JP2006094536A - Electronic still camera - Google Patents

Abstract

An electronic still camera capable of preventing falsification, duplication, partial use, and unauthorized use of digital data is provided.
A CPU generates a public key and a secret key by a public key cryptosystem. At this time, the ID image stored in the security memory 8-1 is used as a random number sequence generation source. Further, the CPU 3 attaches additional information to the image data input from the photographing system 1, encrypts the data with the secret key, and generates electronic signature data. Furthermore, the input data body attached with the additional information, the electronic signature data, the public key, etc. are collected to generate a data file. When the data file is restored, if the data obtained by decrypting the electronic signature data using the public key attached to the data file matches the data obtained from the data body of the data file, the data file is altered. It can be determined that no editing or the like has been added.
[Selection] Figure 1

Description

  The present invention relates to a digital data recording apparatus such as an electronic still camera, and more particularly to an electronic still camera that improves security when browsing and distributing recorded digital data.

  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.

  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 is a processing such as digital watermarking for inserting copyright information and the like for detection / suppression of illegal duplication and partial use (see, for example, Patent Document 1).

With these existing methods, it is possible to take security measures for image, audio, and moving image data captured in a personal computer (see, for example, Patent Document 2). 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.
JP 2004-227283 A JP 2004-274478 A

  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.

  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.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic still camera that can prevent digital data from being tampered with, duplicated, partially used, or illegally used.

  In order to achieve the above object, an electronic still camera according to the first aspect of the present invention includes a key generation unit that generates a public key and a secret key by a public key cryptosystem, an input unit that inputs digital data, and an input from the input unit Generating additional information related to the digital data and attaching to the digital data input from the input means; storage means for storing the data generated by the additional information generation means as an input data body; An input data body stored in the storage means is encrypted with a secret key generated by the key generation means to generate electronic signature data; an input data body stored in the storage means; the electronic data The electronic signature data generated by the signing means, the public key generated by the key generating means, and the data file Collectively openable public information, characterized by comprising a viewing file generation means for generating a viewing files.

  Further, as a preferred aspect, for example, as in claim 2, in the electronic still camera according to claim 1, the digital signature data attached to the browse file is decrypted by the public key added to the browse file. Comparing the decrypting means to the input data body attached to the browsing file and the data restored by the decrypting means, and if both match, it is determined that the input data body has not been tampered with If both do not match, a display for displaying the determination result by the determination means together with the determination means for determining that the input data body is falsified and the digital data of the input data body attached to the browse file Means.

  As a preferred mode, for example, as in claim 3, in the electronic still camera according to claim 1, feature data is extracted from the input data body and digested before the input data body is encrypted. It comprises feature data extraction means, and the electronic signature means encrypts the data digested by the feature data extraction means with the private key generated by the key generation means to generate electronic signature data. And

  Further, as a preferred aspect, for example, as in claim 4, in the electronic still camera according to claim 1, the key generation means is configured to use a public key and a public key based on identification data for identifying a digital data recorder. A secret key is generated.

  As a preferred mode, for example, as described in claim 5, in the electronic still camera according to claim 4, the identification data is arbitrary identification image data selected by a digital data recorder. .

  As a preferred aspect, for example, as in claim 6, the electronic still camera according to claim 5, further comprising a thinning means for thinning the identification image data to a predetermined size, wherein the additional information generating means comprises the thinning-out means. The identification image data thinned out by the means is attached as additional information to the digital data inputted from the input means.

  Moreover, as a preferable aspect, for example, as described in claim 7, in the electronic still camera according to claim 1, for each distribution partner, identification image data preset by the distribution partner is used as identification information for specifying the distribution partner. Distribution partner information storage means for storing, and distribution destination selection means for selecting the distribution partner of the browse file generated by the browse file generation means by designating identification image data stored in the distribution partner information storage means It is characterized by comprising.

