Information intermediary system and information intermediary method

Abstract

An information intermediary system in which first to third public keys and first to third secret keys are allocated to a providing-side terminal device, an intermediary device, and a receiving-side terminal device. The providing-side terminal device generates first encrypted data by encrypting provided data with a third public key. The providing-side terminal device also generates a first electronic signature using the first secret key, and transmits the first encrypted data and the first electronic signature to the intermediary device. The intermediary device generates a second electronic signature using the second secret key, and transmits the first encrypted data, the first electronic signature, and the second electronic signature to the receiving-side terminal device. The receiving-side terminal device decodes the first encrypted data with the third secret key and obtains the provided data. The receiving-side terminal device also verifies the first electronic signature with the first public key and verifies the second electronic signature with the second public key.

Description

Technical Field

[0001] The present invention relates to an information mediation system and an information mediation method for mediating data transfer and reception.

Background Art

[0002] A data transfer system for mediating data transfer (for example, see Patent Document 1) is known. This data transfer system is configured to manage transfer based on the expiration date of data by a data mediation device, and to encrypt / decrypt data transferred between a data transmission device and a data reception device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, when mediating the transfer and reception including data transfer between a data transmission device and a data reception device by a data mediation device such as the above Patent Document 1, the data transmission device and the data reception device do not directly exchange data. Therefore, the authenticity of the data transferred by the data mediation device and the integrity such as the fact that the data is not altered by passing through the data mediation device cannot be completely ensured simply by encrypting / decrypting the data. This is an important factor not only for the parties involved in the data transfer and reception but also for the administrator who mediates the information.

[0005] Furthermore, in order to construct a secure data trading market, it is also an important factor to ensure the authenticity and integrity of transmission information such as provided data and data use right certificates.

[0006] The present invention aims to provide an information mediation system and an information mediation method that can guarantee the authenticity and completeness of the mediated information and ensure security. [Means for solving the problem]

[0007] The information mediation system according to the present invention comprises a provider terminal device that transmits transmission information including provided data, a receiving terminal device that receives the transmitted information, and an intermediary device that mediates the exchange of the transmitted information between the provider terminal device and the receiving terminal device. In this information mediation system, the provider terminal device is assigned a first public key and a first private key, the intermediary device is assigned a second public key and a second private key, and the receiving terminal device is assigned a third public key and a third private key. The provider terminal device encrypts the provided data with the third public key to generate first encrypted data, generates a first digital signature using the first private key, and transmits the first encrypted data and the first digital signature to the intermediary device. The intermediary device generates a second digital signature using the second private key and transmits the first encrypted data, the first digital signature, and the second digital signature to the receiving terminal device. The receiving terminal device decrypts the first encrypted data with the third private key to obtain the provided data, verifies the first digital signature with the first public key, and verifies the second digital signature with the second public key.

[0008] The information mediation method according to the present invention is an information mediation method in an information mediation system comprising: a providing terminal device that transmits transmission information including provided data; a receiving terminal device that receives the transmitted information; and an intermediary device that mediates the exchange of the transmitted information between the providing terminal device and the receiving terminal device, wherein the providing terminal device is assigned a first public key and a first private key; the intermediary device is assigned a second public key and a second private key; the receiving terminal device is assigned a third public key and a third private key; and the providing terminal device transmits the provided data using the third public key The first encrypted data is generated by encrypting it, and a first digital signature is generated using the first private key. The first encrypted data and the first digital signature are transmitted to the intermediary device. The intermediary device generates a second digital signature using the second private key. The first encrypted data, the first digital signature, and the second digital signature are transmitted to the receiving terminal device. The receiving terminal device decrypts the first encrypted data with the third private key to obtain the provided data, verifies the first digital signature with the first public key, and verifies the second digital signature with the second public key.

[0009] Another information intermediary system according to the present invention is formed within a system that forms a data distribution market and comprises a first terminal device that transmits transmission information, a second terminal device that receives the transmission information, and an intermediary device that mediates the exchange of the transmission information between the first terminal device and the second terminal device, wherein the first terminal device is assigned a first public key and a first private key, the intermediary device is assigned a second public key and a second private key, the second terminal device is assigned a third public key and a third private key, and the first terminal device transmits the transmission information to the third The first encrypted data is generated by encrypting it with the public key, and the first digital signature is generated using the first private key, and the first encrypted data and the first digital signature are transmitted to the intermediary device, the intermediary device generates a second digital signature using the second private key, and transmits the first encrypted data, the first digital signature and the second digital signature to the second terminal device, the second terminal device decrypts the first encrypted data with the third private key to obtain the transmission information, verifies the first digital signature with the first public key, and verifies the second digital signature with the second public key. [Effects of the Invention]

[0010] According to the present invention, the authenticity and completeness of the mediated information can be guaranteed, and security can be ensured. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram showing the configuration of an information mediation system according to the first embodiment of the present invention. [Figure 2] This is a sequence diagram showing an overview of the information mediation system. [Figure 3] This is a sequence diagram showing an overview of the information mediation system. [Figure 4] This is a block diagram showing the configuration of an information mediation system according to a second embodiment of the present invention. [Figure 5] This is a sequence diagram showing an overview of the information mediation system. [Figure 6]It is a sequence diagram showing an overview of the information mediation system. [Figure 7] It is a sequence diagram showing an overview of the information mediation system. [Figure 8] It is a block diagram showing the configuration of the information mediation system according to the third embodiment of the present invention. [Figure 9] It is a sequence diagram showing an overview of the information mediation system. [Figure 10] It is a sequence diagram showing an overview of the information mediation system. [Figure 11] It is a sequence diagram showing an overview of the information mediation system according to the fourth embodiment of the present invention. [Figure 12] It is a sequence diagram showing an overview of the information mediation system. [Figure 13] It is a sequence diagram showing an overview of the information mediation system according to the fifth embodiment of the present invention. [Figure 14] It is a sequence diagram showing an overview of the information mediation system. [Figure 15] It is a sequence diagram showing an overview of the information mediation system according to the sixth embodiment of the present invention. [Figure 16] It is a sequence diagram showing an overview of the information mediation system. [Figure 17] It is a sequence diagram showing an overview of the information mediation system according to the seventh embodiment of the present invention. [Figure 18] It is a sequence diagram showing an overview of the information mediation system.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, referring to the accompanying drawings, the information mediation system and the information mediation method according to the embodiments of the present invention will be described in detail. However, the following embodiments do not limit the invention according to each claim, and not all combinations of the features described in the embodiments are essential for the solution means of the invention. Also, in the drawings, there are cases where the scale and dimensions of each component are exaggerated and cases where some components are omitted.

[0013] [First Embodiment] [Configuration of Information Mediation System] FIG. 1 is a block diagram showing the configuration of an information mediation system according to the first embodiment of the present invention. As shown in FIG. 1, the information mediation system 100 according to the present embodiment includes a provider terminal device (A) 1 that transmits transmission information including provided data, a recipient terminal device (C) 2 that receives this transmission information, and a mediation device (B) 3 that mediates the exchange of transmission information between the provider terminal device (A) 1 and the recipient terminal device (C) 2. In the information mediation system 100, these provider terminal devices (A) 1, recipient terminal devices (C) 2, and mediation devices (B) 3 are connected via a network 5 such as the Internet that can communicate with each other. A public key certification authority (CA) 4, which is an external third-party institution, is further connected to this network 5.

[0014] In FIG. 1, two provider terminal devices (A) 1 and two recipient terminal devices (C) 2 are illustrated as examples, but the present invention is not limited thereto. Also, the connection mode of each component such as the provider terminal device (A) 1 is not limited to the network 5 and may be a cloud or the like. Further, the provider terminal device (A) 1, the recipient terminal device (C) 2, and the mediation device (B) 3 may adopt configurations such as known information processing devices, arithmetic processing devices, and terminal devices such as personal computers, smartphones, tablet terminals, workstations, and server devices.

[0015] As a prerequisite for the information mediation system 100 of the present embodiment, a public key (Kp) and a secret key (Ks) consisting of an encryption method such as RSA for encrypting / decrypting transmission information are assigned to the provider terminal device (A) 1, the mediation device (B) 3, and the recipient terminal device (C) 2.

[0016] Specifically, the provider terminal device (A)1 is assigned the provider's public key (KpA), which is the first public key, and the provider's private key (KsA), which is the first private key. If the provider's public key (KpA) is registered with Public Key Certificate Authority (CA) 4, the provider terminal device (A)1 possesses the provider's public key certificate (CKpA), which is the first public key certificate issued by Public Key Certificate Authority (CA) 4.

[0017] Furthermore, the intermediary device (B) 3 is assigned the intermediary's public key (KpB), which is the second public key, and the intermediary's private key (KsB), which is the second private key. If the intermediary's public key (KpB) is registered with the public key certification authority (CA) 4, the intermediary device (B) 3 possesses the intermediary's public key certificate (CKpB), which is the second public key certificate issued by the public key certification authority (CA) 4.

[0018] Furthermore, the receiving terminal device (C)2 has a third public key, which is the recipient's public key (KpC). The recipient's private key (KsC), which is a third private key, is assigned to the first and third public keys. If the recipient's public key (KpC) is registered with Public Key Certification Authority (CA) 4, the receiving terminal device (C) 2 has the recipient's public key certificate (CKpC), which is a third public key certificate issued by Public Key Certification Authority (CA) 4. Since the first to third public key certificates (CKpA, CKpB, CKpC) are authenticated by Public Key Certification Authority (CA) 4, they can be used to prevent impersonation by sending them to the other party in the information exchange.

