JP6649173B2 - Virtual currency management method and virtual currency management program - Google Patents

Description

  The present invention relates to a virtual currency management method and a virtual currency management program.

  2. Description of the Related Art In recent years, not only transactions of goods such as yen and dollars but also business transactions using virtual currency such as electronic money have been performed. Furthermore, a service using a virtual currency called "Bitcoin (registered trademark)" which is assumed to be open and distributed has been proposed (for example, see Non-Patent Document 1).

  In this bitcoin, a technology called “blockchain” is used for realization. First, in the transaction using bitcoin, the authenticity of the transaction information is secured using a hash function and a public key cryptosystem. Transaction information (hereinafter, referred to as “transaction”) of the virtual currency performed using the encryption technology is transmitted by broadcast to all terminals that use bitcoin. The transmitted transaction is verified for its authenticity by a terminal called a miner (miner), and when it is approved, it is put into a block and recorded in a ledger called a block chain. In Bitcoin transactions, transactions are prevented from being tampered with by allowing miners to perform a calculation process called mining and then adding blocks to the blockchain.

  Here, the last block of the block chain includes a plurality of transactions, the hash value of the block immediately before the last block of the block chain, and an appropriate value (“Nonce (nonce)”) whose conditions are determined in advance. ) Is stored. The miner performs a brute-force search for a nonce that generates a hash to be used for the next block from the hash value of the last block of the block chain and the transaction whose authenticity is to be guaranteed, as mining.

  At this time, an enormous amount of calculation is required for the miner to discover Nonce ahead of other miners. The extremely large amount of calculation is the basis for the authenticity of the contents of the blockchain. Such a method of spending a large amount of calculation to agree and authenticate each transaction on the network is called a proof of work. The proof of work is applied to show the authenticity of various information such as virtual currency.

  Various applications are being studied for this blockchain technology, and a similar cryptocurrency system (orthocoin) has been proposed based on the mechanism of bitcoin. Ortho coins include Litecoin, Dogecoin, Monacoin (registered trademark) and the like, and it is said that there are currently more than 500 cryptocurrency systems.

  In such a service that provides open and decentralized virtual currencies, the authenticity of the information (in the case of bitcoin, a transaction) described in the blockchain is calculated by the miner that supports the system. Depends on quantity.

  In other words, depending on the amount of calculation, an attack on the blockchain becomes possible. For example, it is known that if a malicious group or individual exceeds 50% or more of the total calculation amount, it will dominate over 50% or more of the mining speed of the entire network and illegal transactions will be possible (51%). attack).

  Therefore, in order to guarantee the authenticity of the proof of work, that is, to prevent tampering by an attacker, it is extremely difficult for the attacker to exceed the amount of calculation spent for the attack. A requirement is that the miner spends a very large amount of computation.

“Bitcoin: A Peer-to-Peer Electronic Cash System”, [May 6, 2016 search, Internet <URL: https://bitcoin.org/bitcoin.pdf>

  However, such an altcoin is a service premised on being open and distributed, so that a miner can freely participate or leave. For this reason, depending on the spread of the service, there is a possibility that a sufficient minor cannot be secured. That is, it is assumed that the amount of calculation by the miner cannot be sufficiently secured depending on the degree of spread of the service. In this case, there is a problem that the authenticity of information recorded in the block chain such as a transaction cannot be guaranteed, and the service cannot achieve its original purpose.

  The present invention has been made in view of the above, and a virtual currency management method and a virtual currency that can increase the degree of assurance of the authenticity of transaction information of virtual currencies provided by open and distributed services The purpose is to provide a management program.

  In order to solve the above-described problems and achieve the object, a virtual currency management method according to the present invention provides a virtual currency management method executed by a plurality of terminals that perform distributed virtual currency transaction processing provided by a predetermined service. In the method, the terminal stores a transaction history in which transaction information on virtual currency provided by a predetermined service is transaction history linked in a time series in a predetermined transaction unit and is information indicating authenticity. Having a unit, the terminal obtains a transaction history related to the distributed virtual currency provided in another service different from the predetermined service, the terminal, the transaction history corresponding to the obtained other services, storage Combining the transaction history stored in the storage unit and the terminal storing the combined transaction history in the storage unit.

  ADVANTAGE OF THE INVENTION According to this invention, the degree of guarantee of the authenticity of the transaction information of the virtual currency provided by the service which presupposes open and dispersion can be raised.

