JP2007318412A - Image recording device, and alteration detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording device and an alteration detecting method that can decide whether an alteration is made or not and alteration places by fields of digital image data even when there are alterations by "impersonation". <P>SOLUTION: The image recording device includes a first hash value generating means 41 of generating first hash values based upon image data and second hash values based upon header information by the fields from the digital image data including the image data and the header information relating to the image data, and a hash value adding means 42 of adding the first hash values and second hash values to image data of fields on which the calculation of the first and second hash values is based, also incorporating the first hash values and second hash values in header information of fields right after the fields on which the calculation of the first and second hash values is based, and outputting the resulting data to an image storage means 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image recording apparatus having a function for determining whether or not digital image data stored in an information recording medium has been falsified, and a falsification detection method.

  In recent years, digital image data such as JPEG (Joint Picture Experts Group), motion JPEG, and JPEG2000 using an image compression technique has been used in various fields. Such digital image data is used, for example, in the field of a monitoring system for monitoring a predetermined monitoring target, to continuously store a video signal captured by an imaging camera in an image storage device after image compression. Has been. The digital image data stored by the surveillance system may be provided as evidence video when an incident occurs. Therefore, in the monitoring system, it is essential to ensure the reliability (truth) of the stored digital image data, and it is significant that it can be proved that the stored digital image data has not been tampered with.

  On the other hand, in recent years, application software that can synthesize digital image data with other digital image data, or can modify or delete a part of the digital image data has become widespread. Therefore, it is possible to tamper with digital image data relatively easily.For this reason, when stored digital image data is tampered with, a technique that can detect tampering and determine the tampering location, It is necessary to detect tampering due to

  An example of such a technique is disclosed in Patent Document 1. In this document, at the time of recording, one field of image data is blocked so as to be n bytes long in the horizontal (horizontal) direction, and the blocked data is calculated in the vertical (vertical) direction. The byte data is stored as the first falsification detection data or stored together with the image data in the recording medium, and the second detection data is obtained by performing the same calculation as the above recording on the image data during reproduction. An apparatus is described that compares the first detection data with the second detection data and determines whether the image data has been tampered with based on the comparison result.

Japanese Patent No. 3022472 (paragraphs 0014-0019, FIG. 3)

  However, in the above-described conventional apparatus, since the process for obtaining the detection data is based on a relatively simple and monotonous calculation process, the calculation contents are easily guessed, and the person who alters the image data can detect the detection data. In addition, there is a possibility that tampering may be permitted by “spoofing” that prevents tampering from being detected. For this reason, the above-described conventional apparatus has a low accuracy of falsification detection and has a problem in reliability.

  Further, in the above-described conventional apparatus, when tampering is detected, whether the tampering is in the display image part of the digital image data or in the information part (for example, imaging date / time, imaging location, recording condition, etc.) There was also a problem that it could not be determined.

  Therefore, an object of the present invention is made to solve the above-described problems of the prior art, and the purpose is that even when the stored digital image data is altered by “spoofing”, An object of the present invention is to provide an image recording apparatus and a falsification detection method capable of discriminating whether or not falsification has occurred, a falsified field, and a falsification location.

  The image recording apparatus of the present invention includes, from digital image data including image area data and header information related to the image area data, for each field of the digital image data, a first hash value based on the image area data and First hash value generation means for generating a second hash value based on the header information, the first hash value and the second hash value are used as the basis for calculating the first and second hash values. A hash value adding means for adding to the digital image data in the field and outputting to the image storage means.

  The falsification detection method of the present invention includes a first hash value based on the image data and the header information for each field of the digital image data from digital image data including image data and header information related to the image data. Generating a second hash value based on the first hash value and adding the first hash value and the second hash value to the image data of the field from which the first and second hash values are calculated In addition, the first hash value and the second hash value are included in the header information of the field next to the field from which the first and second hash values are calculated, and output to the image storage unit. And a step of performing.

  According to the present invention, even if the stored digital image data is altered by “spoofing”, the presence / absence of alteration, the field with alteration, and the alteration location can be determined.

  FIG. 1 is a block diagram schematically showing the configuration of an image recording apparatus 20 according to an embodiment of the present invention (that is, an apparatus capable of performing the falsification detection method according to Embodiment 1).

