JP2009290508A - Electronized information distribution system, client device, server device and electronized information distribution method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronized information distribution system capable of maintaining high security even though a normal user of content accesses and uses content without being conscious of security. <P>SOLUTION: A client device 200 stores a client certificate 245 composed of a client public key 242 and signature information 243, and a client secret key 241 in an authentication information storing part 240, and decrypts encrypted electronized information 111 distributed from a server device 100 with the client secret key 241. Meanwhile, the server device 100 previously registers a client certificate 145 in an authentication information storing part 140, and authenticates the client device 200 by comparing it with the client certificate 245 received from the client device 200. When authenticated, the electronized information 110 is encrypted with the client public key 242 and transmitted to the client device 200. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a computerized information distribution system, a client device, a server device, and a computerized information distribution method capable of distributing the computerized information only to a limited number of connected devices in a system for transferring computerized information over a network. .

  One method of using the Internet is a service that enables distribution of digitized information (hereinafter also referred to as “content”) held by a server only to specific clients. In general, the client is a personal computer (hereinafter referred to as “PC”) connected to a network, and the contents are various data files and files such as videos, images, moving images, and music.

  A typical method for restricting file distribution to clients on a network is a method using a user identification code (hereinafter referred to as “ID”) and a password.

  There are many examples of restricting operations using IDs and passwords. For example, Patent Document 1 describes this. The main purpose of this Patent Document 1 is to propose a plurality of photo albums registered on the network and a mechanism for performing search restriction for each album. A search management method using an ID obtained by registration for using the service and a password for further increasing the restriction level is described. As a matter of course, it is necessary to inform the searcher who is permitted to search either the ID or the password or both in advance.

On the other hand, as a method for restricting connection to a server without using the above ID and password, use of a device authentication system using public key cryptography can be mentioned. For example, Patent Document 2 describes a mechanism in which a video input / output device connected to a communication network receives a certificate from a public key certificate issuing device existing in the same network and performs an operation on the network. Yes.
Japanese Patent Laid-Open No. 11-203359 JP 2006-238274 A

  In the method using the ID and password as in Patent Document 1 above, the PC user obtains and stores the ID and password in advance, and the ID and password are obtained every time the server is accessed and content is acquired. Must be entered. Also, when the ID and password are leaked to a third party, it is not a sufficiently safe system from the viewpoint of security because it is easily connected to the server from a PC of an owner different from the original owner. Furthermore, in order to reduce this risk, it is desirable to periodically update one or both of the ID and the password, but this is a very troublesome and unusable system for the user.

  On the other hand, the device authentication method using a public key described in Patent Document 2 has recently been widely used, but device authentication for a user device (usually a PC) to receive a specific service is performed. The purpose of this is to encrypt the content to be distributed, and it is necessary to prepare another method separately. In addition, since an algorithm for generating a public key is usually executed by software in a PC, there is a risk that the software itself may be wiretapped.

  The present invention has been made to solve the above problems, and an electronic information distribution system capable of maintaining a high level of security even if an authorized user of content accesses and uses the content without being aware of security. An object of the present invention is to provide a client device, a server device, and an electronic information distribution method.

  In order to achieve the above object, an electronic information distribution system according to claim 1 of the present invention is an electronic system in which a server device that distributes electronic information and a client device that receives the electronic information are connected to a network. In the information distribution system, the client device includes a client-side authentication information storage unit that stores a client certificate including a client public key and signature information and a client private key, and encrypted electronic information distributed from the server device. A server-side authentication information storage unit for storing client information registered in advance to authenticate the client device, and a client received from the client device. Information stored in the certificate and the client stored in the server-side authentication information storage A client authentication unit that authenticates a client device by comparing the information with the information, and an electronic device that generates encrypted electronic information by encrypting the electronic information distributed with the client public key of the client certificate received from the client device And an information encryption unit.

  With this configuration, when distributing computerized information from a server device to a specific client device on a network, it is possible to operate connected device restrictions that do not require an ID or password and are highly secure. Since it is not necessary to use a separate system for encrypting the encrypted information, service operation and device design burden are reduced. Furthermore, even if an authorized service user accesses the system without being aware of security, a high level of security is guaranteed, so the service can be used with peace of mind.

