequency component of the selection block representing the pixel as a digital watermark, but the falsification detection information is directly embedded in the header portion 10 of the moving image data. It may be added. For example, in step 205, the falsification detection information is added to the extension area 10a included in the header portion 10 of the MPEG coded data, and in step 605 of the falsification detection device according to the second embodiment, the information added from the extension area 10a. The same effect can be obtained by detecting.

Further, in step 201, a 128-bit hash value calculated from the frequency component is used as the unique information, but the present invention is not limited to this. The same effect can be obtained if the information is unique to each image. Further, although one unique information is calculated from all the P pictures and B pictures included in the unit interval, the unique information may be calculated independently or the unique information may be calculated in units of a plurality of images. Further, the interval from the I picture to the next image in the accumulation order from the I picture to the immediately preceding image is set as a unit interval, but the unit interval is not limited to this.

Further, in step 203, a number increasing by 16-bit 1 is used as the information indicating continuity, but the information is not limited to this as long as it is information indicating continuity. As long as it follows a common rule when embedding a digital watermark and when detecting a digital watermark, it is not limited to the number, and may be, for example, alphabetical order, each character of a meaningful sentence, an appropriate sequence of numbers, or the like.

Further, in step 205, as a method of embedding the falsification detection information, a method of allocating one bit at a time to a selected block and changing one frequency component of the block is shown, but this is only an example. It is desirable to use an embedding method that suppresses image quality deterioration that does not affect the original moving image data as much as possible.

Further, in step 205, the first I picture of the unit interval is embedded, but the embedding is not limited to the I picture, and if possible, the P picture or the B picture may be embedded.

Further, in step 609, when it is determined to be continuous in step 607 and the difference output in step 608 is "0", it is determined that there is no tampering, but when the difference is equal to or less than the threshold value, it is determined that there is no tampering. By making a judgment, it is possible to distinguish between mere irreversible image conversion and malicious tampering.

The first and second embodiments can be further modified in various ways. Hereinafter, each aspect of information embedding and falsification detection will be described with reference to FIGS. 9 to 14.

(Embodiment 3) FIG. 9 is an explanatory diagram of information embedding and falsification detection in the third embodiment of the present invention. In this embodiment, sequence information is embedded as a digital watermark in each of the frame images F1 to F5 constituting the data unit 20 of the moving image data. Further, at the time of tampering detection, the digital watermark embedded in each frame image F1 to F5 is detected and the order information is obtained.

If there is an abnormality in the obtained order information, it is determined that there is falsification on the time axis, and if not, it is determined that there is no falsification on the time axis.

(Embodiment 4) FIG. 10 is an explanatory diagram of information embedding and falsification detection in the fourth embodiment of the present invention.

In the present embodiment, unlike the third embodiment, the order information of the frame images F1 to F5 is stored in the extension area 10a of the header portion 10, whereby the falsification determination is performed. Even in this way, the order information cannot be visually recognized.

(Embodiment 5) FIG. 11 is an explanatory diagram of information embedding in the fifth embodiment of the present invention, and FIG. 12 is an explanatory diagram of falsification detection in the fifth embodiment of the present invention.

In this embodiment, as shown in FIG. 11, based on the previous frame image F1 (another frame image) located immediately before the current frame image F2 (specific frame image) of interest on the time axis. Unique information is calculated. Then, the calculated unique information is embedded as a digital watermark in the current frame image F2.

At the time of tampering detection, as shown in FIG. 12, the digital watermark embedded in the current frame image F2 is detected, and the first unique information is obtained.

In addition, the unique information is calculated from the previous frame image F1 and the second unique information is obtained.

Then, these first and second unique information are compared, and if they are equal, it is determined that there is no tampering on the time axis, and if not, it is determined that there is tampering on the time axis. Further, even when the frame image itself is tampered with (first tampering), the same relationship as described above is established. Therefore, according to this embodiment, both the first and second tampering can be detected at once. ..

Further, in this way, the previous frame image F1 and the current frame image F2 are in a so-called chained relationship. If this is repeated for all frames, all frames will be chained together. Then, all tampering on the time axis can be countered. This is because whenever tampering on the time axis is carried out, any part of the chain will be cut, and this break can be easily detected.

(Embodiment 6) FIG. 13 is an explanatory diagram of information embedding in the sixth embodiment of the present invention, and FIG. 14 is an explanatory diagram of falsification detection in the sixth embodiment of the present invention.

In the present embodiment, unlike the fifth embodiment, the unique information is stored in the extension area 10a of the header portion 10 instead of being embedded in the frame image as a digital watermark. That is, in this embodiment, processing is performed so as to have a relationship between the third embodiment and the fourth embodiment with respect to the fifth embodiment.

Of course, Embodiments 3 to 6 can be carried out alone or in combination as appropriate, and any of the embodiments is included in the present invention.

Typically, as shown in FIG. 8, each function realized by the information embedding device and the tampering detection device according to the first and second embodiments is a storage device 702 (ROM, ROM,) in which predetermined program data is stored. It is realized by the CPU701 (central processing unit) that executes the program data (RAM, hard disk, etc.). In this case, each program data may be introduced via a storage medium 705 such as a CD-ROM or a flexible disk.

The information embedding device according to the present invention can be suitably used in, for example, a field (monitoring record, copyright management) in which moving image data is handled while guaranteeing the presence or absence of falsification with high credibility.

<figref num="1">Block diagram of the information embedding device according to the first embodiment of the present invention</figref><figref num="2">Flow chart of the information embedding device according to the first embodiment of the present invention</figref><figref num="3">Explanatory drawing of information embedding in Embodiment 1 of this invention</figref><figref num="4">Explanatory drawing of relationship between tampering detection information and embedding target block in Embodiment 1 of this invention</figref><figref num="5">Explanatory drawing of embedding target block in Embodiment 1 of this invention</figref><figref num="6">Block diagram of the falsification detection device according to the second embodiment of the present invention</figref><figref num="7">Flow chart of the falsification detection device according to the second embodiment of the present invention</figref><figref num="8">Block diagram of the recording medium according to the first and second embodiments of the present invention.</figref><figref num="9">Explanatory drawing of information embedding and falsification detection in Embodiment 3 of this invention</figref><figref num="10">Explanatory drawing of information embedding and falsification detection in Embodiment 4 of this invention</figref><figref num="11">Explanatory drawing of information embedding in Embodiment 5 of this invention</figref><figref num="12">Explanatory drawing of tampering detection in Embodiment 5 of this invention</figref><figref num="13">Explanatory drawing of information embedding in Embodiment 6 of this invention</figref><figref num="14">Explanatory drawing of tampering detection in Embodiment 6 of this invention</figref><figref num="15">Block diagram of conventional tampering detection device</figref>

Code description

101 Sequence information input unit 102 Unique information calculation unit 103 Unique information holding unit 104 Information embedding unit 501 Input unit 502 Unique information calculation unit 503 Unique information holding unit 504 Detection unit 505 Detection information holding unit 506 Comparison unit 507 Continuity judgment unit 508 Tampering Judgment unit 701 CPU702 Storage device 703 Bus 704 Drive 705 Recording medium 801 Key input unit 802 Frequency conversion unit 803 Tampering verification data embedding unit 804 Control unit 805 External storage device 806 Quantization unit 807 Block division unit 808 Huffman coding unit 809 Image Data input unit 810 Pseudo random number generation unit 811 Tampering verification data generation unit 812 Memory 813 Data display unit