JP3788056B2 - Electronic still camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital data recording apparatus such as an electronic still camera, and aims to improve security when browsing and distributing recorded digital data. Electronic still camera About.
[0002]
[Prior art]
Input / digital conversion devices such as electronic still cameras can be used for copyrighted meanings, business records, evidence, etc. due to their ease of connection and transfer with personal computers. Therefore, editing and falsification can be performed relatively freely.
[0003]
On the other hand, for the security of communication and communication between parties, the main methods of encryption and electronic signature using public key method and shared key method for secret communication between parties and content certification communication In addition, there are processes such as digital watermarking, particularly for inserting copyright information, etc., in order to detect / suppress illegal duplication and partial use.
[0004]
With these existing methods, it is possible to take security measures for image, audio, and moving image data captured in a personal computer. However, these are processing programs on a personal computer, and there has been no method for guaranteeing the recording / generation of image and audio files as raw data.
[0005]
[Problems to be solved by the invention]
Therefore, with regard to raw data files such as digital image data, electronic still camera> PC, even in secret communication between parties, whether it is data that has been digitally signed and guaranteed by the Internet publication or the like. Since there was no guarantee in the route of the above and at the moment of shooting, it was not possible to determine whether or not the guarantee data was added when the illegally obtained image was taken into the personal computer.
[0006]
Also, when using digital images, etc. in business, the validity of the data must be proved, such as preventing falsification, and this is added at the time of raw data shooting (creation) Otherwise, it was a problem in terms of security and user convenience. Also, in the case of digital watermarking, considering that a photographed image is used as it is as a copyrighted work, there is a similar problem because information cannot be entered when data is created.
[0007]
Therefore, the present invention Captured image data Can prevent falsification, duplication, partial use and unauthorized use Electronic still camera The purpose is to provide.
[0008]
In order to achieve the above object, an electronic still camera according to the first aspect of the present invention includes an image pickup means, an ID image storage means for storing a thumbnail of a specific image picked up by the image pickup means as an ID image, and a device-specific device at the time of manufacture. Written as a unique value Device unique ID storage means for storing the device unique ID; A key generation unit that generates a public key and a secret key by a public key cryptosystem using the ID image and the device unique ID at the time of shooting by the imaging unit, and additional information regarding the image captured by the imaging unit. Generated and attached to the image data captured by the imaging means, storage means for storing the data generated by the additional information generation means as a captured image data body, and generated by the key generation means. The captured image data body stored in the storage means is encrypted with the private key, and the electronic signature means for generating electronic signature data, the captured image data body stored in the storage means, and the electronic signature means are generated. The electronic signature data, the public key generated by the key generation means, and the public information that can be disclosed about the data file. Because, characterized by comprising a viewing file generation means for generating a viewing files.
[0009]
Moreover, as a preferable aspect, for example, as in claim 2, in claim 1, Electronic still camera And decrypting means for decrypting the electronic signature data attached to the browsing file with the public key added to the browsing file, and attached to the browsing file Captured image When the data body and the data restored by the decryption means are compared and both match, Captured image If it is determined that the data itself has not been tampered with and the two do not match, Captured image Judgment means for judging that the data body has been falsified and attached to the browse file Captured image Of the data body Captured image And display means for displaying a result of the determination by the determination means.
[0010]
Moreover, as a preferable aspect, for example, as in claim 3, the claim 1 Electronic still camera In the above Captured image Before the data body is encrypted, Captured image Feature data extraction means for extracting and digesting feature data from the data body, and the electronic signature means uses the secret key generated by the key generation means to convert the data digested by the feature data extraction means. The digital signature data is generated by encryption.
[0014]
Moreover, as a preferable aspect, for example, a claim 4 As described, the claim 1 Electronic still camera The distribution partner information storage means for storing identification image data preset by the distribution partner as identification information for specifying the distribution partner for each distribution partner, and the identification image data stored in the distribution partner information storage means And a delivery destination selection means for selecting a delivery partner of the browse file generated by the browse file generation means.
[0015]
Moreover, as a preferable aspect, for example, a claim 5 As described, the claim 1 Electronic still camera A distribution partner information storage means for storing identification image data preset by the distribution partner and a public key distributed in advance by the distribution partner as identification information for specifying the distribution partner for each distribution partner; The digital signature data generated by the signature generation means includes encryption means for encrypting with the public key of the distribution partner stored in the distribution partner information storage means, and the browsing file generation means includes the encryption The encrypted data encrypted by the means and the publicly available public information are collected and a browsing file is generated.
[0016]
Moreover, as a preferable aspect, for example, as in claim 6, 5 Described Electronic still camera The public information includes at least image data that can be disclosed.
[0017]
Moreover, as a preferable aspect, for example, a claim 7 As stated 6 Described Electronic still camera The second decryption means for decrypting the browse file with its own private key Equipped with The decrypting means decrypts the electronic signature data attached to the restored data with the public key attached to the data restored by the second decrypting means.
[0018]
Moreover, as a preferable aspect, for example, a claim 8 As stated 7 Described Electronic still camera When the restoration by the second decryption unit fails, the determination unit determines that the browsing file has been obtained illegally, and the display unit is attached to the browsing file. Captured image Of the data body Image data picked up by the image pickup means At the same time, it is characterized by displaying publicly available image data included in the public information.
[0019]
Moreover, as a preferable aspect, for example, a claim 9 As described, claims 1 to Any of 9 Described Electronic still camera In the above, the public information is attached to the browsing file Captured image It is characterized by including file type information indicating whether the data body is an encrypted file, a file with a digital signature, or a file without security information.
[0020]
Moreover, as a preferable aspect, for example, a claim 10 As described, the claim 1 Electronic still camera Prior to generation of electronic signature data by the electronic signature means, Image data picked up by the image pickup means The digital watermarking means for inserting the public key generated by the key generating means as digital watermark information.
