JP2001285620A - Digital evidence camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital evidence camera system that can surely prevent falsification of image data photographed by using a digital camera so as to enhance the authenticity of the image data. SOLUTION: An image display section 4 displays image data picked up by an image pickup device 2, a 1st authenticator generating section 21 attaches a message authenticator MAC generated by using a secret key of the camera to the image data to form a file format, the image display section 4 displays the image data with this file format to allow a 3rd party to confirm the data, a 2nd authenticator generating means 22 generates a message authenticator by using the secret key on the basis of the image data at that time, and comparing the generated authenticator with the authenticator by the 1st authenticator generating means detects falsification. When no falsification is detected, a 3rd authenticator generating means 23 generates a message authenticator by using the secret key of the 3rd party and encrypting the file format generated by the 1st authenticator generating means so as to form a final file format.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital proof camera system for detecting falsification of image data obtained by capturing an image of a subject by a camera.

[0002]

2. Description of the Related Art Conventionally, for example, photographs and sounds recorded in analog form on camera films and media have been used as proof in trials and the like. 2. Description of the Related Art Digital cameras that record sound as digital data have become widespread. When such digital cameras are used, it is necessary to add a function of preventing tampering of digital data.

As a device for preventing the falsification of digital data, a device described in Japanese Patent Application No. 11-308564 has been proposed.

[0004] In this conventional example, a message digest MD (Message Dig) is created by using a hash function in a message digest creating unit with image data captured by an imaging means.
est), and encrypts this message digest using a secret key built in the digital camera in advance, to obtain a message authenticator MAC (Message Authentic
ation Code), and the created message authenticator M
A digital evidence camera system is described in which an AC, personal authentication data, and image header information are added to image data for filing.

[0005]

However, in the above-mentioned conventional digital proof camera system, a message digest is created based on the image data captured by the image capturing means, and the message digest is encrypted using a secret key. However, since there is no means for confirming whether or not the image data captured by the image capturing means is credible, the digital proof camera is tampered with and the output side of the image capturing means is connected to another digital camera. When inputting recorded image data or inputting other image data created in a predetermined file format prior to creating a message digest, a message digest is created for these image data, and a message authentication is performed. The child is created and treated as if it were created with a digital proof camera. There, there is an unsolved problem that it is impossible to ensure the authenticity of the image data.

Accordingly, the present invention has been made in view of the above-mentioned unresolved problems of the prior art, and a third party authenticates an image captured by an image capturing section, thereby enabling highly credible image data to be obtained. It is intended to provide a digital proof camera system that can be formed.

[0007]

In order to achieve the above object, a digital proof camera system according to claim 1 comprises:
In a digital evidence camera system for detecting tampering of image data obtained by capturing an image of a subject with a camera, an imaging unit for capturing an image of the subject, and a third-party secret key input unit for inputting a third-party secret key A digital camera having an encryption processing unit for creating falsification detection data using image data obtained by the imaging unit, a secret key of a third party, and an encryption key stored in advance; And a falsification detection unit that detects whether or not the image data has been falsified based on the result of the decryption using the decryption key corresponding to .

In the invention according to the first aspect, the image data picked up by the image pickup section is encrypted by the encryption processing section using the secret key of the third party, so that the image data can be confirmed by the third party. After that, the image data can be encrypted, and the authenticity of the image data is authenticated by a third party, so that the exchange of the image data can be reliably prevented.

Further, in the digital proof camera system according to claim 2, in the invention according to claim 1, the encryption processing section uses a predetermined function based on the image data obtained by the imaging section to perform a message digest. And a first authenticator creating means for creating a message authenticator by encrypting the message digest using an encryption key, and displaying the image data after the message authenticator is created by the authenticator creating means. And a second authenticator for creating a message digest based on the image data displayed by the image display means and then encrypting the message digest using an encryption key to create a message authenticator. Creating means; and an authenticator determining means for comparing the message authenticators created by the first and second authenticator creating means to determine whether they match. An image data discarding unit for discarding the image data captured by the image capturing unit when the determination result of the witness determination unit does not match; and an image of a third party when the determination result of the authenticator determination unit matches. A third authenticator creating means for creating a message digest based on the image data and the message authenticator after confirmation, and then encrypting the message digest using a secret key of a third party to create a final message authenticator. It is characterized by having.

