JP5211137B2 - License generation system, license generation method, and license generation program - Google Patents

Description

  The present invention relates to a technique for generating a decryption license capable of decrypting encrypted digital content.

  2. Description of the Related Art Conventionally, there has been a technique for generating a decryption license capable of decrypting encrypted digital content using a user ID and a license ID transmitted from a user terminal in a server. In particular, in order to prevent impersonation of the user, an encryption key unique to the user terminal (hereinafter referred to as user key) is registered in the server in advance, and a license acquisition request transmitted from the user terminal is transmitted between the plaintext part and the encryption part. The encryption part is decrypted to confirm the identity with the plaintext part. Furthermore, by generating a decryption license and then encrypting it with the user key, it is possible to generate a decryption license unique to the user terminal (see Non-Patent Document 1). Hereinafter, such a conventional license generation system will be described.

  FIG. 8 is a diagram showing an overall configuration of a conventional license generation system. The license generation / encryption / decryption device 100 corresponding to the server uses the plaintext part (user ID, license ID) and the encryption part (user ID, license ID) transmitted from the user terminal 300 as follows. Each process is performed, and the generated decryption license is issued to the user terminal 300.

  Here, the user ID is an ID for identifying the user terminal 300, the license ID is an ID for identifying a license of digital content, and the user key is an encryption key of the user terminal associated with the user terminal 300.

  First, a license acquisition request having a plaintext part (user ID, license ID) and an encryption part (user ID, license ID) transmitted from the user terminal 300 by the license generation / encryption / decryption apparatus 100 is issued. Received (S701).

  Next, the user key DB is searched using the user ID of the plaintext part received in S701 as a key, and the user key of the user terminal 300 is acquired (S702). Here, the user key DB is a DB that holds the user ID of the user terminal 300 and the user key of the user terminal 300 on a one-to-one basis, and holds a user key set for each user ID. If no user key exists as a result of searching the user key DB, the process proceeds to S709-2.

  Next, using the user key acquired in S702, the encryption unit (user ID, license ID) received in S701 is decrypted, and the user ID and license ID are extracted, and compared with the user ID and license ID in the plaintext part. Whether or not they are the same is determined (S703). If the user ID and the license ID are not the same, the validity of the license acquisition request is denied, and the process proceeds to S709-2. Decryption is a process of decrypting data encrypted by the user key back to plain text.

  Next, if the user ID and license ID are the same as a result of the determination in S703, the contract DB is searched using the user ID and license ID of the plaintext part received in S701 as a key, and whether or not the corresponding record exists. Is determined (S704). Here, the contract DB holds the user ID of the user terminal 300 and the license ID of the digital content license on a one-to-many basis, and holds the license ID of the license contracted for each user ID. Yes, if a record exists, it means that a contract exists. If there is no corresponding record as a result of searching the contract DB, the process proceeds to S709-2.

  Next, if there is a corresponding record as a result of the determination in S704, the license information DB is searched using the license ID of the plaintext part received in S701 as a key, and license information corresponding to the license ID is acquired ( S705). Here, the license information DB is a DB that holds license IDs and license information on a one-to-one basis, and holds license information set for each license ID. License usage conditions are defined in the license information. If the license information does not exist as a result of searching the license information DB, the process proceeds to S709-2.

  Next, a license A is generated by combining the license information acquired in S705 and the plaintext part user ID received in S701 (S706). Note that the license A is a license in a state where the encryption process using the user key is not performed.

  Next, the content key DB is searched using the license ID of the plaintext part received in S701 as a key, and the content key corresponding to the license ID is acquired (S707). Here, the content key DB is a DB that holds a license ID and a content key on a one-to-one basis, and holds a content key set for each license ID. The content key is a digital content encryption key for decrypting the digital content. If the content key does not exist as a result of searching the content key DB, the process proceeds to S709-2.

  Next, the content key acquired in S707 is combined with the license A generated in S706, and the license B is generated by performing encryption using the user key acquired in S702 and used for encryption (S708). Note that the encryption is a process of keeping data secret by regularly rearranging data signals with an encryption key.

  Next, a decryption license is generated by combining the user ID with the license B generated in S708 (S709-1).

  On the other hand, when the user key does not exist in S702, the user ID and the license ID are not the same in S703, the corresponding record does not exist in S704, the license information does not exist in S705, or the content key does not exist in S707. In step S709-2, a message indicating that the decryption license cannot be issued is generated using the user ID and license ID of the plaintext part received in step S701.

  Finally, the decryption license generated in S709-1 or the message generated in S709-2 is transmitted to the user terminal 300 (S710).

Shuichi Nishioka, 7 others, “Construction of Rights Distribution Base for Digital Contents”, Transactions of Information Processing Society of Japan, Vol.45, No.SIG 7, June 2004, p.243-254

  As described above, in the conventional license generation system, an encryption key unique to the user terminal is held in advance in the server, and decryption and encryption are performed using the encryption key held in advance. When there are a plurality of service providers that provide services to user terminals using the service provider, it is necessary to share the encryption key unique to the user terminal among the service providers.

  However, since the encryption key unique to the user terminal is highly confidential information, it is a security problem to directly send and receive the key value itself between service providers. In addition, since the case where the service policy for generating the decryption license differs for each service provider is considered, it is difficult to appropriately share the conventional license generation system across all service providers. is there.

