JPWO2020144863A1 - Random number generation system, random number generator, random number generation method and program - Google Patents

Abstract

It provides a random number generation system that quickly generates random numbers that are fair to the user. The random number generation system includes a terminal and a random number generator that generates random numbers for the terminal. The random number generator generates a sealed value of the initial random number. The terminal generates a user random number after the seal value of the initial random number is generated. The random number generator inputs a value based on an initial random number, a user random number, and at least a random number related to the generation of the random number used by the terminal into the hash function, and generates a random number based on the output result of the hash function.

Description

The present invention relates to a random number generation system, a random number generator, a random number generation method and a program.

With the progress of network technology and information processing technology, various services (also called online services) are provided via the network. An online game exists as an example of the above service. There are various forms of online games, for example, online games in which the game server is responsible for the progress of the game (for example, role-playing games), and online games in which the game server provides a field in which users compete with each other. (For example, a board game such as chess) exists.

Further, the game server may generate a random number for the purpose of enhancing the entertainment element of the game (see Patent Document 1).

In addition to games, there are online services that use random numbers. For example, in an electronic lottery, a random number is used to determine a winner.

Japanese Unexamined Patent Publication No. 2018-50973

The disclosure of the above prior art document shall be incorporated into this document by citation. The following analysis was made by the present inventors.

As described above, in the online service, the generated random number may be treated as an element of the service execution. As a result, for example, in an online game, the generated random numbers may have a great influence on the progress of the game. For example, when the damage given to a monster in a role-playing game is determined by a random number, whether or not the monster can be defeated depends largely on the random number.

If the monster is successfully defeated, the user will not be dissatisfied with the result, but if the monster cannot be defeated, the user will "generate a random number in favor of the server." Isn't it? " Furthermore, in the case of a game in which whether or not an item can be acquired is determined by a lottery using random numbers, it is expected that the above suspicion will become even greater. Thus, in online services that use random numbers, users may suspect that fair random numbers are not being used, as long as the server manages the random numbers.

In order to solve such a problem, in Patent Document 1, random numbers are generated by the following processing (procedure). The random number generator generates an initial random number prior to generating a random number for the terminal. Further, the terminal generates a user random number according to the generation of the sealed value of the initial random number and provides it to the random number generator. The random number generator uses the previously generated initial random number and the user random number to generate a random number for the terminal. In order to generate a random number by the random number generator, an initial random number and a user random number that the random number generator and the terminal cannot operate on each other are required, so that a fair random number is generated for the user who operates the terminal.

In Patent Document 1, as described above, two random numbers (initial random number and user random number) are used to generate random numbers for terminals. Specifically, the random number generator calculates the hash value using the initial random number and the user random number, and further calculates the hash value using the calculated hash value and the user random number to calculate the random number used by the terminal. (Paragraphs [0064] and [0065] of Patent Document 1). However, the processing load of using a continuous hash function (reading the hash function twice) is large in the generation of random numbers, which causes a problem that the required random numbers cannot be obtained immediately. That is, the processing load of the hash function itself is high, and a random number generation method that continuously uses such a hash function can become a bottleneck in the random number generation processing.

It is an object of the present invention to provide a random number generation system, a random number generator, a random number generation method and a program that contribute to the rapid generation of random numbers that are fair to the user.

According to the first aspect of the present invention, the random number generator includes a terminal and a random number generator that generates a random number for the terminal, the random number generator generates a sealed value of an initial random number, and the terminal is a random number generator. After the sealed value of the initial random number is generated, a user random number is generated, and the random number generator uses a value based on the initial random number, the user random number, and at least a random number related to the generation of the random number used by the terminal as a hash function. A random number generation system is provided that inputs and generates the random number based on the output result of the hash function.

According to the second viewpoint of the present invention, a first random number generator that generates an initial random number and generates a sealed value of the initial random number, and a terminal generated after the sealed value of the initial random number is generated. A second random number generator that inputs a user random number, the initial random number, and a value based on at least a random number related to the random number used by the terminal into the hash function, and generates the random number based on the output result of the hash function. A random number generator is provided.

According to the third viewpoint of the present invention, in a system including a terminal and a random number generator for generating a random number for the terminal, the random number generator generates a sealed value of an initial random number. In the step of generating a user random number after the terminal has generated the sealed value of the initial random number, and in the order of the random number generator regarding the generation of the initial random number, the user random number, and at least the random number used by the terminal. A random number generation method including a step of inputting a value based on the hash function and generating the random number based on the output result of the hash function is provided.

According to the fourth viewpoint of the present invention, a process of generating an initial random number and generating a sealed value of the initial random number, a user random number generated by the terminal after the sealed value of the initial random number is generated, and the initial stage. A program is provided that inputs a random number and at least a value based on a random number related to the random number used by the terminal into a hash function, and causes a computer to execute a process of generating the random number based on the output result of the hash function.
Note that this program can be recorded on a computer-readable storage medium. The storage medium may be a non-transient such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present invention can also be embodied as a computer program product.

According to each viewpoint of the present invention, a random number generation system, a random number generator, a random number generation method, and a program that contribute to the rapid generation of random numbers that are fair to the user are provided.

It is a figure for demonstrating the outline of one Embodiment. It is a figure which shows an example of the structure of the game system which concerns on 1st Embodiment. It is a sequence diagram which shows an example of the operation outline of the game system which concerns on 1st Embodiment. It is a block diagram which shows an example of the hardware composition of the game server which concerns on 1st Embodiment. It is a block diagram which shows an example of the processing structure of the game server which concerns on 1st Embodiment. It is a block diagram which shows an example of the processing structure of the terminal which concerns on 1st Embodiment. It is a sequence diagram which shows an example of the operation of the game system which concerns on 1st Embodiment. It is a flowchart which shows an example of the operation which concerns on the fairness verification of a random number by a terminal. It is a block diagram which shows an example of the processing configuration of the management server which concerns on 1st Embodiment. It is a figure which shows an example of the block generated by the management server which concerns on 1st Embodiment. It is a sequence diagram which shows an example of the operation of the management server which concerns on 1st Embodiment. It is a figure which shows an example of the structure of the game system which concerns on the modification of 1st Embodiment. It is a sequence diagram which shows an example of the operation of the game system which concerns on 2nd Embodiment. It is a sequence diagram which shows an example of the operation of the game system which concerns on the modification of 2nd Embodiment. It is a sequence diagram which shows an example of the operation of the game system which concerns on the modification of 2nd Embodiment. It is a figure which shows an example of the display screen when a user is involved in the generation of a random number.

First, an outline of one embodiment will be described. It should be noted that the drawing reference reference numerals added to this outline are added to each element for convenience as an example for assisting understanding, and the description of this outline is not intended to limit anything.

The random number generation system according to one embodiment includes a terminal 101 and a random number generation device 102 that generates a random number for the terminal 101. The random number generator 102 generates a sealed value of the initial random number. The terminal 101 generates a user random number after the seal value of the initial random number is generated. The random number generator 102 inputs a value based on an initial random number, a user random number, and at least a random number related to the generation of the random number used by the terminal 101 into the hash function, and generates a random number based on the output result of the hash function.

In the above random number generation system, the random number generation device 102 generates an initial random number prior to the generation of the random number for the terminal 101. Further, the terminal 101 generates a user random number according to the generation of the sealed value of the initial random number, and provides the user random number to the random number generation device 102. The random number generation device 102 generates a random number for the terminal 101 by using the initial random number, the user random number, and the ordinal number related to the generation of the random number generated earlier. In order to generate a random number by the random number generator 102, an initial random number and a user random number that the random number generator 102 and the terminal 101 cannot operate on each other are required, so that a fair random number is generated for the user who operates the terminal 101. .. Further, the random number generator 102 can realize rapid random number generation by inputting an initial random number, a user random number, and a value based on the order related to the generation of the random number into the hash function and generating a random number based on the result. That is, the random number generator 102 generates a random number by using the hash function once, and the call of the hash function having a high processing load is restricted (the number is reduced as compared with the technique of Patent Document 1). .. As a result, random numbers can be generated quickly.