[0019] [Information Intermediation Flow of Information Intermediation System 100] Figures 2 and 3 are sequence diagrams showing an overview of information transmission and reception in the information mediation system 100. For the handling of information in this system, it is assumed that the public keys (KpA, KpB, KpC) and public key certificates (CKpA, CKpB, CKpC) have been exchanged in advance between the providing terminal device (A)1, the mediating device (B)3, and the receiving terminal device (C)2.

[0020] The information transmitted by the first terminal device, the providing terminal device (A)1, to the second terminal device, the receiving terminal device (C)2, includes, for example, first data, such as the data file that is the subject of the transaction, which is the provided data (D), and second data, such as transaction conditions (T), which includes information such as the scope of use and the price of the provided data (D). Of these, the provided data (D) cannot be viewed by the intermediary device (B)3. On the other hand, the transaction conditions (T) must be viewed by the intermediary device (B)3.

[0021] As shown in Figure 2, first, the provider terminal device (A)1 encrypts the provided data (D) with the recipient's public key (KpC) to generate the first encrypted data (D·KpC) (step S1). Next, the provider terminal device (A)1 encrypts the transaction terms (T) with the intermediary's public key (KpB) to generate the second encrypted data (T·KpB) (step S1). Furthermore, the provider terminal device (A)1 encrypts the transaction terms (T) with the recipient's public key (KpC) to generate the third encrypted data (T·KpC) (step S1). Note that the transaction terms (T) include a hash value (Hash(D·KpC)) obtained by functionalizing the first encrypted data (D·KpC) with a one-way function such as a hash function (Hash) in order to relate it to the provided data (D). Hereafter, when "hash value" is used, it refers to the "hash value" functionalized by the hash function.

[0022] Furthermore, the provider terminal device (A) 1 generates the provider's digital signature (Ca=Hash(D·KpC)·KsA), which is the first digital signature, using the hash value (Hash(D·KpC)) obtained from the first encrypted data (D·KpC) and the provider's private key (KsA). The provider terminal device (A) 1 then transmits each of the encrypted data (D·KpC, T·KpB, T·KpC) generated in this way, along with the provider's digital signature (Ca), to the intermediary device (B) 3 (step S1).

[0023] Intermediary device (B) 3 decrypts the received second encrypted data (T·KpB) with the intermediary's private key (KsB) to obtain the transaction terms (T) (step S2). Intermediary device (B) 3 also generates a hash value (Hash(D·KpC)) from the received first encrypted data (D·KpC) (step S3). Furthermore, intermediary device (B) 3 decrypts the hash value (Hash(D·KpC)) from the provider's digital signature (Ca) using the provider's public key (KpA) (step S4). Then, intermediary device (B) 3 checks whether the hash value (Hash(D·KpC)) included in the transaction terms (T), the hash value (Hash(D·KpC)) generated from the first encrypted data (D·KpC), and the hash value (Hash(D·KpC)) decrypted from the provider's digital signature (Ca) all match. The intermediary device (B)3 can verify, upon confirmation that all of these match, that the sent transaction terms (T) relate to the provided data (D), that the information is intended for the intermediary device (B)3, and that the sender is the providing terminal device (A)1 (step S5).

[0024] Next, as shown in Figure 3, the intermediary device (B) 3 generates a second digital signature, the intermediary's digital signature (Cb = Hash(D·KpC)·KsB), using the hash value (Hash(D·KpC)) obtained from the received first encrypted data (D·KpC) and the intermediary's private key (KsB) (step S11). Then, the intermediary device (B) 3 transmits the received encrypted data (D·KpC, T·KpC), the provider's digital signature (Ca), and the generated intermediary's digital signature (Cb) to the receiving terminal device (C) 2 (step S11).

[0025] The receiving terminal device (C)2 decrypts the received encrypted data (D·KpC, T·KpC) using the recipient's private key (KsC) to obtain the provided data (D) and the transaction terms (T) (step S12). The receiving terminal device (C)2 also generates a hash value (Hash(D·KpC)) as the result of the calculation from the obtained provided data (D) (step S13). The receiving terminal device (C)2 also verifies the provider's digital signature (Ca) with the provider's public key (KpA) (KpA(Ca)=Hash(D·KpC)) to obtain a hash value (Hash(D·KpC)) as the result of decryption (step S14). Simultaneously, the receiving terminal device (C)2 verifies the intermediary's digital signature (Cb) with the intermediary's public key (KpB) (KpB(Cb) = Hash(D·KpC)) to obtain a hash value (Hash(D·KpC)) as the decryption result (step S14).

[0026] Then, the receiving terminal device (C)2 checks whether the hash value (Hash(D·KpC)) included in the transaction terms (T), the hash value (Hash(D·KpC)) generated from the provided data (D), the hash value (Hash(D·KpC)) decrypted from the provider's digital signature (Ca), and the hash value (Hash(D·KpC)) decrypted from the intermediary's digital signature (Cb) all match. Upon confirming that all of these match, the receiving terminal device (C)2 can verify that the sent transaction terms (T) relate to the provided data D, that the information is directed to the receiving terminal device (C)2, that the sender is the provider terminal device (A)1, and that the intermediary is the intermediary device (B)3 (Step S15).

[0027] Thus, according to this embodiment, if, as a result of verification, it is determined that all the obtained hash values ​​(Hash(D·KpC)) are the same (True in step S15), it can be determined that the provided data (D) and transaction conditions (T) are genuine, provided from the providing terminal device (A)1, and transmitted to the receiving terminal device (C)2 via the intermediary device (B)3.

[0028] On the other hand, if the verification results indicate that either of the obtained hash values ​​(Hash(D·KpC)) is different (False in step S15), it can be determined that the provided data (D) or transaction terms (T) are not genuine, were not provided by the provider, or were not mediated by the intermediary. In this case, there is a high possibility that the provided data (D) or transaction terms (T) have been tampered with or impersonated, so the recipient may take countermeasures such as notifying the provider. Furthermore, by pinpointing the sender and communication path of the information that shows a different result among the above results, it is possible to attempt to uncover any tampering or other fraud.

[0029] Furthermore, the transmission of data from the intermediary device (B)3 to the receiving terminal device (C)2 in step S11 above may be performed only when the intermediary device (B)3 receives payment information, such as the price for the provided data (D), from the receiving terminal device (C)2 to the provider terminal device (A)1. This prevents the encrypted data (D·KpC), the provider's electronic signature (Ca), and the intermediary's electronic signature (Cb) from being carelessly transmitted to the receiving terminal device (C)2 without confirmation of the recipient's payment to the provider.

[0030] Furthermore, in step S11 above, the intermediary's digital signature (Cb) from the intermediary device (B) 3 to the receiving terminal device (C) 2 may include the provider's digital signature (Ca) to confirm that it has been reliably received from the providing terminal device (A) 1. For example, the intermediary's digital signature (Cb) can be generated using a hash value (Hash(D·KpC+Ca)) that includes the provider's digital signature (Ca) and the intermediary's private key (KsB) (Cb=Hash(D·KpC+Ca)·KsB).

[0031] [Second Embodiment] [Configuration of the Information Intermediation System] Figure 4 is a block diagram showing the configuration of an information mediation system according to a second embodiment of the present invention. In Figure 4, components similar to those in Figure 1 are denoted by the same reference numerals, and descriptions of redundant components are omitted. As shown in Figure 4, the information mediation system 200 according to this embodiment is the same as the information mediation system 100 shown in Figure 1, but with the addition of a Time Stamping Authority (TSA) 6. The Time Stamping Authority (TSA) 6 is connected to the providing terminal device (A) 1, the receiving terminal device (C) 2, the mediating device (B) 3, and the public key certification authority (CA) 4 via the network 5. When the Time Stamping Authority (TSA) 6 receives data (X) to be time-stamped in the form of a hash value (Hash(X)), it returns a timestamp (token) Ts, which is the hash value (Hash(X)) with time information added to it. The other configurations are the same as in Figure 1.

[0032] [Information Intermediation Flow of Information Intermediation System 200] Figures 5 to 7 are sequence diagrams showing an overview of information transmission and reception in the information mediation system 200. Similar to the previous embodiment, the handling of information here involves the prior exchange of public keys (KpA, KpB, KpC) and public key certificates (CKpA, CKpB, CKpC) between the provider-side terminal device (A) 1, the mediation device (B) 3, and the recipient-side terminal device (C) 2.

[0033] As shown in Figure 5, first, the provider terminal device (A) 1 sends the hash value (Hash(T)) obtained by functionalizing the transaction conditions (T) with a one-way function to the time authentication authority (TSA) 6 (step S21). The time authentication authority (TSA) 6 sends a timestamp (TsA), which is a first timestamp obtained by adding time information (ta) to the hash value (Hash(T)), to the provider terminal device (A) 1 (step S22). Upon receiving the timestamp (TsA), the provider terminal device (A) 1 generates first time authentication data (Ta) by adding the timestamp (TsA) to the transaction conditions (T) (step S23).