  Therefore, only the processing (S702, S703, S707, S708) related to encryption and decryption using the encryption key unique to the user terminal is separated (divided) from the overall processing related to license issuance (S701 to S710). Encryption is divided into an encryption / decryption provider that performs encryption / decryption processing using a unique encryption key, and a service provider that determines the license generation policy and provides services to user terminals. / Decryption processing needs to be shared by a plurality of service providers.

  Here, if only the encryption / decryption process is simply separated (divided) from the entire process, when issuing one decryption license, the service provider and the encryption / decryption company Since data is transferred twice (two times at the time of decryption at S702 and S703 and at the time of encryption at S707 and S708), the processing time and processing load related to generation and issue of the decryption license increase. End up.

  The present invention has been made in view of the above, and even when there are a plurality of service providers that issue decryption licenses, a highly confidential encryption key is handled with high security, and for decryption. It is an object to reduce the processing time required for generating a license and shorten the processing time.

  The license generation system according to claim 1, comprising a license generation device and a data encryption / decryption device, wherein the license generation system generates a decryption license capable of decrypting the encrypted digital content. The license generation device includes a first storage unit that stores a license ID that identifies a license of the digital content and license information that defines a use condition of the license, and a plaintext user transmitted from the user terminal Receiving means for receiving a license acquisition request having an ID and license ID and a user ID and license ID encrypted with the encryption key of the user terminal; and license information corresponding to the plaintext license ID in the first storage means From the plaintext and the encrypted user I And a transmission means for transmitting to the data encryption / decryption device together with the license ID, and a generation means for generating the decryption license using the encrypted data transmitted from the data encryption / decryption device. The data encryption / decryption device includes a second storage unit that stores a user ID for identifying a user terminal and an encryption key of the user terminal in association with each other, and the license ID is encrypted. Third storage means for storing an associated digital content encryption key for decrypting the digital content, the license information transmitted from the license generating device, the plain text, and the encrypted user ID and license ID. And receiving the encryption key of the user terminal corresponding to the plaintext user ID from the second storage means, Decrypting means for decrypting the encrypted user ID and license ID using the encryption key of the user terminal, and the decrypted user ID and license ID match the plain text user ID and license ID. In such a case, an encryption key for acquiring a digital content encryption key corresponding to the license ID from the third storage means and combining with the license information is encrypted with the encryption key of the user terminal used for the decryption. And a transmission means for transmitting encrypted data of the encrypted license information and the encryption key of the digital content to the license generation apparatus.

  According to the present invention, an encryption / decryption function is encrypted / decrypted by a configuration in which a function for generating a decryption license and a function for encryption / decryption using a highly confidential encryption key are divided. A wide variety of service providers that can be executed only by a decryption company and can handle highly confidential encryption keys with high security even when there are multiple service providers that issue decryption licenses. Can flexibly respond to services. Further, since decryption and encryption are continuously performed at a time, the number of times of data transfer between the license generation device and the data encryption / decryption device is reduced, and processing required for generating a decryption license The load can be suppressed and the processing time can be shortened.

  The license generation system according to claim 2 is the license generation system according to claim 1, wherein the second storage unit stores the user ID and the encryption key of the user terminal in association with a process ID. The decryption means, when a process ID is included in the license acquisition request, obtains an encryption key of the user terminal further corresponding to the process ID from the second storage means and performs the decryption. And

  According to the present invention, the user ID and the encryption key of the user terminal are stored in association with the process ID, and the encryption key of the user terminal further corresponding to the process ID is acquired and decrypted. Thus, the encryption key of the user terminal used for encryption / decryption can be changed, and security can be improved.

  The license generation system according to claim 3 is the license generation system according to claim 1 or 2, wherein the third storage unit stores the license ID and the encryption key of the digital content in association with an operator ID. In addition, when the license acquisition request includes an operator ID, the encryption means acquires an encryption key of digital content further corresponding to the operator ID from the third storage means, and It is characterized by becoming.

  According to the present invention, the license ID and the digital content encryption key are stored in association with the business ID, and the digital content encryption key further corresponding to the business ID is acquired and encrypted. The content encryption key can be changed according to the ID, and security can be improved.

  The license generation method according to claim 4, comprising a license generation device and a data encryption / decryption device, wherein the license generation method generates a decryption license capable of decrypting the encrypted digital content. The license generating device stores the license ID for identifying the license of the digital content and the license information defining the license usage conditions in association with each other in the first storage unit, and the license is transmitted from the user terminal. A receiving step of receiving a license acquisition request having a plain text user ID and license ID and a user ID and license ID encrypted with the encryption key of the user terminal; and license information corresponding to the plain text license ID The plaintext and the encryption obtained from one storage means A transmission step of transmitting to the data encryption / decryption device together with the received user ID and license ID, the user ID for identifying the user terminal by the data encryption / decryption device, and the user terminal A storage step of associating an encryption key with the second storage means, and storing the license ID and the encryption key of the digital content for decrypting the encrypted digital content in the third storage means in association with each other. A storing step; a receiving step for receiving the license information transmitted from the license generating device; the plain text and the encrypted user ID and license ID; and an encryption of the user terminal corresponding to the plain text user ID. A key is obtained from the second storage means, and the encrypted data is obtained using the obtained encryption key of the user terminal. A decrypting step for decrypting the user ID and license ID, and encryption of the digital content corresponding to the license ID if the decrypted user ID and license ID match the plain text user ID and license ID An encryption step of acquiring a key from the third storage means and combining the license information with the encryption information of the user terminal used for the decryption; the encrypted license information and the digital content A transmission step of transmitting the encrypted data with the encryption key to the license generation device, and the decryption license using the encrypted data transmitted from the data encryption / decryption device by the license generation device. And a generating step for generating.