  The computerized information distribution system according to claim 2 of the present invention is a computerized information distribution system in which a server device that distributes computerized information and a client device that receives the computerized information are connected to a network. The device receives a client side authentication information storage unit that stores a client certificate and a client private key including a client public key and signature information, and receives encrypted digital information and an encrypted common key distributed from the server device. A first decryption unit that decrypts the encrypted common key with the client secret key, and a second decryption unit that decrypts the encrypted electronic information with the decrypted common key. A server-side authentication information storage unit that stores client information registered in advance to authenticate the client, and a class received from the client device. The client authentication unit that authenticates the client device by comparing the information contained in the ant certificate with the client information stored in the server-side authentication information storage unit, and the encrypted digital information distributed with the common key A first encryption unit for generating computerized information, and a second encryption unit for generating an encrypted common key by encrypting the common key with the client public key of the client certificate received from the client device. It was.

  With such a configuration, a common key method (secret key method) is used for encryption of digitized information that requires relatively high-speed processing, and a public key method that has a low processing speed but excellent security for transmission of the common key. By using, encryption and decryption that achieve both processing speed and safety can be realized. Accordingly, it is possible to distribute digitized information that requires high-speed real-time processing, such as voice and moving images, or to distribute a large amount of data in a short time even when real-time processing is unnecessary.

  The computerized information distribution system according to claim 3 of the present invention is the computerized information distribution system according to claim 1 or 2, wherein the client information stored in the server-side authentication information storage unit is a client certificate. is there.

  With such a configuration, the server device uses a client certificate authenticated in advance by a trusted certificate authority in order to authenticate the client device, so that higher security can be ensured.

  The computerized information distribution system according to claim 4 of the present invention is the computerized information distribution system according to any one of claims 1 to 3, wherein the client side authentication information storage unit includes a client certificate and a client. This is realized by a security chip in which a secret key is built in one semiconductor element.

  With this configuration, the software functions independently from the software in the client device such as a PC and uses a security chip directly attached to the board outside the hard disk of the client device. It is completely secure against theft. In addition, since authentication information necessary for the product at the time of shipment from the factory is already written in the client device, the user of the client device does not need to set authentication information.

  The electronic information distribution system according to claim 5 of the present invention is the electronic information distribution system according to claim 4, wherein the signature information of the client certificate is a hash value generated from a client public key by a predetermined hash function. It is encrypted with the vendor private key provided by the security chip manufacturer.

  With this configuration, since the signature information of the client certificate is encrypted with the vendor private key, it is impossible for a malicious third party who does not have the vendor private key to alter the signature information. Reliability can be ensured.

  The computerized information distribution system according to claim 6 of the present invention is the computerized information distribution system according to claim 5, wherein the client authentication unit of the server device has a predetermined value from the client public key of the client certificate received from the client device. A first hash value is generated by the hash function, and the signature information of the client certificate is decrypted with the vendor public key provided by the manufacturing company to generate a second hash value, and the first hash value and the second hash value are generated. The hash value is compared to authenticate the client device.

  With such a configuration, when the client public key is falsified by a malicious third party, the first hash value changes from the original value, so that the signature information (second hash value) of the client certificate and By comparing, it becomes possible to detect tampering easily and reliably.

  According to a seventh aspect of the present invention, there is provided a client device for receiving computerized information from a server device, wherein the client side authentication information stores a client certificate consisting of a client public key and signature information and a client private key. A storage unit, and an electronic information decryption unit that decrypts the encrypted electronic information distributed from the server device with a client secret key. The client-side authentication information storage unit responds to a request from the server device by a client. Send the certificate to the server device.

  A server apparatus according to claim 8 of the present invention is a server apparatus that distributes computerized information in response to a request from a client apparatus, and stores server information registered in advance to authenticate the client apparatus. The client certificate of the client device is received by requesting the client certificate from the client device in response to the request for the digitized information received from the client side authentication information storage unit and the client device, and included in the received client certificate The client authentication unit authenticates the client device by comparing the stored information with the client information stored in the server-side authentication information storage unit, and encrypts the digitized information with the client public key of the client certificate received from the client device. To generate encrypted electronic information and send it to the client device And a electronic information encrypting unit for signal.

  A client device according to claim 9 of the present invention is a client device that receives computerized information from a server device, and stores client-side authentication information that stores a client certificate composed of a client public key and signature information and a client private key. The storage unit, the first decryption unit that receives the encrypted computerized information and the encrypted common key distributed from the server device, and decrypts the encrypted common key with the client secret key, and the decrypted common key A second decryption unit that decrypts the encrypted digitized information, and the client side authentication information storage unit transmits a client certificate to the server device in response to a request from the server device.