Specific embodiments will be described in more detail below with reference to the drawings. In each embodiment, the same components are designated by the same reference numerals, and the description thereof will be omitted.

[First Embodiment]
The first embodiment will be described in more detail with reference to the drawings.

[Overview of system configuration]
FIG. 2 is a diagram showing an example of the configuration of the game system according to the first embodiment. Referring to FIG. 2, the game system includes a game server 10, terminals 20-1 to 20-n (n is a positive integer, the same applies hereinafter), and a data management system 30. The game server 10, the terminals 20-1 to 20-n, and the data management system 30 are each connected to each other via a network such as the Internet. In the following description, if there is no particular reason for distinguishing terminals 20-1 to 20-n, it is simply referred to as "terminal 20".

The first embodiment will be described by taking a game system as an example, but it goes without saying that the fair random number generation method described below can be applied to other systems. For example, the method may be applied to random number generation of an electronic lottery system that electronically draws lots.

The game server 10 is a device that provides an online game to a user. Specifically, the game server 10 performs a process of authenticating a user (login / logout process), a process related to game progress (game progress process), and the like. The online game assumed in the first embodiment is assumed to be a type of game (for example, a role-playing game) in which the game server 10 is responsible for the progress of the game. That is, the game server 10 operates as a random number generation device that generates random numbers for the terminal 20.

The terminal 20 is a device used by a user who plays an online game. For example, an information processing device such as a personal computer or a smartphone corresponds to the above terminal.

The data management system 30 is a system operated by an organization or the like that is independent of the online game operating company. The data management system 30 is a system that provides an electronic bulletin board capable of writing and reading data to an outside (third party). The data management system 30 manages various types of information by a so-called blockchain.

By paying a predetermined fee, the data management system 30 can add information to any entity, read the written information, and delete or falsify the once written information. Providing a never-ending electronic bulletin board. More precisely, the data management system 30 is a system that provides an interface related to data input / output that can be handled like an electronic bulletin board from an external device. In the following description, it is assumed that the data management system 30 is operated and managed by an organization or the like independent of the operating company of the game server 10, but the validity of the data management by the data management system 30 is ensured. In that case, the operating company such as the game server 10 may provide the above electronic bulletin board. Of course, in this case, the game server 10 or the like can use the electronic bulletin board without paying a fee.

In the game system shown in FIG. 2, data necessary for the progress of the game (more accurately, sealed data in which the initial random number described later is sealed) is exchanged via an electronic bulletin board provided by the data management system 30. As described above, since the data management system 30 is a system that provides an electronic bulletin board to a third party, data unrelated to the sealing data (for example, product sales data, etc.) is stored in the electronic bulletin board. It will be mixed.

The data management system 30 is composed of a plurality of management servers 40-1 to 40-4. The example in FIG. 2 does not mean that the number of management servers constituting the data management system 30 is limited to four. The data management system 30 may be configured to include two or more management servers.

As shown in FIG. 2, the plurality of management servers 40 forming the data management system 30 are directly connected to each other. That is, the data management system 30 includes a plurality of management servers 40 connected by P2P (Peer to Peer).

In the data management system 30, each of the plurality of management servers 40 connected by P2P has a ledger (hereinafter referred to as a data management ledger) for managing data (random data, sales data, etc.) received from the outside. The data management system 30 distributes and shares and manages the data management ledger among a plurality of management servers 40.

In the following description, data transfer between the data management system 30 and the outside thereof will be described only between the data management system 30, the game server 10, and the terminal 20. However, in reality, since the data management system 30 widely provides a general-purpose electronic bulletin board system to a third party, data is exchanged with other than the game server 10 and the like.

[Overview of system operation]
Next, the outline of the operation of the game system according to the first embodiment will be described with reference to the drawings. FIG. 3 is a sequence diagram showing an example of an outline of the operation of the game system according to the first embodiment.

A user who wishes to play an online game provided by a game server 10 operates a terminal 20 to access, for example, a WEB (web) page prepared by an operating company of the game server 10 and perform user registration (account registration). (Step S01). After completing the account registration, the user acquires authentication information (ID (Identifier), password) for logging in to the game server 10.

Further, the information related to the ID and the password is arranged so that the game server 10 can refer to the information. For example, when the account registration process is completed, the above information is transmitted to the game server 10 and stored in the internal storage device of the game server 10. Alternatively, the above information (ID, password) may be stored in a database accessible to the game server 10.

The user provides the acquired authentication information (combination of ID and password) to the game server 10 and logs in to the game server 10 (step S02).

The game server 10 performs user authentication using the authentication information provided by the user, and starts the game when it is confirmed that the user is a legitimate user (step S03).

In the online game, various forms are conceivable for exchanging information between the server (game server 10) and the client (terminal 20), but any form may be used in the disclosure of the present application. For example, the online game may be provided by general-purpose processing in the HTML (Hyper Text Markup Language) source without installing the game-dedicated application on the terminal 20, or the dedicated application may be installed on the terminal 20. It may be in the form.

The game server 10 determines whether or not it is necessary to generate a random number while the game is in progress (step S04).

When it is necessary to generate a random number (step S04, Yes branch), the game server 10 starts a process related to random number generation (step S05). At that time, information necessary for random number generation is exchanged between the game server 10, the terminal 20, and the data management system 30, and random numbers necessary for the progress of the game are generated. Details of the process related to random number generation in step S05 will be described later.

The game server 10 determines whether or not the game has ended by checking various conditions (for example, conditions such as time over) provided for the end of the game (step S06). While the game continues (step S06, No branch), the necessity of random number generation is confirmed (step S04), and if random number generation is required, random numbers continue to be generated. When the game server 10 determines that the game is finished (step S06, Yes branch), the game server 10 notifies the terminal 20 to that effect (step S07).

The terminal 20 that has received the notification verifies whether or not the random numbers (random numbers generated by the game server 10) used while playing the game are fair (step S08). The terminal 20 acquires the sealing data necessary for verifying the fairness of random numbers from the electronic bulletin board provided by the data management system 30, and verifies the fairness of the random numbers using the data. Details of the processing related to the fairness verification of random numbers by the terminal 20 will be described later.

As a result of the verification, if there is any doubt about the fairness of random number generation by the game server 10, the user can take an action such as notifying (protesting) to the operating company of the game server 10 to that effect.

Although the description of FIG. 3 does not describe the logout from the game server 10 by the terminal 20, the user logs out from the game server 10 when he / she does not intend to continue the game.

[Hardware configuration]
Next, the hardware configuration of various devices constituting the game system according to the first embodiment will be described. FIG. 4 is a block diagram showing an example of the hardware configuration of the game server 10 according to the first embodiment.

The game server 10 can be configured by an information processing device (computer), and includes the configuration illustrated in FIG. For example, the game server 10 includes a CPU (Central Processing Unit) 11, a memory 12, an input / output interface 13, a NIC (Network Interface Card) 14 which is a communication means, and the like, which are connected to each other by an internal bus.

However, the configuration shown in FIG. 4 is not intended to limit the hardware configuration of the game server 10. The game server 10 may include hardware (not shown), or may not include an input / output interface 13 if necessary. Further, the number of CPUs and the like included in the game server 10 is not limited to the example shown in FIG. 4, and for example, a plurality of CPUs may be included in the game server 10.