  According to the present invention, the encryption / decryption process is encrypted / decrypted by the configuration in which the process of generating a decryption license and the process of encryption / decryption using a highly confidential encryption key are divided. A wide variety of service providers that can be executed only by a decryption company and can handle highly confidential encryption keys with high security even when there are multiple service providers that issue decryption licenses. Can flexibly respond to services. Further, since decryption and encryption are continuously performed at a time, the number of times of data transfer between the license generation device and the data encryption / decryption device is reduced, and processing required for generating a decryption license The load can be suppressed and the processing time can be shortened.

  The license generation method according to claim 5 is the license generation method according to claim 4, wherein the second storage means stores the user ID and the encryption key of the user terminal in association with a process ID. In the decryption step, when a process ID is included in the license acquisition request, an encryption key of the user terminal further corresponding to the process ID is acquired from the second storage unit, and the decryption is performed. And

  According to the present invention, the user ID and the encryption key of the user terminal are stored in association with the process ID, and the encryption key of the user terminal further corresponding to the process ID is acquired and decrypted. Thus, the encryption key of the user terminal used for encryption / decryption can be changed, and security can be improved.

  The license generation method according to claim 6 is the license generation method according to claim 4 or 5, wherein the third storage unit stores the license ID and the encryption key of the digital content in association with an operator ID. In the encryption step, when a license ID is included in the license acquisition request, an encryption key of digital content further corresponding to the license ID is acquired from the third storage unit, and the encryption is performed. It is characterized by becoming.

  According to the present invention, the license ID and the digital content encryption key are stored in association with the business ID, and the digital content encryption key further corresponding to the business ID is acquired and encrypted. The content encryption key can be changed according to the ID, and security can be improved.

  A license generation program according to a seventh aspect causes a computer to execute each step in the license generation method according to any one of the fourth to sixth aspects.

  According to the present invention, even when there are a plurality of service providers that issue decryption licenses, a highly confidential encryption key is handled with high security, and the processing load required to generate a decryption license is reduced. It is possible to suppress the processing time.

It is a figure which shows the whole structure of a license production | generation system. It is a figure which shows the functional block structure of the license generation system which concerns on 1st Embodiment. It is a figure which shows the processing flow of the license generation system which concerns on 1st Embodiment. It is a figure which shows the functional block structure of the license generation system which concerns on 2nd Embodiment. It is a figure which shows the processing flow of the license generation system which concerns on 2nd Embodiment. It is a figure which shows the functional block structure of the license generation system which concerns on 3rd Embodiment. It is a figure which shows the processing flow of the license generation system which concerns on 3rd Embodiment. It is a figure which shows the whole structure of the conventional license generation system.

  The present invention provides a process for generating a decryption license in a process for generating a decryption license for decrypting encrypted digital content using a user ID and a license ID received from a user terminal, It is characterized by dividing the process of encryption / decryption using a high encryption key.

  Further, when the license generation process is performed by the license generation apparatus and the process using the encryption key is performed by the data encryption / decryption apparatus, the encryption process is performed after the decryption process and the license generation apparatus. This is performed before transmitting the encrypted data. In other words, the process of decrypting by using the encryption key unique to the user terminal and confirming the identity and the process of encrypting the generated license are continuously performed at once by the data encryption / decryption device. To do. Note that the decryption process and the encryption process may be performed at the same time, but this simultaneous is just one example.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes and should not be construed as being limited to the description of the present embodiment.

[First Embodiment]
First, the configuration of the license generation system will be described. FIG. 1 is a diagram showing the overall configuration of the license generation system. The overall configuration shown in FIG. 1 is common to second and third embodiments described later.

  This license generation system is a configuration example when used for a paid content viewing service for digital broadcasting, and a user terminal 300 that receives encrypted digital content through a digital broadcast wave, and a user terminal via an IP network 500 The license generation apparatus 100a and the data encryption / decryption apparatus 100b are configured to generate a decryption license capable of decrypting the digital content.

  In the overall configuration shown in FIG. 1, a plurality of license generation devices 100a are shown, but the functions are the same. It is assumed that the license generation device 100a is used by a service provider, and the data encryption / decryption device 100b is used by an encryption / decryption operator. The reason why a plurality of license generation apparatuses 100a are used is based on the assumption that a service policy for generating a decryption license is different for each service provider while a process for generating and issuing a decryption license is common. .

  FIG. 2 is a diagram illustrating a functional block configuration of the license generation system according to the first embodiment.

  In order to decrypt the encrypted digital content, the user terminal 300 requests the license generation device 100a for a decryption license using the user ID and the license ID, and digitally uses the returned decryption license. It has a function of decrypting content. The license acquisition request transmitted at the time of request includes the plain text user ID and license ID (plain text portion), and the user ID and license ID (encryption portion) encrypted with the user key of the user terminal 300. Yes.