[0010] In the invention according to claim 2, the first authenticator creating means based on the image data picked up by the image pickup unit,
For example, a message digest is created using a hash function, and the message digest is encrypted using an encryption key containing the message digest to create a message authenticator. Then, the image data in which the message authenticator has been created is displayed on the image display unit. The message authenticator is created by the second authenticator creating means for the image data displayed at this time, and the first and second image authenticators are created. By determining whether or not the message authenticator created by the authenticator creating means matches the authenticator determining means, when the two do not match, it is determined that the image data has been replaced, and the image data discarding means is determined. To discard the image data. On the other hand, when the message authenticators match, the authenticator determining means determines that there is no replacement of the image data, and the third party confirms the image displayed on the image display section, and then enters the third party secret key. Means for inputting a secret key of a third party, and a message based on the image data by the third authenticator creating means and the data including the first message authenticator created by the first authenticator creating means. Create an authenticator. Therefore, a third party can confirm the credibility of the captured image data and then create the message authenticator again, so that highly credible image data can be stored.

Further, in the digital proof camera system according to claim 3, in the invention according to claim 1 or 2, the third-party secret key input means outputs a secret key from a recording medium in which the authenticated secret key is registered. It is characterized in that it is configured to read key data.

According to the third aspect of the present invention, since the secret key data registered in a recording medium such as an IC card is input to the digital camera, the secret key data is securely viewed without being seen by others. be able to.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a digital proof camera system according to an embodiment of the present invention, which comprises a digital proof camera 1 and a tampering inspection device 50.

A digital proof camera 1 captures an image and outputs digital image data, an image memory 3 for storing digital image data output from the image capturing device 2, and a storage for the image memory 3. An image display unit 4 composed of, for example, a liquid crystal display for displaying the obtained image data, a file format conversion unit 5 for reading out the image data stored in the image memory 3 and converting it into a standard image format such as JPEG, TIFF, etc. And an encryption processing unit 6 for encrypting the file format in which the header information is added to the image data by the file format conversion unit 5.

Here, the imaging device 2 includes a photographing lens 11
, An image sensor 12 composed of a CCD element, and the amplifier 1
3, an A / D converter 14, and a signal processing unit 15. A subject image incident through the photographing lens 11 is captured by the image sensor 12. The electric signal obtained by this imaging is amplified by an amplifier 13, converted into a digital signal by an A / D converter 14, subjected to predetermined signal processing by a signal processor 15, and then stored in the image memory 3 as image data. It is memorized.

The encryption processing unit 6 has first, second and third authenticator creating means 21, 22 and 23. The first authenticator creating unit 21 receives the file format converted by the file format converting unit 5 and applies a predetermined function such as a hash function to the image data included in the file format, thereby obtaining the message digest MD. And a message digest creation unit 24 that creates the message digest MD.
And a message authenticator MAC which is encrypted using a secret key K _C stored in advance in the header section and stored in a header section.

The second authenticator creating unit 22 extracts image data from the file format created by the first authenticator creating unit 21 and outputs the image data to the image display unit 4. A message digest creation unit 27 for creating a message digest MD by applying a predetermined function such as a hash function to the image data output from the data extraction unit 24; and a secret key memory for storing the created message digest MD. 16 has an authenticator creating unit 28 that creates a message authenticator MAC by encrypting using a secret key K _C stored in advance.

The message authenticator M created by the first authenticator creating means 21 and the second authenticator creating means 22
The AC is input to the authenticator judging section 29, and the authenticator judging section 29 judges whether or not the two match, and when the two do not match, judges that the data has been replaced and discards the image data. The unit 30 discards the image data.

On the other hand, the judgment result of the authenticator judgment unit 29 is the first
When the message authenticator MACs created by the authenticator creating unit 21 and the second authenticator creating unit 22 match, the gate unit 31 is opened, and the file storing the image data and the message authenticator MAC is stored. The format is input to the third authenticator creating means 23.

The third authenticator creating means 23 applies a predetermined function such as a hash function to all data including the image data and the message authenticator MAC based on the file format input from the gate unit 31. A message digest creating unit 32 for creating a message digest MD,
An authenticator creating unit 34 that encrypts the digest MD as a third-party secret key input unit using a third-party secret key K _P3 input from the IC card reader 33 to create a message authenticator MAC2.