The memory 12 is a RAM (Random Access Memory), a ROM (Read Only Memory), and an auxiliary storage device (hard disk or the like).

The input / output interface 13 is a means that serves as an interface for a display device or an input device (not shown). The display device is, for example, a liquid crystal display or the like. The input device is, for example, a device that accepts user operations such as a keyboard and a mouse.

The function of the game server 10 is realized by various processing modules described later. The processing module is realized, for example, by the CPU 11 executing a program stored in the memory 12. In addition, the program can be downloaded via a network or updated using a storage medium in which the program is stored. Further, the processing module may be realized by a semiconductor chip. That is, there may be a means for executing the function performed by the processing module by some hardware and / or software.

The terminal 20 and the management server 40 can also be configured by an information processing device like the game server 10, and the basic hardware configuration thereof is not different from that of the game server 10, so the description thereof will be omitted.

[Game server]
Next, the details of the game server 10 will be described.

FIG. 5 is a block diagram showing an example of the processing configuration of the game server 10 according to the first embodiment. Referring to FIG. 5, the game server 10 includes a communication control unit 201, a storage unit 202, and a game execution control unit 203.

The communication control unit 201 is a means for realizing communication with other devices. The communication control unit 201 is also a means for distributing a message (packet) received from another device to each processing module unit or transmitting a message acquired from each processing module to another device.

The storage unit 202 stores, for example, data necessary for processing of the game execution control unit 203 or the like.

The game execution control unit 203 is a means for controlling and managing the progress of the game. The game execution control unit 203 includes three submodules, a user authentication unit 211, a first random number generation unit 212, and a second random number generation unit 213.

The user authentication unit 211 is a submodule that is activated when a user logs in to the game server 10 or logs out of the game server 10. Any method of user authentication may be used. For example, as described above, an authentication method using a password may be used, or biometric authentication using biometric information (fingerprint information, etc.) of a user may be used. The user authentication unit 211 authenticates a user who uses the terminal 20 by comparing the data provided from the terminal 20 (authenticated data) with the data stored in a database or the like (verification data).

The game execution control unit 203 provides the online game to the user or refuses to play the online game by the user according to the authentication result by the user authentication unit 211.

The first random number generation unit 212 and the second random number generation unit 213 are submodules that are activated when the game execution control unit 203 determines that random number generation is necessary. As will be described later, for one user, the random number is generated using the random number already generated. That is, since it is necessary to manage the generation of random numbers for each user, the suffix j is used in the following description to distinguish the users.

When the random number generation process starts, the first random number generation unit 212 generates the initial random number s _j for the user j.

Next, the first random number generation unit 212 seals the _{initial random number s j.} More specifically, the first random number generation unit 212 calculates the hash value H (s _j ) of _{the initial random number s j.}

After that, the first random number generation unit 212 _{transmits the sealing value of the initial random number s j} (that is, the hash value H (s _j )) and the hash function used for calculating the hash value to the data management system 30, and these Ask to write information (hash value, hash function) to the electronic bulletin board.

Further, the first random number generation unit 212 transmits to the terminal 20 used by the user j that _{the calculated hash value H (s j) has been written on the electronic bulletin board system.} At that time, _{the transaction ID is also notified so that the terminal 20 can acquire the hash value H (sj} ) and the like from the data management system 30. The transaction ID is an identifier notified from the data management system when the game server 10 writes data to the electronic bulletin board, and is an identifier that identifies the transaction in which the sealing data is written.

The terminal 20 that has received the above notification from the game server 10 acquires the _{hash value H (sj) from the electronic bulletin board system.} Terminal 20 itself (user j) for the hash value H (s _j) is confirms that written on the electronic bulletin board, generates a random number r _j, and transmits the random number r _j to the game server 10. In the following description, the random number generated by the terminal 20 will be referred to as a user random number.

The second random number generation unit 213 generates a random number applied to the user j (used for the game played by the user j). Specifically, when the second random number generation unit 213 receives the user random number r _j , the initial random number s _j , the user random number r _j , and the ordinal number i related to the generation of the random number are used, and the random number x is calculated by the following equation (1). Calculate _j.

x _j (i) = Hash (s _j || r _j || i) mod m ... (1)

In the equation (1), the symbol “||” indicates a concatenation, i is a positive integer (i ≧ 1), and the same applies to the following description. The numbers in parentheses following x _j and y _j indicate the order in which random numbers are generated. For example, the first generated random number x _j is _{expressed as x j} (1) (i = 1).

Further, m is a constant for determining the range of the generated random numbers x _j. For example, when _{the range of the random number x j} is an integer of 0 to 5, "6" is set in m. Further, when the random number x _j is used instead of the dice roll, "1" may be added to the value calculated by the equation (1).

As described above, the second random number generation unit 213 inputs the user random number r _{j of} the user j, the initial random number s _j for the user j, and the order i related to the generation of the random number into the hash function, and calculates the hash value. generating a random number x _j for user j by. That is, the second random number generation unit 213 generates _{at least a random number used by the terminal 20 based on the initial random number s j} , the user random number r _j, and the ordinal number i relating to the generation of the random number. At that time, as the input to the hash function, _{a value obtained by concatenating the initial random number s j} , the user random number r _j, and the ordinal number i related to random number generation is used.

Game execution control unit 203 notifies the random number _{x j} after using the random number _{x j} to the terminal 20 (user j). The timing of the random number x _j is notified to the terminal 20, if after using the random number x _j, can be any timing. For example, it may be notified sequential use random number x _j during the course of the game, after the game, a random number x _j which is used may be notified to the terminal 20 in a lump.

Further, the game execution control unit 203 notifies the terminal 20 of the type of the hash function used in the equation (1) at an arbitrary timing up to the “random number fairness verification” in step S08 of FIG. For example, the terminal 20 is notified of the type of the hash function used in the equation (1) at the time of the first random number notification (notification of the random number x _{j (1)) or after the end of the game.} Further, the game execution control unit 203 notifies the terminal 20 (user j) of _{the previously generated initial random number s j} when the game by the user j ends (that is, when no further random number generation is required). do. That is, the game execution control unit 203 opens the seal of the initial random number in the terminal 20 after the random number generation for the terminal 20 becomes unnecessary.

In the above description, it has been described that the hash function used by the first random number generation unit 212 is written on the electronic bulletin board system, and the hash function used by the second random number generation unit 213 is notified to the terminal 20. However, if there is an agreement between the game server 10 and the terminal 20 regarding the hash function to be used, it is not necessary to write to the electronic bulletin board system or notify the terminal 20 as described above.

As the hash function used by the first random number generation unit 212 and the second random number generation unit 213, for example, a hash function such as SHA-2 (Secure Hash Algorithm 2) or Kecak (Kecak) can be used. Further, it is used in the hash function used by the first random number generation unit 212 (the hash function _{for calculating the hash value of the initial random number s j} ) and the hash function used by the second random number generation unit 213 (formula (1)). Hash functions) may be the same or different.

Here, the hash function has one-way that the original data cannot be restored from the hash value, collision difficulty that the same hash value cannot be generated from different data, and the same hash value from the same data. It has properties such as determinism that it is generated and uniformity that the calculated hash value is not biased. Hash value calculation of the initial random number s _j by the first random number generation unit 212, the initial random number s _j concealed by the entities other than the game server 10 (seal) while the game is in progress, and, the initial random number s _j This is done to ensure that the initial random number s _{j has not changed since the hash value was calculated.} That is, the hash value calculation by the first random number generation unit 212 mainly utilizes one-wayness and collision difficulty among the properties of the hash function. On the other hand, the hash function in the second random number generation unit 213 is used as a function that can generate a random numerical value and can reproduce the process of random number generation. That is, the hash value calculation by the second random number generation unit 213 mainly utilizes determinacy and uniformity among the properties of the hash function. Therefore, the first random number generation unit 212 and the second random number generation unit 213 have different properties required for the hash function, and the hash function suitable for each purpose may be used properly.