  Moreover, as a preferable aspect, for example, as described in claim 8, in the electronic still camera according to claim 1, for each distribution partner, identification image data set in advance by the distribution partner as identification information for specifying the distribution partner Distribution partner information storage means for storing a public key distributed in advance by the distribution partner, and electronic signature data generated by the electronic signature generation means is stored in the distribution partner information storage means. It comprises encryption means for encrypting with a public key, and the browsing file generation means collects the encrypted data encrypted by the encryption means and publicly available public information, and generates a browsing file. .

  As a preferred aspect, for example, as in claim 9, in the electronic still camera according to claim 8, the public information includes at least image data that can be disclosed.

  Further, as a preferred aspect, for example, as in claim 10, in the electronic still camera according to claim 9, the second decryption means for decrypting the browse file with its own private key, and the decryption means include: The digital signature data attached to the restored data is decrypted with the public key attached to the data restored by the second decryption means.

  As a preferred aspect, for example, as in claim 11, in the electronic still camera according to claim 10, when the restoration by the second decryption unit fails, the determination unit stores the browsing file. It is determined that the information has been illegally obtained, and the display means displays the publicly available image data included in the public information together with the digital data of the input data body attached to the browsing file.

  Further, as a preferred aspect, for example, as in claim 12, in the electronic still camera according to claims 1 to 11, the public information includes a data body attached to a browsing file as an encrypted file, a file with an electronic signature, and the like. And file type information indicating whether the file has no security information.

  Further, as a preferred aspect, for example, as described in claim 13, in the electronic still camera according to claim 1, prior to generation of electronic signature data by the electronic signature means, digital data input from the input means is Electronic watermark means for inserting the public key generated by the key generation means as digital watermark information is provided.

  Further, as a preferred aspect, for example, as in claim 14, in the electronic still camera according to claim 13, the determination means includes a public key added to the browsing file and an electronic data in the data body of the browsing file. A public key inserted as watermark information is compared, and if both match, the input data body is determined to be data from a valid distributor.

  In order to achieve the above object, an electronic still camera according to the invention described in claim 15 includes a key generation unit that generates a public key and a secret key by a public key cryptosystem, an input unit that inputs digital data, and the input unit. Generating additional information related to the digital data input from the input means and attaching the additional information generating means attached to the digital data input from the input means; and storage means for storing the data generated by the additional information generating means as the input data body 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 input data body stored in the storage means is encrypted with the secret key generated by the generation means, and the electronic signature data Electronic signature means to be generated, input data main body stored in the storage means, electronic signature data generated by the electronic signature means, public key generated by the key generation means, and public disclosure relating to this data file A first browsing file generation unit that collects information and generates a browsing file; and a browsing file generated by the first browsing file generation unit is stored in the distribution partner information storage unit. A browsing file for a specific partner is created by combining encryption means that encrypts with a key, file type information indicating the type of the file body, encrypted data encrypted by the encryption means, and publicly available image data. And second browsing file generation means.

  In order to achieve the above object, an electronic still camera according to the invention described in claim 16 includes a key generation unit that generates a public key and a secret key by a public key cryptosystem, an input unit that inputs digital data, and the input unit. A digital watermark means for inserting the public key generated by the key generation means as digital watermark information into the digital data inputted from the digital data, and generating additional information relating to the digital data inputted from the input means, and the digital watermark means By means of additional information generating means to be attached to the data subjected to digital watermarking, storage means for storing the data generated by the additional information generating means as an input data body, and a secret key generated by the key generating means, An electronic signature means for encrypting the input data body stored in the storage means and generating electronic signature data; and Collecting the input 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 publicly available public information about this data file, and generating a browsing file And browsing file generation means.

  According to the first aspect of the present invention, additional information relating to the digital data is attached to the digital data input from the input means by the additional information generation means, stored in the storage means as the input data body, and by the electronic signature means. The input data body stored in the storage means is encrypted with the secret key generated by the key generation means to generate electronic signature data, and the input data body stored in the storage means is generated by the file generation means, Since the digital signature data generated by the electronic signature means, the public key generated by the key generation means, and public information that can be made public about this data file are collected, the final browsing file is generated. The advantage is that tampering, duplication, and partial use can be prevented.