[0021]
Moreover, as a preferable aspect, for example, a claim 11 As stated 10 Described Electronic still camera The determination means includes a public key added to the browsing file and the browsing file. Captured image When comparing the public key embedded as digital watermark information in the data body and if both match, Captured image The data body is determined to be data from a valid distributor.
[0022]
In order to achieve the above object, an electronic still camera according to a twelfth aspect of the present invention includes an imaging unit, an ID image storage unit that stores a thumbnail of a specific image captured by the imaging unit as an ID image, and a device at the time of manufacture. Written as a unique unique value Device unique ID storage means for storing the device unique ID; A key generation unit that generates a public key and a secret key by a public key cryptosystem using the ID image and the device unique ID at the time of shooting by the imaging unit, and additional information regarding the image captured by the imaging unit. Additional information generating means for generating and attaching to the image data captured by the imaging means, storage means for storing the data generated by the additional information generating means as a captured image data body, and for each distribution partner As identification information for specifying the identification information, a distribution partner information storage unit that stores identification image data preset by the distribution partner and a public key distributed in advance by the distribution partner, and a secret key generated by the key generation unit An electronic signature means for encrypting a captured image data body stored in the storage means to generate electronic signature data; and First, the stored captured image data main body, the electronic signature data generated by the electronic signature unit, the public key generated by the key generation unit, and the publicly available public information about the data file are collected to generate a browsing file. 1 browsing file generation means; and an encryption means for encrypting the browsing file generated by the first browsing file generation means with the public key of the distribution partner stored in the distribution partner information storage means; File type information indicating the type of the file body, encrypted data encrypted by the encryption means, and public image data that can be disclosed, and a second browsing file generation means for generating a browsing file for a specific partner; It is characterized by comprising.
[0023]
In order to achieve the above object, an electronic still camera according to a thirteenth aspect of the present invention is an image pickup means, an ID image storage means for storing a thumbnail of a specific image picked up by the image pickup means as an ID image, and a device at the time of manufacture. Written as a unique unique value Device unique ID storage means for storing the device unique ID; A key generation unit that generates a public key and a secret key by a public key cryptosystem using the ID image and the device unique ID at the time of shooting by the imaging unit; and image data captured by the imaging unit, A digital watermark means for inserting the public key generated by the key generation means as digital watermark information, and additional information relating to the image captured by the imaging means are generated, and attached to the data subjected to the digital watermark by the digital watermark means Additional information generating means for storing, storage means for storing data generated by the additional information generating means as a captured image data body, and a captured image stored in the storage means by a secret key generated by the key generating means An electronic signature means for encrypting a data body and generating electronic signature data; a captured image data body stored in the storage means; A browsing file generation unit that collects the electronic signature data generated by the electronic signature unit, the public key generated by the key generation unit, and public information that can be disclosed about the data file, and generates a browsing file. It is characterized by.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
First, prior to the embodiment, the RSA public key encryption method among the public key encryption methods assumed by the present embodiment will be briefly described. RSA public key cryptography is a method proposed in 1979 by MIT (Massachusetts Institute of Technology) Riverst, Shamir, Adelman. The RSA public key encryption is described in US Pat. No. 4,405,829 (encrypted communication system and method).
[0025]
In this embodiment, the encryption method is not particularly limited as long as it is an encryption method that can perform both encryption and digital signature using the public key method, even if it is not RSA encryption. Further, as far as the function of exchanging encrypted files is concerned, it is possible to deal with common key encryption (DES, FEAL, etc.) in almost the same manner as in this embodiment. Here, FIG. 1 is a flowchart for explaining the RSA public key cryptosystem. Hereinafter, the RSA public key cryptosystem will be described with reference to the flowchart of FIG.
[0026]
First, in the encryption process, two large prime numbers p and q are selected in step A10. In the present embodiment, prime numbers p and q different for each user are generated using a unique ID and random number for each user. Next, in step A12, n = pq is calculated. At this time, n is set to be larger than M described later. Next, in step A14, φ (n) = (p−1) (q−1) is calculated, and in step A16, a natural number e (1 <e <n) that is relatively prime with φ (n) is selected. In step A18, n and e are disclosed.
[0027]
Next, in step A20, a natural number d (1 <d <) that satisfies e ^ d≡1 (mod.φ (n)) is obtained. The pair (n, e) is a public key and d is a secret key. The prime numbers p and q are secrets and are values that should never be disclosed. It is known that it is difficult to obtain the secret key d from the public key (n, e). In step S22, it is determined whether or not encryption is performed. If encryption is performed, the number of encoded plaintexts (messages) is set to M (1 ≦ M <n) in step A24, and the public key (e, m), the encryption code C is generated by the calculation C = M ^ e (mod.n).
[0028]
In the decryption process, in step B10, M = C ^ d (mod.n) is calculated according to a coefficient n determined by the relationship between the encrypted code C, the secret key d, and e and d. To obtain the message M. Since the secret key d is known only by the receiving party, only the receiver can decrypt it.
[0029]
Note that the encryption method using the public key provided by the present portable device has the following characteristics. [About public key encryption]
1. Separate encryption key and decryption key.
2. Encryption is very easy.
3. Decrypting without a key is virtually impossible, even if the mechanism is known.
4). The encryption key is made public (public key). The decryption key is a secret (secret key).
5. By adding the data encrypted with the private key to the text and confirming it with the public key, digital signature is possible to prevent tampering and spoofing while keeping the text data open (however, all public keys are digital Does not support signatures).
[0030]
B. First embodiment
Hereinafter, an embodiment of the present invention will be described as an example applied to an electronic still camera with reference to the drawings.