Further, in view of the hash value calculation by the first random number generation unit 212, the function used by the first random number generation unit 212 when sealing the initial random number is not only a hash function but also a commitment function. A function that "seals (confidential) the data" and a function that "opens the data (verifies that it has not been changed)" can be substituted.

[Terminal]
Next, the details of the terminal 20 will be described.

FIG. 6 is a block diagram showing an example of the processing configuration of the terminal 20 according to the first embodiment. Referring to FIG. 6, the terminal 20 includes a communication control unit 301, a storage unit 302, and a game execution unit 303.

The communication control unit 301 is a means for realizing communication with other devices. The communication control unit 301 is also a means for distributing a message (packet) received from another device to each processing module unit or transmitting a message acquired from each processing module to another device.

The storage unit 302 stores, for example, data necessary for processing of the game execution unit 303 and the like.

The game execution unit 303 is a means for realizing game play by the user. More specifically, the game execution unit 303 inputs the user's operation by an input means such as a keyboard or a mouse. The game execution unit 303 transmits information according to the user's operation to the game server 10. For example, when a user logs in to the game server 10, authentication information (for example, a combination of an ID and a password) is transmitted to the game server 10. Further, while the user is playing the game, information related to the key operation by the user is transmitted to the game server 10.

The game execution unit 303 includes two submodules, a random number generation unit 311 and a random number verification unit 312.

The random number generation unit 311 is a means for generating a user random number after the game server 10 generates a sealed value of the initial random number (hash value of the initial random number). More specifically, the random number generation unit 311 generates a user random number in response to the hash value H (s _{j ) of the initial random number s j being written on the electronic bulletin board.} The random number generation unit 311 is _{activated when the game server 10 notifies that the hash value H (s j} ) has been written on the electronic bulletin board. In this case, the random number generation unit 311 presents the transaction ID notified from the game server 10 to the data management system 30, and acquires the _{hash value H (s j) written on the electronic bulletin board by the game server 10.} Then, the random number generation unit 311 generates a user random number _{r j,} and transmits the generated user random number _{r j} to the game server 10. Incidentally, the generation of the user the random number r _j are by random number generation unit 311, it is possible to use various functions and methods, including the hash function.

_{The random number verification unit 312 verifies whether or not the series of random numbers x j} (x _j (1), x _j (2), ...) Used by the game server 10 for the progress of the game is fair. It is a means. More specifically, the random number verification unit 312 acquires the hash value H (s _{j ) of the initial random number s j} written in the electronic bulletin board, and opens it by the acquired hash value H (s _j ) and the game server 10. The fairness of random number generation by the game server 10 is verified based on the initial random number s _{j obtained} , the order (i) related to the generation of the random number, and the random number x _{j notified as the used random number.}

The random number verification unit 312 confirms the fairness of the _{random number x j by performing two-step verification.}

The first verification is the verification that the initial random number s _j used in the above equation (1) is not changed from the value generated before the acquisition of the _{user random number r j} provided from the terminal 20. ..

The second verification is the verification that the game server 10 _{generates the random number x j} according to the equation (1) (the game server 10 does not arbitrarily determine the _{random number x j).}

The random number verification unit 312 inputs the hash value H (s _j ) acquired from the electronic bulletin board and the hash value H'(s _j ) _{calculated using the initial random number s j} opened by the game server 10 after the game is completed. Compare and perform the first verification. As a result of the comparison, if the two hash values match, the random number verification unit 312 may perform the second verification because the random number generation by the game server 10 may be fair.

On the other hand, if the two hash values do not match, the random number verification unit 312 determines that the random number generation by the game server 10 is unfair (the random number generation by the game server 10 is unreasonable or inappropriate).

_{The random number verification unit 312 generates a random number x j} '(i) according to the equation (1), and compares the _{random number x j} '(i) with the random number x _{j (i) notified from the game server 10.} Perform the second verification.

Here, according to the above equation (1), the _{information required for generating the random number x j} is the initial random number s _j , the user random number r _j , and the number of times the random number is generated (ordinal number i). Of the two random numbers, the user the random number r _j is because it is information that is generated by the own device, the random number verification unit 312 is of course possible grasp. Further, the initial random number s _j is information that can be acquired from the game server 10 after the game is completed. Further, as described above, the hash function used in the equation (1) is notified from the game server 10 to the terminal 20.

_{Further, the random numbers x j} (i) used by the game server 10 for the progress of the game are sequentially notified to the terminal 20. Therefore, the terminal 20 is information that can naturally grasp the number of random number generations (ordinal number j). Using the above information, the random number verification unit 312 _{generates a random number x j} '(i) each time by applying the equation (1) to _{two random numbers (initial random number s j} , user random number r _{j) and the like.} can do.

The random number verification unit 312 _{confirms that the two random numbers (x j} '(i) and x _j (i)) match or do not match, so that the game server 10 _{arbitrarily changes the random numbers x j} (i). It can be verified that a series of random numbers x _j (i) are generated using the initial random number s _j initially generated and the user random number r _{j presented by the terminal 20.}

If the above two random numbers x _j '(i) and x _j (i) match, the random number verification unit 312 is fair in random number generation by the game server 10 (random number generation by the game server 10 is valid and appropriate). Judge that there is. On the other hand, _{if there is a difference between the two random numbers x j} '(i) and x _j (i), the random number verification unit 312 determines that the random number generation by the game server 10 is unfair.

The random number verification unit 312 notifies the user of the above determination result as necessary. Specifically, the random number verification unit 312 performs measures such as displaying the verification result on a display unit such as a liquid crystal panel.

Next, with reference to the drawings, the operations of random number generation by the game server 10 and random number verification by the terminal 20 will be described.

FIG. 7 is a sequence diagram showing an example of the operation of the game system according to the first embodiment. FIG. 7 mainly describes an operation related to random number generation by the game server 10.

In step S101, the game server 10 generates an _{initial random number s j.}

The game server 10 generates a hash value H (s _j ) of the initial random number s _j (step S102).

The game server 10 transmits the generated hash value H (s _j ) to the data management system 30 (step S103). That is, the game server 10 _{writes the generated hash value H (s j} ) in the electronic bulletin board system.

When the writing of the hash value H (s _j ) to the electronic bulletin board by the data management system 30 is completed (step S104), the game server 10 _{notifies the terminal 20 that the hash value H (s j} ) has been written to the electronic bulletin board. (Step S105).

When the terminal 20 receives the notification from the game server 10, the terminal 20 _{reads the hash value H (sj} ) from the electronic bulletin board system (step S106).

Thereafter, the terminal 20 generates the user random number _{r j,} and transmits the random number to the game server 10 (step S107).

The game server 10 that has acquired the user random number r _{j generates a random number x j} (1) according to the above equation (1) (step S108-1).

The game server 10 uses the generated random number x _j (1) for the progress of the game, _{and notifies the terminal 20 of the used random number x j} (1) (step S109-1).

When the game server 10 needs to generate a further random number as the game progresses, the game server 10 has a process of generating a random number according to the above equation (1) (step S108-i) and a process of notifying the random number (step S109-i). )repeat.

After that, when the game ends (step S110), the game server 10 _{opens the initial random number s j} generated in step S101 to the terminal 20 (step S111).

In step S112, the terminal 20 verifies the fairness of the _{random number x j generated by the game server 10.}

FIG. 8 is a flowchart showing an example of the operation related to the fairness verification of the random number x _{j by the terminal 20.}

First, the terminal 20 compares the hash value H (s _j ) obtained from the electronic bulletin board with the hash value H'(s _{j ) calculated using the initial random number s j} opened from the game server 10, and the second The verification of 1 is performed (step S201).