  A server device according to claim 10 of the present invention is a server device that distributes computerized information in response to a request from a client device, and that stores client information registered in advance to authenticate the client device. The client certificate of the client device is received by requesting the client certificate from the client device in response to the request for the digitized information received from the client side authentication information storage unit and the client device, and included in the received client certificate Authentication information is compared with the client information stored in the server-side authentication information storage unit, the client authentication unit authenticates the client device, and the encrypted information is generated by encrypting the digitized information with a common key. A first encryption unit to be transmitted to the client device, and received from the client device It encrypts the common key with the client's public key of the client certificate to generate encrypted common key, and a second encryption unit for transmitting to the client device.

  According to an eleventh aspect of the present invention, there is provided an electronic information distribution method in an electronic information distribution system in which a server device that distributes electronic information and a client device that receives the electronic information are connected to a network. A method for transmitting a distribution request for electronic information from a client device to a server device; a client certificate requesting step for requesting a client certificate from a server device that has received the distribution request; The client device stores a client certificate including a client public key and signature information, and a client private key. The client device reads a client certificate and transmits the client certificate to the server device. To authenticate client devices An authentication step in which a client certificate is registered in advance and the client device is authenticated by comparing the registered client certificate with the client certificate received from the client device, and the client device authenticates in the authentication step. If it is, the encryption step of encrypting the digitized information with the client public key of the received client certificate to generate the encrypted digitized information, and transmitting the encrypted digitized information from the server device to the client device The electronic information transmission step, and the client device includes a decryption step of decrypting the encrypted electronic information received with the client private key stored in the client device.

  According to a twelfth aspect of the present invention, there is provided a computerized information distribution method in a computerized information distribution system in which a server device that distributes computerized information and a client device that receives the computerized information are connected to a network. A method for transmitting a distribution request for electronic information from a client device to a server device; a client certificate requesting step for requesting a client certificate from a server device that has received the distribution request; The client device stores a client certificate including a client public key and signature information, and a client private key. The client device reads a client certificate and transmits the client certificate to the server device. To authenticate client devices An authentication step in which a client certificate is registered in advance and the client device is authenticated by comparing the registered client certificate with the client certificate received from the client device, and the client device authenticates in the authentication step. If so, a first encryption step for encrypting the digitized information distributed with the common key to generate encrypted digitized information, and encrypting the common key with the client public key of the received client certificate A second encryption step for generating an encrypted common key; an encrypted information transmission step for transmitting the encrypted digitized information and the encrypted common key from the server device to the client device; and the client device stored in the client device. A first decryption code for decrypting the encrypted common key received with the client secret key Comprising a-up, and a second decoding step of decoding the encrypted electronic information received by the common key decrypted.

  According to the present invention, when distributing computerized information from a server device to a specific client device on a network, it is possible to operate a connected device restriction that does not require an ID or password and is highly secure. Since it is not necessary to use a separate system for encrypting the encrypted information, service operation and device design burden are reduced.

  Embodiments of an electronic information distribution system according to the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the computerized information distribution system according to the first embodiment of the present invention. The computerized information distribution system according to the present embodiment includes a server device 100, a client device 200, a network 300 that connects both, and an authentication authority 400 that authenticates information for client authentication. Normally, a plurality of client devices are connected to individually acquire computerized information from the server device, but FIG. 1 will be described by taking out one of the client devices.

  First, in the client device 200, authentication information previously authenticated from the authentication authority 400 is stored in the authentication information storage unit 240. This authentication information includes the client public key 242 for client authentication used for authentication of the client device 200, the client secret key 241, and the signature information 243 authenticated by the certification authority 400 for supporting the validity thereof. It is. The authentication information including the client public key 242 and the signature information 243 is called a client certificate 245. The client certificate 245 is used to authenticate whether or not the client device 200 is a legitimate client device, and the client public key. 242 can be prevented from being falsified. This authentication and tampering prevention mechanism will be described in detail later.

  On the other hand, in the server apparatus 100, a client certificate 145 including a client public key 142 and signature information 143 corresponding to the client apparatus 200 that requests distribution of the digitized information 110 is registered and stored in the authentication information storage unit 140 in advance as client information. Keep it. When responding to electronic information distribution requests from a plurality of client devices, a client certificate composed of a client public key and signature information corresponding to each client device is registered and stored as client information. As will be described later, a user ID or the like may be used as client information.