[0031]
FIG. 2 is a block diagram showing the configuration of the electronic still camera according to the first embodiment of the present invention. In the figure, a photographing system 1 includes a CCD that converts a still image formed through a lens into an electric signal, an A / D converter that converts the still image signal into digital data (hereinafter referred to as image data), and the like. The image data is supplied to the CPU. The image recording memory 2 stores image data (luminance signal and color signal) compressed by a compression method such as a JPEG (Joint Photographic Coding Experts Group) method by a compression / expansion unit (not shown). The image recording memory 2 may be a replaceable medium such as a flash memory card.
[0032]
The CPU 3 controls the operation of the entire electronic still camera by executing a program. The ROM 5 stores the program executed by the CPU 3. The work RAM 4 is used as a working area for the CPU 3. The timer unit 6 counts the clock to measure the date and time and supplies it to the CPU 3. The display device 7 is composed of a liquid crystal display, and displays video shot by the shooting system (real-time display) and image data after shooting stored in the image recording memory 2.
[0033]
The nonvolatile memory 8 stores information including important components of the present invention. As described above, when the image recording memory 2 is replaceable, it is necessary that the block is a separate block as shown in this configuration diagram. The nonvolatile memory 8 related to the security processing is divided into a security memory 8-1 that stores security information regarding the device itself and a public key bundle memory 8-2 that manages the public key of an external user.
[0034]
As shown in FIG. 3A, the security memory 8-1 includes its own device unique ID, ID image, password information required for device use, encrypted secret key data used for encryption, and Public key data is stored. The device unique ID is a unique value written in advance at the time of manufacturing, and is a random value, a manufacturing number, or the like. The ID image is attached to image data to be transferred in order to make the receiving user recognize the source user in file transfer / communication between users.
[0035]
As the ID image, an ID indicated by the image is used. For example, an image of a user's face, a favorite illustration, a still life related to a hobby, or the like is used. As a storage form of the ID image, it is converted into a small image (thumbnail) such as 16 × 16 or 32 × 32 and handled in order to reduce transfer and memory capacity. Since the original information is lost because it is converted into a thumbnail, the thumbnail conversion is effective even in the sense that the source of the random number sequence is not traced. The password information is for performing user authentication for security-related operations and overall camera operations. The data in the security memory 8-1 is recorded when the user first possesses this device, and is not basically rewritten thereafter.
[0036]
As shown in FIG. 3 (b), the public key ring memory 8-2 encrypts image data for each party to which the image data is transmitted and can restore the image data encrypted only to the other party. It stores a public key used when encrypting image data, an ID image, and a device ID for specifying a partner device. The ID image is used to select a receiving user when transmitting data in file transfer / communication between users. Information in these public key ring memories 8-2 is added and updated as needed.
[0037]
Also, in order to keep the guarantee data at the time of shooting unique, secret keys and passwords cannot be transferred. Even in the storage format on the memory, encryption is performed in combination with the program, and the hardware It is desirable to be strong against malicious information stealing, such as by decomposition.
[0038]
The switch unit 9 includes a shutter switch, a display image feed switch, a cursor key, and the like, and the on / off state of each switch is detected by the CPU 3. The communication unit 10 is a communication unit such as an interface that transfers image data to a personal computer or the like, or a modem that transmits image data to an external device via a communication line.
[0039]
C. Operation of the first embodiment
The overall operation will be described below with reference to the flowcharts shown in FIGS. C-1. Security information generation processing
When power is supplied to the device, first, initialization is performed in step S10, the contents of the security memory 8-1 are confirmed in step S12, and it is determined in step S14 whether or not it is the first activation. . In the case of the first activation, the user must generate user-specific security information before using the device. As described above, in order to generate the RSA encryption system, it is necessary to generate an ID, a secret key d, a public key e, and a password for managing them. As for the ID, in this embodiment, a combination of a device unique ID and a user ID (ID image) is used.
[0040]
The purpose of combining the two pieces of ID information in this way is to perform management such as encrypting the device unique ID. For example, all the processing methods related to the present invention are abused and forgery from the camera level is performed. In this case, it is possible to add another level of security to detect whether the device unique ID is a valid value and to add the user ID in the file transfer / communication between users. This is because an image data transmission source user can be easily recognized by a receiving user.
[0041]
As described above, the device unique ID is written in advance in the security memory 8-1 shown in FIG. Further, the user generates a user ID. In this embodiment, an image (ID image: thumbnail, 16 × 16) preset by the user is used as the user ID. As a result, the input of a character string by a key operation can be omitted as much as possible, and the ID becomes easier to see than the character string.
[0042]
If it is determined in step S14 shown in FIG. 4 that the activation is the first time, first, the ID image photographing request mode is set. In step S16, an ID image (for example, a user's face, favorite illustration, still life related to hobbies, etc.) is photographed and compressed by a predetermined compression method, for example, to be a 16 × 16 dot thumbnail image.
[0043]
Next, in step S18, a password is requested from the user. This password is used for user authentication for security-related operations and overall camera operations. Since the password needs to be repeatedly input when the device is used, image input cannot be used like an ID, and alphanumeric input using a key is required. However, if the user determines that device level security is not required, this password setting process can be omitted.
[0044]
Next, in step S20, a secret key e and a public key d are generated according to the following procedure. First, in accordance with step A10 shown in FIG. 1, processing for selecting two large different primes p and q is performed. For this,
f (device ID, image ID) = (p, q)
Key generation is performed by processing the function f.
[0045]
In this key generation algorithm, it is necessary to set a combination of relatively large prime numbers so that they do not overlap between different users, and it is usual to perform prime number generation processing using a random number generation mechanism for input data. If the algorithm is clarified, it is easy to forge the same key by generating pseudo-random numbers using mathematical formulas. For example, cryptographic software on a personal computer uses key input intervals, mouse coordinates, etc. The source of random sequences. In the present embodiment, the ID image itself is used as a random sequence generation source as a random sequence source that does not follow the deterministic process.
