Information management system, control method for information management system, and program

Abstract

To appropriately manage modification to an image while securing authenticity of the modification from the original image.SOLUTION: There are provided: managing means which manages, in a block chain form, first information regarding a first image and second information regarding a second image modified from the first image; and determination means which determines whether contents of the modification of the second image is within a permissible rage on the basis of information contained in the first information and indicating the permissible range to the first image. When it is determined being within the permissible range by the determination means, the managing means registers the second information to the block chain.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an information management system, a control method for an information management system, and a program. [Background technology]

[0002] In recent years, with the development of image editing technology, fake images have been created that are so elaborate that it is difficult to tell whether they are real images or not. Therefore, there is a demand for guaranteeing the authenticity of captured images. Patent Document 1 discloses a method of generating a hash value from an image using a hash function when capturing an image, adding a digital signature to the hash value, and registering it in a blockchain. Patent Document 2 discloses a technology for managing the history of content changes using a blockchain. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-209744 A [Patent Document 2] JP 2019-121946 A Summary of the Invention [Problem to be solved by the invention]

[0004] According to the above-mentioned prior art documents, it is possible to guarantee the authenticity of an image and to manage the modification history of an image that has been modified from the original image. However, since no restrictions are placed on the modification of an image, it is not possible to appropriately manage the modification of an image.

[0005] Therefore, an object of the present invention is to appropriately manage alterations made to an image while ensuring the authenticity of the alterations made from the original image. [Means for solving the problem]

[0006] The information management system of the present invention comprises a management means for managing first information related to a first image and second information related to a second image altered from the first image in the form of a blockchain, and a judgment means for judging whether the alteration of the second image is within the permitted range based on information contained in the first information indicating the permitted range of alteration to the first image, and is characterized in that the management means registers the second information in the blockchain when the judgment means judges that the alteration is within the permitted range. Effect of the Invention

[0007] According to the present invention, alterations made to an image can be appropriately managed while ensuring the authenticity of the alterations made to the original image. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 1 illustrates an example of a system configuration. [Figure 1B] FIG. 2 is a diagram illustrating an example of a hardware configuration of an information management system. [Diagram 2] FIG. 2 is a diagram illustrating an example of a functional configuration of an information management system. [Diagram 3] 13 is a flowchart showing an alteration content determination process. [Figure 4] FIG. 2 is a sequence diagram showing a series of operations performed by the information management system. [Diagram 5] FIG. 2 is a diagram illustrating an example of a functional configuration of an information management system. [Figure 6] FIG. 13 is a diagram for explaining reward distribution. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment does not limit the present invention related to the scope of the claims, and not all of the combinations of features described in the present embodiment are necessarily essential to the solution of the present invention. Note that the same components are described with the same reference numerals.

[0010] [First embodiment] FIG. 1A is a diagram showing an example of a system configuration including an information management system according to the present embodiment. The information management system 1 is a system that manages images acquired from image registration devices 2 and 4, information related to the images, and modification history of the images. As shown in FIG. 1A, the information management system 1, the image registration device 2, the image modification device 3, and the image registration device 4 are connected to each other via a network 5, and data can be transmitted and received. The image registration device 2 is a device for registering an original image to be modified in the information management system 1, and is a camera, a smartphone, a PC (personal computer), or the like. The image modification device 3 is a device for modifying an original image acquired from the information management system 1, and is a camera, a smartphone, a PC, or the like equipped with an image editing application. An image modified by the image modification device 3 (hereinafter, referred to as a modified image) is provided to the image registration device 4. The image registration device 4 is a device for registering the modified image provided by the image modification device 3 in the information management system 1, and is realized by a device configuration similar to that of the image registration device 2. The image modification device 3 and the image registration device 4 may be integrally configured.