  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. Comparing the attached input data body and the data restored by the decryption means, if both match, it is determined that the input data body has not been tampered, and if both do not match, Since it is determined that the input data body has been tampered with, and the determination result by the determining means is displayed on the display means together with the digital data of the input data body attached to the browse file, The advantage that duplication and partial use can be prevented is obtained.

  According to a third aspect of the present invention, before the input data body is encrypted, feature data is extracted from the input data body by the feature data extraction means, digested, and electronic signature data is generated. In doing so, the digital signature means encrypts the data digested by the feature data extraction means with the private key generated by the key generation means, so that the digital data can be altered or copied, The advantage that partial use can be prevented is obtained.

  According to the invention described in claim 4, since the public key and the secret key are generated based on the identification data for identifying the writer of the digital data, tampering, duplication, and partial use of the digital data are prevented. The advantage is that it can be prevented.

  According to the invention described in claim 5, since the identification data is arbitrary identification image data selected by the digital data recorder, it is possible to prevent falsification, duplication, and partial use of the digital data. Benefits are gained.

  According to the invention described in claim 6, the identification image data is thinned to a predetermined size by the thinning means, and the thinned identification image data is attached as additional information to the digital data input from the input means. Since it did in this way, the advantage that alteration, duplication, and partial use of digital data can be prevented is acquired.

  According to the seventh aspect of the invention, for each distribution partner, identification image data preset by the distribution partner is stored in the distribution partner information storage means as identification information for specifying the distribution partner, and the distribution destination By designating the identification image data by the selection means, the distribution partner of the browsing file is selected, so that it is possible to prevent tampering, duplication, and partial use of the digital data.

  According to the invention described in claim 8, for each distribution partner, identification image data preset by the distribution partner and a public key distributed in advance by the distribution partner are distributed as identification information for specifying the distribution partner. The electronic signature data generated by the electronic signature generation means is encrypted with the public key of the distribution partner stored in the distribution partner information storage means, stored in the counterpart information storage means, and encrypted. Since the browsing file generation unit collects the encrypted data encrypted by the encryption unit and publicly available public information and generates a browsing file, it prevents falsification, duplication, and partial use of digital data. The advantage that it can be obtained.

  According to the ninth aspect of the invention, since the public information is at least image data that can be disclosed, there is an advantage that tampering, duplication, and partial use of digital data can be prevented.

  According to a tenth aspect of the present invention, the second decryption unit decrypts the browse file with its own private key, and then the decryption unit restores the second decryption unit. Since the digital signature data attached to the restored data is decrypted with the public key attached to the original data, the digital data can be prevented from being altered, duplicated or partially used. can get.

  According to the eleventh aspect of the present invention, when restoration by the second decryption means fails, the judgment means judges that the browse file has been obtained illegally and is attached to the browse file. The displayable image data included in the public information is displayed on the display unit together with the digital data of the input data body, so that tampering, duplication, partial use, and unauthorized use of the digital data can be prevented. The advantage is obtained.

  According to the invention of claim 12, file type information indicating whether the data body attached to the browse file is an encrypted file, a file with an electronic signature, or a file without security information. Therefore, there is an advantage that digital data can be prevented from being altered, duplicated, partially used, or illegally used.

  According to a thirteenth aspect of the present invention, prior to the generation of electronic signature data by the electronic signature means, the digital watermark means generates digital data input from the input means by the key generation means. Since the public key is inserted as digital watermark information, there is an advantage that digital data can be prevented from being altered, duplicated, partially used or illegally used.

  According to the invention of claim 14, the public key added to the browsing file is compared with the public key inserted as the digital watermark information in the data body of the browsing file, and the two match. In this case, since the input data body is determined to be data from a valid distributor, there is an advantage that digital data can be prevented from being altered, duplicated, partially used, or illegally used.