  As shown in FIG. 1, an image recording apparatus 20 according to the present embodiment includes a video signal input terminal 1, an NTSC decoder 2, an image compression processing unit 3, a control processing unit 4, an image memory 5, A video signal information input terminal 6, a CPU (Central Processing Unit) 7, a program memory 8, a working memory 9, an instruction input unit 10, an image data input / output terminal 11 connected to the image storage device 21; The image expansion processing unit 12, the NTSC decoder 13, the composition processing circuit 14, and a video signal output terminal 15 connected to a monitor 22 are provided. The image recording device 20 constitutes, for example, a video monitoring system together with an imaging camera, an image storage device 21 and a monitor 22 (not shown). For example, the image recording device 21 receives a video signal and imaging information from the imaging camera. And / or displayed on the monitor 22.

Further, as shown in FIG. 1, NTSC decoder 2, a video signal input through the video signal input terminal 1 (for example, video signals from the imaging camera or the like in a surveillance system) the NTSC signal of the analog system is S _PI into image data D ₀ is a digital signal. Image compression processing unit 3 compresses the image data _{D 0} obtained through the NTSC decoder 2 by a predetermined method such as JPEG2000, and outputs the image data _{D 1.}

Further, as shown in FIG. 1, the control processing unit 4 transfers the header information D _HE and various data created based on the imaging information input from the video signal information input terminal 6, generates hash values, Processing such as signal synchronization adjustment and falsification detection is executed. The image memory 5 temporarily stores the compressed image data D ₁ and header information D _HE from the image compression processing unit 3 input through the control processing unit 4. The CPU 7 operates based on the program stored in the program memory 8 and the user instruction information from the instruction input unit 10 to control the operation of the control processing unit 4. Working memory 9, tampering with the digital image data D ₂ read out from the image storage unit 21 when it is detected, stores the tampering contents.

When displaying a video signal from an imaging camera (not shown) on the monitor 22, the image decompression processing unit 12 decompresses the image data D ₁ input from the video signal input terminal 1 and generated by decoding and compressing the digital image data. and outputs it as a D _3. Further, when reproducing the digital image data stored in the image storage device 21, the image expansion processing unit 12 uses the digital image data D ₂ read from the image storage device 21 through the image data input / output terminal 11. decompression and outputs the digital image data D _3.

NTSC encoder 13 converts the digital image data _{D 3} that is decompressed by the image decompression processing unit 12 into an analog video signal _{S PO.} Synthesis processing circuit 14, when the tampering into digital image data D ₂ read out from the image storage device 21 has been detected, store the analog video signal S _PO tamper contents output from the NTSC encoder 13 working The video signal related to the falsification detection result information 31 from the memory 9 is superimposed.

  The image storage device 21 is an information storage device including an information recording medium such as a hard disk recording device, an optical disk recording device, and a magnetic tape recording device, and a plurality of image storage devices 21 are connected in parallel or in series to the image recording device 20. It can also be connected. Further, the image storage device 21 may be incorporated as a part of the image recording device 20.

  FIG. 2 is a functional block diagram showing functions of the control processing unit 4 of the image recording apparatus 20 according to the present embodiment.

As shown in FIG. 2, the control processing unit 4 includes a first hash value generation unit 41 and a hash value addition unit 42 as functional blocks that perform operations during image recording. The first hash value generation means 41 generates image data for each field from digital image data 52 including image data D ₁ (or 50) and header information D _HE (or 51) related to the image data D _1. generating a first hash value 61 and the second hash value 62 for extracting features of header information D _HE extracting features of the image data D ₁ on the basis of all the pixels of D _1. The image data D ₁ is data corresponding to the displayed image portions of the digital image data, header information D _HE corresponds to the information portion of the digital image data (e.g., image pickup date, imaging place, recording condition, etc.) It is data. The hash value adding means 42 uses the first hash value 61 and the second hash value 62 as the image data of the digital image data 52 of the field from which the first and second hash values 61 and 62 are calculated. A process of adding to D ₁ and including it in the header information 51 of the next field of the field from which the first and second hash values 61 and 62 are calculated is output to the image storage device 21. .