[0011] 1B is a diagram showing an example of a hardware configuration of an information management system 1 according to this embodiment. The information management system 1 is composed of a CPU 201, a storage device 202, and a network I / F (interface) 203, and these components are connected to each other via a bus 204. The CPU 201 controls the overall operation of the information management system 1. The CPU 201 executes processing based on programs stored in the storage device 202. The storage device 202 is realized by a HDD, a flash memory, etc., and stores various programs, image data, databases, etc. The network I / F 203 is an interface for network communication with external devices. The information management system 1 receives processing requests from the image registration devices 2, 4 and the image modification device 3 via the network I / F 203, performs various processing, and transmits and receives data.

[0012] In this embodiment, a case is exemplified in which one CPU 201 executes a program stored in the storage device 202 or the like to execute the processes shown in the flowcharts and sequence diagrams described below, but other aspects are also possible. For example, each process described below can be executed by multiple CPUs, HDDs, etc. in cooperation with each other. Furthermore, the information management system 1 is not necessarily realized by one device, but may be realized by multiple devices according to the functions.

[0013] 2 is a diagram showing an example of the functional configuration of the information management system 1 according to this embodiment. The information management system 1 includes an image management unit 11 and an alteration content determination unit 12, and manages information related to images registered in the image management unit 11 using a blockchain 10. The blockchain 10 is a distributed management ledger on a network using encryption technology. The blockchain 10 according to this embodiment may be configured as a peer-to-peer network or may be configured as a specific server device. In this embodiment, the blockchain 10 manages information regarding image modification and the history of modification. Details will be described later.

[0014] The image management unit 11 is a functional unit that manages images, and may be configured in a peer-to-peer network or in a specific server device. In this embodiment, as shown in Fig. 1B, the image management unit 11 manages an original image 110, an image identifier 111 which is an identifier corresponding to the original image 110, a modified image 112, and an image identifier 113 which is an identifier corresponding to the modified image 112. In this embodiment, an example is shown in which the image management unit 11 holds one each of an original image and its image identifier, and a modified image and its image identifier, but the image management unit 11 may hold more images and their image identifiers.

[0015] The alteration content determination unit 12 is a functional unit that determines whether the alteration content of the altered image transmitted from the image registration device 4 is permitted, and may be configured as a specific server device, or may be configured integrally with the blockchain 10 and the image management unit 11. In this embodiment, the alteration content determination unit 12 determines whether the alteration content of the altered image is permitted based on the information of the image that is the original of the altered image stored in the blockchain 10. If the alteration content determination unit 12 determines that the alteration content is permitted, information related to the altered image is registered in the blockchain 10, and if the alteration content determination unit 12 determines that the alteration content is not permitted, the altered image is not registered in the blockchain 10. A specific determination method will be described later in the flowchart of FIG. 3. In addition, a determination program used for the determination may be managed within the blockchain 10. In that case, the alteration content determination unit 12 functions as a so-called smart contract that is executed in response to a request to register an altered image on a general blockchain.

[0016] Next, we will explain the details of blockchain 10. The blockchain 10 manages the blocks 100 and 101 by linking them together. FIG. 1B shows an example in which information related to the original image 110 is registered in the block 100, and information related to the modified image 112 is registered in the block 101. The number of blocks managed by the blockchain 10 is not limited to two. For example, the blockchain 10 may further link a block to the block 101 and register information related to an image modified from the modified image 112 in the block. In addition, the configuration is not limited to one in which information related to one image is registered in one block, and one block may be configured to register information related to multiple images. The blocks 100 and 101 are blocks in which transaction information for a certain period of time is collected in a general blockchain.

[0017] First, block 100 will be described. Block 100 is composed of a previous block hash value 1000 and a transaction 1001. In this embodiment, for the sake of simplicity, an example in which one block contains one transaction is shown, but one block may contain multiple transactions, and the number of transactions is not limited. The previous block hash value 1000 is a value obtained by hashing information specifying a block (not shown) linked before block 100 using a hash function, and is information indicating a link relationship with the previous block.