  The user ID is an ID for identifying the user terminal 300. The license ID is an ID for identifying a license of digital content.

  On the other hand, the license generation apparatus 100a holds a function for generating a decryption license based on a user-specific contract from the user ID and license ID transmitted from the user terminal 300, and contract information corresponding to the user ID and license ID. And a DB that holds license information corresponding to the license ID. Specifically, it includes a transmission / reception unit 11, a search / determination unit 12, a search / acquisition unit 13, a generation unit 14, a contract DB 15, and a license information DB 16.

  The transmission / reception unit 11 has a function of receiving a license acquisition request transmitted from the user terminal 300 via the IP network 500 and a function of transmitting a decryption license to the user terminal 300 via the IP network 500. . In addition, the data encryption / decryption device 100b has a function of transmitting and receiving data.

  The search / determination unit 12 has a function of searching the contract DB 15 using the user ID and license ID as keys and determining whether or not a corresponding record exists.

  The search / acquisition unit 13 has a function of searching the license information DB 16 using the license ID as a key and acquiring license information corresponding to the license ID.

  The generation unit 14 combines the user ID and the license information to generate a license A, or generates a decryption license by combining the user ID with the license B generated by the data encryption / decryption device 100b. And a function for generating a message indicating that the decryption license cannot be issued.

  The contract DB 15 holds user IDs and license IDs in a one-to-many manner, and has a function of holding a license ID of a license contracted for each user ID. If a record exists, it means that a contract exists.

  The license information DB 16 holds license IDs and license information on a one-to-one basis, and has a function of holding license information set for each license ID. Note that the license information is right information that defines license usage conditions.

  On the other hand, the data encryption / decryption device 100b is communicably connected to the license generation device 100a, and is encrypted / decrypted with an encryption key using the license A, user ID, and license ID transmitted from the license generation device 100a. A DB that holds a user key corresponding to the user ID, and a DB that holds a content key corresponding to the license ID. Specifically, it includes a transmission / reception unit 31, a search / acquisition unit 32, a decryption / determination unit 33, an encryption / generation unit 34, a user key DB 35, and a content key DB 36.

  The user key is an encryption key unique to the user terminal, and the content key is an encryption key for digital content for decrypting the digital content.

  The transmission / reception unit 31 has a function of transmitting / receiving data to / from the license generation apparatus 100a.

  The search / acquisition unit 32 searches the user key DB 35 using the user ID as a key, searches the content key DB 36 using the function that acquires the user key corresponding to the user ID, and the license ID as a key, and corresponds to the license ID. Has a function of acquiring a content key to be used.

  The decryption / determination unit 33 has a function of decrypting the encryption unit using the user key, extracting the user ID and license ID, and determining whether or not they are the same as compared with the user ID and license ID of the plaintext part. doing.

  The encryption / generation unit 34 combines the content key with the license A generated by the license generation device 100a continuously after the decryption, and encrypts the license B using the user key used for encryption. It has a function to generate. Note that the encryption process is preferably performed simultaneously with the decryption process.

  The user key DB 35 holds a user ID and a user key on a one-to-one basis, and has a function of holding a user key set for each user ID.

  The content key DB 36 holds a license ID and a content key on a one-to-one basis, and has a function of holding a content key set for each license ID.

  Next, the operation of the license generation system according to the present embodiment will be described. FIG. 3 is a diagram showing a processing flow of the license generation system according to the present embodiment.

  First, the plaintext part (user ID, license ID) transmitted from the user terminal 300 by the transmission / reception part 11 of the license generation device 100a and the encryption part (user ID) encrypted with the user key of the user terminal 300 are used. , License ID) is received (S101).

  Next, the search / determination unit 12 searches the contract DB 15 using the user ID and license ID of the plaintext part received in S101 as keys, and determines whether or not a corresponding record exists (S102). As a result of searching the contract DB 15, if there is no corresponding record, the process proceeds to S113-2.

  Next, if there is a corresponding record as a result of the determination in S102, the search / acquisition unit 13 searches the license information DB 16 using the license ID of the plaintext part received in S101 as a key, and corresponds to the license ID. License information is acquired (S103). If the license information does not exist as a result of searching the license information DB 16, the process proceeds to S113-2.

  Next, the license A is generated by combining the license information acquired in S103 and the plaintext user ID received in S101 by the generating unit 14 (S104). Note that the license A is a license in a state where the encryption process using the user key is not performed.

  Next, the license A generated in S104, the plaintext part (user ID, license ID) and the encryption part (user ID, license ID) received in S101 are transmitted to the data encryption / decryption device 100b by the transmission / reception unit 11. (S105).

  Next, the license A, the plaintext part (user ID, license ID), and the encryption part (user ID, license ID) transmitted from the license generation apparatus 100a by the transmission / reception part 31 of the data encryption / decryption apparatus 100b. Received (S106).

  Next, the search / acquisition unit 32 searches the user key DB 35 using the plaintext user ID received in S106 as a key, and acquires the user key of the user terminal 300 (S107). As a result of searching the user key DB 35, if the user key does not exist, the process proceeds to S113-2.