  Further, as shown in FIG. 2, the control processing unit 4 includes a second hash value generation unit 43, a first comparison unit 44, a first determination unit 45, and the first determination unit 45. A determination result output means 46 for outputting the determination result and a reproduction stop means 47 are provided. In addition, the control processing unit 4 includes a second comparison unit 48 and a second determination unit 49. The second hash value generation unit 43, the first comparison unit 44, the first determination unit 45, and the determination result output unit 46 are functional blocks that perform an alteration detection operation. The second comparison unit 48, the second determination unit 49, and the determination result output unit 46 are functional blocks that perform an alteration detection operation by “spoofing”.

The falsification detection process by the first comparison unit 44 and the first determination unit 45 is activated by, for example, a reproduction start operation from the instruction input unit 10. During falsification detection operation, the second hash value generation unit 43, from the digital image data D ₂ read out from the image storage device 21, for each field, by the same process as the first hash value generation unit 41, for example, Based on all the pixels of the image data 50, a third hash value 63 for extracting features of the image data 50 and a fourth hash value 64 for extracting features of the header information 51 are generated. The first comparison unit 44 compares the third hash value 63 generated during the tampering detection operation with the first hash value 61 added to the same field, and the fourth hash generated during the tampering detection operation. The value 64 is compared with the second hash value 62 added to the field. First determination means 45, based on the comparison result of the first comparison means 44, whether the digital image data D ₂ stored in the image storage apparatus 21 has been tampered with, addition, alteration portion image data 50 And the header information 51 are determined for each field. Judgment result output means 46, when the digital image data D ₂ stored in the image storage apparatus 21 by the first determination unit 45 is determined to have been tampered with, the judgment result in a falsification detection by the first determination means 45 The result information 31 is output to the synthesis processing circuit 14 as a video signal through the determination result output means 46. Reproduction stop means 47, when the digital image data D ₂ stored in the image storage apparatus 21 by the first determination unit 45 is determined to have been tampered, and outputs a stop signal to the CPU7 order to stop the playback operation.

The falsification detection process by “spoofing” by the second comparison unit 48 and the second determination unit 49 is performed subsequent to the falsification detection process by the first comparison unit 44 and the first determination unit 45. In the falsification process, a third hash value 63 for extracting features of the image data 50 and a fourth hash value 64 for extracting features of the header information 51 are generated based on all the pixels of the image data 50. The first comparison unit 44 compares the third hash value 63 generated during the tampering detection operation with the first hash value 61 added to the same field, and the fourth hash generated during the tampering detection operation. The value 64 is compared with the second hash value 62 added to the field. This comparison is performed by the first comparison unit 44 and the comparison result is performed by the first determination unit 45. A third hash value 63 for extracting the characteristics of the newly generated image data 50 and a fourth hash value for extracting the characteristics of the header information 51 when it is determined by the first determination means 45 that there is no alteration. 64, the hash value 61 of the image data 50 generated by the first hash generation means added to the header information 51 of the next field of the same field and the hash value 62 of the header information 51 are again compared with each other in the second comparison. Comparison is made by means 48. When the comparison result is determined by the second determination unit 49 and it is determined that there is falsification, the field is determined to be falsified by “spoofing”, and the falsification detection result information 32 by “spoofing” is determined by the determination result output unit 46. It outputs to the composition processing circuit 14 as a continuous video signal. Reproduction stop means 47, stops when it is determined that tampering by "spoofing" the digital image data D ₂ stored in the image storage apparatus 21 by the second determination unit 49 is present, the CPU7 order to stop the reproduction operation Output a signal.

  Note that each means 41 to 49 shown in FIG. 2 indicates the function of the control processing unit 4, and means that there is necessarily a configuration (circuit) corresponding to each of the means 41 to 49. is not. In FIG. 2, the functions shown as the units 41 to 49 may be realized by software, or may be realized by hardware such as an arithmetic processing circuit.

  FIG. 3 is a diagram for explaining the image data temporarily stored in the image memory 5 of the image recording apparatus 20 according to the present embodiment. FIG. 4 is an operation at the time of image recording by the control processing unit 4. It is a figure for demonstrating. FIG. 5 is a diagram for explaining the digital image data stored in the image storage device 21. Further, FIG. 6 is a flowchart showing the processing contents at the time of image recording by the control processing unit 4 of the image recording apparatus 20 according to the present embodiment.

  Hereinafter, an operation at the time of image recording by the control processing unit 4 of the image recording apparatus 20 according to the present embodiment will be described with reference to FIGS.