[0018] The transaction 1001 includes an image identifier 1002, alteration permission information 1003, authorizer information 1004, an image hash value 1005, and a digital signature 1006. The image identifier 1002 is the same as the image identifier 111 managed by the image management unit 11, and is information for linking the transaction 1001 with the original image 110 managed by the image management unit 11. The alteration permission information 1003 is information indicating the permitted range of alteration of the original image 110. The alteration permission information 1003 is set by the owner of the original image 110 (photographer, administrator, copyright owner, blockchain registrant, etc.). The alteration permission information 1003 may be information indicating the permitted range, or may be information indicating the not permitted range. Specifically, the alteration permission information 1003 is set with information indicating whether or not a specific color change is permitted, whether or not editing of a specific pixel range is permitted, whether or not image enlargement / reduction is permitted, and whether or not image rotation is permitted. The alteration permission information 1003 may be a character string in a standard language such as English, or may be an encoded character string. If it is an encoded character string, it can be decoded by a device such as the image alteration device 3. If it is decoded by the image alteration device 3, the information management system 1 may control the image alteration device 3 to restrict a specific image alteration operation based on the content of the alteration permission information 1003. Methods for imposing restrictions include graying out buttons that instruct specific operations on the GUI (Graphical User Interface) of the image editing application, and displaying a warning screen when a specific operation is attempted.

[0019] The authorizer information 1004 is information indicating a range of users who are permitted to modify the original image 110. The authorizer information 1004 is set by the owner of the original image 110 (photographer, administrator, copyright owner, blockchain registrant, etc.). The authorizer information 1004 may be information indicating a range that is not permitted, instead of information indicating a range that is permitted. A user who uses the information management system 1 needs to register as a user, and the authorizer information 1004 is set with the user's account name and user ID (Identification). In addition, a value generated from an electronic signature or a public key in a general blockchain may be used. In addition, a group name or group ID indicating a group of multiple users grouped under a specific condition may be set in the authorizer information 1004.

[0020] The image hash value 1005 is a value obtained by hashing the original image 110 using a hash function, and is information for linking the original image 110 with the transaction 1001 and enhancing the authenticity of the original image 110. The digital signature 1006 is a typical digital signature in a blockchain, and is a signature for verifying the registrant of the original image 110. For example, it is a value obtained by encrypting data to be registered in the information management system 1 with a private key.

[0021] Next, a description will be given of the block 101. The block 101 is composed of a previous block hash value 1000 and a transaction 1001. The block 101 is composed of a previous block hash value 1010 and a transaction 1011. The previous block hash value 1010 is similar to the previous block hash value 1000, and in this embodiment, is a value obtained by hashing information for identifying block 100, which is the block preceding block 101, using a hash function. The transaction 1011 includes an image identifier 1012, an image identifier 1013, alteration information 1014, alteration permission information 1015, authorizer information 1016, an image hash value 1017, and a digital signature 1018. The image identifier 1012 is the same as the image identifier 111 and the image identifier 1002. The image identifier 1012 is information for linking the transaction 1011 with the original image 110 managed by the image management unit 11, and indicates that the original image 110 is the altered image associated with the transaction 1011.

[0022] The image identifier 1013 is the same as the image identifier 113 , and is information for linking the transaction 1011 with the altered image 112 managed by the image management unit 11 . The modification information 1014 is information indicating how the original image 110 was modified to generate the modified image 112. Specifically, the image modification information is information such as a change in a specific color, editing of a specific pixel range, image enlargement / reduction, and image rotation. The modification information 1014 may be a character string in a standard language such as English, or may be an encoded character string. The content of the image modification indicated in the modification information 1014 is modification content within the range permitted by the modification permission information 1003. This is because if it is not within the permitted range, the modification content determination unit 12 does not permit registration in the blockchain 10.