[0046]
Note that since the ID image has the luminance data as it is, the value varies depending on the photographing condition and the photographing target, and therefore processing such as performing a uniform variation of the value for each data block by applying a hash function described later. is required. If p and q are obtained, a public key e and a secret key d are generated according to the procedure described in step A12 and subsequent steps in FIG.
[0047]
In step S22, the ID image is thumbnailed and stored in the security memory 8-1, and in step S24, the password information, the public key e, and the secret key d are stored in the security memory 8-1.
[0048]
C-2. Shooting data guarantee information addition processing
Next, an operation for generating a file in which a digital signature is added in normal shooting and data contents are guaranteed at the time of shooting will be described.
[0049]
When the device is powered on, if it is not the first activation, the process proceeds from step S14 to step S26 shown in FIG. In step S26, it is determined whether the operation mode of the device is a REC (photographing) mode, a PLAY (playback) mode, or a communication mode. Here, when the REC mode is set or the REC mode is selected, the photographing process is performed in step S28, the digital signature is added in step S30, and then stored in the image recording memory 2. Then, the process returns to step S26.
[0050]
Here, FIG. 7 schematically shows how information such as a source image and date / time is used as a data file with a digital signature. As shown in the figure, the photographing data main body includes date and time information at the time of photographing, a device ID stored in the security memory 8-1, a photographer ID (ID image), and compressed image data. Note that the image data is compressed at the time of shooting. However, the present invention is not limited to this, and the entire image data may be compressed after encryption. First, feature data is extracted from the photographic data body with a hash function, and then the digested data is encrypted with a secret key to generate electronic signature data. Then, a final data file is composed of a header (identification, area information, etc.), a file type (content certification), a public key (recorder), the electronic signature data, and the photographic data body. The digesting method and the cryptographic calculation processing are omitted because they are well known in other documents. Here, the user's public key is also attached as information for signature confirmation.
[0051]
It should also be noted here that even a camera having such a security mechanism can only add its own digital signature only during shooting. Whether the data received from others is encrypted or has a digital signature, it is impossible in this embodiment to add a new digital signature. Therefore, if the security level of the device ID management is increased, it is automatically proved that the image having the device ID is always a captured image.
[0052]
Here, the security guarantee by the device unique ID will be described with reference to FIG. For example, assume that 65536 devices are managed. In this case, the device unique ID is represented by 16 bits (source), and is redundantly encoded in a larger numerical value, for example, a 32-bit numerical value to generate a 32-bit device unique ID. Therefore, even if the device unique ID is appropriately set, the probability that the device unique ID is valid is 1/65536. In the present embodiment, since the validity of the device ID is checked simultaneously with the digital signature check, it is almost impossible to simulate the device unique ID.
[0053]
C-3. Digital signature check, decryption and viewing of images
When the operation mode of the device is set to the PLAY (playback) mode or the PLAY (playback) mode is selected, in step S32 to step S42, the captured data is related to the file with security. Processing for browsing / manipulating / confirming is executed.
[0054]
First, in step S32, the data file designated by the display pointer is taken out. Next, in step S34, the type of the retrieved data file is determined with reference to the header area of the data file in FIG. In the present invention, since there are various security functions, this is performed by the processing in steps S34 to S40.
[0055]
Here, in the case of data with a digital signature, the process proceeds to step S36, and a check is performed by a process as shown in FIG. This check applies to data files of other people that came from outside through memory cards or communications, as well as data files that you photographed (things you photographed or obtained from past data via a card or communications). Is similarly performed.
[0056]
That is, the electronic signature data is decrypted using the public key attached to the data file, and the digested data is acquired. In addition, feature data is extracted from the data body of the data file with a hash function or the like, and digested data is acquired. Here, if any of the data body, header, or signature is tampered or edited somewhere in the data, the above two data do not match, and tampering, editing, etc. If not, the two data match. Further, date / time information, device ID, photographer ID (ID image), and image data are cut out from the data body.
[0057]
In addition, since the public key information is added to the data file with the digital signature of the present embodiment, in order to be able to perform encryption processing on the other party who registered the public key in step S38, as necessary, The recorder's public key attached to the data file is registered in the public key ring memory 8-2 shown in FIG.
[0058]
Next, display according to the check result is performed in step S42. As a result of the check in step S36, if the digested data acquired from the electronic signature data matches the digested data acquired from the data body, that is, if consistency is obtained, additional information is displayed as additional information. As shown in FIG. 12 (a), together with the image data, a message indicating that the content has been proved (“signature check OK!”), Authentication contents, shooting date, device ID, and photographer ID image are displayed. .
[0059]
These additional information can be turned ON / OFF by operation. In the case of intentional or intentional editing or format information forgery, the display is as shown in FIG. Since the image data and the additional information are stored as they are as shown in FIG. 8, they can be displayed, but once falsified, they cannot be matched with the digital signature. A warning is displayed. In addition, even if the file has consistency, it is not possible to have a unique device ID, or whether it is inconsistent with an ID registered in the past (the ID image is the same, the unique device ID is different, etc.). A check is also performed. If there is a mismatch, a display as shown in FIG.
[0060]
On the other hand, if it is determined by the file header determination in step S34 that the file is an encrypted file, if it is an encryption addressed to itself, it should be encrypted with the public key published by itself. As shown in FIG. 11, the decryption process is performed with its own secret key. The generation of the encrypted file will be described later. From the header (identification, area information, etc.), file type (encryption), encrypted data body (addressed to a specific partner), dummy data body (public image data addition) Become. In the decryption process of the encrypted file, first, the encrypted data body of the encrypted data file is decrypted with its own private key to generate a data file including the header, the public key, the electronic signature, and the data body.
[0061]
Here, if the decryption is successful, since the digital signature is basically attached to the encrypted file, the process proceeds to steps S36 and S38 as digital signature check processing. If the decryption with the public key attached to the data file is successful, in step S42, additional information as shown in FIG.