FIG. 1 is a diagram schematically illustrating an embodiment of the present invention. FIG. 2 is a diagram schematically illustrating an embodiment of the present invention. FIG. 3 is a diagram schematically illustrating an example of the configuration of the virtual currency management system according to the embodiment of the present invention. FIG. 4 is a block diagram showing the configuration of the minor shown in FIG. FIG. 5 is a diagram illustrating an example of the configuration of the block chain illustrated in FIG. FIG. 6 is a block diagram showing an example of the configuration of the user shown in FIG. FIG. 7 is a diagram for explaining the combining process performed by the combining unit illustrated in FIGS. 4 and 6. FIG. 8 is a diagram for explaining the combining process performed by the combining unit illustrated in FIGS. 4 and 6. FIG. 9 is a diagram for explaining an example of the connection timing. FIG. 10 is a flowchart illustrating a processing procedure of a combining process performed by the combining unit illustrated in FIGS. 4 and 6. FIG. 11 is a diagram illustrating a first modification of the present embodiment. FIG. 12 is a diagram illustrating a second modification of the present embodiment. FIG. 13 is a diagram illustrating a second modification of the present embodiment. FIG. 14 is a diagram illustrating an example of a computer in which a minor and a user are realized by executing a program.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by this embodiment. In the description of the drawings, the same parts are denoted by the same reference numerals.

[Embodiment]
An embodiment of the present invention will be described. In the embodiment of the present invention, a virtual currency management method for a service that provides open and distributed virtual currency is described. First, an outline of a virtual currency management method according to an embodiment will be described.

[Outline of Embodiment]
1 and 2 are diagrams for explaining an outline of an embodiment of the present invention. As an example, a service K using a blockchain (transaction history) B (K) as shown in FIG. 1A and a blockchain B (T) as shown in FIG. A description will be given of a case where there is a service T and a service T. The block chain is information in which transaction units (blocks) indicating transaction information relating to the virtual currency are connected in chronological order and indicates authenticity, and functions as a ledger that records transactions of the virtual currency.

  The service K provides a virtual currency that is open and distributed. The service T is a virtual currency that is open and distributed, and provides a different type of virtual currency from the virtual currency provided by the service K. Each of the services K and T has a P2P configuration in which a plurality of terminals (players), in which a virtual currency management program corresponding to each of the services K and T is installed, communicate with each other. In the example of FIG. 1, in the service K, there are miners (miners) K1 to K3 for guaranteeing the authenticity of the transaction information (transaction) indicating the content of the transaction processing of the virtual currency in the service K. In the service T, there are minors T1 and T2 for guaranteeing the authenticity of the transaction in the service T.

  Here, in the present embodiment, as shown by an arrow Y1 in FIG. 2, the block chain B (K) of the service K and the block chain B (T) of the service T are integrated, and the service K and the service T New blockchain B (K + T) that inherits the transaction history of In other words, the block chains B (K) and B (T) of the two services K and T are combined to construct a new service (K + T).

  As a result, in the service (K + T), the number of minors for guaranteeing authenticity increases to minors K1 to K3, T1, and T2. Therefore, in the service (K + T), the amount of calculation performed by the minors K1 to K3, T1, and T2 to guarantee authenticity increases, and the degree of assurance of authenticity increases. The reason for this is that by combining the two services K and T, it is possible to supply a larger amount of calculation that guarantees the authenticity of the information (see the frame C1 in FIG. 2).

  As described above, in the embodiment, when there are two services K and T to which the block chain is applied, the block chains B (K) and B (T) of the services K and T are integrated and a new block chain B is added. (K + T) is generated. When there are minor groups M (S) and M (T) in the services K and T, the integration of the block chains B (K) and B (T) results in (M (S) ∪M (T)) can be assumed. As a result, the number of minors increases, so that the amount of calculations performed by the miners to guarantee authenticity also increases, and the degree of authenticity assurance can be increased.

[Configuration of virtual currency management system]
Next, a configuration of the virtual currency management system according to the embodiment will be described. FIG. 3 is a diagram schematically illustrating an example of the configuration of the virtual currency management system according to the embodiment of the present invention.

  As shown in FIG. 3, the virtual currency management system 1 has a P2P (Peer to Peer) type configuration in which a plurality of client terminal devices communicate with each other. The virtual currency management system 1 has a configuration in which a plurality of terminals (minor 10K, 10T, users 20K, 20T) using the virtual currency are connected to a network 30 such as the Internet or a dedicated line.

  The minors 10K and 10T and the users 20K and 20T are terminal devices on which the virtual currency management program of the virtual currency management system 1 is installed. For example, the minors 10K and 10T and the users 20K and 20T are a mobile phone, a smartphone, a PC (Personal Computer), a PDA (Personal Digital Assistants), and the like.

  The minors 10K and 10T are terminals that conduct transactions using virtual currencies and verify and approve transactions for virtual currencies. The users 20K and 20T are terminals that conduct transactions using virtual currency. The minor 10K and the user 20K are terminals that use the service K described above. On the other hand, the minor 10T and the user 20T are terminals that use the service T described above. In the embodiment, a method of managing virtual currency will be described by taking as an example a case where the virtual currency management system 1 integrates a service K and a service T.