[0034] Next, the provider terminal device (A)1 encrypts the provided data (D) with the recipient's public key (KpC) to generate first encrypted data (D·KpC) (step S24). The provider terminal device (A)1 also encrypts the first time authentication data (Ta) with the intermediary's public key (KpB) to generate second encrypted data (Ta·KpB) (step S24). The transaction terms (T) included in the first time authentication data (Ta) include a hash value (Hash(D·KpC)) obtained by functionalizing the first encrypted data (D·KpC) with a one-way function such as a hash function (Hash) in order to associate it with the provided data (D).

[0035] Furthermore, the provider terminal device (A) 1 generates the provider's digital signature (CaT=Hash(Ta·KpB)·KsA) using the hash value (Hash(Ta·KpB)) obtained from the second encrypted data (Ta·KpB) and the provider's private key (KsA) (step S24). The provider terminal device (A) 1 then transmits the encrypted data (D·KpC,Ta·KpB) and the provider's digital signature (CaT) generated in this way to the intermediary device (B) 3 (step S24).

[0036] Intermediary device (B) 3 decrypts the received second encrypted data (Ta·KpB) with the intermediary's private key (KsB) to obtain the first time authentication data (Ta) (step S25). Intermediary device (B) 3 extracts a hash value (Hash(T)) or timestamp TsA from the decrypted first time authentication data (Ta) and sends it to the Time Authentication Authority (TSA) 6 for verification (step S26). The Time Authentication Authority (TSA) 6 returns the authenticated time information (ta) or verification result to the intermediary device (B) 3 corresponding to the received hash value (Hash(T)) or timestamp TsA (step S27). Intermediary device (B) 3 receives the time information (A) or verification result sent from the Time Authentication Authority (TSA) 6 and verifies that the time information (ta) is authentic (step S28).

[0037] Next, as shown in Figure 6, the intermediary device (B) 3 generates a hash value (Hash(D·KpC)) from the received first encrypted data (D·KpC) (step S31). The intermediary device (B) 3 also generates a hash value (Hash(Ta·KpB)) from the decrypted first time authentication data (Ta) using the intermediary's public key (KpB) (step S32). Furthermore, the intermediary device (B) 3 verifies the provider's digital signature (CaT) with the provider's public key (KpA) (KpA(CaT)=Hash(Ta·KpB)) and obtains a hash value (Hash(Ta·KpB)) (step S33). Then, by confirming that the transaction conditions (T) contained in the decrypted first time authentication data (Ta) contain the hash value (Hash(D·KpC)), it can be verified that the sent transaction conditions (T) relate to the provided data D (step S34). Furthermore, by checking whether the hash value (Hash(Ta·KpB)) obtained from the decrypted first time authentication data (Ta) and the received first digital signature (Ca) are identical, it is possible to verify that the information sent is intended for the intermediary device (B) 3 and that the sender is the provider terminal device (A) 1 (step S34).

[0038] Next, the intermediary device (B) 3 transmits the hash value (Hash(Ta)) of the decrypted first time authentication data (Ta) to the time authentication authority (TSA) 6 (step S35). The time authentication authority (TSA) 6 transmits a timestamp (TsB), which is a second timestamp obtained by adding time information (tb) to the hash value (Hash(Ta)), to the intermediary device (B) 3 (step S36). Upon receiving the timestamp (TsB), the intermediary device (B) 3 adds the timestamp (TsB) to the first time authentication data (Ta) to generate the second time authentication data (Tb) (step S37). As a result, the second time authentication data (Tb) will include the transaction terms (T) and two timestamps (TsA, TsB).

[0039] Intermediary device (B) 3 transmits the received first encrypted data (D·KpC) and the second time authentication data (Tb) encrypted with the recipient's public key (KpC) to the receiving terminal device (C) 2 (step S38). Intermediary device (B) 3 also transmits the received first digital signature (CaT) of the provider and the intermediary's second digital signature (CbT=Hash(Tb·KpC)·KsB) generated using the intermediary's private key (KsB) from the hash value (Hash(Tb·KpC)) of the third encrypted data (Tb·KpC) to the receiving terminal device (C) 2 (step S38).

[0040] As shown in Figure 7, the receiving terminal device (C) 2 decrypts the received encrypted data (D·KpC, Tb·KpC) using the recipient's private key (KsC) to obtain the provided data (D) and the second time authentication data (Tb) (step S41). The receiving terminal device (C) 2 extracts the hash value (Hash(T), Hash(Ta)) or timestamps TsA, TsB from the decrypted second time authentication data (Tb) and sends them to the Time Authentication Authority (TSA) 6 for verification (step S42). The Time Authentication Authority (TSA) 6 returns the authenticated time information (ta, tb) or verification result to the receiving terminal device (C) 2 corresponding to the received hash value (Hash(T), Hash(Ta)) or timestamps TsA, TsB (step S43). The receiving terminal device (C)2 receives the time information (ta,tb) or verification result transmitted from the time authentication authority (TSA) 6 and verifies whether the time information (ta,tb) is authentic (step S44).

[0041] Next, the receiving terminal device (C)2 generates hash values ​​(Hash(D·KpC), Hash(Ta·KpB), Hash(Tb·KpC)) from the obtained provided data (D) and the second time authentication data (Tb) (step S45). The receiving terminal device (C)2 also verifies the first and second digital signatures (CaT, CbT) with the public keys (KpA, KpB) of the provider and intermediary, respectively, to obtain hash values ​​(Hash(Ta·KpB), Hash(Tb·KpC)) (step S46).

[0042] The receiving terminal device (C)2 then checks whether the hash value (Hash(D·KpC)) contained in the transaction conditions (T) in the second time authentication data (Tb) matches the hash value (Hash(D·KpC)) generated from the provided data (D). This confirms that the transaction conditions (T) relate to the provided data (D) (step S47). It also checks whether the hash values ​​(Hash(Ta·KpB),Hash(Tb·KpC)) generated from the decrypted provided data (D) and the first and second time authentication data (Ta,Tb) match the hash values ​​(Hash(Ta·KpB),Hash(Tb·KpC)) obtained from the first and second digital signatures (CaT,CbT). By confirming that these match, it is possible to verify that the transmitted provided data (D) and transaction terms (T) are information intended for the receiving terminal device (C)2, that the sender is the providing terminal device (A)1, the intermediary is the intermediary device (B)3, and that the time information (ta,tb) in which they were created is authentic (step S47).

[0043] Thus, according to this embodiment, verification results allow for the confirmation that the transmitted information was provided by the providing terminal device (A)1 and transmitted to the receiving terminal device (C)2 via the intermediary device (B)3, and the time at which that information was created can also be verified.

[0044] [Third Embodiment] [Configuration of the Information Intermediation System] Figure 8 is a block diagram showing the configuration of an information mediation system according to the third embodiment of the present invention. In the following description, including Figure 8, the same reference numerals are used for components that are the same as those in the first and second embodiments, so redundant explanations will be omitted below.

[0045] As shown in Figure 8, the information mediation system 300 according to the third embodiment includes a provider terminal device (A) 1 that transmits transmission information including provided data, and a first receiving terminal device (C) 2 and a second receiving terminal device (E) 7 that receive this transmission information. The information mediation system 300 also includes an intermediary device (B) 3 that mediates the exchange of transmission information between the provider terminal device (A) 1 and the first and second receiving terminal devices (C) 2, (E) 7, or between the first receiving terminal device (C) 2 and the second receiving terminal device (E) 7. These provider terminal device (A) 1, the first and second receiving terminal devices (C) 2, (E) 7, and the intermediary device (B) 3 are connected to each other so as to be able to communicate with one another via a network 5 to which an external third-party organization, a public key certification authority (CA) 4, is connected.

[0046] As a prerequisite for the information mediation system 300 of the third embodiment, the providing terminal device (A)1, the mediating device (B)3, and the first and second receiving terminal devices (C)2,(E)7 are equipped with a public key (Kp) and a private key (Ks) consisting of an encryption method such as RSA for encrypting / decrypting transmitted information. ) is assigned.

[0047] Specifically, regarding the provisioning terminal device (A)1 and the intermediary device (B), the assignment of each public key (KpA, KpB) and each private key (KsA, KsB), as well as the possession of each public key certificate (CKpA, CKpB), are the same as in the first embodiment, so the explanation is omitted here.

[0048] The first receiving terminal device (C)2 is assigned the first recipient's public key (KpC) and private key (KsC). The second receiving terminal device (E)7 is assigned the second recipient's public key (KpE) and private key (KsE). If the public keys (KpC, KpE) of the first and second recipients are registered with Public Key Certification Authority (CA) 4, then the first and second receiving terminal devices (C)2 and (E)7 possess the public key certificates (CKpC, CKpE) of the first and second recipients, which are public key certificates issued by Public Key Certification Authority (CA) 4. Since each public key certificate (CKpA, CKpB, CKpC, CKpE) is authenticated by Public Key Certification Authority (CA) 4, it can be used to prevent impersonation by sending it to the other party in the information exchange.

[0049] [Information Intermediation Flow of Information Intermediation System 300] Figures 9 and 10 are sequence diagrams showing an overview of information transmission and reception in the information mediation system 300. For the handling of information in this system, it is assumed that the public keys (KpA, KpB, KpC, KpE) and public key certificates (CKpA, CKpB, CKpC, CKpE) have been exchanged in advance between the providing terminal device (A) 1, the mediating device (B) 3, the first receiving terminal device (C) 2, and the second receiving terminal device (E) 7.