[0062]
On the other hand, if the encrypted data file is destroyed or has been tampered with in the middle, as shown in FIG. 11, the decryption with the private key fails, so the processing of steps S36 and S38 is skipped. Is done. In this case, the display is as shown in FIG. In the present embodiment, as shown in FIG. 10 or FIG. 11, when the encrypted file is generated, it is possible to embed public image data indicating warning information or advertisement in the dummy data body (details). In the example shown in FIG. 12E, a message that the file is broken or an encrypted file that is not addressed to the user is displayed, and public image data is displayed.
[0063]
Also, for image data without security information, such as when the format is converted from image data without normal security guarantee, or when an image editing tool that has a function to remove security information when editing is performed, etc. Directly proceeds to step S42, and as shown in FIG. For the added data, additional information such as date information is displayed without guarantee.
[0064]
C-4. Image data encryption, etc.
When the image data is displayed in step S42 described above, the process proceeds to step S44 shown in FIG. 6, where the key operation is determined, and encryption or other processing is performed on the stored image in accordance with the determined key operation.
[0065]
If the operation / edit key is operated, the process proceeds to step S46, and edit processing such as movement of the display pointer, deletion, display image sending, and return operation is performed. The details are the same as those of a normal digital electronic still camera with a monitor, and the description thereof will be omitted.
[0066]
When a key operation for the encryption process is performed, the encryption process is started for the currently displayed image. First, since the public key of the recipient is required for encryption, in step S48, the selection screen for the ID image of another user stored in the public key ring memory 8-2 is displayed (see FIG. 13). (Refer to), and a destination ID is selected from the images. In addition, it is also possible to encrypt for yourself as encryption. In this case, even if secret image data is mistakenly sent through a memory card or communication, it cannot be restored to others.
[0067]
When the selection is completed, the public key of the ID user is extracted from the public key ring memory 8-2, and the encryption process shown in FIG. 10 is performed in step S50. That is, the data file to which the digital signature created in step S30 described above is added is encrypted with the public key of the destination partner to generate encrypted data. Next, a new (encrypted) data file is generated from the header (identification, area information, etc.), the encrypted data body, and the dummy data body. Further, if necessary, an image for publication is embedded in a dummy data book. In the illustrated example, the telephone number of the data inquiry destination is embedded with image data. The data file that has been encrypted is stored in the image recording memory 2 as a new file in step S52.
[0068]
C-5. Communication processing
Further, in step S26 shown in FIG. 5, if the operation mode of the device is set or selected as the communication mode, the process proceeds to step S54 shown in FIG. As described above, a data file is transmitted (or received) to another camera or personal computer using a serial port or a built-in modem. The data file path with the digital signature includes, for example, disclosure to the Internet (HTTP, FTP server) 21, personal computers 22 and 24, and electronic still camera 23.
[0069]
In the personal computer 22, after restoring the data file with the digital signature from the electronic still camera 20, the image data is edited and altered, and further transmitted to the electronic still camera 25 and the personal computer 26. In this case, in the personal computer 25 or the electronic still camera 26, since the data file has been tampered with, the digital signatures do not match and the image data and the additional information can be displayed, but a warning is displayed. Further, since the electronic still camera 23 receives the data file as it is transmitted from the electronic still camera 20, the image data and the additional information whose contents are guaranteed are displayed. Further, the personal computer 24 transmits the data file transmitted from the electronic still camera 20 to the electronic still camera 27 without any operation. In this case, the contents are guaranteed in the same manner as the electronic still camera 23. The displayed image data and additional information are displayed.
[0070]
The path of the encrypted digital signature-added data file includes, for example, an electronic still camera 27 and personal computers 28 and 29. In this case, the electronic still camera 20 needs to obtain and register the public key of the other party to be transmitted in advance. In other words, a user who wants to receive an encrypted data file needs to publicize his / her public key in advance. In the illustrated example, the electronic still camera 27 and the personal computer 29 correspond to this.
[0071]
The data file is encrypted with the public key of the transmission destination by the electronic still camera 20 and transmitted to the counterpart device. Since the electronic still camera 27 or the personal computer 29 can naturally decrypt the data file encrypted with its own public key, the image data and the additional information whose contents are guaranteed are displayed. On the other hand, the personal computer 28 cannot decrypt a data file not addressed to itself.
[0072]
Note that the signature check function of this embodiment can be realized as viewer software on a personal computer as it is. In this file format, the public key is embedded in the file for easy operability. However, since the registration of the first public key for a certain user is important for security, the exchange of the public key may be performed by another route without being embedded in the file. It is also effective to use a scheme such as a fingerprint key (Key Finger Print) in order to check the validity of the public key itself.
[0073]
Here, the security guarantee against malicious information stealing by hardware disassembly will be described. In the present embodiment, device-specific IDs, ID images, private key data, and public key data are stored in the security memory 8-1 as security-related information, as shown in FIG. Even if the hardware is disassembled and the secret key data and public key data are obtained illegally and the technique for extracting the random number sequence is known, as shown in FIG. Since there is no image, a regenerated counterfeit copy is not possible. Also, it is almost impossible from the encryption algorithm to forge and copy the secret key by inverse calculation from the information that is disclosed. Furthermore, as shown in FIG. 15C, even if the device unique ID and ID image are illegally obtained and the secret key and public key are forged, the public key match / mismatch is checked based on the device unique ID. Therefore, complete counterfeit replication is impossible unless both sides match.
[0074]
In the first embodiment, security information can be added at the same time as recording by being incorporated in the device, and a security code providing means is incorporated in the device, which makes it difficult for the user to easily modify and analyze the information. is there.
[0075]
In the first embodiment, security information is added when recording an image of a digital electronic still camera. However, the present invention may be applied to general input devices that generate digital files, such as a voice recorder, a scanner, and a digital moving image photographing apparatus.