  Next, the decryption / determination unit 33 decrypts the encryption unit (user ID, license ID) received in S106 using the user key acquired in S107, and extracts the user ID and license ID. It is determined whether or not the user ID and the license ID are the same (whether or not they match) (S108). If the user ID and the license ID are not the same, the validity of the license acquisition request is denied, and the process proceeds to S113-2. Decryption is a process of decrypting data encrypted by the user key back to plain text.

  Next, if the search / acquisition unit 32 determines that the user ID and the license ID are the same as a result of the determination in S108, immediately after decryption in S108, the content key DB 36 using the plaintext part license ID received in S106 as a key. Is retrieved, and the content key corresponding to the license ID is acquired (S109). If the content key does not exist as a result of searching the content key DB 36, the process proceeds to S113-2.

  Next, immediately after the acquisition of S109, the encryption / generation unit 34 combines the content key acquired in S109 with the license A received in S106, and encrypts it using the user key acquired and encrypted in S107. As a result, a license B (encrypted data) is generated (S110). Note that the encryption is a process of keeping data secret by regularly rearranging data signals with an encryption key.

  Next, the transmission / reception unit 31 transmits the license B generated in S110 to the license generation device 100a (S111).

  Next, the license B transmitted from the data encryption / decryption device 100b is received by the transmission / reception unit 11 of the license generation device 100a (S112).

  Next, the generating unit 14 combines the user ID with the license B received in S112 to generate a decryption license (S113-1).

  On the other hand, if there is no corresponding record in S102, no license information exists in S103, no user key exists in S107, if the user ID and license ID are not the same (does not match) in S108, the content key in S109 Is not generated, the generation unit 14 generates a message indicating that the decryption license cannot be issued using the user ID and license ID of the plaintext part (S113-2).

  Finally, the transmission / reception unit 11 transmits the decryption license generated in S113-1 or the message generated in S113-2 to the user terminal 300 (S114).

  As a result, the user terminal 300 can decrypt the decryption license using its own user key, and decrypt the digital content using the content key obtained by the decryption.

  According to the present embodiment, when providing a service for issuing a decryption license to the user terminal 300 from a plurality of service providers, the license generation apparatus 100a that defines a service policy for generating a decryption license. And the data encryption / decryption device 100b that performs processing using a highly confidential encryption key, the license generation device 100a can be held for each service provider, thereby diversifying services. The data encryption / decryption device 100b can be held by the encryption / decryption provider, and security can be improved.

  Further, according to the present embodiment, the number of communications between the license generation device 100a and the data encryption / decryption device 100b is reduced by performing the encryption process and the decryption process at once. Therefore, it is possible to reduce the processing load required for generating the decryption license and shorten the processing time.

[Second Embodiment]
Next, a second embodiment will be described. FIG. 4 is a diagram illustrating a functional block configuration of the license generation system according to the second embodiment.

  The user terminal 300 has a function of transmitting a license acquisition request further having a process ID for identifying a process to the license generation apparatus 100a. This processing ID is passed in advance from the service provider to the user of the user terminal 300 in combination with the license ID.

  The user key DB 35 of the data encryption / decryption device 100b has a function of holding the held user ID and user key in association with the processing ID. FIG. 4 shows a user key DB (1) 35a associated with one process ID and a user key DB (2) 35b associated with a second process ID. The relationship between the process ID, the user ID, and the user key is presented in advance from the service provider to the encryption / decryption provider.

  The search / acquisition unit 32 of the data encryption / decryption device 100b has a function of acquiring a user key corresponding to the process ID from the user key DB 35 when the process ID is included in the license acquisition request. .

  In addition, since the function of each other function part is the same as that of what was demonstrated in 1st Embodiment, the overlapping description is abbreviate | omitted.

  Next, the operation of the license generation system according to the present embodiment will be described. FIG. 5 is a diagram showing a processing flow of the license generation system according to the present embodiment.

  First, the plaintext part (user ID, license ID, processing ID) transmitted from the user terminal 300 by the transmission / reception part 11 of the license generation device 100a and the encryption part encrypted with the user key of the user terminal 300 A license acquisition request having (user ID, license ID) is received (S301).

  Next, the search / determination unit 12 searches the contract DB 15 using the user ID and license ID of the plaintext part received in S301 as keys, and determines whether or not the corresponding record exists (S302). If the corresponding record does not exist as a result of searching the contract DB 15, the process proceeds to S314-2.

  Next, if there is a corresponding record as a result of the determination in S302 by the search / acquisition unit 13, the license information DB 16 is searched using the license ID of the plaintext portion received in S301 as a key, and the corresponding license ID is obtained. License information is acquired (S303). As a result of searching the license information DB 16, if there is no license information, the process proceeds to S314-2.

  Next, the license A is generated by combining the license information acquired in S303 and the plaintext user ID received in S301 by the generating unit 14 (S304).

  Next, the license A generated in S304, the plaintext part (user ID, license ID, processing ID) received in S301, and the encryption part (user ID, license ID) are encrypted and decrypted by the transmission / reception unit 11. (S305).

  Next, the license A, plaintext part (user ID, license ID, processing ID), and encryption part (user ID, license ID) transmitted from the license generation apparatus 100a by the transmission / reception part 31 of the data encryption / decryption apparatus 100b. ) Is received (S306).