[0023] The alteration permission information 1015 is information indicating the permitted range of alterations to the altered image 112. The alteration permission information 1015 is set by the owner (creator, administrator, copyright owner, blockchain registrant, etc.) of the altered image 112. The specific information content is the same as that of the alteration permission information 1003. The authorizer information 1016 is information indicating a range of users who are permitted to modify the modified image 112. The authorizer information 1016 is set by the owner (creator, administrator, copyright owner, blockchain registrant, etc.) of the modified image 112. The specific information content is the same as that of the authorizer information 1004. The image hash value 1017 is a value obtained by hashing the altered image 112 using a hash function, and is information for linking the altered image 112 with the transaction 1011 and enhancing the authenticity of the altered image 112 . The digital signature 1018 is a typical blockchain digital signature, and is a signature for verifying the registrant of the modified image 112. The specific content is the same as that of the digital signature 1006.

[0024] Next, the alteration content determination process performed by the alteration content determination unit 12 will be described in detail. Fig. 3 is a flowchart showing the alteration content determination process. The flowchart in Fig. 3 is realized by the CPU 201 executing a program stored in the storage device 202 or the like. Each process (step) in the flowchart will be described below with an S (step) added to the beginning of each reference number. As a premise for executing the alteration content determination process, the information management system 1 stores the original image 110 and the image identifier 111 of the original image 110 transmitted from the image registration device 2 in a storage area of ​​the storage device 202 managed by the image management unit 11 in response to a request from the image registration device 2. The information management system 1 also registers information related to the original image 110 in the transaction 1001 and stores it in a storage area of ​​the storage device 202 managed by the blockchain 10. After that, the information management system 1 transmits the original image 110 and the image identifier 111 corresponding to the original image 110 to the image alteration device 3 in response to a request from the image alteration device 3. The image alteration device 3 transmits the altered image 112 altered from the original image 110 to the image registration device 4. The flowchart of FIG. 3 shows a process executed when the information management system 1 receives a registration request for the altered image 112 from the image registration device 4.

[0025] First, in S301, the CPU 201 receives a registration request for the modified image 112 from the image registration device 4 via the network I / F 203. The received registration request includes the image identifier 111 of the original image 110 that is the source of the modified image 112, and modification information 1014 indicating the image modification content from the original image 110. The registration request further includes modification permission information 1015 for the modified image 112, authorizer information 1016 for the modified image 112, and a digital signature 1018 for the modified image 112.

[0026] Next, in S302, the CPU 201 acquires information on the image to be altered from the storage area of ​​the storage device 202 managed by the blockchain 10. Specifically, the CPU 201 acquires information on the transaction 1001 including the image identifier 1002 that is the same as the image identifier 111 included in the registration request. Next, in S303, CPU 201 determines whether the user who transmitted the request to register the altered image is within the range of users permitted to make alterations, based on the information acquired in S302. Specifically, CPU 201 refers to authorized person information 1004 included in transaction 1001, and determines whether the user of image registration device 4 is within the range of users permitted by authorized person information 1004. If CPU 201 determines that the user is permitted to make alterations, processing proceeds to S304. If CPU 201 determines that the user is not permitted to make alterations, processing proceeds to S308.

[0027] In S304, the CPU 201 checks the alteration content of the altered image against the permission information acquired in S302. Specifically, the CPU 201 checks the alteration information 1014 of the altered image 112 against the alteration permission information 1003 included in the transaction 1001. Next, in S305, the CPU 201 determines whether the modification content of the modified image is within the permitted range. Specifically, the CPU 201 determines whether the modification information 1014 is within the range permitted by the modification permission information 1003. As an example, it is assumed that the modification permission information 1003 is set to permit image reduction and image rotation. If the modification information 1014 includes content that is neither image reduction nor image rotation, such as a color change, the CPU 201 determines that the modification content is outside the permitted range, and the process proceeds to S308. On the other hand, if the modification information 1014 includes both image reduction and image rotation, or either one of them, the CPU 201 determines that the modification content is within the permitted range, and the process proceeds to S306.

[0028] In S306, the CPU 201 acquires the original image 110 corresponding to the image identifier 111 received in S301 from the memory area of ​​the memory device 202 managed by the image management unit 11, and generates a verification image using the acquired original image 110 and the modification information 1014. Next, in S307, the CPU 201 determines whether the altered image 112 received in S301 matches the verification image generated in S306. If the CPU 201 determines that the altered image 112 matches the verification image, the process proceeds to S309. If the CPU 201 determines that the altered image 112 does not match the verification image, the process proceeds to S308.