If the two hash values do not match (step S201, No branch), it is determined that the random number generation by the game server 10 is unfair (step S204).

When the two hash values match (step S201, Yes branch), the second verification is executed.

Terminal 20 generates a random number _{x j} 'and (i) produced in accordance with Equation (1), it compares the random number is notified from the game server 10 _x j (i), performing a second verification (step S202).

If the two random numbers do not match (step S202, No branch), it is determined that the random number generation by the game server 10 is unfair (step S204). If the two random numbers match (step S202, Yes branch), it is determined that the random number generation by the game server 10 is fair (step S203).

[Management server]
Next, the details of the management server 40 forming the data management system 30 will be described.

FIG. 9 is a block diagram showing an example of the processing configuration of the management server 40 according to the first embodiment. Referring to FIG. 9, the management server 40 includes a communication control unit 401, a storage unit 402, and a ledger management unit 403.

The communication control unit 401 is a means for realizing communication with other devices. The communication control unit 401 is also a means for distributing a message (packet) received from another device to each processing module unit or transmitting a message acquired from each processing module to another device.

The storage unit 402 is a means for storing information necessary for processing of each processing module. The storage unit 402 includes a temporary storage area for temporarily storing data and an area for storing a data management ledger.

The ledger management unit 403 is a means for processing an access request to the electronic bulletin board from the game server 10 or the terminal 20. Specifically, for example, when a request for writing the seal data (hash value) from the game server 10 to the electronic bulletin board is received, the seal data is added to the data management ledger stored in the storage unit 402. Further, when the ledger management unit 403 receives a request for reading the electronic bulletin board from an external device (for example, the terminal 20), the ledger management unit 403 searches the data management ledger using the transaction ID associated with the request as a key, and the ID is assigned. Extract the data (sealed data). The ledger management unit 403 transmits the extracted sealing data to an external device.

The ledger management unit 403 has two submodules, a block generation unit 411 and a block verification unit 412.

The block generation unit 411 shares the data management ledger with another management server 40 and generates a block for management.

When the ledger management unit 403 acquires the seal data from the game server 10, the ledger management unit 403 stores the acquired seal data in the temporary storage area of the storage unit 402. After that, the block generation unit 411 "guarantees validity" from the header of the block generated immediately before and the data stored in the temporary storage area (for example, sealing data and sales data; data added to the data management ledger). Generate "data". For example, when the block generation unit 411 calculates the hash value of the additional data, the header of the previous block, and the validity guarantee data, the value that makes the calculated hash value conform to a predetermined rule (so-called nonce value or Nonce value) is generated as validity guarantee data. In addition, the validity guarantee data includes the electronic signature of the management server 40 that generated the block.

The block generation unit 411 generates a block having a header of the block generated immediately before and a header composed of the above-mentioned validity guarantee data. Specifically, a block as shown in FIG. 10 is generated.

When the block generation by the block generation unit 411 is completed, the block is added to the data management ledger. Further, the block generation unit 411 distributes (transmits) the generated block to another management server 40 via the communication control unit 401.

The communication control unit 401 of the management server 40 that has received the block from the other management server 40 hands over the acquired block to the block verification unit 412.

The block verification unit 412 is a means for verifying the validity of a block transmitted by another management server 40 based on a data management ledger (block) stored in the storage unit 402 of the own device. Specifically, the block verification unit 412 of the management server 40 that received the block determines the validity of the received block as the block generated by the management server 40 that transmitted the block and its own device (the management server 40 that received the block). ) Is managed and verified using the header of the block generated immediately before.

First, the block verification unit 412 confirms that the validity assurance data included in the received block is given the electronic signature of the management server 40 as the transmission source, and describes the "previous block" described in the received block. "Header" is specified based on the data management ledger that it manages. After that, the block verification unit 412 inputs the additional data in the received block and the header of the previous block, and whether or not the validity guarantee data in the header is consistent (the validity guarantee data conforms to a predetermined rule). Whether or not to do) is confirmed.

If the consistency of the validity guarantee data can be confirmed, the block verification unit 412 determines that the block transmitted by the other management server 40 is valid. On the other hand, if the consistency of the validity guarantee data cannot be confirmed, the block verification unit 412 determines that the block transmitted by the other management server 40 is unreasonable.

When the block verification unit 412 determines that the block transmitted by the other management server 40 is valid, the ledger management unit 403 updates the data management ledger of the storage unit 402 (additional block including additional data). do). That is, the block verification unit 412 performs a process of reflecting the addition of data to the ledger of another management server 40 in the ledger of its own device. If the block verification unit 412 determines that the block transmitted by the other management server 40 is unreasonable, the block verification unit 412 discards the block.

Further, the block verification unit 412 notifies the management server 40 that has transmitted the block of information regarding the verification result (the received block is valid or invalid).

The operation of the management server 40 is summarized in the sequence diagram shown in FIG. Note that FIG. 11 shows a case where the management server 40-1 acquires the sealing data from the game server 10 and adds the data to the data management ledger.

When the management server 40-1 acquires the sealing data from the game server 10 (step S201), the management server 40-1 replicates the data in the temporary storage area of the storage unit 402 of the own device (step S202).

After that, the management server 40-1 generates the above-mentioned block based on the data stored in the temporary storage area under the condition that a predetermined amount of the data duplicated in the temporary storage area is accumulated (step S203). After that, the management server 40-1 transmits the generated block to the other management servers 40-2 to 40-4 (step S204).

Each of the management servers 40-2 to 40-4 that received the block individually verifies the block generated by the management server 40-1 (step S205). Each of the management servers 40-2 to 40-4 updates the data management ledger of its own device when the validity of the block can be confirmed (step S206).

As described above, the addition of data to the data management ledger by at least one management server 40 among the plurality of management servers 40 forming the data management system 30 is reflected in the data management ledger of the other management server 40.

If the validity of the block transmitted from the other management server 40 cannot be confirmed, the block is discarded and the management server 40 notifies the management server 40 that transmits the block to that effect. Upon receiving the notification, the ledger management unit 403 of the management server 40 regains the state of the data management ledger before the block transmission.

As described above, the game server 10 according to the first embodiment generates an initial random number s _{j prior to the generation of the random number x j} , and writes the hash value H (s _j ) on the electronic bulletin board system. _{Further, the user j generates a user random number r j} in response to the hash value H (s _j ) being written on the electronic bulletin board system, and provides the user random number r j to the game server 10. The game server 10 generates a _{random number x j} by using the initial random number s _j generated earlier, the user random number r _j provided by the user j, and the ordinal number i related to the generation of the random number. As described above, in order to _{generate the random number x j} , the game server 10 and the user j need an initial random number s _j and a user random number r _j that cannot be operated by each other, so that a fair random number x _j is generated. Further, the game server 10 _{generates a random number x j} by reading the hash function once (see equation (1)). As a result, the use of the hash function having a high processing load is restricted, and a random number x _j is quickly generated.

The game server 10 cannot know the user random number r _{j before generating the initial random number s j.} In addition, the game server 10, for himself is writing a hash value H (s _j) to the electronic bulletin board that can not affect, after the writing of the hash value H (s _j) changes the initial random number s _j I can't. Therefore, the game server 10 cannot operate the generation of the random number x _j by changing the initial random number s _{j after acquiring the user random number r j.}

Since the user j cannot obtain the initial random number s _{j from the hash value H (s j} ) written on the electronic bulletin board, he cannot operate the generation of the _{random number x j.}

Data transfer between the game server 10 and the terminal 20 (exchange of hash value H (s _j )) uses an electronic bulletin board whose data is managed by the blockchain, so the hash value H (s _j ) should be tampered with. Is very difficult. Further, only a small amount of data such as a hash value H (s _j ) and a hash function can be written on the electronic bulletin board, and the fee for using the electronic bulletin board can be suppressed to a small amount.