  First, a user instruction to start recording is input from the instruction input unit 10 (step ST1 in FIG. 6).

The control processing unit 4, when the image data D ₁ in field units and the header information D _HE is input (step ST2 in FIG. 6), as shown in FIG. 3, the image data D ₁ input _(or 50 ) And header information D _HE (or 51) are temporarily stored in the image memory 5 in field units (reference numeral 53 indicates one field) (step ST3 in FIG. 6).

  Next, as shown in FIG. 4, the control processing unit 4 reads the digital image data 52 of the image memory 5 in units of fields, and performs a second hash based on the first hash value 61 based on the image data 50 and the header information 51. Is generated (step ST4 in FIG. 6).

  Next, as shown in FIG. 4, the control processing unit 4 generates the generated first hash value 61 (or 61a,..., 61e,...) And the second hash value 62 (or 62a,..., 62e). ,... Are added to the field from which the first and second hash values 61 and 62 of the digital image data 52 are calculated and the header information of the next field, respectively, and output to the image storage device 21 ( Step ST5 in FIG. 6). As a result, as shown in FIG. 5, the image storage device 21 has a first hash value 61 (or 61a,..., 61e,...) And a second hash value 62 (or 62a,..., 62e,. ) Is added to the digital image data 52.

  FIG. 7 is a diagram for explaining the processing contents during the falsification detection operation by the image recording apparatus 20 according to the present embodiment, and FIG. 8 is based on “spoofing” by the image recording apparatus 20 according to the present embodiment. It is a figure for demonstrating the processing content at the time of the detection operation of alteration. FIG. 9 is a flowchart showing the processing contents during the tampering detection operation by the control processing unit 4 of the image recording apparatus 20 according to the present embodiment. Further, FIG. 10 is a diagram showing an example of display on the monitor 22 when tampering is detected by the image recording apparatus 20 according to the present embodiment, and FIG. 11 is an image recording apparatus 20 according to the present embodiment. FIG. 10 is a diagram illustrating an example of display on the monitor 22 when tampering due to “spoofing” is detected.

  In the following, with reference to FIGS. 7 to 11, the alteration detection operation by the control processing unit 4 of the image recording apparatus 20 according to the present embodiment and the alteration detection operation by “spoofing” will be described.

  First, a user instruction to start falsification detection is input from the instruction input unit 10 (step ST11 in FIG. 9).

Next, the control unit 4 reads out the digital image data _{D 2} from the image storage apparatus 21 the first and second hash values 61, 62 is added (step ST12 in FIG. 9).

Next, as shown in FIG. 7, the control processing unit 4, the digital image data D ₂ read out, for each field, identical to the first hash value generation unit 41 (shown in FIG. 2) processing To generate a third hash value 63 (or 63a,..., 63e,...) Based on the image data 50 and a fourth hash value 64 (or 64a,..., 64e,...) Based on the header information 51 (FIG. 9 step ST13).

  Next, as shown in FIG. 7, the control processing unit 4 uses the first hash value 61 (or 61a,..., 61e,...) Added to the image data 50 for each field at the time of recording in the same field. The generated third hash values 63 (or 63a,..., 63e,...) Are compared, and second hash values 62 (or 62a,..., 62e,...) Added to the image data 50 on a field basis at the time of recording are compared. ) And the generated four hash values 64 (or 64a,..., 64e,...) Are compared for the same field (step ST14 in FIG. 9).

Next, the control unit 4, based on the comparison result, whether the digital image data D ₂ stored in the image storage apparatus 21 has been tampered with, and if it is determined that there tampering, alteration locations Whether the image data 50 and the header information 51 are both or not is determined for each field. Specifically, the first hash value 61 (or 61a, ..., 61e, ...) added to the image data 50 at the time of recording and the generated third hash value 63 (or 63a, ..., 63e, ...). ) Is determined to have not been tampered with, and it is determined that the image data 50 in the non-matching field has been tampered with. Further, the second hash value 62 (or 62a,..., 62e,...) Added to the image data 50 at the time of recording matches the generated four hash values 64 (or 64a,..., 64e,...). It is determined that there is no falsification in the header information 51 of the field, and it is determined that there is falsification in the header information 51 of the mismatched field (steps ST15 and ST16 in FIG. 9).