[0029] In S308, the CPU 201 transmits an error notification to the image registration device 4, indicating that it was not possible to register the altered image 112. Thereafter, the series of processes in the flowchart shown in FIG. In S309, the CPU 201 stores the modified image 112 received in S301 in a storage area of ​​the storage device 202 managed by the image management unit 11. The CPU 201 also registers information related to the modified image 112 in the transaction 1011 of the block 101 linked to the block 100, and stores the information in a storage area of ​​the storage device 202 managed by the blockchain 10. The information included in the registration request received in S301 is used as the information to be registered in the transaction 1011. Thereafter, the series of processes in the flowchart shown in FIG. 3 ends.

[0030] According to the above-described alteration content determination process, only when the image that the image registration device 4 is attempting to register in the information management system 1 is within the range of permitted alterations, it can be registered in the blockchain 10. This makes it possible to limit the altered content and the users who can make alterations.

[0031] 4 is a sequence diagram showing a series of operations of the information management system 1 according to this embodiment. In the following description, each process (step) is represented by adding an S to the beginning, and the representation of the process (step) is omitted. S401 to S403 show the flow of an original image registration process executed when an original image is registered in the information management system 1. In S401, the image registration device 2 requests the information management system 1 to register the original image 110, and the blockchain 10 registers the modification permission information 1003, the authorizer information 1004, and the electronic signature 1006 of the original image 110 in the transaction 1001. In parallel with S401, in S402, the image management unit 11 registers the original image 110.

[0032] Then, in S403, the image management unit 11 generates an image hash value 1005 by hashing the original image 110 and an image identifier 111 corresponding to the original image 110, and provides these to the blockchain 10. The blockchain 10 registers the provided image hash value 1005 and an image identifier 1002 that is the same as the image identifier 111 in the transaction 1001. This links the original image 110 and the transaction 1001. Alternatively, the image registration device 2 may receive the image identifier 111 generated by the image management unit 11 and directly register it in the transaction 1001, and is not limited to this. Also, the image registration device 2 may generate an image hash value 1005 from the original image 110 and directly register it in the transaction 1001, and is not limited to this.

[0033] S411 to S418 show the flow of an altered image registration process executed when an altered image is registered in the information management system 1. First, in S411, the image alteration device 3 acquires the original image 110 and the image identifier 111 corresponding to the original image 110 from the image management unit 11. Next, in S412, the image alteration device 3 transmits the altered image 112 obtained by altering the original image 110 to the image registration device 4. Next, in S413, the image registration device 4 makes a registration request for the altered image 112 to the information management system 1. The registration request includes the altered image 112, the image identifier 111, the alteration information 1014, the alteration permission information 1015, the authorizer information 1016, and the electronic signature 1018. Next, in S414, the alteration content determination unit 12 acquires the alteration permission information 1003 and the authorizer information 1004 included in the transaction 1001 linked to the image identifier 111. Thereafter, the alteration content determination unit 12 determines whether the alteration information 1014 and the user of the image registration device 4 are authorized based on the acquired information.

[0034] S415 to S417 show the flow of processing executed when the judgment by the alteration content judgment unit 12 is OK, that is, when the alteration content of the altered image 112 is within the range permitted by the alteration permission information 1003 and the permitter information 1004. At S415, in response to an instruction from the alteration content determination unit 12, the blockchain 10 registers the image identifier 1012, alteration information 1014, alteration permission information 1015, authorizer information 1016, and electronic signature 1018 in the transaction 1011. In parallel with S415, at S416, in response to an instruction from the alteration content determination unit 12, the image management unit 11 registers the altered image 112.