[0076]
D. Second embodiment
In the first embodiment described above, authentication information at the time of shooting is added in file exchange by encryption between parties or file disclosure for an unspecified number of people. This is effective for maintaining the evidence and correctness of the image, but in the second embodiment, the configuration is further effective for preventing duplication and partial use.
[0077]
On the other hand, especially in the protection of copyright and the like, there is “digital watermark” as an effect of suppressing duplication and partial use. Although there are various methods for digital watermarking, it is possible to insert digital watermark information at the time of recording an image, as with a digital signature or the like. The effect of this is shown in FIG. In the illustrated example, the electronic still camera 20 inserts “02934857367” as a digital watermark into the image data of the data file with the digital signature and transmits it to the personal computer 22. Here, it is assumed that the personal computer 22 takes out the image data portion, duplicates and edits it, generates another file, and sends it to the Internet and other devices. Then, the leaked data file is taken in by another electronic still camera 23 or a personal computer 24, and the suspicion of unauthorized use is checked. At this time, if the watermark information of the original data file matches the watermark information of the captured data file, it can be understood that the data file is illegally used. In this way, it can be seen that the image data portion of the data file with a digital signature can be extracted and detected even when it is illegally used.
[0078]
A method of simply using a digital watermark is to use the image data main body shown in FIG. 7 with the digital watermark inserted in the image data. In terms of the operation flow, step S30 shown in FIG. Only the “digital watermark information insertion process” is inserted before this process.
[0079]
In addition, as an advantage when this embodiment is applied to a digital electronic still camera, in a normal image, something like a copyright ID management company is required to add a digital watermark later on a personal computer. However, if the device ID information of the security memory 8-1 of FIG. 2 embedded in the device is used, the right ID check system can be facilitated.
[0080]
Next, FIG. 17 and FIG. 18 show a configuration when the digital watermark and the public key are used in a more advanced manner. In the encryption (watermarking process or electronic signature process) shown in FIG. 17, first, a public key (which may be a fingerprint key), which is information used for the electronic signature, is inserted into the compressed image data as watermark information. Next, date and time information, device ID, and photographer ID (ID image) are added to the image data (compressed and watermark-processed) to form a photographic data body. Then, the digital signature data is generated by encrypting the photographed data body with the secret key for the digested data. Furthermore, a final data file is generated from the header (identification, area information, etc.) / File type (content proof), public key, electronic signature data, and photographing data body.
[0081]
In the decryption shown in FIG. 18, first, the digital signature data is decrypted using the public key attached to the data file, and the digested data is obtained. Also, feature data is extracted from the data body of the data file by a hash function or the like, digested data is obtained, and compared with the restored digested data. Here, if any of the data body, header, or signature is tampered or edited somewhere in the data, the above two data do not match, and tampering, editing, etc. If not, the two data match. Further, the public key is extracted from the watermark information extracted from the image data of the data body, and compared with the public key attached to the data file, the consistency of the digital watermark content is checked. And if each comparison result is materialized, neither forgery nor tampering is performed.
[0082]
In this way, by adding the photographic data body, it is possible to check the digital signature and the consistency of the digital watermark content. In this case, in order to forge and tamper, it is necessary to break the public key cryptography and to remove and re-insert the digital watermark, thereby further improving the security level of content assurance.
[0083]
【The invention's effect】
According to the first aspect of the present invention, the thumbnail of the specific image picked up by the image pickup means is stored as an ID image in the ID image storage means. And the key When the image is taken by the image pickup means, the generation means Stored in the device unique ID storage means A public key and a secret key are generated by a public key cryptosystem using the device unique ID, and additional information regarding the image captured by the imaging unit is attached to the image data captured by the imaging unit by the additional information generation unit The captured image data body is stored in the storage means, and the electronic signature means is used to encrypt the captured image data body stored in the storage means with the secret key generated by the key generation means to generate electronic signature data. The captured image data main body stored in the storage means, the electronic signature data generated by the electronic signature means, the public key generated by the key generation means, and the public disclosure available for the data file by the file generation means Since the information was compiled and the final browsing file was generated, falsification and duplication of the captured image data, part The advantage is obtained that it is possible to prevent the use.
[0084]
According to the second aspect of the present invention, the decryption means decrypts the electronic signature data attached to the browse file with the public key added to the browse file, and the judgment means decrypts the digital signature data into the browse file. Attached Captured image When the data body and the data restored by the decryption means are compared and both match, Captured image If it is determined that the data itself has not been tampered with and the two do not match, Captured image Judging that the data itself has been tampered with and attached to the browse file Captured image Of the data body Captured image Since the judgment result by the judgment means is displayed on the display means together with the data, Captured image data The advantage is that tampering, duplication, and partial use can be prevented.
[0085]
According to a third aspect of the present invention, Captured image Before the data body is encrypted, the feature data extraction means Captured image When the feature data is extracted from the data body, digested, and the electronic signature data is generated, the electronic signature means generates the data digested by the feature data extraction means by the key generation means. Because it was encrypted with the private key Captured image data The advantage is that tampering, duplication, and partial use can be prevented.
[0089]
Claims 4 According to the described invention, for each distribution partner, identification image data set in advance by the distribution partner is stored in the distribution partner information storage unit as identification information for specifying the distribution partner, and the distribution destination selection unit performs identification. By specifying the image data, we selected the viewing file distribution partner. Captured image data The advantage is that tampering, duplication, and partial use can be prevented.
[0090]
Claims 5 According to the described invention, for each distribution partner, the identification image data set in advance by the distribution partner and the public key distributed in advance by the distribution partner as identification information for specifying the distribution partner in the distribution partner information storage means. The browsing file generation means stores the encrypted digital signature data generated by the electronic signature generation means using the distribution partner public key stored in the distribution partner information storage means. Thus, the encrypted data encrypted by the encrypting means and the publicly available public information are collected and a browsing file is generated. Captured image data The advantage is that tampering, duplication, and partial use can be prevented.