  The first hash value 61 (or 61a,..., 61e,...) Added to the image data 50 by the control unit 4 at the time of recording and the generated third hash value 63 (or 63a,..., 63e,. The second hash value 62 (or 62a,..., 62e,...) And the generated four hash values 64 (or 64a,..., 64e,. If it is determined that there is no falsification in the image data 50 of that field, the first hash value 61 (or 61a, ..., 61e, ...) included in the header information 51 of the next field The generated third hash value 63 (or 63a, ..., 63e, ...) is compared, and the generated second hash value 62 (or 62a, ..., 62e, ...) is compared with the generated fourth hash value 63 (or 63a, ..., 63e, ...). Hash value 64 (or 64a ..., 64e, ...) comparing (Fig. 9 step ST18), and determines that there is tampering by "spoofing" in the case of disagreement (step ST19, ST20 of FIG. 9). That is, when the field is altered, a hash value is calculated again for each field based on the digital image data of the altered field, and when this is added to the image data, this is regarded as alteration by “spoofing”. To detect.

  Next, when it is determined that the digital image data 52 stored in the image storage device 21 has been tampered with, or when it is determined that there has been tampering due to “spoofing”, the control processing unit 4 operates the determination result. While being stored in the memory 9, the falsification detection result information 31 or the falsification detection result information 32 by “spoofing” is output to the synthesis processing circuit 14 as a video signal. At the same time, the control processing unit 4 instructs the CPU 7 to stop reproduction (steps ST17 and ST21 in FIG. 9). As a result, as shown in FIG. 10 or FIG. 11, the falsification detection result information 31 read from the working memory 9 or the falsification detection result information 32 by “spoofing” is read by the monitor 22 through the synthesis processing circuit 14. Is displayed. As shown in FIG. 10, the alteration detection result information 31 displayed on the monitor 22 includes a message 31 a (for example, “there is“ falsification ”) indicating that there is alteration, and the field of the alteration. A field number 31b (for example, “Field NO: 985363”) and an item 31c (“Image” or “Header” indicating whether the falsified portion of the falsified field is image data and / or header information. Or “image, header”). Further, as shown in FIG. 11, the alteration detection information 32 based on “spoofing” includes a message 32a that informs of alteration by “spoofing” (for example, “There is“ tampering ”due to“ spoofing ”). Field number 32b (for example, “Field NO: 9834976”), field number 32b (for example, “Field NO: 985363”) for a field that has been altered by “spoofing”, and the altered location is image data. And an item 32c (“image” or “header” or “image, header”) indicating either or both of the header information.

  The field number is recorded in the header information 51. Therefore, when it is determined that the header information 51 has been tampered with, the header information 51 itself cannot be trusted, and therefore, the tampering is performed based on the header information of the field before the field where it is determined that the header information 51 has been tampered with. Determine the field number of the assigned field.

  The falsification detection process and the falsification detection process by “spoofing” are performed on the digital image data converted from the continuous video signal in real time and for each field. Also, when it is determined by these detection processes that there has been tampering or tampering due to “spoofing”, the sending of new digital image data to the image expansion processing unit 12 is stopped, and tampering or tampering with “spoofing” is determined. The result and the field number of the altered digital image data are stored in the working memory 9.

As described above, in the image recording apparatus 20 according to the present embodiment, the first hash value 61 based on the image data 50 and the second hash based on the header information 51 are provided for each field of the digital image data 52. A value 62 is generated, and the generated first hash value 61 and second hash value 62 are added to the digital image data 52 of the corresponding (same) field, and the header of the next field of the corresponding (same) field The data 51 is included in the information 51, output to the image storage device 21 through the image data input / output terminal 11, and stored in the image storage device 21. Therefore, according to the image recording apparatus 20 or the alteration detection method according to this embodiment, when the tamper detection operation, from the digital image data D ₂ read out from the image storage device 21, for each field, the image data 50 A third hash value 63 based on the header information 51 and a fourth hash value 64 based on the header information 51 are generated, and the first hash value 61 added to the image data 50 is compared with the generated third hash value 63. , by comparing the fourth hash value 64 and the generated second hash value 62 is added to the image data 50, whether the digital image data D ₂ that is stored has been tampered with, addition, alteration It can be determined whether the location is the image data 51 or the header information 50.