The message authenticator MAC2 created by the third authenticator creating means 23 is stored in the header recording unit 35.
The message authentication code MAC2 is stored in the image header by the header recording unit 35, and the file format created in this way is stored in the filing management unit 36.
And performs file management for the created image file in the file format.

Such an image file is stored in the removable storage medium 38 under the control of the storage medium control unit 37 and is carried through the communication line 40 while being carried, or under the control of the communication control unit 39. A tampering detection device 50 is used to detect whether tampering has occurred on the way.

That is, the image file stored in the storage medium 38 attached to the tampering inspection device 50 is read out to the filing management section 52 under the control of the storage medium control section 51. Alternatively, the image file is sent to the filing management unit 52 via the communication line 54 under the control of the communication control unit 53. In the filing management unit 52,
The image file is separated into MAC and image data (this image data may include header information such as JPEG or TIFF in addition to the image data itself).
Is input to the first decoding unit 55, and the image data is input to the message digest creation unit 56.

The first decryption unit 55 decrypts the message authenticator MAC by using the public key K _P3P corresponding to the third party's secret key K _P3 stored in the public key memory 57 in advance, and Decrypts the message authenticator MC1 and the image data encrypted with the secret key K _P of
8 and the public key memory 59
By decoding the message authentication code MAC1, decrypts the message digest MD using the public key K _CP to be prestored camera secret key K _C and a pair of the.

On the other hand, the image data separated from the image file is supplied to a message digest creating section 56, and creates a message digest MD by applying a predetermined function such as a hash function.

Then, the message digest MD decrypted by the second decryption unit 58 and the message digest MD created by the message digest creation unit 56 are input to the digest determination unit 60, and are input by the digest determination unit 60. When the two message digests MD match, it is determined that tampering has not been performed halfway, and a normal message indicating that tampering has not been performed is displayed on the display unit 61. It is determined that there has been tampering, and an abnormal message indicating that tampering has occurred is displayed on the display unit 61.

Next, the operation of the above embodiment will be described.

First, a desired subject is photographed by the image pickup device 2, and an image of the subject is incident on the image pickup device 12 through the photographing lens 11, and is converted into an electric signal by the image pickup device. A /
The digital signal is converted into a digital signal by the D converter 14, and the digital signal is subjected to predetermined signal processing by the signal processing unit 15 to form image data, which is stored in the image memory 3. The image data stored in the image memory 3 is displayed on a liquid crystal display or the like by being input to the image display unit 4.

On the other hand, the image data stored in the image memory 3 is read out by the file format conversion unit 5, and the file format conversion unit 5 converts the image data such as standard JPEG, TIFF or the like as shown in FIG. The data is converted into a predetermined file format in which a header is added to the data, and is input to the first authenticator creating means 21.

In the first authenticator creating means 21, a predetermined function such as a hash function is applied to the image data by the message digest creating unit 24, as shown in FIG.
Create a message digest MD shown in (b),
Next, in the authenticator creating unit 25, the message digest MD is encrypted using the camera secret key K _C stored in the secret key memory 16 in advance to create the message authenticator MAC1 shown in FIG. Message authenticator MAC
Is stored in the header section to form the file format shown in FIG.

The file format formed by the first authenticator creating means 21 is the same as that of the second authenticator creating means 22.
The image data is extracted by the image data extracting unit 26 and sent to the image display unit 4. The image display unit 4 replaces the image data from the image memory 3 with the first authenticator creating unit 21. The passed image data is displayed.

Therefore, a third party can check whether or not the image displayed on the image display unit 4 and the subject image captured by the imaging device 2 match.

At this time, the image data sent from the image data extraction unit 26 to the image display unit 4 is input to the message digest creation unit 27, and the message digest M
D is created and input to the message authenticator creating unit 28, which is encrypted using the camera secret key K _C stored in the secret key memory 16 to generate the message authenticator M.
An AC is created.

Then, the newly created message authenticator MAC and the message authenticator MAC1 created by the first authenticator creating means 21 are input to the authenticator judging section 29, and whether or not the two match each other is determined. If the two do not match, it is determined that the image data has been tampered with or replaced, and the image data discarding unit 30 discards the image data. For this reason, falsification of the falsified or replaced image data can be reliably prevented.

If the result of the authentication by the authenticator judging section 29 matches the message authenticators MAC1 and MAC created by the first and second authenticator creating means 21 and 22, a normal image without tampering or replacement is obtained. It is determined that the data is data, and the file format created by the second authenticator creating unit 22 is input to the third authenticator creating unit 23 via the gate unit 31.