[0050] Furthermore, the following assumes, for example, that after step S15 is True, the first receiving terminal device (C) 2, which has already obtained the data to be traded (D) such as a data file and the transaction conditions (T), becomes the provider. That is, the first recipient of the first receiving terminal device (C) 2 provides transmission information to the second recipient of the second receiving terminal device (E) 7, which is also a recipient, i.e., the case in which the data to be traded (transferred, re-transferred) is described. Therefore, in this embodiment, the first receiving terminal device (C) 2 becomes the first terminal device, and the second receiving terminal device (E) 7 becomes the second terminal device. Also, the public key (KpC) and private key (KsC) of the first recipient become the first public key and the first private key, respectively, and the public key (KpE) and private key (KsE) of the second recipient become the third public key and the third private key, respectively.

[0051] The information transmitted by the first receiving terminal device (C)2 to the second receiving terminal device (E)7 includes, for example, the provided data (D) and the terms of trade (T1), which include information such as the scope of use and price of the provided data (D). Of these, the provided data (D) cannot be viewed by the intermediary device (B)3, but the terms of trade (T1) must be viewed by the intermediary device (B)3.

[0052] As shown in Figure 9, first, the first receiving terminal device (C)2 encrypts the provided data (D) with the second recipient's public key (KpE) to generate the first encrypted data (D·KpE) (step S51). Next, the first receiving terminal device (C)2 encrypts the transaction terms (T1) with the intermediary's public key (KpB) to generate the second encrypted data (T1·KpB) (step S51). Furthermore, the first receiving terminal device (C)2 encrypts the transaction terms (T1) with the second recipient's public key (KpE) to generate the third encrypted data (T1·KpE) (step S51). Furthermore, the transaction terms (T1) include encrypted data (D·KpC), the value obtained by adding the digital signature (Ca,Cb) to the encrypted data (D·KpE), and the hash values ​​(Hash(D·KpC), Hash(D·KpE+Ca+Cb)) respectively, in order to relate them to the provided data (D).

[0053] Furthermore, the first receiving terminal device (C)2 generates a hash value (Hash(D·KpE+Ca+Cb)) of the encrypted data (D·KpE) including the provider's digital signature (Ca) and the intermediary's digital signature (the intermediary's first digital signature) (Cb), and uses this hash value (Hash(D·KpE+Ca+Cb)) and the private key (KsC) of the first recipient, who is the provider in this case, to generate the first recipient's digital signature (Cc=Hash(D·KpE+Ca+Cb)·KsC) (step S51). The first receiving terminal device (C)2 transmits each of the encrypted data generated in this manner (D·KpE, T1·KpB, T1·KpE), the provider's digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc) to the intermediary device (B)3 (step S51).

[0054] Intermediary device (B) 3 decrypts the received second encrypted data (T1·KpB) with the intermediary's private key (KsB) to obtain the transaction conditions (T1) (step S52). Intermediary device (B) 3 also generates hash values ​​(Hash(D·KpC)) and (Hash(D·KpE+Ca+Cb)) from the decrypted transaction conditions (T1) (step S53).

[0055] Furthermore, the intermediary device (B) 3 decrypts the hash value (Hash(D·KpC)) from the provider's digital signature (Ca) using the provider's public key (KpA) (step S54). Also, the intermediary device (B) 3 decrypts the hash value (Hash(D·KpC)) from the intermediary's first digital signature (Cb) using the intermediary's public key (KpB) (step S54). Furthermore, the intermediary device (B) 3 decrypts the hash value (Hash(D·KpE+Ca+Cb)) from the first recipient's digital signature (Cc), which includes the provider's digital signature (Ca) and the intermediary's first digital signature (Cb), using the first recipient's public key (KpC) (step S54).

[0056] Then, the intermediary device (B) 3 checks whether the hash value (Hash(D·KpC)) included in the transaction terms (T1), the hash value (Hash(D·KpC)) decrypted from the provider's digital signature (Ca), and the hash value (Hash(D·KpC)) decrypted from the intermediary's first digital signature (Cb) all match (step S55).

[0057] Furthermore, the intermediary device (B) 3 checks whether the hash value generated from the first encrypted data (D·KpE), the provider's digital signature (Ca), and the intermediary's first digital signature (Cb) (Hash(D·KpE+Ca+Cb)), the hash value contained in the transaction terms (T1) (Hash(D·KpE+Ca+Cb)), and the hash value decrypted from the first recipient's digital signature (Cc) (Hash(D·KpE+Ca+Cb)) all match (step S55). Once the intermediary device (B) 3 has confirmed that all of these hash values ​​match, it can verify that the sent transaction terms (T1) relate to the provided data (D), that the information was intended for the intermediary device (B) 3 via the provider terminal device (A) 1, the intermediary device (B) 3, and the first receiving terminal device (C) 2, and that the sender is the first receiving terminal device (C) 2 (step S55).

[0058] Next, as shown in Figure 10, the intermediary device (B) 3 generates a hash value (Hash(D·KpE+Ca+Cb+Cc)) which is the sum of the received first encrypted data (D·KpE), the provider's digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc). Using this hash value (Hash(D·KpE+Ca+Cb+Cc)) and the intermediary (B)'s private key (KsB), the intermediary generates a second digital signature, which is the intermediary's digital signature (the intermediary's second digital signature) (Cb2=Hash(D·KpE+Ca+Cb+Cc)·KsB) (step S61). Then, the intermediary device (B) 3 receives the encrypted data (D·KpE, T1·KpE), the provider's digital signature (Ca), and the intermediary's first digital signature. The signature (Cb), the first recipient's electronic signature (Cc), and the generated intermediary's second electronic signature (Cb2) are transmitted to the second receiving terminal device (E) 7 (step S61).

[0059] The second receiving terminal device (E) 61 decrypts the received encrypted data (D·KpE, T1·KpE) using the second recipient's private key (KsE) to obtain the provided data (D) and the transaction terms (T1) (step S62). The second receiving terminal device (E) 7 also generates hash values ​​(Hash(D·KpC), Hash(D·KpE+Ca+Cb), and Hash(D·KpE+Ca+Cb+Cc)) from the obtained provided data (D) (step S63). The second receiving terminal device (E) 7 also generates hash values ​​(Hash(D·KpC) and Hash(D·KpE+Ca+Cb)) from the obtained transaction terms (T1) (step S63).

[0060] Furthermore, the second receiving terminal device (E) 7 verifies the provider's digital signature (Ca) with the provider's public key (KpA) (KpA(Ca) = Hash(D·KpC)) to obtain a hash value (Hash(D·KpC)) (step S64). Also, the second receiving terminal device (E) 7 verifies the intermediary's first digital signature (Cb) with the intermediary's public key (KpB) (KpB(Cb) = Hash(D·KpC)) to obtain a hash value (Hash(D·KpC)) (step S64).

[0061] Furthermore, the second receiving terminal device (E) 7 verifies the first recipient's digital signature (Cc) with the first recipient's public key (KpC) (KpC(Cc) = Hash(D·KpE+Ca+Cb)) to obtain a hash value (Hash(D·KpE+Ca+Cb)) (step S64). In addition, the second receiving terminal device (E) 7 verifies the intermediary's second digital signature (Cb2) with the intermediary's public key (KpB) (KpB(Cb2) = Hash(D·KpE+Ca+Cb+Cc)) to obtain a hash value (Hash(D·KpE+Ca+Cb+Cc)) (step S64).

[0062] The second receiving terminal device (E) 7 then checks whether the hash value (Hash(D·KpC)) included in the transaction terms (T1), the hash value (Hash(D·KpC)) generated from the provided data (D), the hash value (Hash(D·KpC)) decrypted from the provider's digital signature (Ca), and the hash value (Hash(D·KpC)) decrypted from the intermediary's first digital signature (Cb) all match. Furthermore, the second receiving terminal device (E) 7 checks whether the hash value (Hash(D·KpE+Ca+Cb)) included in the transaction terms (T1), the hash value (Hash(D·KpE+Ca+Cb)) obtained from the first encrypted data (D·KpE) plus the provider's digital signature (Ca) and the intermediary's first digital signature (Cb), and the hash value (Hash(D·KpE+Ca+Cb)) obtained from the first recipient's digital signature (Cc) all match. Furthermore, the second receiving terminal device (E) 7 checks whether the hash value obtained from the first encrypted data (D·KpE) plus the provider's digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc) (Hash(D·KpE+Ca+Cb+Cc)) matches the hash value obtained from the intermediary's second digital signature (Cb2) (Hash(D·KpE+Ca+Cb+Cc)).

[0063] The second receiving terminal device (E)7 can verify, upon confirmation that all of these values ​​match, that the sent transaction terms (T1) relate to the provided data (D), that the information was intended for the second receiving terminal device (E)7 via the providing terminal device (A)1, the intermediary device (B)3, the first receiving terminal device (C)2, and the intermediary device (B)3, that the sender is the first receiving terminal device (C)2 and the intermediary device (B)3 (step S65).

[0064] Thus, according to this embodiment, if the verification result is determined to be genuine (True in step S65), it can be determined that the provided data (D) and transaction terms (T1) are genuine, and that they were provided by the first receiving terminal device (C) 2 through intermediary device (B) 3 and transmitted to the second receiving terminal device (E) 7.