  Next, the operation of the computerized information distribution system in the present embodiment will be described using FIG. 1 and FIG. FIG. 2 is an operation sequence diagram showing a procedure until the client device 200 requests the server device 100 to distribute the digitized information and uses it.

  First, when the client device 200 requests distribution of the specific electronic information 110 in the server device 100 (step S501), the server device 100 requests a client certificate from the client device 200 (step S502). The client device 200 transmits the client certificate 245 stored in the authentication information storage unit 240 to the server device 100 (step S503). In the server apparatus 100, the client authentication unit 130 confirms that the signature information 243 is valid with an authentication server (not shown) or the like, and the client certificate 245 is attached to the transmitted client certificate 245. It is confirmed that the certificate 245 is the same as the client certificate 145 registered in the server apparatus 100 in advance (step S504). When it is confirmed in step S504 that the client certificate 245 is valid, the server apparatus 100 encrypts the electronic information 110 by encrypting the electronic information 110 with the client public key 242 of the client certificate 245 in the electronic information encryption unit 120. The computerized information 111 is generated (step S505), and the encrypted computerized information 111 is transmitted to the client device 200 (step S506). The client device 200 that has received the encrypted computerized information 111 decrypts the encrypted computerized information 111 using the client secret key 241 stored in the authentication information storage unit 240 in the computerized information decryption unit 220. (Step S507), the client device 200 extracts and uses the decrypted digitized information 110 (step S508).

  Next, operations of the client device 200 and the server device 100 of the computerized information distribution system in this embodiment will be described with reference to FIGS. 3 and 4. 3 and 4 are flowcharts showing operations of the client device 200 and the server device 100, respectively.

  First, the operation of the client device 200 will be described. In FIG. 3, the client device 200 transmits a specific computerized information request for distribution to the server device 100 (step S511). Next, when a client certificate request is received from the server apparatus 100 (step S512), the client certificate 245 stored in the authentication information storage unit 240 is transmitted to the server apparatus 100 (step S513). Thereafter, it is determined whether or not the encrypted digitized information 111 is received from the server apparatus 100 (step S514). When the encrypted digitized information 111 is received (“Y” in step S514), the client certificate 245 is determined. The encrypted digitized information 111 is decrypted with the public key (client public key 242) (step S515). On the other hand, if the encrypted computerized information 111 has not been received from the server apparatus 100 (“N” in step S514), the process proceeds to step S516 to determine whether or not to retry, and in the case of retry (“Y”). Returns to the first step S511 and repeats the flow of steps S511 to S514. If no retry is performed ("N"), the process ends.

  Next, the operation of the server apparatus 100 will be described. In FIG. 4, the server apparatus 100 stands by until a distribution request is received from the client apparatus 200 in step S521. When the distribution request is received (“Y”), the client certificate request is transmitted to the client device 200 (step S522). Next, in step S523, it is determined whether or not the client certificate 245 has been received. When the client certificate 245 is received ("Y"), in step S524, the client authentication unit 130 uses the received client certificate 245 as the server device. In order to authenticate the client device registered in advance in 100, it is determined whether or not the client certificate 245 (client device 200) received in comparison with the client certificate 145 is authentic. If it is determined in step S524 that the client certificate 245 is authentic (“Y”), the digitized information encryption unit 120 encrypts the digitized information 110 with the client public key 242 included in the client certificate 245 (step S524). Finally, the encrypted computerized information 111 is transmitted to the client apparatus 200 (step S526).

  On the other hand, if the client certificate has not been received in step S523 ("N") or if it is determined in step S524 that the client certificate 245 is not authentic ("N"), the process proceeds to step S527 and the retry is performed. In the case (“Y”), the process returns to step S522, and a client certificate request is transmitted to the client apparatus 200.

  In the above description, the client certificate 245 for authenticating the client device 200 has been described as being stored in the authentication information storage unit 240. However, in this embodiment, the authentication information storage unit 240 is a security chip that is a one-chip semiconductor. It consists of As is well known, the security chip is a TPM (Trusted Platform Module) based on the security specifications proposed by the TCG (Trusted Computing Group), and is directly attached on a substrate in an information terminal such as a PC, and the data protection and terminal in the terminal Used for storing encryption keys used for authentication, encryption and decryption. Since it functions independently of the software in the terminal and is installed outside the hard disk of the terminal such as a PC, safety is completely ensured against unauthorized software analysis and hard disk theft.