[Overview of virtual currency]
Here, an outline of the virtual currency provided by the virtual currency management system 1 will be described. This virtual currency is a P2P digital currency provided by a cryptocurrency system (orthocoin) similar to the existing bitcoin mechanism. In the virtual currency, the integrity of transaction information is secured by a digital signature using a public key cryptosystem and a hash function. In addition, information and history that function in virtual currency transactions are distributed and managed throughout the virtual currency management system 1 as a blockchain.

  Before the integration of the service K and the service T, the minor 10K and the user 20K use the virtual currency provided by the service K and store the blockchain B (K). The minor 10T and the user 20T use the virtual currency provided by the service T, and store the blockchain B (T). After the integration of the service K and the service T, the minors 10K and 10T and the users 20K and 20T use the virtual currency provided by the integrated service (K + T) and store the blockchain B (K + T).

  The miners 10K and 10T have installed programs for executing a wallet function for trading virtual currency and a mining function for verifying the authenticity of the virtual currency and approving the transaction. The users 20K and 20T have installed programs for executing the wallet function.

  The minors 10K and 10T and the users 20K and 20T can purchase and trade virtual currencies by installing a program for executing the wallet function, respectively, by assigning account addresses. Transaction information (transaction) of the virtual currency performed using the cryptographic technology is managed by the blockchain. The minors 10K and 10T verify the authenticity of the transaction, and when approving the valid transaction, generate a block composed of the approved transaction and connect it to the end of the block chain. Therefore, the device configuration of the minors 10K and 10T will be described.

[Minor configuration]
FIG. 4 is a block diagram showing an example of the configuration of the minor 10K shown in FIG. The minor 10T has the same functional configuration as the minor 10K. Hereinafter, when the minors 10K and 10T are described without distinction, they are described as minor 10. As illustrated in FIG. 4, the minor 10K includes a communication unit 11, a storage unit 12, a control unit 13, an input unit 14, and an output unit 15.

  The communication unit 11 is a communication interface that transmits and receives various information to and from other minors 10K and 10T and users 20K and 20T connected via the network 30. When the virtual currency is traded, the communication unit 11 broadcasts the transaction to other miners and users who use the same service under the control of the control unit 13.

  The storage unit 12 is realized by a semiconductor memory device such as a random access memory (RAM) or a flash memory, or a storage device such as a hard disk or an optical disk, and executes a processing program for operating the minor 10K and execution of the processing program. Data and the like used therein are stored. The storage unit 12 stores a block information storage unit 121, a public key storage unit 122, and an account information storage unit 123.

  The block information storage unit 121 stores a block chain of a service K (predetermined service) used by the minor 10K. This block chain will be described using a block chain B (K) in service K as an example. FIG. 5 is a diagram illustrating an example of the configuration of the block chain B (K).

  As shown in FIG. 5, the block chain B (K) has a configuration in which, for example, blocks B0 to B3 are connected in time series. The block B0 is the first block, and each of the blocks B1 to B3 is a transaction unit indicating transaction information on virtual currency provided by the service K. For example, in the block B2, the area Ra includes a hash (H (B1)) of the immediately preceding block B1, and the area Rb includes a plurality of transactions (Transactions) performed using encryption technology. The region Rc includes Nonce.

  Here, the hash is obtained by converting arbitrary data into a value of a certain short length by executing a hash function. Nonce is a key that makes the hash (H (B2)) of the next block B3 a value that satisfies a set condition, and is an arbitrary value having a fixed length. For example, Nonce is a key that sets the hash used for the block B3 to be “a value in which a certain number of consecutive 0s”.

  Note that the minor 10K uses a brute force search for a nonce that generates a hash (H (B2)) to be used for the next block B3 from the hash value of the block B2 and the transaction whose authenticity is to be guaranteed. Perform calculation processing (mining: mining). Further, the block information storage unit 121 stores the block chain B (K) before the integration of the service K and the service T, and stores the block chain B (K + T) after the integration of the service K and the service T. . It is desirable that the minor 10K stores the entire block chain B (K).

  Returning to FIG. 4, the public key storage unit 122 will be described. The public key storage unit 122 stores account addresses of all minors and all users who use the service in association with public keys. The account information storage unit 123 stores the secret key of the operator who uses the minor 10K. The secret key functions as a password used for remittance.

  The control unit 13 has an internal memory for storing programs that define various processing procedures and the like and required data, and executes various processes by using these. For example, the control unit 13 is an electronic circuit such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit). The control unit 13 includes a wallet unit 131, a mining unit 132, and a combining unit 133.

  When the purchase of the virtual currency or the remittance of the virtual currency is accepted by the processing of the operator of the minor 10K, the wallet unit 131 creates a transaction related to this transaction and distributes it to the network 30. When the delivered transaction is approved by mining by another miner and connected to the blockchain, the transaction is settled.