[0091]
Claims 6 According to the described invention, the public information is at least image data that can be disclosed. Captured image data The advantage is that tampering, duplication, and partial use can be prevented.
[0092]
Claims 7 According to the described invention, after the browsing file is decrypted with its own private key by the second decryption means, it is attached to the data restored by the second decryption means by the decryption means. The digital signature data attached to the restored data is decrypted with the public key Captured image data The advantage is that tampering, duplication, and partial use can be prevented.
[0093]
Claims 8 According to the described invention, when restoration by the second decryption means fails, the judging means judges that the browse file has been obtained illegally and is attached to the browse file. Image data picked up by the image pickup means At the same time, the displayable image data included in the public information is displayed on the display means. Captured image data The advantage is that tampering, duplication, partial use, and unauthorized use can be prevented.
[0094]
Claims 9 According to the described invention, the public information is attached to the browsing file. Captured image Since the file body information indicates whether the data body is an encrypted file, a file with a digital signature, or a file without security information, Captured image data The advantage is that tampering, duplication, partial use, and unauthorized use can be prevented.
[0095]
Claims 10 According to the described invention, prior to the generation of the electronic signature data by the electronic signature means, the electronic watermark means Image data picked up by the image pickup means Since the public key generated by the key generation means is inserted as digital watermark information, Captured image data The advantage is that tampering, duplication, partial use, and unauthorized use can be prevented.
[0096]
Claims 11 According to the described invention, the public key added to the browsing file and the browsing file Captured image When comparing the public key embedded as digital watermark information in the data body and if both match, Captured image Since the data body is determined to be from a valid distributor, Captured image data The advantage is that tampering, duplication, partial use, and unauthorized use can be prevented.
[0097]
According to the twelfth aspect of the present invention, the thumbnail of the specific image picked up by the image pickup means is stored as an ID image in the ID image storage means. And the key When the image is taken by the image pickup means, the generation means Stored in the device unique ID storage means A public key and a secret key are generated by a public key cryptosystem using the device unique ID, and additional information regarding the image captured by the imaging unit is attached to the image data captured by the imaging unit by the additional information generation unit The captured image data body is stored in the storage means, and the electronic signature data is generated by encrypting the captured image data body stored in the storage means with the private key generated by the key generation means by the electronic signature means. First, the captured image data body stored in the storage unit by the first browsing file generation unit, the electronic signature data generated by the electronic signature unit, the public key generated by the key generation unit, and the main data The publicly available public information about the file is collected to generate a browsing file, and then the browsing file is encrypted by an encryption unit. Encrypted with the public key of the distribution partner stored in the communication partner information storage means, and further, the second browsing file generation means encrypts the file type information indicating the type of the captured image data body, and the encryption means Since the final browsing file is generated by collecting the encrypted data and the public image data that can be disclosed, the advantage of preventing falsification, duplication, partial use, and unauthorized use of the captured image data Is obtained.
[0098]
According to the sixteenth aspect of the present invention, the thumbnail of the specific image picked up by the image pickup means is stored as an ID image in the ID image storage means. And the key When the image is taken by the image pickup means, the generation means Stored in the device unique ID storage means A public key and a secret key are generated by a public key cryptosystem using the device unique ID, the public key generated by the key generation unit is inserted as digital watermark information by the digital watermark unit, and the imaging is performed by the additional information generation unit Additional information relating to the image captured by the means is attached and stored in the storage means as the captured image data body, and then the image captured by the electronic signature means is stored in the storage means by the secret key generated by the key generation means. Encrypts the image data body, generates electronic signature data, and generates the captured image data body stored in the storage means, the electronic signature data generated by the electronic signature means, and the key generation means by the browsing file generation means The public key and the public information that can be made public about this data file, Since, captured tampering or duplication of image data, partial use, the advantage is obtained that it is possible to prevent unauthorized use.
[Brief description of the drawings]
FIG. 1 is a flowchart for explaining an RSA public key cryptosystem.
FIG. 2 is a block diagram showing a configuration of an electronic still camera according to the first embodiment of the present invention.
FIG. 3 is a conceptual diagram showing a data configuration of a nonvolatile memory 8;
FIG. 4 is a flowchart for explaining the operation of the electronic still camera.
FIG. 5 is a flowchart for explaining the operation of the electronic still camera.
FIG. 6 is a flowchart for explaining the operation of the electronic still camera.
FIG. 7 is a conceptual diagram for explaining a method for generating a data file with an electronic signature.
FIG. 8 is a conceptual diagram for explaining a method for restoring a data file with an electronic signature.
FIG. 9 is a conceptual diagram for explaining security assurance by a device unique ID.
FIG. 10 is a conceptual diagram for explaining an encryption method.
FIG. 11 is a conceptual diagram for explaining a method of restoring an encrypted data file with an electronic signature.
FIG. 12 is a conceptual diagram illustrating a display example.
FIG. 13 is a conceptual diagram illustrating an example of an ID image.
FIG. 14 is a conceptual diagram for explaining an example of a transmission path of a data file.
FIG. 15 is a conceptual diagram for explaining security guarantee for information capture;
FIG. 16 is a conceptual diagram when applying a digital watermark according to the second embodiment of the present invention;
FIG. 17 is a conceptual diagram for explaining a method of generating a data file with a digital signature when a digital watermark is applied.
FIG. 18 is a conceptual diagram for explaining a method of restoring a data file with a digital signature when a digital watermark is applied.