[0065] On the other hand, if the verification results are determined to be inauthentic (False in step S65), it can be determined that the provided data (D) or transaction terms (T1) are inauthentic, not provided by the provider, not mediated by the intermediary, not provided by the first recipient, or not mediated again by the intermediary. In this case as well, there is a high probability that the provided data (D) or transaction terms (T1) have been tampered with or impersonated as described above, so the second recipient can take the various countermeasures described above or attempt to uncover the tampering, etc.

[0066] [Fourth Embodiment] [Information Intermediation Flow of Information Intermediation System 300] Figures 11 and 12 are sequence diagrams showing an overview of the information mediation system according to the fourth embodiment of the present invention. In the first to third embodiments described above, the manner in which information mediation systems 100 to 300 transmit and receive transmission information including provided data (D) and transaction conditions (T, T1) was described, but in the fourth embodiment, the manner in which data usage rights (Dt) are handled as transmission information will be described. Note that the system configuration of the information mediation system of the fourth embodiment can be configured in the same way as the information mediation system 300 of the third embodiment, so it is not shown in the diagram.

[0067] Here, a Data Usage Rights Certificate (Dt) is a certificate that defines the rights related to the use of data, clarifying the rights related to the use of data (Provided Data D) that will be circulated in the data trading market. In other words, a Data Usage Rights Certificate (Dt) is a certificate that specifies, as an agreement, the rights and obligations of both the provider (A) and the users (recipients C, E) with respect to the target data (Provided Data D). The agreement includes, for example, the target data, the provision period, and the scope and purpose of use. It is important to note that a Data Usage Rights Certificate (Dt) is linked to a copy of the target data (Provided Data D). In this case, the copy of the Data Usage Rights Certificate (Dt) that is linked to the Data Usage Rights Certificate (Dt) is the copy of the data (Provided Data D) that will be circulated. Therefore, it is possible to issue multiple copies of this combination of a copy of Provided Data (D) and a Data Usage Rights Certificate (Dt).

[0068] Furthermore, the issuer (provider (A)) managing the number of issued certificates helps to establish exclusivity and manage scarcity for the data (provided data D). Additionally, the issuer (provider (A)) and intermediary (B) electronically signing the data usage certificate (Dt) clarifies its provenance, and recipients (C, E) can endorse and transfer it, enabling the independent circulation of the data usage certificate (Dt). In other words, introducing the data usage certificate (Dt) into the data distribution market and forming a data usage rights trading market makes it possible to promote data utilization.

[0069] Furthermore, with the introduction of the Data Usage Rights Certificate (Dt), the provider (A) is certified by a third party (intermediary (B)) as the legitimate creator of the provided data (D). Therefore, if the value of the data (provided data D) is assessed after data distribution, the provider (A) may be recognized as the original provider.

[0070] Furthermore, the recipient (C,E) is verified by a third party (intermediary (B)) as being a legitimate user of the provided data (D). In addition, the data usage rights certificate (Dt) is signed by the issuer (provider (A)) and the intermediary (B), making its origin clear (traceability), thus ensuring safe distribution while guaranteeing the authenticity and completeness of the data. It becomes possible.

[0071] Furthermore, in data usage rights transactions within the information intermediary system 300, in addition to the data usage rights themselves, detailed information about the data (provided data D) (such as acquisition history, whether an agreement exists, measurement environment, etc., which cannot be expressed by the data itself (hereinafter referred to as "ancillary information")) is important, after a data usage rights certificate (Dt) based on the above concept has been realized.

[0072] Therefore, in the data usage rights trading market, it is assumed that this supplementary information, the data usage rights certificate (Dt), and the provided data (D) will ultimately circulate as a set. However, the provided data (D) that is paired with the data usage rights certificate (Dt) only needs to be appropriately provided at the time the rights related to data usage indicated in the data usage rights certificate (Dt) are exercised. Therefore, it is not necessarily required that the provided data (D) exists at the time the data usage rights certificate (Dt) is issued. In other words, the data usage rights certificate (Dt) can be used as a certificate that can be issued not only for the present but also for the provided data (D) that will be provided in the future.

[0073] [Process for issuing Data Usage Rights Certificates (Dt)] When issuing a Data Usage Rights Certificate (Dt), it is assumed that the data provider notifies the intermediary of the issuance of the Data Usage Rights Certificate (Dt) and its contents, the intermediary solicits purchases of the Data Usage Rights Certificate (Dt) from recipients, and the recipients notify the intermediary of their desire to purchase the Data Usage Rights Certificate (Dt). The prerequisites for handling information, such as public keys, private keys, and public key certificates, are the same as in the third embodiment. Here, the issuance of a Data Usage Rights Certificate (Dt) from the provider terminal device (A)1 to the first recipient terminal device (C)2 will be described. The information transmitted by the provider terminal device (A)1 to the first recipient terminal device (C)2 includes, for example, a Data Usage Rights Certificate (Dt) for provision data (D) that is in a state where it can be collected and provided, or provision data (D) that is planned to be provided in the future. The Data Usage Rights Certificate (Dt) cannot be viewed by the intermediary device (B)3. Furthermore, the Data Usage Rights Certificate (Dt) may include various information as supplementary information, such as the transaction terms (T,T1) mentioned above.

[0074] As shown in Figure 11, the provider terminal device (A) 1 encrypts the data usage rights certificate (Dt) with the first recipient's public key (KpC) to generate the first encrypted data (Dt·KpC) (step S71). The provider terminal device (A) 1 also generates the provider's digital signature (Ca=Hash(Dt·KpC)·KsA), which is the first digital signature, using the hash value (Hash(Dt·KpC)) obtained from the encrypted data (Dt·KpC) and the provider's private key (KsA) (step S71). The provider terminal device (A) 1 transmits the encrypted data (Dt·KpC) and the provider's digital signature (Ca) generated in this way to the intermediary device (B) 3 (step S71).

[0075] Intermediary device (B) 3 generates a hash value (Hash(Dt·KpC)) from the received encrypted data (Dt·KpC) (step S72). Intermediary device (B) 3 also verifies the provider's digital signature (Ca) with the provider's public key (KpA) (KpA(Ca)=Hash(Dt·KpC)) to obtain a hash value (Hash(Dt·KpC)) (step S73). Then, intermediary device (B) 3 checks whether the hash value (Hash(Dt·KpC)) generated from the encrypted data (Dt·KpC) matches the hash value (Hash(Dt·KpC)) decrypted from the provider's digital signature (Ca). By confirming that the hash values ​​(Hash(Dt·KpC)) match, intermediary device (B) 3 can verify that the sender of the transmitted encrypted data (Dt·KpC) is provider terminal device (A) 1 (step S74).

[0076] Next, as shown in Figure 12, the intermediary device (B) 3 includes the provider's digital signature (Ca) in the received encrypted data (Dt·KpC) to create a hash value (Hash(Dt·KpC+Ca) The intermediary device (B) 3 generates a hash value and encrypts this hash value with the intermediary's (B) private key (KsB) to generate a second digital signature, which is the intermediary's digital signature (Cb = Hash(Dt·KpC+Ca)·KsB) (step S81). Then, the intermediary device (B) 3 transmits the received encrypted data (Dt·KpC), the provider's digital signature (Ca), and the generated intermediary's digital signature (Cb) to the first receiving terminal device (C) 2 (step S81).

[0077] The first receiving terminal device (C)2 decrypts the received encrypted data (Dt·KpC) using the first recipient's private key (KsC) to obtain a data usage right certificate (Dt) (step S82). The first receiving terminal device (C)2 also generates a hash value (Hash(Dt·KpC)) and a hash value (Hash(Dt·KpC+Ca)) from the obtained data usage right certificate (Dt) (step S83). The first receiving terminal device (C)2 also verifies the provider's digital signature (Ca) with the provider's public key (KpA) (KpA(Ca)=Hash(Dt·KpC)) to obtain a hash value (Hash(Dt·KpC)) (step S84). Furthermore, the first receiving terminal device (C)2 verifies the intermediary's electronic signature (Cb) with the intermediary's public key (KpB) (KpB(Cb) = Hash(Dt·KpC+Ca)) to obtain a hash value (Hash(D·KpC+Ca)) (step S84).

[0078] The first receiving terminal device (C)2 then checks whether the hash value (Hash(Dt·KpC)) generated from the data usage right certificate (Dt) matches the hash value (Hash(Dt·KpC)) decrypted from the provider's digital signature (Ca). The first receiving terminal device (C)2 also checks whether the hash value (Hash(Dt·KpC+Ca)) generated from the data usage right certificate (Dt) matches the hash value (Hash(Dt·KpC+Ca)) decrypted from the intermediary's digital signature (Cb). Once these matches are confirmed, the first receiving terminal device (C)2 can verify that the sent data usage right certificate (Dt) is information intended for the first receiving terminal device (C)2, that the sender is the provider terminal device (A)1, and that the intermediary is the intermediary device (B)3 (step S85). Furthermore, the first receiving terminal device (C)2 can verify that the received electronic signature (Ca,Cb) is a transaction relating to the data usage right certificate (Dt) because it includes a hash value generated from the data usage right certificate (Dt).