  According to the fifteenth aspect of the present invention, the key generation means for generating the public key and the secret key by the public key cryptosystem, and the digital data input from the input means are subjected to the digital data by the additional information generation means. Is attached to the storage means as an input data body, and the electronic signature data is encrypted by the electronic signature means by encrypting the input data body stored in the storage means with the secret key generated by the key generation means. Once, the first browsing file generation means, the input data 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 A browse file is generated by collecting publicly available public information related to the data file, and then the browse file is encrypted by an encryption unit. Encrypted by the public key of the distribution partner stored in the distribution partner information storage means, and further by the second browsing file generation means, the file type information indicating the type of the file body, encrypted by the encryption means Since the final browsing file is generated by combining the encrypted data and the public image data that can be disclosed, there is an advantage that the digital data can be prevented from being altered, duplicated, partially used, or illegally used. .

  According to the sixteenth aspect of the present invention, the key generation means for generating the public key and the secret key by the public key cryptosystem, and the digital data input from the input means by the digital watermark means by the key generation means. The generated public key is inserted as digital watermark information, and additional information relating to the digital data is attached by the additional information generation means, stored in the storage means as the input data body, and then generated by the key generation means by the electronic signature means The input data body stored in the storage unit is encrypted with the secret key thus generated, and electronic signature data is generated. The browsing file generation unit generates the input data body stored in the storage unit and the electronic signature unit. The public digital signature data, the public key generated by the key generation unit, and the publicly available public data related to this data file Summary information, since to generate a browsing files, alteration and duplication of digital data, partial use, the advantage is obtained that it is possible to prevent unauthorized use.

  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).

  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.

  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.

  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 A22, it is determined whether or not it is encrypted. If it is encrypted, in step A24, the number of coded plaintexts (messages) is set as M (1 ≦ M <n), and the public key (e, m), the encryption code C is generated by the calculation C = M ^ e (mod.n).

  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.

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).

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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

C. Operation of First Embodiment The overall operation will be described below with reference to the flowcharts shown in FIGS.
C-1. Security Information Generation Processing When the device is powered on, first, initialization is performed in step S10, the contents of the security memory 8-1 are confirmed in step S12, and whether or not it is the first activation in step S14. Determine whether. 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.

  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.

  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.

  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.

  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.

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.

  In this key generation algorithm, it is necessary to set a combination of relatively large prime numbers so that they do not overlap with each other between different users. Usually, a prime number generation process using a random number generation mechanism is performed on 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.

  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.

  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.

C-2. Shooting Data Guarantee Information Adding Process Next, an operation for generating a file in which a digital signature is added in normal shooting and the data contents are guaranteed at the time of shooting will be described.

  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.

  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.

  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.

  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.

C-3. Digital signature check of image, decryption and viewing Also, when the operation mode of the device is set to PLAY (playback) mode or PLAY (playback) mode is selected, in steps S32 to S42, Processing for browsing / manipulating / confirming the photographed data with respect to the file with security is executed.

  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.

  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.

  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.

  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.

  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. .

  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.

  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.

  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.

  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.

  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.

C-4. When the image data is displayed in the above-described step S42, the process proceeds to step S44 shown in FIG. 6 to determine the key operation, and in accordance with the determined key operation, the stored image is encrypted or other Process.

  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.

  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.

  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.

C-5. Communication Processing If the operation mode of the device is set to the communication mode or is selected in step S26 shown in FIG. 5, the process proceeds to step S54 shown in FIG. As shown, the 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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

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.

  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.

  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.

  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.

  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.

  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.

  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.

It is a flowchart for demonstrating a RSA public key encryption system. It is a block diagram which shows the structure of the electronic still camera in the 1st embodiment of this invention. 3 is a conceptual diagram showing a data configuration of a nonvolatile memory 8. FIG. It is a flowchart for demonstrating operation | movement of an electronic still camera. It is a flowchart for demonstrating operation | movement of an electronic still camera. It is a flowchart for demonstrating operation | movement of an electronic still camera. It is a conceptual diagram for demonstrating the production | generation method of the data file with an electronic signature. It is a conceptual diagram for demonstrating the restoration method of the data file with an electronic signature. It is a conceptual diagram for demonstrating the security guarantee by apparatus specific ID. It is a conceptual diagram for demonstrating the encryption method. It is a conceptual diagram for demonstrating the restoration method of the data file with an electronic signature with encryption. It is a conceptual diagram which shows a display example. It is a conceptual diagram which shows the example of ID image. It is a conceptual diagram for demonstrating the transmission path | route example of a data file. It is a conceptual diagram for demonstrating the security guarantee with respect to information capture. It is a conceptual diagram at the time of applying the digital watermark by the 2nd Embodiment of this invention. It is a conceptual diagram for demonstrating the production | generation method of the data file with a digital signature at the time of applying a digital watermark. It is a conceptual diagram for demonstrating the restoration method of the data file with a digital signature at the time of applying a digital watermark.