In the third authenticator creating unit 23, the message digest creating unit 32 applies a predetermined function such as a hash function to all data in the file format created by the second authenticator creating unit. To create a message digest MD2, and then a message authenticator creating unit 34 creates a message digest M2.
D2 is encrypted using a third-party secret key K _P3 input from an IC card reader 33 serving as a third-party secret key input means to create a message authenticator MAC2.

Then, the created message authenticator MA
C2 is updated and stored in the header of the file format to create a final file format, which is stored as an image file in the filing management unit 36 in the storage medium 38 by the storage medium control unit 37, and stored in the storage medium 398.
Is set in the tampering inspection device 50 or the communication control unit 39
And transmits it to the falsification inspection device 50 via the communication line 40.

In the tampering inspection device 50, the storage medium 38
Or the image file input via the communication lines 40 and 54 is stored in the filing management unit 52, and the image file is read from the filing management unit 52,
The image data and the message recognizer MAC are separated, and a message digest MD is created for the image data by applying a predetermined function such as a hash function in the message digest creating unit 56, and the message authenticator MA is created.
For C, the first decryption unit 55 decrypts the message authenticator MAC1 and the image data by using the public key K _P3P paired with the secret key K _P3 of the third party to decrypt the message authenticator MAC1. The message digest MD is decoded by being input to the second decoding unit 58.

Then, the decrypted message digest MD and the message digest M created by the message digest creating unit 56 based on the image data
D is input to the digest determination unit 60, and if the two match, it is determined that the image data is normal image data that has not been tampered with, and a message indicating normality is displayed on the display unit 61 together with the image data. Is displayed.

On the other hand, the decrypted message digest MD and the message digest MD created by the message digest creation unit 56 based on the image data.
If they do not match, it is determined that tampering has been performed, and a message indicating that the image data is abnormal is displayed on the display unit 61 together with the image data.

As described above, according to the above embodiment, the falsification detection data (MAC) is created from the image data by using the encryption key in the camera, and the falsification detection data is stored in the image file, for example, the header of the image. A file format is formed by writing the information in the information, and the image data of the formed file format is displayed on the image display unit 4 so that a third party can confirm the authenticity of the image data. Here, the third party is preferably a public figure such as a notary public, a police officer, a public prosecutor, but is not limited to this, and may be another person other than the photographer.

In this case, since the image data is confirmed by a third party at the shooting site, another image data or file format is put on the output side of the image pickup apparatus 2 or the output side of the file format conversion unit 5 to convert the data. When the replacement has been performed, the third party compares the image displayed on the image display unit 4 with the subject, so that it is possible to visually recognize that the third party has committed an improper act such as replacement of data. Filing of unauthorized data can be reliably prevented.

Further, at this time, a message digest MD is created for the image data to be displayed on the image display unit 4, and a message authenticator MAC is created by encrypting the message digest MD with the secret key K _C of the camera. By comparing the message authenticator MAC1 created by the first authenticator creating unit 21, even a small tampering can be reliably detected.

After that, the third authenticator creating means 23 applies a predetermined function such as a hash function to all data in the file format to apply the message digest MD2.
Is created, and the created message digest MD2
The third party encrypts the message using the secret key K _P3 of the third party to create a final message authenticator MAC2, forms a formal file format, and saves it as an image file. Unless the authentication is performed, the image file cannot be saved, and highly reliable image data can be saved.

For the stored image file, the falsification checking device 50 uses the public key K _P3P corresponding to the third party's secret key K _P3 from the image file to send a message.
The digest MD2 is decrypted, and the decrypted message digest MD2 is further added to the camera secret key K.
By decrypting the message digest MD1 using the public key K _CP corresponding to _C , and comparing this with the message digest MD created from the image data,
It is possible to reliably check whether the image data of the image file is normal.

In the above embodiment, the first authenticator creating means 21 and the second authenticator creating means 22 use the camera secret key K _C stored in the secret key memory 16 in advance to send a message. Although the case where the authenticator MAC is created has been described, the message digest DM is encrypted by using a recording medium such as an IC card in which the photographer's secret key K _P is registered separately from the message authenticator MAC, and the message digest is separately created. By recognizing and creating a MAC _P and storing it in the header, the two message authenticators MA encrypted with the camera's secret key K _C and the photographer's secret key K _P
C may be stored in the header portion. In this case, the tampering checking device 50 individually decrypts both message authenticators MAC, decrypts the message digest MD, and performs the decryption based on this and the image data. The created message
The tampering inspection may be performed by comparing with the digest MD.