  By using this security chip for the authentication information storage unit 240, authentication information necessary for the product at the time of factory shipment is already written in the client device 200. It is not necessary to perform setting or to input an ID, a password, etc. every time the server apparatus 100 is connected.

  Next, the creation procedure of the client certificate 245 and the authentication procedure of the client certificate of the computerized information distribution system according to this embodiment will be described with reference to FIGS. First, the client certificate 245 is created. As shown in FIG. 5, the TPM chip manufacturing company (chip vendor) generates a client private key 241 and a client public key 242 in pairs at the time of chip manufacturing. Next, the client public key 242 is signed with the electronic certificate of the chip vendor (attached with the signature information 243) to generate a client certificate 245, which is stored in the chip together with the client private key 241. Here, the signature information 243 is generated by generating a hash value 244 of the client public key 242 using a predetermined hash function built in the chip and encrypting the hash value 244 with a vendor private key 441 owned by the chip vendor. . A hash function is a function known as a one-way function, which converts data of an arbitrary length into fixed-length data (hash value). This conversion can be performed relatively easily from a hash value. It has the property that it is difficult to calculate back to the original data. Utilizing this property, it becomes possible to efficiently detect falsification of data before and after transmission.

  Next, the authentication procedure of the client certificate 245 of the computerized information distribution system in this embodiment will be described with reference to FIG. The authentication in FIG. 6 is performed by the client authentication unit 130 in FIG. Further, the client certificate 245 in FIG. 6 is received from the client apparatus 200 in FIG. 1, and the registered client certificate 145 is client information stored in the authentication information storage unit 140 in FIG.

  The client certificate 245 received from the client device is compared with client information registered in advance in the server device to authenticate whether it is a legitimate client. In FIG. 6, a client certificate 145 is stored as client information, and the client certificate 245 and the registered client certificate 145 are compared. If both certificates match, the client is determined to be a legitimate client. Here, in client authentication, the entire client certificate may be compared, or a part of information included in the client certificate may be compared. For example, a client public key included in the client certificate may be compared, or a user ID (not shown) included in the client certificate may be compared. In this case, it is not necessary to store the entire client certificate as client information in the authentication information storage unit 140 of the server device, and it is sufficient to store only the client public key or user ID to be compared. .

  The verification procedure for checking whether or not the client certificate 245 has been tampered with is as follows. That is, the client public key 242 of the received client certificate 245 is used to generate a hash value 244 with the same hash function used when creating the signature information 243. Next, the signature information 243 of the client certificate 245 is decrypted with the vendor public key 442 included in the vendor certificate 445 acquired in advance from the chip vendor to obtain decrypted signature information 444. Finally, if the hash value 244 of the client public key 242 and the decryption signature information 444 are compared and matched, it is proved that no falsification has been performed. That is, since the signature information 243 is encrypted with the vendor private key 441, it is impossible for a third party who does not have the vendor private key 441 to falsify the signature information 243. Since the hash value 244 changes from the original value, it is possible to reliably detect tampering by comparing with the signature information 243.

  As described above, the authentication of the client device 200 is automatically performed based on the authentication information stored in advance in the client device 200 and the authentication information registered in advance in the server device 100. No need to enter password. Further, since no input operation or display is performed, there is no fear that an electronic information distribution request from an unauthorized client device will be made due to wiretapping of the ID and password.

  In addition, encryption and decryption of digitized information uses the client public key and client secret key originally used for client authentication, so a new key structure for digitized information encryption is prepared and operated separately. There is no need to do. As a result, the design burden and manufacturing burden of the client device 200 and the operational burden of the computerized information distribution system are reduced, and a highly reliable computerized information distribution system can be configured at low cost.

(Second Embodiment)
Next, an electronic information distribution system according to the second embodiment of the present invention will be described. This embodiment further enhances the practicality of the functions of the computerized information encryption unit 120 and the computerized information decryption unit 220 of the computerized information distribution system in the first embodiment.