  Next, the process ID received in S306 is confirmed by the search / acquisition unit 32 (S307). If the process ID is 1, the process proceeds to S308-1, and if the process ID is 2, the process proceeds to S308-2.

  Next, when the processing ID is 1 as a result of the confirmation in S307, the search / acquisition unit 32 searches the user key DB (1) 35a using the user ID of the plaintext part received in S306 as a key, and the user terminal 300 User key A is acquired (S308-1). As a result of searching the user key DB (1) 35a, if the user key does not exist, the process proceeds to S314-2.

  On the other hand, if the processing ID is 2 as a result of the confirmation in S307, the user key DB (2) 35b is searched using the plaintext part user ID received in S306 as a key, and the user key B of the user terminal 300 is obtained. (S308-2). As a result of searching the user key DB (2) 35b, if the user key does not exist, the process proceeds to S314-2.

  Next, the decryption / determination unit 33 decrypts the encryption unit (user ID, license ID) received in S306 using the user key A acquired in S308-1 or the user key B acquired in S308-2. Then, the user ID and the license ID are extracted, and compared with the user ID and the license ID in the plaintext part, it is determined whether or not they are the same (whether they match) (S309). When the user ID and the license ID are not the same, the validity of the license acquisition request is denied, and the process proceeds to S314-2.

  Next, if the search / acquisition unit 32 determines that the user ID and the license ID are the same as a result of the determination in S309, immediately after the decryption in S309, the content key DB 36 using the plaintext part license ID received in S306 as a key. Is retrieved, and a content key corresponding to the license ID is acquired (S310). If the content key does not exist as a result of searching the content key DB 36, the process proceeds to S314-2.

  Next, immediately after acquisition of S310, the content key acquired in S310 is combined with the license A received in S306 by the encryption / generation unit 34, and the user acquired in S308-1 or S308-2 and used for encryption By encrypting with the key, a license B (encrypted data) is generated (S311).

  Next, the transmission / reception unit 31 transmits the license B generated in S311 to the license generation apparatus 100a (S312).

  Next, the license B transmitted from the data encryption / decryption device 100b is received by the transmission / reception unit 11 of the license generation device 100a (S313).

  Next, the generating unit 14 combines the user ID with the license B received in S313, thereby generating a decryption license (S314-1).

  On the other hand, if the corresponding record does not exist in S302, the license information does not exist in S303, the user key does not exist in S308-1 or S308-2, the user ID and the license ID are not the same (does not match) in S309. In this case, if the content key does not exist in S310, the generation unit 14 generates a message indicating that the decryption license cannot be issued using the plaintext part user ID and license ID (S314-2). .

  Finally, the transmission / reception unit 11 transmits the decryption license generated in S314-1 or the message generated in S314-2 to the user terminal 300 (S315).

  According to this embodiment, the user ID and the user key are stored in association with the process ID, and the encryption key of the user terminal corresponding to the process ID is further acquired and decrypted. The user key used for encryption / decryption can be changed, and security can be improved. As a result, the service provider can use a plurality of user keys in accordance with the processing ID, and security can be improved.

[Third Embodiment]
Next, a third embodiment will be described. FIG. 6 is a diagram illustrating a functional block configuration of a license generation system according to the third embodiment.

  The user terminal 300 has a function of transmitting a license acquisition request further having a business ID for identifying a service business to the license generation device 100a. The provider ID is handed over in advance from the service provider to the user of the user terminal 300 in combination with the license ID.

  The content key DB 36 of the data encryption / decryption device 100b has a function of holding the held license ID and content key in association with the provider ID. FIG. 6 shows a content key DB (1) 36a associated with one operator ID and a content key DB (2) 36b associated with a second operator ID. The relationship between the provider ID, the license ID, and the content key is previously presented by the service provider to the encryption / decryption provider.

  The search / acquisition unit 32 of the data encryption / decryption device 100b has a function of acquiring a content key corresponding to the business ID from the content key DB 36 when the business ID is included in the license acquisition request. ing.

  In addition, since the function of each other function part is the same as that of what was demonstrated in 1st Embodiment, the overlapping description is abbreviate | omitted.

  Next, the operation of the license generation system according to the present embodiment will be described. FIG. 7 is a diagram showing a processing flow of the license generation system according to the present embodiment.

  First, the plaintext part (user ID, license ID, business ID) transmitted from the user terminal 300 by the transmission / reception part 11 of the license generation device 100a and the encryption encrypted with the user key of the user terminal 300 are encrypted. A license acquisition request having a part (user ID, license ID) is received (S501).

  Next, the search / determination unit 12 searches the contract DB 15 using the user ID and license ID of the plaintext part received in S501 as keys, and determines whether or not a corresponding record exists (S502). As a result of searching the contract DB 15, if there is no corresponding record, the process proceeds to S514-2.

  Next, if there is a corresponding record as a result of the determination in S502, the search / acquisition unit 13 searches the license information DB 16 using the license ID of the plaintext part received in S501 as a key, and corresponds to the license ID. License information is acquired (S503). If the license information does not exist as a result of searching the license information DB 16, the process proceeds to S514-2.

  Next, the license A is generated by combining the license information acquired in S503 and the plaintext part user ID received in S501 by the generating unit 14 (S504).