[Modified example of the first embodiment]
A modified example of the first embodiment will be described.

In the first embodiment, the data written on the electronic bulletin board is limited to the sealing data (hash value of the initial random number). In the modification according to the first embodiment, not only the sealed data but also the user random number generated by the terminal 20 and the random number generated by the game server 10 as the game progresses and the random numbers used are also written on the electronic bulletin board system will be described. ..

As described above, in the first embodiment, data other than the sealing data (user random number r, random number x) is exchanged between the terminal 20 and the game server 10. By exchanging and exchanging the data via the electronic bulletin board, the fairness of random number generation by the game server 10 can be verified by a device other than the terminal 20 (that is, a third party).

For example, as shown in FIG. 12, the system may include a verification device 50 having a function equivalent to that of the “random number verification unit” described as one function of the terminal 20. For example, the verification device 50 is a device installed in an institution such as a court, and monitors the validity of services provided to users (for example, online games and electronic lottery).

As described above, the terminal 20 may write the user random number on the electronic bulletin board, and the game server 10 (random number generator) may write the random number used for the progress of the game on the electronic bulletin board. In that case, a third party other than the party (user of the terminal 20) uses the sealed value of the initial random number, the used random number, and the user random number written on the electronic bulletin board, and the fairness of random number generation by the game server 10. Can be verified.

[Second Embodiment]
Subsequently, the second embodiment will be described in detail with reference to the drawings.

In the first embodiment, a fair random number generation method has been described by taking, so to speak, a game of a type in which a game server 10 and a user play against each other as an example. In the second embodiment, a fair random number generation method in a type of game in which the game server 10a provides a field in which users compete with each other will be described.

In the second embodiment, as the above-mentioned game, a fair random number generation method will be described by taking "backgammon" as an example. Although detailed explanation of the rules of backgammon is omitted, it is a game in which two users alternately roll dice and move pieces according to the numbers of the rolls. The game server 10a according to the second embodiment uses random number generation, which will be described later, for selecting the dice rolls.

Since the configuration of the game system, the hardware configuration of each device, and the processing configuration can be the same as those of the first embodiment, the description thereof will be omitted.

The difference between the first and second embodiments is that the random number generation method in the game server 10a and the generated random numbers are provided to two users (plurality of users).

FIG. 13 is a sequence diagram showing an example of the operation of the game system according to the second embodiment. In FIG. 13, it is assumed that the user j1 and the user j2 play against each other. Further, it is assumed that the user j1 and the user j2 have completed the account registration, respectively, prior to the start of the game.

First, the two users log in to the game server 10a and start the game (step S301).

When the game is started and a random number generation (dice roll) is required, the processes after step S302 in FIG. 13 are executed.

In step S302, the first random number generation unit 212 of the game server 10a generates an initial random number s _j1 for the user j1 and writes the hash value H (s _j1 ) on the electronic bulletin board. Further, the game server 10a notifies the user j1 (terminal 20) of the writing.

The random number generation unit 311 of the terminal 20 (the terminal 20 operated by the user j1) that received the notification _{confirms that the hash value H (s j1} ) is written on the electronic bulletin board, and then generates the user random number r _j1 to generate the game. It is transmitted to the server 10a (step S303).

Similarly, the game server 10a generates an initial random number _{s j2} for user j2, writes the hash value H of the _{(s j2)} the electronic bulletin board (step S304). Further, the terminal 20 of the user _j2 generates a user random number r j2 and transmits it to the game server 10a (step S305).

The second random number generation unit 213 of the game server 10a, which has received the user random numbers r _j1 and r _j2 from the two users, generates _{random numbers x j by the following equation (2).}
x _j (i) = Hash (s _j1 || s _j2 || r _j1 || r _j2 || i) mod m ... (2)

At the time of the first random number generation, the random number x _j (1) is obtained by the equation (2) (step S306-1). The generated random number x _j (1) is notified to the two users j1 and j2 (step S307-1). After that, the game server 10a _{applies the random number x j} (1) to the first user (step S308-1). For example, the game server 10a _{converts the random number x j} (1) into dice rolls (1 to 6) and notifies the first user. The user who receives the notification moves the piece according to the dice roll and advances the game.

The generation of the random number x _j (2) for the second-attack user is also performed according to the equation (2) (step S306-2). The generated random number x _j (2) is notified to the two users j1 and j2 (step S307-2). After that, the game server 10a _{applies the random number x j} (2) to the second-attack user (step S308-2).

The game ends while repeating the above-mentioned random number generation, random number notification, and application to the user (step S309).

When the game is completed, the game server 10a notifies the users j1 and j2 of the initial random number and the user random number (step S310). Specifically, the game server 10a, to the user j1, at least, to notify the user the random number _{r j2} with opening the initial random number _{s j1, s j2} which are sealed. Similarly, the game server 10a opens at least the sealed initial random numbers s _j1 and s _j2 and notifies the user j2 of the user random numbers r _j1.

Each user who receives the notification _{verifies the fairness of the random number x j} (steps S311 and S312). Since the fairness verification of random numbers in the user j1 and the user j2 can be performed in the same process, only the fairness verification in the user j1 will be described.

The fairness verification of random numbers in the second embodiment is basically the same as that in the first embodiment, and is performed by a two-step verification.

In the first verification, it is verified that the initial random numbers s _j1 and s _j2 obtained in step S310 are not changed after the transmission of the user random numbers r _j1 and r _j2. Specifically, the user j1 (terminal 20) _{calculates the hash values of the initial random numbers s j1} and s _j2 , and first verifies whether the hash values match the hash values obtained from the electronic bulletin board. I do.

After that, the user j1 uses a random number x _j (x _j (1), x _j (2), ...) Notified by the game server 10a and a random number (initial random number, ...) notified from the game server 10a as the game progresses. The second verification is performed by comparing the _{random numbers x j} '(x _j '(1), x _j '(2), ...) obtained by applying the equation (2) to the user random number). ..

In the above description, random number generation when two users compete against each other has been described, but even when three or more users compete against each other, it can be dealt with by appropriately extending the equation (2). That is obvious to those skilled in the art.

As described above, in the second embodiment, the game server 10a generates random numbers by using the initial random numbers generated for each of the plurality of users and the user random numbers acquired from each of the plurality of users. At that time, the game server 10a cannot know the user random number before the initial random number is generated, and cannot change the random number once the initial random number is generated, so that the random number cannot be manipulated. .. In this way, random numbers used in games targeting a plurality of users can be generated using initial random numbers generated for each user and user random numbers individually generated by each user. Further, each user can verify the fairness of random number generation by the game server 10a.

[Modified example of the second embodiment]
A modified example of the second embodiment will be described.

In the second embodiment, as long as the game server 10a treats the two users j1 and j2 equally, a fair random number is generated. However, for example, when the game server 10a and the user j2 (the terminal 20 operated by the user j2) collude, there is room for generating an unfair (unfair) random number for the user j1. Specifically, the game server 10a generates _{the initial random number s j2} for the user j2 after acquiring the _{user random number r j1} generated in step S303 of FIG. However, for example, by colluding the game server 10a and the user j2, the user j2 can generate the user random number r _{j2 before the game server 10a generates the initial random number s j2,} and can provide the user random number r j2 to the game server 10a. As a result, the game server 10a has room to select the _{initial random number s j2} so as to obtain a favorable result for the user j2 when calculating the _{hash value y j shown in the equation (2).}

In the modified example of the second embodiment, the game server and the user collude to provide a system for preventing unfair random number generation for other users as described above.