  The mining unit 132 verifies the authenticity of the transaction transmitted from another miner or user, and when approved by the other miner, collects the excavated blocks and records them in the block chain. The mining unit 132 performs a calculation process called mining. Mining is a calculation process of brute-force searching for a Nonce that generates a hash to be used for the next block from a hash value of a block at the end of the block chain and a transaction whose authenticity is to be guaranteed. If the mining unit 132 finds a correct Nonce that matches the new block, it creates a block and connects the created block to the end of the block chain. In other words, a miner who finds the correct Nonce can create a block and gain the right to connect the created block to the blockchain.

  The combining unit 133 performs a combining process of combining the block chain B (K) of the service K and the block chain B (T) of the service T different from the service K. In other words, the combining unit 133 integrates the block chain B (K) and the block chain B (T), and combines a new block chain B (K + T) that inherits the transaction history between the service K and the service T. As a result, the virtual currency management system 1 can integrate the service K and the service T and construct a new service (K + T). The combining unit 133 includes a timing control unit 1331, a combining processing unit 1332, and a determining unit 1333.

  The timing control unit 1331 controls the start of the combining process at a timing according to a predetermined rule. In the example of FIG. 1, the timing control unit 1331 controls the start of the combining process for combining the block chains B (K) and B (T) at a timing according to a predetermined rule.

  The connection processing unit 1332 obtains a block chain related to a distributed virtual currency provided by another service different from the predetermined service. Subsequently, the combination processing unit 1332 combines the transaction history corresponding to the acquired other service and the block chain stored in the block information storage unit 121. In other words, the combination processing unit 1332 acquires the block chain B (T) of the service T. Subsequently, the combining processing unit 1332 combines the obtained block chain B (T) of the service T and the block chain B (K) of the service K stored in the block information storage unit 121, and connects the service K with the service T. New blockchain B (K + T) that inherits the transaction history of

  In this case, the combining processing unit 1332 generates a hash from each last block of each transaction history to be combined using a cryptographic hash function, and sets the hash as the first hash of the combined transaction history. Then, the combination processing unit 1332 broadcasts the combined blockchain B (K + T) to other miners and users using the services K and T via the communication unit 11.

  In the case of the minor 10T, the combination processing unit 1332 acquires the block chain B (K) of the other service K, and the combination processing unit 1332 acquires the block chain B (K) of the acquired service (K). Is combined with the block chain B (T) of the service T to be stored, and a new block chain B (K + T) is combined.

  The determination unit 1333 receives, via the communication unit 11, a block chain B (K + T) in which other miners and users using the services K and T are combined. Then, the determining unit 1333 determines a block chain to be adopted as the combined block chain among the received block chains B (K + T) according to a predetermined rule. Subsequently, the determining unit 1333 stores the block chain B (K + T) adopted as the combined block chain in the block information storage unit 121.

  The input unit 14 is an input interface that receives various operations from the operator of the minor 10K. For example, the input unit 14 includes buttons, a touch panel, a voice input device, and an input device such as a keyboard and a mouse. The output unit 15 is, for example, a liquid crystal display, a printer, or the like, and outputs various information related to management of virtual currency.

[User Configuration]
Next, the device configuration of the users 20K and 20T will be described. FIG. 6 is a block diagram showing an example of the configuration of the user 20K shown in FIG. Note that the user 20T has the same functional configuration as the user 20K. Hereinafter, when the users 20K and 20T are described without distinction, they are described as the user 20. As shown in FIG. 6, the user 20K has a communication unit 21, a storage unit 22, a control unit 23, an input unit 24, and an output unit 25.

  The communication unit 21 is a communication interface having the same function as the communication unit 11. The storage unit 22 has the same function as the storage unit 12, and is realized by a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk. The storage unit 22 stores a block information storage unit 121, a public key storage unit 122, and an account information storage unit 123, like the storage unit 12.

  The control unit 23 has the same function as the control unit 13 and is an electronic circuit such as a CPU and an MPU. The control unit 23 has a configuration in which the mining unit 132 is deleted as compared with the control unit 13.

  The input unit 24 is, similarly to the input unit 14, an input interface that receives various operations from the operator of the user 20K. The output unit 25 is, for example, a liquid crystal display, a printer, or the like, and outputs various types of information related to management of the virtual currency.

[Assumptions in join processing]
Next, a description will be given of a premise when the service T and the block chain of the service K are combined.

  In the present embodiment, as described above, it is assumed that there are two services K and T using a block chain operated in P2P type. Block chains generated by the services K and T are B (K) and B (T), respectively, and sets of players related to the services K and T are P (K) and P (T), respectively. The players include the aforementioned minors and users. Further, assuming that a set of minors of the service K is M (S) and a set of minors of the service T is M (T), the minors of the services K and T are a part of the players of the services K and T. Thus, M (K) ⊂P (K) and M (T) ⊂P (T).