  Next, the transmission / reception unit 11 causes the license A generated in S504, the plaintext part (user ID, license ID, business ID) received in S501, and the encryption part (user ID, license ID) to be data encrypted / The data is transmitted to the decryption device 100b (S505).

  Next, the license A, the plaintext part (user ID, license ID, business ID) and the encryption part (user ID, license) transmitted from the license generation apparatus 100a by the transmission / reception part 31 of the data encryption / decryption apparatus 100b. ID) is received (S506).

  Next, the search / acquisition unit 32 searches the user key DB 35 using the plaintext part user ID received in S506 as a key, and acquires the user key of the user terminal 300 (S507). If the user key does not exist as a result of searching the user key DB 35, the process proceeds to S514-2.

  Next, the decryption / determination unit 33 uses the user key acquired in S507 to decrypt the encryption unit (user ID, license ID) received in S506 to extract the user ID and license ID. It is determined whether or not the user ID and the license ID are the same (whether or not they match) (S508). If the user ID and the license ID are not the same, the validity of the license acquisition request is denied, and the process proceeds to S514-2.

  Next, when the user ID and the license ID are the same as a result of the determination in S508, the searcher / acquisition unit 32 confirms the business operator ID received in S506 (S509). If the business ID is 1, the process proceeds to S510-1, and if the process ID is 2, the process proceeds to S510-2.

  Next, when the search / acquisition unit 32 confirms S509 that the provider ID is 1, immediately after decryption of S508, the license ID of the plaintext part received in S506 is used as a key for the content key DB (1) 36a is searched, and the content key A corresponding to the license ID is acquired (S510-1). If the content key does not exist as a result of searching the content key DB (1) 36a, the process proceeds to S514-2.

  On the other hand, if the operator ID is 2 as a result of the confirmation in S509, the content key DB (2) 36b is searched using the plaintext part license ID received in S506 as a key immediately after the decryption in S508, and the license The content key B corresponding to the ID is acquired (S510-2). If the content key does not exist as a result of searching the content key DB (2) 36b, the process proceeds to S514-2.

  Next, immediately after acquisition of S510-1 or S510-2 by the encryption / generation unit 34, the content key A acquired in S510-1 or the content key B acquired in S510-2 is added to the license A received in S506. The license B (encrypted data) is generated by performing the encryption using the user key that has been combined and acquired in S507 and used for the encryption (S511).

  Next, the transmission / reception unit 31 transmits the license B generated in S511 to the license generation apparatus 100a (S512).

  Next, the transmission / reception unit 11 of the license generation device 100a receives the license B transmitted from the data encryption / decryption device 100b (S513).

  Next, the generating unit 14 combines the user ID with the license B received in S513 to generate a decryption license (S514-1).

  On the other hand, if the corresponding record does not exist in S502, the license information does not exist in S503, the user key does not exist in S507, the user ID and the license ID do not match (does not match) in S508, S510-1 or If the content key does not exist in S510-2, the generation unit 14 generates a message indicating that the decryption license cannot be issued using the plaintext part user ID and license ID (S514-2). .

  Finally, the transmission / reception unit 11 transmits the decryption license generated in S514-1 or the message generated in S514-2 to the user terminal 300 (S515).

  According to the present embodiment, the license ID and the digital content key are stored in association with the business ID, and the digital content key further corresponding to the business ID is acquired and encrypted. Accordingly, it becomes possible to change the encryption key of the content, and the security can be improved. In addition, the content key can be stored in a different DB for each service provider, and security can be improved.

  As described above, according to all the embodiments, in a service that provides a decryption license to a user terminal 300 from a plurality of service providers, the license generation device 100a that defines a service policy for a decryption license, By dividing the data encryption / decryption device 100b that performs processing using a highly confidential encryption key, the license generation device 100a can be held for each service provider, and the service can be diversified. The encryption / decryption device 100b can be held by the encryption / decryption provider, and security can be improved.

  In addition, according to all the embodiments, the number of communications between the license generation device 100a and the data encryption / decryption device 100b is reduced by performing the encryption process and the decryption process at once. Thus, the processing load required for generating the decryption license can be suppressed and the processing time can be shortened.

  Further, according to the second embodiment, the user ID and the user key are stored in association with the process ID, and the encryption key of the user terminal corresponding to the process ID is further acquired and decrypted. The user key used for encryption / decryption can be changed according to the ID, and security can be improved. As a result, the service provider can use a plurality of user keys in accordance with the processing ID, and security can be improved.

  According to the third embodiment, the license ID and the digital content key are stored in association with the business ID, and the digital content key further corresponding to the business ID is acquired and encrypted. It becomes possible to change the encryption key of the content in accordance with the provider ID, and to improve the security. In addition, the content key can be stored in a different DB for each service provider, and security can be improved.

  Finally, the license generation system described in the present embodiment is configured by a computer. That is, the contract DB 15, the license information DB 16, the user key DB 35, and the content key DB 36 are realized by storage means such as a memory or a hard disk. The transmission / reception unit 11, the search / determination unit 12, the search / acquisition unit 13, the generation unit 14, the transmission / reception unit 31, the search / acquisition unit 32, the decryption / determination unit 33, and the encryption / generation The unit 34 is realized by a calculation means such as a CPU and executed by a program.