  FIG. 7 is a block diagram showing the configuration of the computerized information distribution system in the present embodiment. The computerized information distribution system according to the present embodiment includes a server device 600, a client device 700, a network 300 that connects both, and an authentication organization 400 that authenticates information for client authentication. In FIG. 7, the same functional blocks as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the server apparatus 600, the computerized information encryption unit 620 includes two encryption units, a first encryption unit 623 and a second encryption unit 622. In the electronic information encryption unit 620, first, the electronic information 110 is encrypted using the common key 621 in the first encryption unit 623 to obtain the encrypted electronic information 112. Next, the second encryption unit 622 encrypts the common key 621 using the client public key 242 of the client certificate 245 sent from the client device 700 to obtain the encrypted common key 624. The encrypted computerized information 112 and the encrypted common key 624 are sent to the client device 700.

  In the client device 700, the computerized information decoding unit 720 includes two decoding units, a first decoding unit 721 and a second decoding unit 722. In the electronic information decryption unit 720, first, the first decryption unit 721 decrypts the received encrypted common key 624 with the client secret key 241 read from the authentication information storage unit 240, and reproduces the original common key 621. Next, in the second decryption unit 722, the received encrypted digitized information 112 is decrypted with the common key 621 reproduced by the first decryption unit 721, and the original digitized information 110 is reproduced. Take out from the takeout terminal 250.

  Next, the operation of the computerized information distribution system of this embodiment will be described. Since the procedure until the client device 700 requests distribution of computerized information to the server device 600 and uses it is substantially the same as that in the first embodiment, the operation sequence diagram corresponding to FIG. 2 is omitted. This embodiment is different from the first embodiment in the method for encrypting and decrypting the digitized information 110.

  8 and 9 are flowcharts showing operations of the client device 700 and the server device 600, respectively. The same processing steps as those in FIGS. 3 and 4 in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  First, the client apparatus 700 determines whether or not the encrypted computerized information 112 and the encrypted common key 624 are received from the server apparatus 600 in step S517 through the processing from step S511 to step S513. When the client device 700 receives these pieces of information (“Y”), first, the client public key 242 of the client certificate 245 stored in the authentication information storage unit 240 is read to decrypt the encrypted common key 624 ( Step S518). Next, in step S518, the encrypted digitized information 112 is decrypted with the decrypted common key 621 (step S519). On the other hand, when the client device 700 does not receive such information (“N” in step S517), the process proceeds to step S516 to select whether to retry or end.

  Next, in the server apparatus 600, the client certificate 245 is received from the client apparatus 700 in the processing steps from step S521 to step S523, and the client certificate 245 received from the client apparatus 700 is registered in the server apparatus 600 in advance in step S524. It is determined whether or not the client certificate 245 (client device 700) received in comparison with the client certificate 145 for authenticating the existing client device is authentic. If the client certificate 245 is authenticated as authentic in step S524 ("Y"), first, the digitized information 110 is encrypted with the common key 621 in step S528. Next, the common key 621 is encrypted with the client public key 242 of the client certificate 245 received from the client device 700 (step S529), and finally the encrypted digital information 112 and the encrypted common key 624 are transmitted to the client device 700. (Step S530), the operation is terminated.

  On the other hand, if the client certificate has not been received in step S523 ("N") or if it is determined in step S524 that the client certificate 245 is not authentic ("N"), the process proceeds to step S527 and the retry is performed. In the case (“Y”), the process returns to step S522, and a client certificate request is transmitted to the client apparatus 700.

  By using this configuration, a common key method (secret key method) is used for encryption of the digitized information 110 that requires relatively high-speed processing, and transmission of the common key 621 is inferior in processing speed but excellent in security. By using the public key method, encryption and decryption that achieve both processing speed and security can be realized. Electronic information to be distributed includes information that requires high-speed real-time processing, such as audio and video, and even when real-time processing is not required, high-speed transmission is required when large amounts of data are to be transmitted in a short time. It is desirable to be processed. The common key scheme includes, for example, a bitwise exclusive logical addition of a pseudo-random number generation sequence using the key as an initial value and information data, and is suitable for high-speed encryption and decryption.

  On the other hand, a public key method with excellent security is used for encryption when the common key 621 is transmitted. However, in this case, it is usually necessary to send one common key to send one digitized information. The burden of is hardly a problem.

  As can be seen from FIG. 7, since the client authentication information authenticated by the certificate authority 400 is used for the encryption of the electronic information 110 in the present embodiment, an additional encryption mechanism is not required, and at the same time security is achieved. There is an advantage that it is sufficiently secured. The client certificate authentication and falsification detection method is the same as in the first embodiment, and a description thereof will be omitted.