  In the embodiment, in order to create and operate a service (K + T) in which the service K and the service T are integrated, a block chain B (K) that combines two block chains B (K) and B (T) is used. K + T). Here, since the connection processing of the block chains is performed between the operating services K and T, in order to perform the connection processing, first, the player P (K) and the player P (T) And the following are agreed upon.

  First, the player P (K) and the player P (T) integrate two services K and T, that is, combine two block chains B (K) and B (T). Agree on itself. Second, the player P (K) and the player P (T) agree on the combination processing according to the agreement and the implementation and distribution of software for operating the combined blockchain.

  Thirdly, the player P (K) and the player P (T) agree on a technical specification relating to the combining process. Specifically, it is the technical specification of the node of the blockchain. Fourth, the players P (K) and P (T) agree on technical specifications of the combined blockchain. Specifically, the player P (K) and the player P (T) agree on a hash function and the like used for generating an initial hash for the combined block chain.

  Fifth, player P (K) and player P (T) agree on the timing of the combination. Sixth, the player P (K) and the player P (T) agree on a rule for determining the “correctness” of the combined block chain.

[Overview of join processing]
“Combining two blockchains (services)”, which is the first of the first to sixth agreements, is based on the premise that the combining process in the present embodiment is performed, and the player P (K ) And the player P (T) are described below. Then, the second agreement, “Implementation and distribution of software for operating the combined blockchain and combined blockchain in accordance with the agreement,” determines the method of the technical specifications described below and follows it. Software is implemented and distributed.

  In the present embodiment, by generating the node of the blockchain in accordance with the “technical specification on processing of joining” which is the third agreement, the “technology of the part 6 chain after the joining” which is the fourth agreement Blockchain that conforms to the “specification”. Therefore, generation of a node of the block chain generated in the combining process will be specifically described.

  FIGS. 7 and 8 are diagrams for explaining the combining process performed by the combining unit 133. The combining unit 133 acquires the block chains B (K) of the service K and the block chain B (T) of the service T to be combined, as shown in FIG. As described above, in the block chain B (K) of the service K, blocks B1 to B (m + 1) are connected in time series from the first block B0. In the block chain B (T) of the service T, blocks B1 'to B (n + 1)' are connected in chronological order from the first block B0 '.

  The combining processing unit 1332 calculates the last block B (m + 1) of the block chain B (K) of the service K and the last block B (n + 1) ′ of the block chain B (T) of the service T from: A new hash Hc (H (Bm + n + 1)) is generated according to the "determined rule" (see (1) in FIG. 7 and FIG. 8).

  Then, the combining processing unit 1332 sets the hash Hc as the first hash of the combined block chain. In other words, the miner 10 and the user 20 of the two services respectively obtain a new block B (m + 1) of the last block B (K) and a last block B (n + 1) ′ of the block chain B (T). A hash Hc (H (Bm + n + 1)) is generated (see arrow Y11 in FIG. 7). This hash Hc becomes a node between the two block chains B (K) and B (T).

  Then, the miner 10 and the user 20 of the two services restart the block chain using the newly generated hash Hc (see (2) in FIG. 7). Specifically, the miner 10 and the user 20 add a block (B (m + n + 1)) including the new hash Hc in addition to the transaction (Transactions) and Nonce as shown by an arrow Y12 in FIG. K) and B (T). This block (B (m + n + 1)) is generated by a miner that succeeds in mining among the miners 10 of the service (K + T).

  Subsequently, the miner 10 that has found a correct Nonce that conforms to the next block (B (m + n + 2)) from the value of the hash Hc of the block (B (m + n + 1)) and the transaction creates the block (B (m + n + 2)). I do. Then, the minor 10 and the user 20 connect the block (B (m + n + 2)) to the block (B (m + n + 1)).

  As shown in FIG. 8, the miners 10 and the users 20 of the two services respectively generate new hashes Hc (H (Bm + n + 1)), and generate block chains B (K) and B (T) using the generated hashes Hc. Nodules. Here, various methods can be selected for the generation rule for generating the first hash Hc for the combined block chain B (K + T).

  For example, the combination processing unit 1332 may select a method of generating a hash using a cryptographic hash function from the combined value of the two blocks B (m + 1) and B (n + 1) ′. For example, SHA-256 is used as the cryptographic hash function.

  When the values of the two blocks B (m + 1) and B (n + 1) 'are the same, the combining processing unit 1332 generates an exclusive OR of the two blocks B (m + 1) and B (n + 1)'. A method of generating a hash using a cryptographic hash function may be selected.