Explanation of symbols

1 photographing system 2 image recording memory 3 CPU
4 Work RAM
5 ROM
6 Timekeeping unit 7 Display device 8 Non-volatile memory 8-1 Security memory 8-2 Public key ring memory 9 Switch unit 10 Communication unit

Claims (16)

Key generation means for generating a public key and a secret key by a public key cryptosystem;
An input means for inputting digital data;
Generating additional information regarding the digital data input from the input unit, and attaching the additional information to the digital data input from the input unit;
Storage means for storing the data generated by the additional information generating means as an input data body;
An electronic signature means for encrypting the input data body stored in the storage means with the secret key generated by the key generation means and generating electronic signature data;
The input 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 public information that can be made public about this data file are collected, An electronic still camera comprising: a browsing file generating 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 input data body attached to the browsing file is compared with the data restored by the decryption means, and if both match, it is determined that the input data body has not been tampered with, and both do not match And a display means for displaying the determination result by the determination means together with the digital data of the input data body attached to the browsing file, and a determination means for determining that the input data body is falsified. The electronic still camera according to claim 1. Before the input data body is encrypted, feature data is extracted from the input 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.   2. The electronic still camera according to claim 1, wherein the key generating unit generates a public key and a secret key based on identification data for identifying a digital data recorder.   5. The electronic still camera according to claim 4, wherein the identification data is arbitrary identification image data selected by a digital data recorder. Comprising thinning means for thinning the identification image data to a predetermined size;
6. The electronic still camera according to claim 5, wherein the additional information generating means attaches the identification image data thinned out by the thinning means as additional information to the digital data inputted from the input means. 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.   9. The electronic still camera according to claim 8, 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. 9. An electronic still camera according to 9. The determination means determines that the browsing file has been obtained illegally when the restoration by the second decryption means fails,
The electronic still camera according to claim 10, wherein the display unit displays publicly available image data included in the public information together with digital data of an input data body attached to the browsing file.   12. The public information includes file type information indicating whether a 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 described.   Prior to the generation of the electronic signature data by the electronic signature means, the digital watermark means includes a digital key input from the input means and the public key generated by the key generation means as digital watermark information. The electronic still camera according to claim 1, wherein:   The determination means compares the public key added to the browsing file with the public key inserted as digital watermark information in the data body of the browsing file, and if both match, the input data body 14. The electronic still camera according to claim 13, wherein the electronic still camera is determined to be data from a valid distributor. Key generation means for generating a public key and a secret key by a public key cryptosystem;
An input means for inputting digital data;
Generating additional information regarding the digital data input from the input unit, and attaching the additional information to the digital data input from the input unit;
Storage means for storing the data generated by the additional information generating means as an input 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 means for encrypting the input data body stored in the storage means with the secret key generated by the key generation means and generating electronic signature data;
The input 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 public information that can be made public about this data file are collected, First browsing file generating 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: Key generation means for generating a public key and a secret key by a public key cryptosystem;
An input means for inputting digital data;
A digital watermark means for inserting the public key generated by the key generation means into the digital data input from the input means as digital watermark information;
Generating additional information about the digital data input from the input unit, and attaching the additional information to the data watermarked by the digital watermark unit;
Storage means for storing the data generated by the additional information generating means as an input data body;
An electronic signature means for encrypting the input data body stored in the storage means with the secret key generated by the key generation means and generating electronic signature data;
The input 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 public information that can be made public about this data file are collected, An electronic still camera comprising browsing file generation means for generating.

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