  As described above, according to the present invention, when a server device holding electronic information on a network such as the Internet distributes the electronic information to a specific client device, the electronic information is obtained. The client apparatus can guarantee high security without using an ID and a password. For this reason, even if a legitimate user of the computerized information stored in the server device accesses and uses the computerized information without being aware of security, high security can be maintained.

  Particularly in a client device using a security chip, the highest level of security can be used for encryption of electronic information to be distributed.

  In the above embodiment, the client public key, the client secret key, and the signature information have been described as being created and stored by the chip vendor at the time of chip manufacture. However, the present invention is not limited to this, and the client may It may be generated each time.

  The present invention makes it possible to distribute computerized information while ensuring a high level of security even if the user is unaware of security, and it is possible to distribute any computerized information such as software, various data, text, still images, audio, and moving images. Applicable for distribution.

The block diagram which shows the structure of the electronic information distribution system in the 1st Embodiment of this invention Operation sequence diagram between server device and client device in the computerized information distribution system A flowchart showing the operation of the client device in the computerized information distribution system A flowchart showing the operation of the server device in the computerized information distribution system Diagram for explaining the procedure for creating a client certificate in the computerized information distribution system Diagram for explaining the procedure for authenticating the client certificate in the computerized information distribution system The block diagram which shows the structure of the digitization information distribution system in the 2nd Embodiment of this invention A flowchart showing the operation of the client device in the computerized information distribution system A flowchart showing the operation of the server device in the computerized information distribution system

Explanation of symbols

100, 600 Server apparatus 110 Electronic information 111, 112 Encrypted electronic information 120, 620 Electronic information encryption unit 130 Client authentication unit 131 Comparison unit 140, 240 Authentication information storage unit 142, 242 Client public key 143, 243 Signature information 145,245 Client certificate 200,700 Client device 220,720 Electronic information decryption unit 241 Client private key 244 Hash value (of client public key) 250 Electronic information extraction terminal 300 Network 400 Authentication authority 441 Vendor private key 442 Vendor public Key 444 Decryption signature information 445 Vendor certificate 621 Common key 622 Second encryption unit 623 First encryption unit 624 Encryption common key 721 First decryption unit 722 Second decryption unit

Claims (12)