  The fifth consensus item “join timing” satisfies the condition that it can ultimately be uniquely determined on the premise of a P2P distributed environment (within a range where there is no problem in actual operation). If possible, various methods can be selected. Similarly, the sixth combination item, “rule for judging“ correctness ”of the combined blockchain”, is also the same assuming a P2P distributed environment (to the extent that there is no problem in actual operation). Various methods can be selected as long as the condition that it can be uniquely determined is satisfied.

  For example, rule example 1 will be described. This is a case where it is possible to assume that each node of the player P (K) and the player P (T) has a clock which is sufficiently synchronized and reliable so that an error can be ignored in operation. In this case, the timing control unit 1331 measures the “combination timing” by a method in which block generation in each service is stopped for a predetermined period of time and the block processing unit 1332 combines the block chains at that time. Can be.

  Subsequently, rule example 2 will be described. FIG. 9 is a diagram for explaining an example of the connection timing. For example, the rule example 2 can be applied when it is possible to predict at what time what block is generated. In this case, in addition to the “rule for determining the correctness of the combined block chain” used by the determination unit 1333, the combining unit 133 sets a rule defined by the following priority, and The combining process is executed at a timing according to the first to fourth rules.

First, the timing control unit 1331 specifies a block length M and a block length N for the service K and the service T as indices of timing to be combined in advance (first rule).
The coupling processing unit 1332 selects the shortest block chain in the block chain in which the block length of the service K is m ≧ M. Ideally, m = M is selected (see FIG. 9) (second rule). Then, the combination processing unit 1332 selects the shortest one among the block chains in which the block length of the service T portion satisfies n ≧ N from among the first and second rules. Ideally, n = N is selected (see FIG. 9) (third rule). From among the above first to third rules, the determination unit 1333 selects the block block having the longest combined block length 1 (see FIG. 9) as the combined block chain (fourth rule).

  By announcing the first to fourth rules in advance to the node of player P (K) ∪P (T), ideally, the length of the block chain B (K) is M And the block whose length is N in the block chain B (T). In other words, the combining unit 133 uses the cryptographic hash function from the last block of the block whose length of B (K) is M and the last block of the block whose length of B (T) is N. Then, a hash Hc is generated as a node of the block chain. Then, the combined block is approved by the determination unit 1333 of the player P (K) ∪P (T), assuming that the longer block chain is correct, and is adopted as the combined block chain.

  In a distributed environment, theoretically, it is not guaranteed that a block chain having an ideal shape as described above is formed. However, in actual operation, it can be assumed that many nodes recognize the block lengths M and N specified in advance. Therefore, if the conventional block is extended without performing the joining process even if the block length is exceeded, the information in this block is not approved, and the mining process is highly likely to be wasted. Many nodes are aware. Therefore, from the viewpoint of the entire player, it is assumed that there is a high possibility that the two block chains will form a block chain in which blocks of the predetermined block lengths M and N are combined.

[Join processing flow]
Subsequently, the processing of the combining unit 133 will be described with reference to FIG. FIG. 10 is a flowchart illustrating a processing procedure of the combining process of the combining unit 133 illustrated in FIGS. 4 and 6.

  First, the combining unit 133 receives a combining instruction for the block chains B (K) and B (T) of the service K and the service T via the communication units 11 and 21 (step S1). This connection instruction is transmitted from the device that manages the service K and the service T in the virtual currency management system 1. Then, the combining unit 133 agrees with the received combining instruction (Step S2), and transmits a message to the effect to the management device. As a result, the combining unit 133 receives the software for operating the combined processing and the combined blockchain according to the agreed items, and mounts the software on the device (step S3).

  Subsequently, the combining unit 133 acquires the block chain to be combined by executing the software (Step S4). For example, when the user is the minor 10K or the user 20K, the combining unit 133 reads the block chain B (K) of the service K used by itself from the block information storage unit 121 and blocks the service T via the network 30. Acquire the chain B (T). When the user is the minor 10T or the user 20T, the combining unit 133 reads the blockchain B (T) of the service T used by the own device from the block information storage unit 121, and reads the blockchain B (K) of the service K. ) To get.

  Then, the timing control unit 1331 controls the start of the combination at a timing according to a predetermined rule (step S5). The combining processing unit 1332 performs a combining process of combining the block chains to be combined according to the timing controlled by the timing control unit 1331 (Step S6). In this processing, the combination processing unit 1332 generates a hash Hc from the last block Bm, Bn ′ of each of the block chains B (K), B (T) to be combined using a cryptographic hash function, This hash Hc is set as the first hash of the transaction history after the combination.

  Then, the determining unit 1333 determines the adoption of the combined block chain (Step S7). Specifically, first, the determining unit 1333 broadcasts the blockchain B (K + T) to which the own device is connected to all the players of the services K and T via the network 30. At the same time, a blockchain B (K + T) in which other miners and users using the other services K and T are combined is received. Then, all the players of the services K and T determine the “correctness” of each block chain according to the “rule for determining the“ correctness ”of the combined block chains”. Then, all the players of the services K and T decide to adopt the blockchain B (K + T) determined to be the most “correct” as the combined blockchain.