Further, for each field, a third hash value 63 based on the image data 50 and a fourth hash value 64 based on the header information 51 are generated, and the first hash value 61 added to the image data 50 is generated. When the third hash value 63 is compared and the second hash value 62 added to the image data 50 is compared with the generated fourth hash value 64, it is determined that there is no falsification. The first hash value 61 included in the header information 51 of the next field of the corresponding field is compared with the generated third hash value 63, and the second hash included in the header information 51 of the next field is compared. by comparing the fourth hash value 64 generated a value 62 again, tampering by "spoofing" is present in the digital image data D ₂ accumulated In addition, when there is a falsification due to “spoofing”, it can be determined whether the falsification part by “spoofing” is the image data 51 or the header information 50.

  In addition, according to the image recording device 20 or the alteration detection method according to the present embodiment, it is possible to easily detect the alteration of an image and the alteration due to “spoofing” without processing any input data, and the alteration result Is the image data of the digital image data or the header information, and the field number of the digital image data in which the alteration is detected can be known. Information regarding tampering by “spoofing” can be displayed on the monitor 22 to notify the user.

1 is a block diagram schematically showing a configuration of an image recording apparatus according to an embodiment of the present invention (that is, an apparatus capable of performing a falsification detection method according to an embodiment). It is a functional block diagram for demonstrating the function of the control process part of the image recording device which concerns on embodiment. It is a figure for demonstrating the digital image data temporarily stored in the image memory of the image recording device which concerns on embodiment. It is a figure for demonstrating the operation | movement at the time of the image recording by the control process part of the image recording device which concerns on embodiment. It is a figure for demonstrating the digital image data accumulate | stored in the image storage device by the control process part of the image recording device which concerns on embodiment. It is a flowchart which shows the processing content at the time of the image recording by the control process part of the image recording device which concerns on embodiment. It is a figure for demonstrating the tampering detection operation | movement by the image recording device which concerns on embodiment. It is a figure for demonstrating the detection operation of the alteration by the "spoofing" by the image recording device which concerns on embodiment. 6 is a flowchart illustrating processing contents during a falsification detection operation by a control processing unit of the image recording apparatus according to the embodiment. It is a figure which shows the example of a monitor display when tampering is detected by the image recording device which concerns on embodiment. It is a figure which shows the example of a monitor display when the alteration by "spoofing" is detected by the image recording apparatus which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Video signal input terminal, 2 NTSC decoder, 3 Image compression process part, 4 Control processing part, 5 Image memory, 6 Video signal information input terminal, 7 CPU (central processing unit), 8 Program memory, 9 Working memory, 10 Instruction input unit, 11 Image data input / output terminal, 12 Image expansion processing unit, 13 NTSC encoder, 14 Composition processing circuit, 15 Video signal output terminal, 20 Image recording device, 21 Image storage device, 22 Monitor, 31 Tampering detection result information 32 Falsification detection result information by “spoofing”, 41 First hash value generation means, 42 Hash value addition means, 43 Second hash value generation means, 44 First comparison means, 45 First determination means, 46 Determination result output means, 47 reproduction stop means, 48 second comparison means, 49 second determination means, 5 0 image data, 51 header information, 52 digital image data, 53 1-field digital image data, 61, 61a, ..., 61e, ... a first hash value generated based on the image data at the time of image recording, 62, 62a ,..., 62e,..., Second hash value generated based on the header information at the time of image recording, 63, 63a,..., 63e,. , 64a, ..., 64e, ... fourth hash value generated based on the header information when the tamper detection operation, _{D 0} image data, _{D 1} compressed image data, the digital image data including a _{D 2} hash values, _{D 3} decompressed digital image data, _{D HE} header information, _{S PI} analog video signal, an analog comprising _{S O} tampering detection result information Image signal.