In the above embodiment, the image data stored in the image memory 3 is converted into a file and then input to the first authenticator creating means 21. However, a digital watermark is added to the image data. By forming image data and inputting the image data to the first authenticator creating means 21, an image file with higher credibility can be stored.

[0049]

As described above, according to the first aspect of the invention, the image data captured by the image capturing unit is encrypted by the encryption processing unit using the secret key of the third party.
The image data can be encrypted after being confirmed by a third party, and the authenticity of the image data can be authenticated by the third party, thereby reliably preventing the image data from being replaced or falsified. The effect that it can be obtained is obtained.

According to the second aspect of the present invention, an encrypted message authenticator is created by the first authenticator creating means based on the image data captured by the imaging section, and a file format to which the encrypted message authenticator is added. Is displayed on the image display section,
A third party confirms the message authenticator based on the image data to be displayed at this time, and creates a message authenticator by the second authenticator creating means, and the message authenticator created by the first authenticator creating means. Can be prevented from being tampered with, and the third party secret key whose image has been confirmed by the third authenticator creating means can be input by the third party secret key input means. The image data and the first
Since the message authenticator is created based on the data including the first message authenticator created by the authenticator creating means, the third party confirms the authenticity of the captured image data and then creates the message authenticator again. Is performed, and an effect that image data with high credibility can be stored can be obtained.

Further, according to the third aspect of the present invention,
Since the secret key data registered in the recording medium such as the C card is input to the digital camera, the secret key data can be securely viewed without being seen by another person.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital proof camera system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation of the embodiment;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 digital evidence camera 2 imaging device 3 image memory 4 image display unit 5 file format conversion unit 6 encryption processing unit 21 first authenticator creating unit 22 second authenticator creating unit 23 third authenticator creating unit 24 message・ Digest creating unit 25 Message authenticator creating unit 26 Image data extracting unit 27 Message digest creating unit 28 Message authenticator creating unit 29 Authenticator judging unit 30 Image data discarding unit 32 Message digest creating unit 33 Third party secret key input Means 34 Message authenticator creation unit 50 Tamper checking device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H04N 101: 00 H04N 101: 00 F term (Reference) 5B017 AA01 BA07 CA15 CA16 5C022 AA13 AB68 5C076 AA14 BA06 5J104 AA08 LA03 LA04 LA05 NA27 PA00 9A001 EE02 EE03 EE04 EE05 KK16 KK31 LL03

Claims (3)

[Claims] 1. A digital proof camera system for detecting tampering of image data obtained by capturing an image of a subject with a camera, an imaging unit for capturing an image of the subject, and a third party inputting a secret key of the third party. A digital camera comprising: secret key input means; and an encryption processing unit for creating tampering detection data using the image data obtained by the imaging unit, a secret key of a third party, and an encryption key stored in advance. A falsification detection unit that decrypts the falsification detection data using a decryption key corresponding to the encryption key, and detects whether or not the image data is falsified based on the result of the decryption. A digital proof camera system, characterized in that: 2. The message processing device according to claim 1, wherein the encryption processing unit creates a message digest using a predetermined function based on the image data obtained by the imaging unit, encrypts the message digest using an encryption key, and authenticates the message. First authenticator creating means for creating an authenticator, image display means for displaying image data on an image display unit after creating a message authenticator by the authenticator creating means, and image data displayed by the image display means A message authenticator that creates a message digest based on the above, and encrypts the message digest using an encryption key to create a message authenticator; and a message created by the first and second authenticator creating means. An authenticator judging means for comparing the authenticators to determine whether they match each other, and destructing the image data taken by the image pickup unit when the judgment result of the authenticator judging means does not match. When the discrimination result of the image data discarding means to be discarded coincides with the authenticator discriminating means, a message digest is created based on the image data and the message authenticator after the image confirmation by the third party, and then the third 3. The digital proof camera system according to claim 1, further comprising third authenticator creating means for creating a final message authenticator by encrypting using a private key of the user. 3. The third-party secret key input means is configured to read secret key data from a recording medium in which an authenticated secret key is registered.
Or the digital evidence camera system of 2.