[Explanation of symbols]
1 Shooting system
2 Image recording memory
3 CPU
4 Work RAM
5 ROM
6 Timekeeping Department
7 Display device
8 Nonvolatile memory
8-1 Security memory
8-2 Public key ring memory
9 Switch part
10 Communication Department

Claims (13)

Imaging means;
ID image storage means for storing a thumbnail of the specific image captured by the imaging means as an ID image;
Device unique ID storage means for storing a device unique ID written as a unique value unique to the device at the time of manufacture;
A key generation unit that generates a public key and a secret key by a public key cryptosystem using the ID image and the device unique ID at the time of shooting by the imaging unit;
Additional information generating means for generating additional information related to the image captured by the imaging means, and attaching the additional information to the image data captured by the imaging means;
Storage means for storing the data generated by the additional information generation means as a captured image data body;
An electronic signature unit that encrypts the captured image data body stored in the storage unit with the secret key generated by the key generation unit and generates electronic signature data;
A browsing file that summarizes the captured image data main body stored in the storage unit, the electronic signature data generated by the electronic signature unit, the public key generated by the key generation unit, and public information that can be disclosed about the data file An electronic still camera, comprising: a browsing file generation means for generating Decryption means for decrypting the electronic signature data attached to the browse file with the public key added to the browse file;
The captured image data body attached to the browse file is compared with the data restored by the decoding means, and if both match, it is determined that the captured image data body has not been tampered with, A determination means for determining that the captured image data body has been tampered with if they do not match;
The electronic still camera according to claim 1, further comprising: a display unit that displays a determination result by the determination unit together with a captured image of the captured image data main body attached to the browsing file. Before the captured image data body is encrypted, feature data is extracted from the captured image data body and digested, and feature data extraction means is provided.
The electronic signature unit according to claim 1, wherein the electronic signature unit encrypts the data digested by the feature data extraction unit with a secret key generated by the key generation unit to generate electronic signature data. Still camera. Distribution partner information storage means for storing identification image data preset by the distribution partner as identification information for specifying the distribution partner for each distribution partner;
Distribution destination selection means for selecting a distribution partner of the browsing file generated by the browsing file generation means by designating identification image data stored in the distribution partner information storage means. The electronic still camera according to claim 1. Distribution partner information storage means for storing identification image data preset by the distribution partner and a public key distributed in advance by the distribution partner as identification information for specifying the distribution partner for each distribution partner;
An encryption means for encrypting the electronic signature data generated by the electronic signature generation means with the public key of the distribution partner stored in the distribution partner information storage means;
The electronic still camera according to claim 1, wherein the browsing file generation unit collects the encrypted data encrypted by the encryption unit and publicly available public information, and generates a browsing file.   The electronic still camera according to claim 5, wherein the public information includes at least image data that can be disclosed. Second decryption means for decrypting the browse file with its own private key;
The decryption unit decrypts the electronic signature data attached to the restored data with a public key attached to the data restored by the second decryption unit. 6. The electronic still camera according to 6.   When the restoration by the second decryption unit fails, the determining unit determines that the browse file has been obtained illegally, and the display unit is a captured image data body attached to the browse file 8. The electronic still camera according to claim 7, wherein image data that can be made public included in the public information is displayed together with the image data taken by the imaging means.     2. The public information includes file type information indicating whether a captured image data body attached to a browse file is an encrypted file, a file with an electronic signature, or a file without security information. The electronic still camera according to any one of Items 9 to 9.   Prior to the generation of the electronic signature data by the electronic signature unit, the digital watermark unit includes a public key generated by the key generation unit as digital watermark information in the image data captured by the imaging unit. The electronic still camera according to claim 1.   The determination means compares the public key added to the browse file with the public key embedded as digital watermark information in the captured image data body of the browse file. 11. The electronic still camera according to claim 10, wherein the image data body is determined to be data from a valid distributor. Imaging means;
ID image storage means for storing a thumbnail of the specific image captured by the imaging means as an ID image;
Device unique ID storage means for storing a device unique ID written as a unique value unique to the device at the time of manufacture;
A key generation unit that generates a public key and a secret key by a public key cryptosystem using the ID image and the device unique ID at the time of shooting by the imaging unit;
Additional information generating means for generating additional information related to the image captured by the imaging means, and attaching the additional information to the image data captured by the imaging means;
Storage means for storing the data generated by the additional information generation means as a captured image data body;
Distribution partner information storage means for storing identification image data preset by the distribution partner and a public key distributed in advance by the distribution partner as identification information for specifying the distribution partner for each distribution partner;
An electronic signature unit that encrypts the captured image data body stored in the storage unit with the secret key generated by the key generation unit and generates electronic signature data;
A browsing file that summarizes the captured image data main body stored in the storage unit, the electronic signature data generated by the electronic signature unit, the public key generated by the key generation unit, and public information that can be disclosed about the data file First browsing file generation means for generating
An encryption means for encrypting the browse file generated by the first browse file generation means with the public key of the distribution partner stored in the distribution partner information storage means;
File type information indicating the type of the file body, encrypted data encrypted by the encryption means, and public image data that can be made public, and second browsing file generation means for generating a browsing file for a specific partner; An electronic still camera comprising: Imaging means;
ID image storage means for storing a thumbnail of the specific image captured by the imaging means as an ID image;
Device unique ID storage means for storing a device unique ID written as a unique value unique to the device at the time of manufacture;
A key generation unit that generates a public key and a secret key by a public key cryptosystem using the ID image and the device unique ID at the time of shooting by the imaging unit;
A digital watermark means for inserting the public key generated by the key generation means into the image data captured by the imaging means as digital watermark information;
Additional information generating means for generating additional information related to the image captured by the imaging means and attaching the data to the data watermarked by the digital watermark means;
Storage means for storing the data generated by the additional information generation means as a captured image data body;
An electronic signature unit that encrypts the captured image data body stored in the storage unit with the secret key generated by the key generation unit and generates electronic signature data;
A browsing file that summarizes the captured image data main body stored in the storage unit, the electronic signature data generated by the electronic signature unit, the public key generated by the key generation unit, and public information that can be disclosed about the data file An electronic still camera, comprising: a browsing file generation means for generating

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