[0079] Thus, according to this embodiment, if the verification result is determined to be genuine (True in step S85), it is possible to determine that the data usage rights certificate (Dt) is genuine, was issued from the provider terminal device (A)1, and transmitted to the first receiving terminal device (C)2 via the intermediary device (B)3.

[0080] On the other hand, if the verification results are determined to be inauthentic (False in step S85), it can be determined that the data usage rights certificate (Dt) is inauthentic, not issued by the provider, or not brokered by an intermediary. In such cases, various measures as described above can be taken, or attempts can be made to uncover any tampering.

[0081] [Fifth Embodiment] [Procedure for purchasing data (D) provided by a data usage rights certificate (Dt)] Figures 13 and 14 are sequence diagrams showing an overview of the information mediation system according to the fifth embodiment of the present invention. Next, we will describe the scenario in which the provider (A)1 of the data usage rights certificate (Dt) becomes able to provide the data (D) covered by the data usage rights certificate (Dt), and the first recipient (C)2 purchases the data (D).

[0082] As shown in Figure 13, first, the first receiving terminal device (C)2 generates encrypted data (Dt·KpA) by encrypting the data usage rights certificate (Dt) with the provider's public key (KpA). Step S91).

[0083] Furthermore, the first receiving terminal device (C)2 generates a hash value (Hash(Dt·KpA+Ca+Cb)) by including the provider's digital signature (Ca) and the intermediary's first digital signature (Cb) in the generated encrypted data (Dt·KpA), and uses this hash value (Hash(Dt·KpA+Ca+Cb)) and the first recipient's (C)2's private key (KsC) to generate the first digital signature, which is the first recipient's digital signature (Cc=Hash(Dt·KpA+Ca+Cb)·KsC) (step S91). The first receiving terminal device (C)2 transmits the generated first recipient's digital signature (Cc) along with the encrypted data (Dt·KpA), the provider's digital signature (Ca), and the intermediary's first digital signature (Cb) to the intermediary device (B)3 (step S91).

[0084] Intermediary device (B) 3 generates a hash value (Hash(Dt·KpA+Ca+Cb)) from the received encrypted data (Dt·KpA), the provider's digital signature (Ca), and the intermediary's digital signature (Cb) (step S92). Intermediary device (B) 3 also obtains a hash value (Hash(Dt·KpA+Ca+Cb)) from the first recipient's digital signature (Cc) using the first recipient's public key (KpC) (step S93).

[0085] Then, the intermediary device (B) 3 checks whether the hash value (Hash(Dt·KpA+Ca+Cb)) generated from the encrypted data (Dt·KpA), the provider's digital signature (Ca), and the intermediary's digital signature (Cb) matches the hash value (Hash(Dt·KpA+Ca+Cb)) decrypted from the first recipient's digital signature (Cc).

[0086] The intermediary device (B) 3 can verify that the transmitted encrypted data (Dt·KpA) originated from the provider terminal device (A) 1 by checking if the hash value (Hash(Dt·KpA+Ca+Cb)) matches (step S94).

[0087] Next, as shown in Figure 14, the intermediary device (B) 3 generates a hash value (Hash(Dt·KpA+Ca+Cb+Cc)) by including the provider's digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc) in the received encrypted data (Dt·KpA). Using the obtained hash value (Hash(Dt·KpA+Ca+Cb+Cc)) and the intermediary's private key (KsB), it generates the intermediary's second digital signature, which is the second digital signature (Cb2=Hash(Dt·KpA+Ca+Cb+Cc)·KsB) (step S101). Then, the intermediary device (B) 3 transmits the received encrypted data (Dt·KpA), the provider's digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc), along with the generated intermediary's second digital signature (Cb2), to the provider terminal device (A) 1 (step S101).

[0088] The provider terminal device (A)1 decrypts the received encrypted data (Dt·KpA) using the provider's private key (KsA) to obtain a data usage right certificate (Dt) (step S102). The provider terminal device (A)1 also generates hash values ​​(Hash(Dt·KpC), Hash(Dt·KpC+Ca), Hash(Dt·KpA+Ca+Cb), and Hash(Dt·KpA+Ca+Cb+Cc)) from the obtained data usage right certificate (Dt) (step S103).

[0089] Furthermore, the provider terminal device (A)1 verifies the provider's digital signature (Ca) with the provider's public key (KpA) (KpA(Ca) = Hash(Dt·KpC)) and obtains a hash value (Hash(Dt·KpC)) (step S104). Also, the provider terminal device (A)1 verifies the intermediary's first digital signature (Cb) with the intermediary's public key (KpB) (KpB(Cb) = Hash(Dt·KpC+Ca)) and obtains a hash value (Hash(Dt·KpC+Ca)) (step S104).

[0090] Furthermore, the provider terminal device (A) 1 verifies the first recipient's digital signature (Cc) with the first recipient's public key (KpC) (KpB(Cc)=Hash(Dt·KpA+Ca+Cb)) to obtain a hash value (Hash(Dt·KpA+Ca+Cb)) (step S104). In addition, the provider terminal device (A) 1 verifies the intermediary's second digital signature (Cb2) with the intermediary's public key (KpB) (KpB(Cb2)=Hash(Dt·KpA+Ca+Cb+Cc)) to obtain a hash value (Hash(Dt·KpA+Ca+Cb+Cc)) (step S104).

[0091] Then, the provider terminal device (A)1 checks whether the hash value generated from the data usage right certificate (Dt) (Hash(Dt·KpC)) matches the hash value decrypted from the provider's digital signature (Ca) (Hash(Dt·KpC)), or whether the hash value generated from the data usage right certificate (Dt) and the provider's digital signature (Ca) (Hash(Dt·KpC+Ca)) matches the hash value decrypted from the intermediary's first digital signature (Cb) (Hash(Dt·KpC+Ca)), or from the data usage right certificate (Dt), the provider's digital signature (Ca), and the intermediary's first digital signature (Cb) The system verifies whether the generated hash value (Hash(Dt·KpA+Ca+Cb)) matches the hash value (Hash(Dt·KpC+Ca+Cb)) decrypted from the first recipient's digital signature (Cc), and whether the hash value (Hash(Dt·KpA+Ca+Cb+Cc)) generated from the data usage rights certificate (Dt), the provider's digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc) matches the hash value (Hash(Dt·KpA+Ca+Cb+Cc)) decrypted from the intermediary's second digital signature (Cb2).

[0092] The provider terminal device (A)1 can verify, upon confirmation that all of these values ​​match, that the transmitted data usage rights certificate (Dt) is information intended for the provider terminal device (A)1, having passed through the provider terminal device (A)1, the intermediary device (B)3, the first receiving terminal device (C)2, and the intermediary device (B)3, and that the sender is the first receiving terminal device (C)2 and the intermediary is the intermediary device (B)3 (step S105).

[0093] Thus, according to this embodiment, if the verification result is determined to be genuine (True in step S105), it is possible to determine that the data usage rights certificate (Dt) is genuine, that it was provided from the provider terminal device (A)1, and that it was transmitted again to the provider terminal device (A)1 via the intermediary device (B)3, the first receiving terminal device (C)2, and the intermediary device (B)3.

[0094] On the other hand, if the verification result is determined to be inauthentic (False in step S105), it can be determined that the data usage rights certificate (Dt) is inauthentic, not provided by the provider, not mediated by an intermediary, or not originated by the first recipient. In this case, various measures as described above can be taken, or attempts can be made to uncover any tampering. After the provider terminal device (A)1 receives an authentic data usage rights certificate (Dt) from the first recipient terminal device (C)2, it can transfer the provided data (D) to the first recipient terminal device (C)2 in accordance with the flow described in the first embodiment. Therefore, the first recipient terminal device (C)2 can purchase the provided data (D) from the provider terminal device (A)1.

[0095] [Sixth Embodiment] [Distribution flow of the provided dataset (Dset)] Figures 15 and 16 are sequence diagrams showing an overview of the information mediation system according to the sixth embodiment of the present invention. Here, the provider (A)1 of the data usage rights certificate (Dt) receives true from the first recipient (C)2. This section describes a scenario in which, after receiving a positive data usage certificate (Dt), the provided data (D) is linked to the data usage certificate (Dt), and these are provided to the first recipient (C)2 as a set of provided datasets (Dset=Dt+D).

[0096] As shown in Figure 15, the provider terminal device (A) 1 generates encrypted data (Dset·KpC) by encrypting the provided dataset (Dset) with the first recipient's public key (KpC) (step S111). The provider terminal device (A) 1 also generates the provider's second digital signature (Ca2=Hash(Dset·KpC)·KsA), which is the first digital signature, using the hash value (Hash(Dset·KpC)) obtained from the encrypted data (Dset·KpC) and the provider's private key (KsA) (step S111). The provider terminal device (A)1 transmits the encrypted data generated in this manner (Dset·KpC), along with the provider's second digital signature (Ca2), the provider's digital signature (provider's first digital signature) (Ca), the intermediary's first digital signature (Cb), the first recipient's digital signature (Cc), and the intermediary's second digital signature (Cb2) to the intermediary device (B)3 (step S111).

[0097] Intermediary device (B) 3 generates a hash value (Hash(Dset·KpC)) from the received encrypted data (Dset·KpC) (step S112). Intermediary device (B) 3 also verifies the provider's second digital signature (Ca2) with the provider's public key (KpA) (KpA(Ca2)=Hash(Dset·KpC)) to obtain a hash value (Hash(Dset·KpC)) (step S113).