A computerized information distribution system in which a server device that distributes computerized information and a client device that receives the computerized information are connected to a network,
The client device is
A client-side authentication information storage unit that stores a client certificate and a client private key including a client public key and signature information;
An electronic information decryption unit that decrypts the encrypted electronic information distributed from the server device with the client secret key;
The server device
A server-side authentication information storage unit that stores client information registered in advance to authenticate the client device;
A client authentication unit that authenticates the client device by comparing the information contained in the client certificate received from the client device with the client information stored in the server-side authentication information storage unit;
An electronic information distribution system comprising: an electronic information encryption unit that encrypts the electronic information distributed with the client public key of the client certificate received from the client device to generate encrypted electronic information. A computerized information distribution system in which a server device that distributes computerized information and a client device that receives the computerized information are connected to a network,
The client device is
A client-side authentication information storage unit that stores a client certificate and a client private key including a client public key and signature information;
A first decryption unit that receives the encrypted digitized information and the encrypted common key distributed from the server device, and decrypts the encrypted common key with the client secret key;
A second decryption unit for decrypting the encrypted digitized information with the decrypted common key,
The server device
A server-side authentication information storage unit that stores client information registered in advance to authenticate the client device;
A client authentication unit that authenticates the client device by comparing information included in the client certificate received from the client device with client information stored in the server-side authentication information storage unit;
A first encryption unit that encrypts the digitized information distributed with the common key to generate encrypted digitized information;
An electronic information distribution system comprising: a second encryption unit that encrypts the common key with the client public key of the client certificate received from the client device and generates an encrypted common key. 3. The computerized information distribution system according to claim 1, wherein the client information stored in the server-side authentication information storage unit is a client certificate. 4. The electronic device according to claim 1, wherein the client side authentication information storage unit is realized by a security chip in which the client certificate and the client secret key are built in one semiconductor element. 5. Information distribution system. 5. The electronic device according to claim 4, wherein the signature information of the client certificate is obtained by encrypting a hash value generated from the client public key by a predetermined hash function with a vendor private key provided by the security chip manufacturer. Information distribution system. The client authentication unit of the server device generates a first hash value from the client public key of the client certificate received from the client device by the predetermined hash function, and the signature information of the client certificate is The decryption is performed using a vendor public key provided by a manufacturing company to generate a second hash value, and the client device is authenticated by comparing the first hash value and the second hash value. The electronic information distribution system described. A client device that receives computerized information from a server device,
A client-side authentication information storage unit that stores a client certificate and a client private key including a client public key and signature information;
An electronic information decryption unit that decrypts the encrypted electronic information distributed from the server device with the client secret key;
The client-side authentication information storage unit is a client device that transmits the client certificate to the server device in response to a request from the server device. A server device that distributes computerized information in response to a request from a client device,
A server-side authentication information storage unit that stores client information registered in advance to authenticate the client device;
Responding to the request for electronic information received from the client device, requesting a client certificate from the client device, receiving the client certificate of the client device, and information included in the received client certificate; A client authentication unit that authenticates the client device by comparing the client information stored in the server-side authentication information storage unit;
A server apparatus comprising: an electronic information encryption unit that encrypts electronic information with the client public key of the client certificate received from the client apparatus, generates encrypted electronic information, and transmits the encrypted information to the client apparatus . A client device that receives computerized information from a server device,
A client-side authentication information storage unit that stores a client certificate and a client private key including a client public key and signature information;
A first decryption unit that receives the encrypted digitized information and the encrypted common key distributed from the server device, and decrypts the encrypted common key with the client secret key;
A second decryption unit for decrypting the encrypted digitized information with the decrypted common key,
The client-side authentication information storage unit is a client device that transmits the client certificate to the server device in response to a request from the server device. A server device that distributes computerized information in response to a request from a client device,
A server-side authentication information storage unit that stores client information registered in advance to authenticate the client device;
Responding to the request for electronic information received from the client device, requesting a client certificate from the client device, receiving the client certificate of the client device, and information included in the received client certificate; A client authentication unit that authenticates the client device by comparing the client information stored in the server-side authentication information storage unit;
A first encryption unit that encrypts the digitized information with a common key to generate encrypted digitized information, and transmits the encrypted digitized information to the client device;
A server device comprising: a second encryption unit that encrypts the common key with the client public key of the client certificate received from the client device, generates an encrypted common key, and transmits the encrypted common key to the client device. A computerized information distribution method in a computerized information distribution system in which a server device that distributes computerized information and a client device that receives the computerized information are connected to a network,
A distribution request transmitting step of transmitting a distribution request for the computerized information from the client device to the server device;
A client certificate requesting step for requesting a client certificate from the server device that has received the distribution request to the client device;
The client device stores a client certificate and a client private key including a client public key and signature information, and the client device reads the client certificate and transmits the client certificate to the server device;
A client certificate for authenticating the client device is pre-registered in the server device, and the client certificate is compared by comparing the registered client certificate with the client certificate received from the client device. An authentication step for authenticating the device;
An encryption step of encrypting the digitized information with the client public key of the received client certificate to generate encrypted digitized information when the client device is authenticated as authentic in the authentication step;
An electronic information transmission step of transmitting the encrypted electronic information from the server device to the client device;
An electronic information distribution method, wherein the client device includes a decrypting step of decrypting the encrypted electronic information received with the client secret key stored in the client device. A computerized information distribution method in a computerized information distribution system in which a server device that distributes computerized information and a client device that receives the computerized information are connected to a network,
A distribution request transmitting step of transmitting a distribution request for the computerized information from the client device to the server device;
A client certificate requesting step for requesting a client certificate from the server device that has received the distribution request to the client device;
The client device stores a client certificate and a client private key including a client public key and signature information, and the client device reads the client certificate and transmits the client certificate to the server device;
A client certificate for authenticating the client device is pre-registered in the server device, and the client certificate is compared by comparing the registered client certificate with the client certificate received from the client device. An authentication step for authenticating the device;
A first encryption step of encrypting the digitized information distributed with a common key to generate encrypted digitized information when the client device is authorized in the authenticating step;
A second encryption step of generating an encrypted common key by encrypting the common key with the client public key of the received client certificate;
An electronic information transmission step of transmitting the encrypted electronic information and the encrypted common key from the server device to the client device;
A first decryption step for decrypting the encrypted common key received by the client private key stored in the client device;
A digitized information distribution method comprising: a second decryption step of decrypting the encrypted digitized information received with the decrypted common key.

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