The difference between the second embodiment and the modified example thereof will be mainly described with reference to FIG.

In step S403, the user j1 generates a _{user random number r j1.} After that, the user j1 transmits the hash value H (r _{j1 ) of the user random number r j1} to the game server 10b (step S404).

In step S405, the game server 10b _{generates an initial random number s j2} for the user j2 and generates a hash value H (s _j2 ). The hash value H (s _j2 ) is written on the electronic bulletin board. After that, the game server 10b transmits the hash value H (r _{j1 ) of the user random number r j1} to the user j2 (step S406).

In step S407, the user j2 generates a user random number _{r j2,} sends the user a random number _{r j2} thus generated to the game server 10b.

In step S408, the game server 10b transmits the _{user random number r j2 to the user j1.}

In step S409, the user j1 who received the transmission _{opens the seal of the user random number r j1} to the game server 10b.

The game server 10b confirms that the opening is correct, and starts the game. That is, the game server 10b uses the initial random numbers s _j1 and s _j2 and the user random numbers r _j1 and r _j2 to appropriately generate random numbers x _j (step S410).

Thus, before generating the initial random number s _j2 for the user j2, user j1 is generating the user random number r _j1, notification of the generation of the random number is a hash value H (r _j1) a game server It is done by being transmitted to 10b. After that, a random number (initial random number s _j2 , user random number r _j2 ) is generated for the user j2, and the hash value H (r _j1 ) is opened from the user j1. Therefore, the game server 10b cannot know the _{user random number r j1} generated by the user j1 before generating _{the initial random number s js for the user j2.} As a result, for example, the user j2 and the game server 10b do not collude with each other to generate a _{random number x j (unfair to the user j1) in favor of the user j2.}

In step S407 of FIG. 14, the hash value H (r _{j2 ) of the user random number r j2} generated by the user j2 is not transmitted to the game server 10b, and the user random number r _j2 is transmitted to the game server 10b. ing. Regarding the user j1, it is also possible to transmit the hash value H (r _j2 ) of the user random number r _j2 of the user j2 to the game server 10b _{from the equilibrium that the hash value H (r j1) is transmitted first.} .. Specifically, the procedure shown in FIG. 15 can be used.

Specifically, the user j2 _{generates the user random number r j2} (step S507), calculates the hash value H (r _j2 ), and transmits the hash value to the game server 10b (step S508).

After that, the game server 10b transmits the hash value H (r _{j2 ) of the user random number r j2} to the user j1 (step S509). The user j1 who has received the hash value _{opens the sealed user random number r j1} to the game server 10b (step S510). Alternatively, in step S512 described later, when the user j2 confirms that the opening of the _{user random number r j1 is correct, the user j1 also opens the user random number r j1} to the user j2.

After that, the game server 10b confirms that the opening by the user j1 is correct, _{and then transmits the user random number r j1} to the user j2 (step S511).

The user j2 confirms that the hash value of the received user random number r _j1 is correct (the opening of the sealed user random number r _j1 by the user j1 is correct), and then the sealed user random number r _j2. Is opened in the game server 10b (step S512).

_{The game server 10b generates a random number x j} after confirming that the opening by the user j2 is correct (step S513).

In the modified example according to the second embodiment shown in FIGS. 14 and 15, information exchange between the users j1 and j2 (terminal 20 used by each user) and the game server 10b is performed via an electronic bulletin board system. Of course, it may be broken. Further, the random number fairness verification operation performed by the users j1 and j2 can be the same as in the second embodiment.

The configuration of the game system (FIG. 2) described in the first and second embodiments is an example, and is not intended to limit the configuration of the system. For example, the game server 10 may be separated into a device responsible for executing a game and a device responsible for generating random numbers (random number generation device). Alternatively, the game server 10 may include a user account registration function.

In the above embodiment, the random number generation used for the progress of the game is a closed process between the game server 10 and the terminal 20, but a part of the random number generation process may be open to the user. .. For example, the user random number is generated in step S107 of FIG. 7 and steps S303 and S305 of FIG. 13, and the user's selection may be reflected in the random number generation at that time. For example, the terminal 20 displays a random number selection screen as shown in FIG. 16 on a liquid crystal panel or the like, and accepts a user's icon selection operation. In FIG. 16, each icon is assigned a random numerical value. The terminal 20 may generate a user random number by using the numerical value assigned to the icon (choice) selected by the user. For example, the terminal 20 may be a user random number by concatenating a random numerical value determined by selecting an icon, a user ID, and a current time. With this configuration, icon selection and random number generation can be performed seamlessly. It should be noted that allowing the user to be involved in the generation of random numbers is possible not only in the first embodiment but also in the second embodiment.

In the above embodiment, the terminal 20 has been described as verifying the random number generation by the game server 10, but the user may be able to select whether or not the random number verification by the terminal 20 is possible. For example, when a message asking "necessity of using verifiable random numbers" and an option (selection button) are displayed on the display screen of the terminal 20, and the user selects "use verifiable random numbers", FIG. 8 is shown. Random number verification as described in use may be performed.

In the above embodiment, the random numbers x _j are generated using the equations (1) and (2), but the equations (1) and (2) are examples and limit the method of generating _{the random numbers x j.} Not the purpose. For example, in the equation (1), a _{value based on the initial random number s j} , the user random number r _j, and the ordinal number i related to the generation of the random number is input to the hash function, and the random number is generated based on the output result of the hash function. With such a calculation, the calculation result may be biased depending on the type of hash function. Of the above three input information, in the generation of the same game (random numbers directed to the same user j), the initial random numbers s _j and the user random numbers r _j are fixed, and only the ordinal number i changes. Then, most of the consolidated data will not change and only a part will change. _{If the random number x j} is generated many times using such input data (concatenated data), the terminal 20 may be able to predict the value of the _{next random number x j.} In order to avoid such inconvenience, the concatenation data to be input to the hash function may be devised as shown in the following equations (3) and (4).
x _j (i) = Hash (i || s _j || r _j || i) mod m ... (3)
x _j (i) = Hash (i || s _j || i || r _j || i) mod m ... (4)

In the equation (3), the initial random number s _j and the user random number r _j are sandwiched by the ordinal number i, and in the equation (4), the ordinal number i and the random numbers (initial random number s _j , user random number r _j ) are arranged alternately. By generating the concatenated data in which the ordinal number i is distributed and input to the hash function in this way, _{the bias of the generated random number x j} can be eliminated (can be reduced). That is, the input value (concatenated data) to the hash function may be generated by using the ordinal i related to the generation of the random number whose value changes each time the random number is generated twice or more.

Alternatively, for the purpose of eliminating the bias of the random number x _{j , the initial random number s j} or the user random number r _j is input to a predetermined function, and the output result of the function is used to generate concatenated data to be input to the hash function. May be good. That is, in the generation of the concatenated data (input value to the hash function) to be input to the hash function, the value _{derived from the initial random number s j} , the value derived from the user random number r _j , and the order i related to random number generation are derived. At least one of the values may be included. In other words, a _{random number may be generated using information based on the initial random number s j} , the user random number r _j , and the ordinal number i (the random number, the ordinal number itself, or the output result of the function, etc.). _{For example, a random number x j} may be generated by the method shown in the equation (5).
x _j (i) = Hash (f (s _j ) || f (r _j ) || i) mod m ... (5)
Further, the hash function may be used for the above function f ().

In the above equations (3) to (5), the ordinal number i itself is _{used to generate the random number x j} , but the ordinal number i is input to a predetermined function and the result is used to generate the _{random number x j.} May be good.

As described above, the input to the hash function _{may include at least one of the value derived from the initial random number s j} , the value derived from the user random number r _j , and the value derived from the ordinal i related to random number generation.