[0098] Then, the intermediary device (B) 3 checks whether the hash value (Hash(Dset·KpC)) generated from the encrypted data (Dset·KpC) matches the hash value (Hash(Dset·KpC)) decrypted from the provider's second digital signature (Ca2).

[0099] The intermediary device (B)3 can verify that the sender of the encrypted data (Dset·KpC) is the provider terminal device (A)1 by checking if the hash value (Hash(Dset·KpC)) matches (step S114).

[0100] Next, as shown in Figure 16, the intermediary device (B) 3 generates a hash value (Hash(Dset·KpC+Ca2)) by including the provider's second digital signature (Ca2) in the received encrypted data (Dset·KpC), and uses this hash value (Hash(Dset·KpC+Ca2)) and the intermediary's private key (KsB) to generate the intermediary's third digital signature (Cb3=Hash(Dset·KpC+Ca2)·KsB), which is the second digital signature (step S121). Then, the intermediary device (B) 3 transmits the received encrypted data (Dset·KpC) and the generated third digital signature of the intermediary (Cb3), along with the provider's first digital signature (Ca), the intermediary's first digital signature (Cb), the first recipient's digital signature (Cc), the intermediary's second digital signature (Cb2), and the provider's second digital signature (Ca2) to the first receiving terminal device (C) 2 (step S121).

[0101] The first receiving terminal device (C)2 decrypts the received encrypted data (Dset·KpC) using the first recipient's private key (KsC) to obtain the provided dataset (Dset) (step S122). The first receiving terminal device (C)2 also generates hash values ​​(Hash(Dt·KpC), Hash(Dt·KpC+Ca), Hash(Dt·KpA+Ca+Cb), Hash(Dt·KpA+Ca+Cb+Cc), Hash(Dset·KpC, and Hash(Dset·KpC+Ca2)) from the obtained provided dataset (Dset) (step S123).

[0102] Furthermore, the first receiving terminal device (C)2 receives the provider's first electronic signature (Ca) from the provider The first receiving terminal device (C) 2 verifies the intermediary's first digital signature (Cb) with the intermediary's public key (KpB) (KpB(Cb) = Hash(Dt·KpC+Ca)) to obtain a hash value (Hash(Dt·KpC+Ca)) (step S124).

[0103] Furthermore, the first receiving terminal device (C)2 verifies the first recipient's digital signature (Cc) with the first recipient's public key (KpC) (KpC(Cc)=Hash(Dt·KpA+Ca+Cb)) to obtain a hash value (Hash(Dt·KpA+Ca+Cb)) (step S124).

[0104] Furthermore, the first receiving terminal device (C)2 verifies the intermediary's second digital signature (Cb2) with the intermediary's public key (KpB) (KpB(Cb2)=Hash(Dt·KpA+Ca+Cb+Cc)) to obtain a hash value (Hash(Dt·KpA+Ca+Cb+Cc)) (step S124).

[0105] Furthermore, the first receiving terminal device (C)2 verifies the provider's second digital signature (Ca2) with the provider's public key (KpA) (KpA(Ca2)=Hash(Dset·KpC)) to obtain a hash value (Hash(Dset·KpC)) (step S124). In addition, the first receiving terminal device (C)2 verifies the intermediary's third digital signature (Cb3) with the intermediary's public key (KpB) (KpB(Cb3)=Hash(Dset·KpC+Ca2)) to obtain a hash value (Hash(Dset·KpC+Ca2)) (step S124).

[0106] The first receiving terminal device (C)2 then checks whether the hash values ​​generated from the provided dataset (Dset) (Hash(Dt·KpC), Hash(Dt·KpC+Ca), Hash(Dt·KpA+Ca+Cb), Hash(Dt·KpA+Ca+Cb+Cc), Hash(Dset·KpC), and Hash(Dset·KpC+Ca2)) match the hash values ​​decrypted from the digital signatures (Ca, Cb, Cc, Cb2, Ca2, and Cb3) (Hash(Dt·KpC), Hash(Dt·KpC+Ca), Hash(Dt·KpA+Ca+Cb), Hash(Dt·KpA+Ca+Cb+Cc), Hash(Dset·KpC), and Hash(Dset·KpC+Ca2)).

[0107] Once all of these values ​​have been confirmed to match, it can be verified that the sent provided dataset (Dset) is information intended for the first receiving terminal device (C)2, that the sender is the providing terminal device (A)1, and that the intermediary is the intermediary device (B)3 (step S125).

[0108] Thus, according to this embodiment, if the verification result is determined to be genuine (True in step S125), it is possible to determine that the provided dataset (Dset) is genuine, provided from the providing terminal device (A)1, transmitted to the first receiving terminal device (C)2 via the intermediary device (B)3, and transmitted to the first receiving terminal device (C)2 via the providing terminal device (A)1, the intermediary device (B)3, the first receiving terminal device (C)2, the intermediary device (B)3, the providing terminal device (A)1, and the intermediary device (B)3.

[0109] On the other hand, if the verification result is determined to be inauthentic (False in step S125), it can be determined that the provided dataset (Dset) is inauthentic, not provided by the provider, not mediated by an intermediary, or not sent from the provider and received by the first recipient via the above-mentioned route. In such cases, various measures as described above can be taken, or attempts can be made to uncover any tampering.

[0110] [Seventh Embodiment] [Transfer process for data usage rights certificates (Dt)] Figures 17 and 18 are sequence diagrams showing an overview of the information mediation system according to the seventh embodiment of the present invention. This section describes the circumstances under which a data usage right certificate (Dt) is transferred independently from the first recipient (C)2 to the second recipient (E)7.

[0111] As shown in Figure 17, first, the first receiving terminal device (C)2 encrypts the data usage rights certificate (Dt) with the second recipient's public key (KpE) to generate encrypted data (Dt·KpE) (step S131).

[0112] Furthermore, the first receiving terminal device (C)2 calculates a hash value (Hash(Dt·KpE+Ca+Cb)) of the encrypted data (Dt·KpE) including the provider's first digital signature (Ca) and the intermediary's first digital signature (Cb), and uses this hash value (Hash(Dt·KpE+Ca+Cb)) and the private key (KsC) of the first recipient, who is the provider in this case, to generate the first recipient's digital signature (Cc=Hash(Dt·KpE+Ca+Cb)) (step S131). The first receiving terminal device (C)2 then transmits the encrypted data (Dt·KpE) thus generated, the provider's first digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc) to the intermediary device (B)3 (step S131).

[0113] Intermediary device (B) 3 generates a hash value (Hash(Dt·KpE+Ca+Cb)) from the received encrypted data (Dt·KpE), the provider's first digital signature (Ca), and the intermediary's first digital signature (Cb) (step S132). Intermediary device (B) 3 also decrypts the hash value (Hash(Dt·KpE+Ca+Cb)) using the first recipient's public key (KpC) from the first recipient's digital signature (Cc), which includes the provider's first digital signature (Ca) and the intermediary's first digital signature (Cb) (step S133).

[0114] Then, the intermediary device (B) 3 checks whether the hash value (Hash(Dt·KpE+Ca+Cb)) generated from the encrypted data (Dt·KpE) matches the hash value (Hash(Dt·KpE+Ca+Cb)) decrypted from the first recipient's digital signature (Cc).

[0115] The intermediary device (B) 3 can verify that the sender of the encrypted data (Dt·KpE) is the first receiving terminal device (C) 2 by checking if the hash value (Hash(Dt·KpE+Ca+Cb)) matches (step S134).

[0116] Next, as shown in Figure 18, the intermediary device (B) 3 generates a hash value (Hash(Dt·KpE+Ca+Cb+Cc)) by including the provider's first digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc) in the received encrypted data (Dt·KpE). Using this hash value (Hash(Dt·KpE+Ca+Cb+Cc)) and the intermediary's private key (KsB), it generates the intermediary's second digital signature (Cb2=Hash(Dt·KpE+Ca+Cb+Cc)·KsB) (step S141).

[0117] Then, the intermediary device (B) 3 transmits the received encrypted data (Dt·KpE) and the generated second digital signature of the intermediary (Cb2), along with the provider's first digital signature (Ca), the intermediary's first digital signature (Cb), and the first recipient's digital signature (Cc), to the second receiving terminal device (E) 7 (step S141).

[0118] The second receiving terminal device (E) 7 decrypts the received encrypted data (Dt·KpE) using the second recipient's private key (KsE) to obtain a data usage right certificate (Dt) (step S142). The second receiving terminal device (E) 7 also generates hash values ​​(Hash(Dt·KpC), Hash(Dt·KpC+Ca), Hash(Dt·KpE+Ca+Cb), and Hash(Dt·KpE+Ca+Cb+Cc)) from the obtained data usage right certificate (Dt) (step S143).

[0119] Furthermore, the second receiving terminal device (E) 7 verifies the provider's first digital signature (Ca) with the provider's public key (KpA) (KpA(Ca) = Hash(Dt·KpC)) and obtains a hash value (Hash(Dt·KpC)) (step S144). Also, the second receiving terminal device (E) 7 verifies the intermediary's first digital signature (Cb) with the intermediary's public key (KpB) (KpB(Cb) = Hash(Dt·KpC+Ca)) and obtains a hash value (Hash(Dt·KpC+Ca)) (step S144).