  According to this result, the determination unit 1333 stores the block chain B (K + T) adopted as the combined block chain in the block information storage unit 121 (step S8). As a result, all the players of the services K and T hold the blockchain B (K + T) adopted as the combined blockchain. Accordingly, the integration of the services K and T into the service (K + T) is completed, and the subsequent transactions by the minors 10K and 10T and the users 20K and 20T are mined by the minors 10K and 10T.

[Effects of Embodiment]
As described above, in the embodiment, the block chains B (K) and B (T) of the services K and T using the block chains are combined to generate a new block chain B (K + T). As described above, as a result of combining the block chains B (K) and B (T), the number of minors of the service (K + T) becomes the total number of the minor groups M (S) and M (T) in the services K and T. Becomes Therefore, according to the embodiment, since the number of miners can be increased by combining the block chains B (K) and B (T), the amount of calculation executed by the miners to guarantee authenticity is also reduced. Increase the degree of assurance of authenticity.

[Modification 1 of Embodiment]
In the present embodiment, it is also possible to continuously combine the block chains. FIG. 11 is a diagram illustrating a first modification of the present embodiment.

  As shown in FIG. 11, for example, the block chains B (K) and B (T) of the services K and T are knotted by the hash Hc (see the arrow Y21) to generate the combined block chain B (K + T). I do. After that, the block chain B (U) of another service U may be combined (see arrow Y22). In this case as well, the combining processing unit 1332 uses a cryptographic hash function from the last block B (m + n + k + 1), B (j + 1) ″ of each of the block chains B (K + T), B (U) to be combined. Generate a hash Hc ′.

  Then, the combining processing unit 1332 sets the hash Hc ′ as the first hash of the combined block chain B (K + T + U), and restarts the block chain. Specifically, the miner that succeeds in mining creates the first block (B (m + n + k + j + 1)) for the combined block chain B (K + T + U) (see cell C2) and connects it via the hash Hc ′. . As described above, in the present embodiment, it is also possible to continuously combine the block chains.

[Modification 2 of Embodiment]
Further, in the present embodiment, three block chains can be connected. FIG. 12 and FIG. 13 are diagrams illustrating Modification Example 2 of the present embodiment.

  As shown in FIG. 12, for example, the block chains B (K), B (T), and B (U) of the services K, T, and U are knotted by a hash Hc ″ (see an arrow Y31) to form three blocks. The chain can also be connected to a blockchain B (K + T + U) '.

  Also in this case, as illustrated in FIG. 13, the combination processing unit 1332 outputs the last blocks B (m + 1) and B (n + 1) of the block chains B (K), B (T), and B (U) to be combined. ) ′, B (j + 1) ″, a hash Hc ″ may be generated using a cryptographic hash function (for example, SHA-256). Since the SHA-256 can calculate a hash value from an original text of an arbitrary length up to 2 to the 64th bit, a single hash (here, the data obtained by connecting the last blocks of the three block chains) is used. Hc ″) is possible.

  Then, the joining processing unit 1332 sets the hash Hc ″ as the first hash of the combined block chain B (K + T + U) ′ and restarts the block chain. Specifically, the miner that succeeds in mining is Creates the first block (B (m + n + j + 1)) for the block chain B (K + T + U) ′, and connects it via the hash Hc ″. Thus, in the present embodiment, three block chains can be connected.

[System configuration, etc.]
Each component of each device illustrated is a functional concept and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed / arbitrarily divided into arbitrary units according to various loads and usage conditions. Can be integrated and configured. Further, all or any part of each processing function performed by each device can be realized by a CPU and a program analyzed and executed by the CPU, or can be realized as hardware by wired logic.

  Further, of the processes described in the present embodiment, all or a part of the processes described as being performed automatically can be manually performed, or the processes described as being performed manually can be performed. All or part can be automatically performed by a known method. In addition, the processing procedures, control procedures, specific names, and information including various data and parameters shown in the above documents and drawings can be arbitrarily changed unless otherwise specified.

[program]
FIG. 14 is a diagram illustrating an example of a computer in which the minor 10 and the user 20 are realized by executing a program. The computer 1000 has, for example, a memory 1010 and a CPU 1020. The computer 1000 has a hard disk drive interface 1030, a disk drive interface 1040, a serial port interface 1050, a video adapter 1060, and a network interface 1070. These components are connected by a bus 1080.