[0035] After that, in S417, the image management unit 11 generates an image hash value 1017 by hashing the modified image 112 and an image identifier 113 corresponding to the modified image 112, and provides them to the blockchain 10. The blockchain 10 registers the provided image hash value 1017 and the image identifier 1013, which is the same as the image identifier 113, in the transaction 1011. This links the modified image 112 and the transaction 1011. Note that the image registration device 4 may receive the image identifier 113 generated by the image management unit 11 and directly register it in the transaction 1011, but is not limited to this. Also, the image registration device 4 may generate an image hash value 1017 from the altered image 112 and directly register it in the transaction 1011, but is not limited to this. With the above, the series of operations in the sequence diagram shown in FIG. 4 is completed.

[0036] S418 shows the flow of processing executed when the alteration content determination unit 12 judges that the alteration content of the altered image 112 is NG, that is, when the alteration content is outside the range permitted by the alteration permission information 1003 and the permitter information 1004. In S418, the alteration content determination unit 12 transmits an error notification indicating that registration was not possible to the image registration device 4. With the above, the series of operations in the sequence diagram shown in FIG.

[0037] According to the first embodiment described above, by using a block chain that links and manages the modification history of an image, it is possible to set restrictions on the modification content of an image and users who can modify an image. This makes it possible to suppress unintended modifications while ensuring the authenticity of modifications from the original image. In other words, image modifications can be appropriately managed.

[0038] [Second embodiment] Fig. 5 is a diagram showing an example of the functional configuration of the information management system 1 according to this embodiment. Fig. 5 differs from Fig. 2 of the first embodiment in that reward distribution information 500 is added to transaction 1001, and reward distribution information 501 is added to transaction 1011. In the second embodiment, a method is described in which, using the reward distribution information 500, 501, a reward is distributed to the registrant of the original image when a reward is generated in the case where the modified image is used commercially, etc. Hereinafter, the same reference numerals are used for the same parts as in the first embodiment, and the description is omitted.

[0039] The reward distribution information 500 is a set value for determining a reward to be distributed when a reward occurs for an image altered from the original image 110. The reward distribution information 500 is registered in the transaction 1001 by the owner of the original image 110 (photographer, administrator, copyright owner, blockchain registrant, etc.). Specific set values ​​and distribution methods will be described with reference to FIG. 6. The reward distribution information 501 is a set value for determining a reward to be distributed when a reward is generated for an image that is further modified from the modified image 112. The reward distribution information 501 is registered in the transaction 1011 by the owner of the modified image 112 (photographer, administrator, copyright owner, blockchain registrant, etc.). Specific set values ​​and distribution methods will be described with reference to FIG. 6.

[0040] 6 is a block diagram showing the modification history of an image and reward distribution information accompanying the image in this embodiment. An example of a reward distribution method will be described with reference to FIG. Image α600 is an image managed by information management system 1, and is an original image that has not been generated by modifying another image. Reward distribution information α601 is reward distribution information for image α600 set by the owner of image α600, and is assumed to be a numerical value of 0.5. Image β602 is an image managed by the information management system 1, and is an image generated by modifying image α600. Reward distribution information β603 is reward distribution information of image β602 set by the owner of image β602, and is assumed to be a numerical value of 0.3. Image γ604 is an image managed by the information management system 1, and is an image generated by modifying image β602. Reward distribution information γ605 is reward distribution information of image γ604 set by the owner of image γ604, and is assumed to be a numerical value of 0.7.

[0041] A method of distributing rewards using the above-mentioned images and reward distribution information will now be described. When reward X (the unit is assumed to be a currency unit, but is not limited to this) is generated for the image α600, the owner of the image α600 can directly acquire the reward X. Here, the reward distribution information α601 is ignored because it is set when a reward is generated for the image after the image α600 has been modified. If reward Y occurs for image β602, the information management system 1 distributes a reward of Y×0.5 to the owner of image α600. The information management system 1 distributes a reward of Y-(Y×0.5) to the owner of image β602. Here, reward distribution information β603 is ignored because it is set when a reward occurs for the image after image β602 has been modified. If reward Z is generated for image γ604, the information management system 1 distributes a reward of Z×0.5 to the owner of image α600. The information management system 1 also distributes a reward of (Z-(Z×0.5))×0.3 to the owner of image β602. Furthermore, the information management system 1 distributes a reward of Z-((Z-(Z×0.5))×0.3) to the owner of image γ604. Here, reward distribution information γ605 is ignored, since it is set when a reward is generated for an image after image γ604 has been modified.