[0120] Furthermore, the second receiving terminal device (E) 7 verifies the first recipient's digital signature (Cc) with the first recipient's public key (KpC) (KpC(Cc)=Hash(Dt·KpE+Ca+Cb)) to obtain a hash value (Hash(Dt·KpE+Ca+Cb)) (step S144).

[0121] Furthermore, the second receiving terminal device (E) 7 verifies the intermediary's second digital signature (Cb2) with the intermediary's public key (KpB) (KpB(Cb2)=Hash(Dt·KpE+Ca+Cb+Cc)) to obtain a hash value (Hash(Dt·KpE+Ca+Cb+Cc)) (step S144).

[0122] The second receiving terminal device (E) 7 then checks whether the hash values ​​generated from the data usage rights certificate (Dt) (Hash(Dt·KpC), Hash(Dt·KpC+Ca), Hash(Dt·KpE+Ca+Cb), and Hash(Dt·KpE+Ca+Cb+Cc)) match the hash values ​​decrypted from the digital signatures (Ca, Cb, Cc, and Cb2) (Hash(Dt·KpC), Hash(Dt·KpC+Ca), Hash(Dt·KpE+Ca+Cb), and Hash(Dt·KpE+Ca+Cb+Cc)).

[0123] Once all of these values ​​have been confirmed to match, it can be verified that the transmitted data usage rights certificate (Dt) is information destined for the second receiving terminal device (E) 7 via the provider terminal device (A) 1, the intermediary device (B) 3, the first receiving terminal device (C) 2, and the intermediary device (B) 3, and that the sender is the first receiving terminal device (C) 2 and the intermediary is the intermediary device (B) 3 (step S145).

[0124] Thus, according to this embodiment, if the verification result is determined to be genuine (True in step S145), it can be determined that the data usage rights certificate (Dt) is genuine, and that it was provided for transfer (transfer) from the first receiving terminal device (C) 2 via the above-mentioned route and transmitted to the second receiving terminal device (E) 7 via the intermediary device (B) 3.

[0125] On the other hand, if the verification results are determined to be inauthentic (False in step S145), it can be determined that the data usage rights certificate (Dt) is inauthentic, not provided by the provider, not mediated by the intermediary, not provided by the first recipient, or not mediated again by the intermediary. In this case as well, there is a high possibility that the data usage rights certificate (Dt) has been tampered with or impersonated as described above, so the second recipient can take various countermeasures or attempt to uncover the tampering.

[0126] In addition, in the third to seventh embodiments, the provided data (D), transaction terms (T1), data usage rights certificate (Dt), provided dataset (Dset), and electronic signature (Ca, Cb, Cc, Cb2, Ca2, etc.) to be transmitted may include a timestamp, as in the second embodiment.

[0127] Although several embodiments of the present invention have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0128] 1. Provider terminal device (A) 2. Receiving terminal device (C) 3 Mediation device (B) 4. Public Key Certificate Authority (CA) 5 Network 6. Time Signature Authority (TSA) 7 Receiving terminal device (E) 100,200,300 Information Intermediation System

Claims

1. A provider terminal device that transmits transmission information including first data which is provided data subject to trading to be distributed in a data trading market and second data which indicates the trading conditions for the provided data, A receiving terminal device that receives the aforementioned transmission information, An intermediary device that mediates the exchange of the transmission information between the providing terminal device and the receiving terminal device, In an information intermediary system equipped with, The providing terminal device is assigned a first public key and a first private key. The aforementioned intermediary device is assigned a second public key and a second private key. The receiving terminal device is assigned a third public key and a third private key. The providing terminal device encrypts the first data with the third public key to generate first encrypted data, encrypts the second data with the second public key to generate second encrypted data, generates a first digital signature using the first private key, and transmits the first encrypted data, the second encrypted data, and the first digital signature to the intermediary device. The intermediary device decrypts the second encrypted data using the second secret key, generates a second digital signature using the second secret key, and transmits the first encrypted data, the first digital signature, and the second digital signature to the receiving terminal device. The second data is encrypted with the third public key at the providing terminal device or the intermediary device and transmitted to the receiving terminal device as the third encrypted data. The receiving terminal device decrypts the first encrypted data with the third private key to obtain the first data, decrypts the third encrypted data with the third private key to obtain the second data, verifies the first digital signature with the first public key, and verifies the second digital signature with the second public key. Information intermediary system.

2. The providing terminal device generates the first digital signature by encrypting the hash value obtained by functionalizing the first encrypted data with a one-way function using the first secret key, The intermediary device generates the second digital signature by encrypting the hash value obtained by performing a one-way function on the first encrypted data with the second secret key. The information mediation system according to claim 1.

3. The receiving terminal device determines the authenticity of the transmitted information based on whether the calculation result obtained by performing a function on the first encrypted data using the one-way function, the decryption result obtained by decrypting the first digital signature with the first public key, and the decryption result obtained by decrypting the second digital signature with the second public key are equal. The information mediation system according to claim 2.

4. The providing terminal device generates first time authentication data by adding a first timestamp obtained from the time authentication authority to the second data, generates second encrypted data by encrypting the first time authentication data with the second public key, and transmits the first and second encrypted data to the intermediary device. The information mediation system according to claim 1.

5. The providing terminal device generates the first digital signature by encrypting the hash value obtained by functionalizing the second encrypted data with a one-way function using the first secret key, The intermediary device generates second time authentication data by decrypting the second encrypted data and adding a second timestamp obtained from the time authentication authority to the first time authentication data obtained; generates third encrypted data by encrypting the second time authentication data with the third public key; and generates the second digital signature by encrypting the hash value obtained by functionalizing the third encrypted data with a one-way function with the second private key. The information mediation system according to claim 4.

6. The receiving terminal device decrypts the second time authentication data from the third encrypted data, separates the first time authentication data from the second time authentication data, and determines the authenticity of the transmitted information based on whether the calculation result of the first and second time authentication data being functioned by the one-way function, the decryption result of decrypting the first digital signature with the first public key, and the decryption result of decrypting the second digital signature with the second public key are equal, and based on the verification results of the first and second timestamps contained in the second time authentication data by the time authentication authority. The information mediation system according to claim 5.

7. A provider terminal device that transmits transmission information including first data which is provided data subject to trading to be distributed in a data trading market and second data which indicates the trading conditions for the provided data, A receiving terminal device that receives the aforementioned transmission information, An intermediary device that mediates the exchange of the transmission information between the providing terminal device and the receiving terminal device, An information mediation method in an information mediation system equipped with, The providing terminal device is assigned a first public key and a first private key. The aforementioned intermediary device is assigned a second public key and a second private key. The receiving terminal device is assigned a third public key and a third private key. The providing terminal device encrypts the first data with the third public key to generate first encrypted data, encrypts the second data with the second public key to generate second encrypted data, generates a first digital signature using the first private key, and transmits the first encrypted data, the second encrypted data, and the first digital signature to the intermediary device. The intermediary device decrypts the second encrypted data using the second secret key, generates a second digital signature using the second secret key, and transmits the first encrypted data, the first digital signature, and the second digital signature to the receiving terminal device. The second data is encrypted with the third public key at the providing terminal device or the intermediary device and transmitted to the receiving terminal device as the third encrypted data. The receiving terminal device decrypts the first encrypted data with the third private key to obtain the first data, decrypts the third encrypted data with the third private key to obtain the second data, verifies the first digital signature with the first public key, and verifies the second digital signature with the second public key. Information mediation methods in information mediation systems.

8. Formed within a system that forms a data distribution market, A first terminal device that transmits transmission information including a data usage rights certificate that specifies the rights and obligations between the parties regarding the use of the data as an agreement, A second terminal device that receives the aforementioned transmission information, An intermediary device that mediates the exchange of the transmission information between the first terminal device and the second terminal device, In an information intermediary system equipped with, The first terminal device is assigned a first public key and a first private key. The aforementioned intermediary device is assigned a second public key and a second private key. The second terminal device is assigned a third public key and a third private key. The first terminal device notifies the intermediary device of the issuance of the data usage right certificate and its contents. The intermediary device solicits the purchase of the data usage rights certificate and receives notification of the desire to purchase the data usage rights certificate from the second terminal device. The first terminal device encrypts the transmission information with the third public key to generate first encrypted data, generates a first digital signature using the first private key, and transmits the first encrypted data and the first digital signature to the intermediary device. The intermediary device generates a second digital signature using the second secret key, and transmits the first encrypted data, the first digital signature, and the second digital signature to the second terminal device. The second terminal device decrypts the first encrypted data with the third private key to obtain the transmission information, verifies the first digital signature with the first public key, and verifies the second digital signature with the second public key. Information intermediary system.

9. The transmitted information includes a data set consisting of the data usage right certificate and the data available for use with the data usage right certificate. The information mediation system according to claim 8.

10. Each time the aforementioned transmission information is transmitted, a newly generated electronic signature is sequentially added to it as information indicating its origin. The information mediation system according to claim 8 or 9.

11. The first terminal device generates the first digital signature by encrypting the hash value obtained by functionalizing the first encrypted data with a one-way function using the first secret key, The intermediary device generates the second digital signature by encrypting the hash value obtained by adding the first digital signature to the first encrypted data using a one-way function with the second secret key. An information mediation system according to any one of claims 8 to 10.

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