Claims (10)

From digital image data including image data and header information related to the image data, a first hash value based on the image data and a second hash value based on the header information are provided for each field of the digital image data. First hash value generation means for generating;
The first hash value and the second hash value are added to the image data of the field from which the first and second hash values are calculated, and the first hash value and the second hash value And a hash value adding means for outputting the hash value to the image accumulating means for inclusion in the header information of the next field of the field from which the first and second hash values are calculated. Image recording device. From the digital image data read from the image storage means, a fourth hash value based on the third hash value based on the image data and the header information is obtained for each field by the same processing as the first hash value generation means. Second hash value generation means for generating a hash value of
The first hash value added to the image data in the same field is compared with the third hash value, and the second hash value and the fourth hash value added to the image data in the same field are compared. A first comparison means for comparing
Based on the comparison result of the first comparison means, for each field, it is determined whether or not the digital image data stored in the image storage means has been tampered with. The image recording apparatus according to claim 1, further comprising: a first determination unit that determines which of the image data and the header information is or both. When the first determination unit determines that the digital image data in the field from which the first and second hash values are calculated has not been tampered with, the first and second hash values Calculation of the first and second hash values by comparing the first hash value and the third hash value included in the header information of the digital image data of the next field of the field that is the basis of the calculation Second comparison means for comparing the second hash value and the fourth hash value included in the header information of the digital image data of the next field of the field that is the source of
An image in which the first hash value added to the image data of the field from which the first and second hash values are calculated based on the comparison result of the second comparison unit is altered. It is determined whether or not the value is a value calculated based on data, and the second hash value added to the image data in the field from which the first and second hash values are calculated is altered. The image recording apparatus according to claim 2, further comprising: a second determination unit that determines whether or not the value is calculated based on the header information.   When the first determination means determines that there has been falsification, information indicating the presence of falsification, information for identifying a field that has been determined to have falsification, and whether the falsification location is image data or header information 4. The image recording apparatus according to claim 2, wherein information indicating either or both is output as a video signal. The second determination means includes
Information for identifying a field that has been determined to be falsified when it is determined that the first hash value added to the image data is a value calculated based on falsified image data, and a falsification location When it is determined that the second hash value added to the image data is a value calculated based on falsified header information, the information indicating that is the image data is output as a video signal. The image recording apparatus according to claim 3, wherein information specifying a field determined to be falsified and information indicating that the falsified portion is header information are output as a video signal. From digital image data including image data and header information related to the image data, a first hash value based on the image data and a second hash value based on the header information are provided for each field of the digital image data. Generating step;
The first hash value and the second hash value are added to the image data of the field from which the first and second hash values are calculated, and the first hash value and the second hash value Including the step of including the hash value of the first and second hash values in the header information of the next field of the field from which the first and second hash values are calculated, and outputting to the image storage means . From the digital image data read from the image storage means, a fourth hash value based on the third hash value based on the image data and the header information is obtained for each field by the same processing as the first hash value generation means. Generating a hash value of
The first hash value added to the image data in the same field is compared with the third hash value, and the second hash value and the fourth hash value added to the image data in the same field are compared. A step of comparing
Based on the comparison result in the same field, for each field, it is determined whether or not the digital image data stored in the image storage means has been tampered with. And tampering detection method according to claim 6, further comprising a step of determining either or both of the header information and the header information. The field from which the first and second hash values are calculated when it is determined that the digital image data of the field from which the first and second hash values are calculated is not falsified. The first hash value and the third hash value included in the header information of the digital image data of the next field of the next field are compared, and the field of the field from which the first and second hash values are calculated Comparing the second hash value and the fourth hash value included in the header information of the digital image data of the next field;
Based on the comparison result in the two fields, the first hash value added to the image data of the field from which the first and second hash values are calculated is converted into the image data that has been altered. It is determined whether or not the value is an originally calculated value, and the second hash value added to the image data in the field from which the first and second hash values are calculated is falsified. The falsification detection method according to claim 7, further comprising a step of determining whether or not the value is calculated based on header information.   In the step of determining based on the comparison result in the same field, when it is determined that there has been falsification, information indicating the presence of falsification, information for identifying the field that has been determined to have falsification, and the falsification location is image data and header 9. The falsification detection method according to claim 7, further comprising a step of outputting information indicating either or both of the information as a video signal.   Information for identifying a field that has been determined to be falsified when it is determined that the first hash value added to the image data is a value calculated based on falsified image data, and a falsification location Is output as a video signal, and the second hash value added to the image data is determined to be a value calculated based on falsified header information. 9. The falsification detection method according to claim 8, further comprising a step of outputting, as a video signal, information for identifying a field determined to be falsified and information indicating that the falsified portion is header information.

Images