  The memory 1010 includes a ROM (Read Only Memory) 1011 and a RAM (Random Access Memory) 1012. The ROM 1011 stores, for example, a boot program such as a BIOS (Basic Input Output System). The hard disk drive interface 1030 is connected to the hard disk drive 1090. The disk drive interface 1040 is connected to the disk drive 1100. For example, a removable storage medium such as a magnetic disk or an optical disk is inserted into the disk drive 1100. The serial port interface 1050 is connected to, for example, a mouse 1110 and a keyboard 1120. The video adapter 1060 is connected to the display 1130, for example.

  The hard disk drive 1090 stores, for example, an OS 1091, an application program 1092, a program module 1093, and program data 1094. That is, a program that defines each process of the minor 10 and the user 20 is implemented as a program module 1093 in which codes executable by a computer are described. The program module 1093 is stored in, for example, the hard disk drive 1090. For example, a program module 1093 for executing the same processing as the functional configuration of the minor 10 and the user 20 is stored in the hard disk drive 1090. The hard disk drive 1090 may be replaced by an SSD (Solid State Drive).

  The setting data used in the processing of the above-described embodiment is stored as the program data 1094 in, for example, the memory 1010 or the hard disk drive 1090. Then, the CPU 1020 reads out the program module 1093 and the program data 1094 stored in the memory 1010 and the hard disk drive 1090 to the RAM 1012 as needed, and executes them.

  The program module 1093 and the program data 1094 are not limited to being stored in the hard disk drive 1090, but may be stored in, for example, a removable storage medium and read out by the CPU 1020 via the disk drive 1100 or the like. Alternatively, the program module 1093 and the program data 1094 may be stored in another computer connected via a network (LAN, WAN, or the like). Then, the program module 1093 and the program data 1094 may be read from another computer by the CPU 1020 via the network interface 1070.

  As described above, the embodiment to which the invention made by the inventor is applied has been described. However, the present invention is not limited by the description and the drawings that form part of the disclosure of the present invention according to the present embodiment. That is, other embodiments, examples, operation techniques, and the like performed by those skilled in the art based on this embodiment are all included in the scope of the present invention.

1 Virtual Currency Management System 10K, 10T Minor 20K, 20T User 30 Network 11, 21, Communication Unit 12, 22, Storage Unit 13, 23 Control Unit 14, 24 Input Unit 15, 25 Output Unit 121 Block Information Storage Unit 122 Public Key Storage Unit 123 Account information storage unit 131 Wallet unit 132 Mining unit 133 Joining unit 1331 Timing control unit 1332 Joining processing unit 1333 Judgment unit

Claims (5)

A cryptocurrency management method executed by a plurality of terminals performing transaction processing of distributed cryptocurrencies provided by a predetermined service,
The terminal has a storage unit for storing transaction history, which is transaction history in which transaction information regarding virtual currency provided by the predetermined service is chronologically linked in a fixed transaction unit and is information indicating authenticity. And
A step in which the terminal acquires the transaction history related to a distributed virtual currency provided in another service different from the predetermined service;
A step in which the terminal combines the transaction history corresponding to the acquired other service and the transaction history stored in the storage unit;
A step in which the terminal stores the combined transaction history in the storage unit;
Only including,
The transaction unit has a hash of the immediately preceding transaction unit, the transaction information and an appropriate value in which conditions are predetermined,
The combining step generates a hash using a cryptographic hash function from the last transaction unit of each of the transaction histories to be combined, and sets the hash as the first hash of the combined transaction history. Virtual currency management method. The virtual currency management method according to claim 1 , further comprising the step of: controlling, by the terminal, a start of the combining step at a timing according to a predetermined rule. The terminal determines, in accordance with a predetermined rule, a transaction history adopted as a post-combination transaction history among transaction histories obtained by combining each terminal using the predetermined service and each terminal using the other service. Process and
3. The virtual currency management method according to claim 1, wherein the storing step stores the transaction history adopted as the post-combination transaction history in the determining step in the storage unit. 4. The acquiring step acquires transaction histories related to virtual currency provided by the plurality of other services, respectively.
The method according to any one of claims 1 to 3 , wherein, in the combining step, the transaction histories respectively corresponding to the acquired other services and the transaction histories stored in the storage unit are combined. The described virtual currency management method. A step of storing a transaction history, which is transaction history related to distributed virtual currency provided by a predetermined service and is information indicating authenticity, which is a transaction history chronologically connected in a certain transaction unit,
Acquiring the transaction history for distributed virtual currency provided in another service different from the predetermined service,
Combining a transaction history corresponding to the other service and a transaction history corresponding to the predetermined service;
Storing the combined transaction history;
To the computer ,
The transaction unit has a hash of the previous transaction unit, the transaction information and an appropriate value in which conditions are predetermined,
The combining step is a virtual currency management program that generates a hash using a cryptographic hash function from the last transaction unit of each of the transaction histories to be combined, and uses the generated hash as the first hash of the combined transaction history .

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