[0042] According to the second embodiment described above, by using a block chain that links and manages the modification history of an image, if a reward is generated for an altered image, the reward can be appropriately distributed to the owner of the original image. Note that the above-mentioned setting values ​​and distribution method of the reward distribution information are merely examples, and reward distribution may be performed using different setting values ​​and distribution methods, and is not limited thereto.

[0043] Although the present invention has been described above with reference to the embodiments, the above embodiments are merely illustrative of the specific examples of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these embodiments. In other words, the present invention can be embodied in various forms without departing from its technical concept or main features.

[0044] (Other embodiments) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions. [Explanation of symbols]

[0045] 1: Information management system, 2, 4: Image registration device, 3: Image modification device

Claims

1. A management means for managing first information related to a first image and second information related to a second image altered from the first image in the form of a block chain; a determination means for determining whether the modification of the second image is within a permitted range based on permission information indicating a permitted range of modification of the first image, the permission information being included in the first information; having An information management system characterized in that the management means registers the second information in the blockchain when the judgment means judges that the second information is within the permitted range.

2. The information management system according to claim 1, characterized in that the management means does not register the second information in the blockchain if the determination means determines that the second information is outside the permitted range.

3. The permission information includes a range of users who are permitted to modify the first image, 3. The information management system according to claim 1, wherein the determining unit determines whether the user who has requested the registration of the second image is within a user range.

4. the determination means generates a verification image using the first image and modification information indicating modification content of the second image, and determines whether the second image and the verification image match; 4. The information management system according to claim 1, wherein the management unit registers the second information when the determination unit determines that the information matches the first information.

5. 5. The information management system according to claim 1, wherein the determination means determines whether or not alterations made to the second image are within a permitted range when a request to register the second image is received.

6. An information management system as claimed in any one of claims 1 to 5, characterized in that the permission information is information that allows or does not allow at least one of changing a specific color, editing a specific pixel range, enlarging an image, reducing an image, and rotating an image.

7. 7. The information management system according to claim 1, wherein the second information includes information indicating a permitted range of modification of the second image.

8. 8. The information management system according to claim 1, wherein the second information includes modification information indicating modification details of the second image.

9. The first information and the second information each include reward distribution information; An information management system as described in any one of claims 1 to 8, characterized in that when a reward is generated for a third image that is modified from the second image, a process of distributing the reward is performed based on the reward distribution information contained in the first information and the reward distribution information contained in the second information.

10. further comprising an image management means for managing the first image, a first identifier corresponding to the first image, the second image, and a second identifier corresponding to the second image; the first information includes the first identifier; 10. The information management system according to claim 1, wherein the second information includes the second identifier.

11. a transmitting means for transmitting the first image to an external device; 11. The information management system according to claim 1, further comprising a control unit that controls the external device so as to restrict a modification operation on the first image based on the permission information.

12. The information management system according to any one of claims 1 to 11, characterized in that the determination means is a function of a smart contract that operates on the blockchain.

13. The information management system according to any one of claims 1 to 12, characterized in that the first information and the second information are registered in a transaction of the blockchain.

14. A method for controlling an information management system having a management unit that manages first information related to a first image and second information related to a second image altered from the first image in the form of a block chain, comprising: a determination step of determining whether the modification content of the second image is within a permitted range based on information indicating a permitted range of modification to the first image, the information being included in the first information; a registration step of registering the second information in the blockchain when the determination step determines that the second information is within the permitted range; 2. A method for controlling an information management system comprising:

15. A program for causing a computer to function as each of the means of the information management system according to any one of claims 1 to 13.

Images