  Further, the license generation system described in the present embodiment is recorded as a program in a readable manner on a recording medium such as an optical storage device or a magnetic storage device, and the recording medium is incorporated in a computer or recorded on the recording medium. Can be downloaded to a computer via an arbitrary communication line or installed from a recording medium, and the computer can be operated by the program, so that each processing operation described above can function as a license generation system. It is.

DESCRIPTION OF SYMBOLS 100a ... License generation apparatus 11 ... Transmission / reception part 12 ... Search / determination part 13 ... Search / acquisition part 14 ... Generation part 15 ... Contract DB
16 ... License information DB
DESCRIPTION OF SYMBOLS 100b ... Data encryption / decryption apparatus 31 ... Transmission / reception part 32 ... Search / acquisition part 33 ... Decryption / determination part 34 ... Encryption / generation part 35 ... User key DB
36 ... Content key DB
300 ... User terminal 500 ... IP network S101-S114, S301-S315, S501-S515, S701-S710 ... step

Claims (7)

A license generation system that includes a license generation device and a data encryption / decryption device, and generates a decryption license capable of decrypting encrypted digital content.
The license generation device includes:
First storage means for storing a license ID for identifying a license of the digital content and license information that defines a use condition of the license in association with each other;
Receiving means for receiving a license acquisition request having a plain text user ID and license ID transmitted from the user terminal and a user ID and license ID encrypted with the encryption key of the user terminal;
Transmission means for acquiring license information corresponding to the plaintext license ID from the first storage means, and transmitting the license information together with the plaintext and the encrypted user ID and license ID to the data encryption / decryption device;
Generating means for generating the decryption license using the encrypted data transmitted from the data encryption / decryption device;
The data encryption / decryption device comprises:
A second storage means for storing the user ID for identifying the user terminal and the encryption key of the user terminal in association with each other;
Third storage means for storing the license ID in association with an encryption key of the digital content for decrypting the encrypted digital content;
Receiving means for receiving the license information transmitted from the license generating device, the plain text, and the encrypted user ID and license ID;
Decryption that acquires the encryption key of the user terminal corresponding to the plaintext user ID from the second storage means and decrypts the encrypted user ID and license ID using the acquired encryption key of the user terminal And
When the decrypted user ID and license ID match the plain text user ID and license ID, an encryption key of the digital content corresponding to the license ID is obtained from the third storage means, and the license information and Encryption means for combining and encrypting with the encryption key of the user terminal used for the decryption;
Transmitting means for transmitting encrypted data of the encrypted license information and the encryption key of the digital content to the license generating device;
A license generation system comprising: The second storage means
The user ID and the encryption key of the user terminal are stored in association with the process ID,
The decoding means includes
2. The process according to claim 1, wherein when a process ID is included in the license acquisition request, an encryption key of a user terminal further corresponding to the process ID is acquired from the second storage unit and decrypted. License generation system. The third storage means
The license ID and the encryption key of the digital content are stored in association with an operator ID,
The encryption means includes
2. When the license acquisition request includes a business ID, the digital content encryption key further corresponding to the business ID is acquired from the third storage unit and encrypted. Or the license generation system according to 2; In a license generation method that includes a license generation device and a data encryption / decryption device and generates a decryption license capable of decrypting encrypted digital content,
By the license generation device,
A storage step of associating the license ID for identifying the license of the digital content with the license information defining the license usage condition in the first storage unit;
Receiving a license acquisition request having a plain text user ID and license ID transmitted from the user terminal and a user ID and license ID encrypted with the encryption key of the user terminal;
Transmitting license information corresponding to the plaintext license ID from the first storage means, and transmitting the license information together with the plaintext and the encrypted user ID and license ID to the data encryption / decryption device; Have
By the data encryption / decryption device,
A storage step of associating the user ID for identifying the user terminal with the encryption key of the user terminal and storing it in the second storage means;
A storage step of associating the license ID with a digital content encryption key for decrypting the encrypted digital content in a third storage means;
Receiving the license information transmitted from the license generating device, the plain text and the encrypted user ID and license ID;
Decryption that acquires the encryption key of the user terminal corresponding to the plaintext user ID from the second storage means and decrypts the encrypted user ID and license ID using the acquired encryption key of the user terminal Step,
When the decrypted user ID and license ID match the plain text user ID and license ID, an encryption key of the digital content corresponding to the license ID is obtained from the third storage means, and the license information and An encryption step of combining and encrypting with the encryption key of the user terminal used for the decryption;
Transmitting the encrypted data of the encrypted license information and the encryption key of the digital content to the license generating device;
By the license generation device,
Generating the decryption license using the encrypted data transmitted from the data encryption / decryption device;
A license generation method characterized by comprising: The second storage means
The user ID and the encryption key of the user terminal are stored in association with the process ID,
The decoding step includes
5. The process according to claim 4, wherein when a process ID is included in the license acquisition request, an encryption key of a user terminal further corresponding to the process ID is acquired from the second storage unit and decrypted. License generation method. The third storage means
The license ID and the encryption key of the digital content are stored in association with an operator ID,
The encryption step includes
5. When the license acquisition request includes a business ID, the digital content encryption key further corresponding to the business ID is acquired from the third storage means and encrypted. Or the license generation method according to 5.   A license generation program that causes a computer to execute each step in the license generation method according to claim 4.

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