By installing the above-mentioned computer program in the storage unit of the computer, the computer can function as a random number generator. Furthermore, by causing the computer to execute the above-mentioned computer program, the random number generation method can be executed by the computer.

Further, in the plurality of flowcharts used in the above description, a plurality of steps (processes) are described in order, but the execution order of the steps executed in each embodiment is not limited to the order of description. In each embodiment, the order of the illustrated processes can be changed within a range that does not hinder the contents, for example, the processes are executed in parallel. In addition, the above-mentioned embodiments can be combined as long as the contents do not conflict with each other.

The disclosure of the above-mentioned patent documents cited shall be incorporated into this document by citation. Within the framework of the entire disclosure (including the scope of claims) of the present invention, it is possible to change or adjust the embodiments or examples based on the basic technical idea thereof. Further, various combinations or selections of various disclosure elements (including each element of each claim, each element of each embodiment or embodiment, each element of each drawing, etc.) within the framework of all disclosure of the present invention. Is possible. That is, it goes without saying that the present invention includes all disclosure including claims, various modifications and modifications that can be made by those skilled in the art in accordance with the technical idea. In particular, with respect to the numerical range described in this document, any numerical value or small range included in the range should be construed as being specifically described even if not otherwise described.

10, 10a, 10b Game server 11 CPU (Central Processing Unit)
12 Memory 13 Input / output interface 14 NIC (Network Interface Card)
20, 20-1 to 20-n, 101 Terminal 30 Data management system 40, 40-1 to 40-4 Management server 50 Verification device 102 Random number generation device 201, 301, 401 Communication control unit 202, 302, 402 Storage unit 203 Game execution control unit 211 User authentication unit 212 First random number generation unit 213 Second random number generation unit 303 Game execution unit 311 Random number generation unit 312 Random number generation verification unit 403 Ledger management unit 411 Block generation unit 412 Block verification unit

Claims (19)

With the terminal
A random number generator that generates random numbers for the terminal,
Including
The random number generator generates a sealed value of the initial random number,
The terminal generates a user random number after the sealing value of the initial random number is generated.
The random number generator inputs a value based on the initial random number, the user random number, and at least a random number related to the generation of the random number used by the terminal into the hash function, and generates the random number based on the output result of the hash function. Generation system. The random number generation system according to claim 1, wherein the input to the hash function is a value obtained by concatenating the initial random number, the user random number, and an ordinal number related to the generation of the random number. The random number system according to claim 1 or 2, wherein the input to the hash function is a value generated by using the ordinal number related to the random number generation two or more times. The input to the hash function is any one of claims 1 to 3 including at least one of a value derived from the initial random number, a value derived from the user random number, and a value derived from the order related to the random number generation. The random number generation system described in item 1. Including a data management system that provides an electronic bulletin board,
The random number generator writes the sealed value on the electronic bulletin board,
The random number generation system according to any one of claims 1 to 4, wherein the terminal generates the user random number in response to the sealed value being written on the electronic bulletin board system. The random number generation system according to any one of claims 1 to 5, wherein the random number generation device notifies the terminal of the used random number after using the generated random number. The random number generation system according to claim 6, wherein the random number generation device opens the seal of the initial random number to the terminal after the random number generation for the terminal becomes unnecessary. The terminal acquires the sealed value of the initial random number written on the electronic bulletin board, the acquired sealed value, the opened initial random number, the random number notified as the used random number, and the random number. The random number generation system according to claim 7, wherein the fairness of random number generation by the random number generator is verified based on the order number related to the generation of the random number. The terminal calculates the seal value of the opened initial random number, and if the calculated seal value and the seal value obtained from the electronic bulletin board do not match, the random number generation by the random number generator is unfair. The random number generation system according to claim 8, wherein the determination is made. In the terminal, the calculated seal value and the seal value obtained from the electronic bulletin board match, and the random number notified as the used random number, the opened initial random number, the user random number, and the random number. The random number generation system according to claim 9, wherein when the random numbers generated from the random numbers related to the generation match, it is determined that the random number generation by the random number generator is fair. The terminal writes the user random number on the electronic bulletin board,
The random number generation system according to claim 5, wherein the random number generation device writes the used random numbers to the electronic bulletin board after using the generated random numbers. A claim further comprising a verification device for verifying the fairness of random number generation by the random number generator using the sealed value of the initial random number, the used random number, and the user random number written on the electronic bulletin board. 11. The random number generation system according to 11. Including multiple terminals
The random number generator generates the initial random number for each of the plurality of terminals.
Each of the plurality of terminals generates the user random number and generates the user random number.
The random number generation system according to any one of claims 1 to 12, wherein the random number generator generates random numbers based on at least the plurality of initial random numbers, the plurality of user random numbers, and an ordinal number relating to the generation of the random numbers. Including the first and second terminals
The random number generator generates the first initial random number for the first terminal.
The first terminal generates the first user random number and transmits the sealed value of the first user random number to the random number generator.
After receiving the sealed value of the first user random number, the random number generator generates the second initial random number for the second terminal and uses the sealed value of the first user random number as the first user random number. Send to 2 terminals,
After receiving the sealed value of the first user random number, the second terminal generates the second user random number and transmits the generated second user random number to the random number generator.
The random number generator transmits the second user random number to the first terminal.
After receiving the second user random number, the first terminal opens the seal of the first user random number in the random number generator.
The random number generation according to claim 13, wherein the random number generator generates random numbers based on at least the first and second initial random numbers, the first and second user random numbers, and the ordinal number related to the generation of the random numbers. system. Including the first and second terminals
The random number generator generates the first initial random number for the first terminal.
The first terminal generates the first user random number and transmits the sealed value of the first user random number to the random number generator.
After receiving the sealed value of the first user random number, the random number generator generates the second initial random number for the second terminal and uses the sealed value of the first user random number as the first user random number. Send to 2 terminals,
After receiving the sealed value of the first user random number, the second terminal generates the second user random number and uses the generated sealed value of the second user random number to the random number generator. Send and
The random number generator transmits the sealed value of the second user random number to the first terminal.
After receiving the seal value of the second user random number, the first terminal opens the seal of the first user random number in the random number generator.
After opening the first user random number, the random number generator transmits the first user random number to the second terminal.
After receiving the first user random number, the second terminal opens the seal of the second user random number in the random number generator.
The random number generation according to claim 13, wherein the random number generator generates random numbers based on at least the first and second initial random numbers, the first and second user random numbers, and the ordinal number related to the generation of the random numbers. system. The random number generation system according to any one of claims 1 to 15, wherein the terminal uses a numerical value associated with a choice selected by the user to generate the user random number. A first random number generator that generates an initial random number and generates a sealed value of the initial random number,
A user random number generated by the terminal after the sealing value of the initial random number is generated, a value based on the initial random number and at least a random number related to the random number used by the terminal are input to the hash function, and the output result of the hash function is A second random number generator that generates the random number based on the above,
A random number generator. With the terminal
A random number generator that generates random numbers for the terminal,
In a system that includes
The step in which the random number generator generates the sealed value of the initial random number,
A step in which the terminal generates a user random number after the sealing value of the initial random number is generated.
A step in which the random number generator inputs a value based on the initial random number, the user random number, and at least a random number related to the generation of the random number used by the terminal into the hash function, and generates the random number based on the output result of the hash function. When,
Random number generation methods, including. The process of generating the initial random number and generating the sealing value of the initial random number,
A user random number generated by the terminal after the sealing value of the initial random number is generated, a value based on the initial random number and at least a random number related to the random number used by the terminal are input to the hash function, and the output result of the hash function is Based on the process of generating the random number,
A program that causes a computer to run.

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