Lottery system, lottery method, and program

Abstract

To provide a lottery system, and the like, for a lottery with improved impartiality.SOLUTION: A lottery system includes: an acquisition unit which acquires an encrypted shard, the encrypted shard being obtained by encrypting a shard associated with each of lottery participants included in a plurality of lottery participants, while designating a time, with an encryption key issued by one or more corresponding key generation apparatuses associated with the lottery participants, out of a plurality of key generation apparatuses; a recording unit which records the encrypted shard in a predetermined distributed ledger database; a decryption unit which decrypts the encrypted shard with a decryption key which is paired with an encryption key issued at or after the designated time by the one or more corresponding key generation apparatuses, to obtain the shard; a random number generation unit which generates a random number based on the shard associated with each of the lottery participants included in the multiple lottery participants; and a lottery processing execution unit which execute lottery processing based on the random number.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lottery system, a lottery method, and a program.

Background Art

[0002] Conventionally, in various fields, lotteries have been conducted to determine winners from among a plurality of lottery participants, and various methods that can be used for such lotteries have been proposed. For example, Patent Document 1 describes a system including a server that executes a lottery process for awarding content to participants using a lottery table in which the probability of obtaining content is set according to the number of participants constituting a group.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when there is no subjective involvement by lottery participants in the lottery, it is difficult for lottery participants to be convinced or verify that the lottery is being conducted fairly.

[0005] Therefore, the present invention has been made in view of the above points, and an object thereof is to provide a lottery system or the like capable of conducting a lottery with improved fairness.

Means for Solving the Problems

[0006] The lottery system according to one aspect of the present invention encrypts a fragment associated with each lottery participant among a plurality of lottery participants at a specified time using an encryption key issued by one or a plurality of corresponding key generation devices, which are key generation devices associated with each lottery participant among the plurality of key generation devices, to obtain an encrypted fragment, an acquisition unit that acquires the encrypted fragment, a recording unit that records the encrypted fragment in a predetermined distributed ledger database, and a decryption unit that decrypts the encrypted fragment using a decryption key that is a pair of encryption keys issued after the specified time by one or a plurality of corresponding key generation devices to obtain the fragment, a random number generation unit that generates a random number based on the fragments associated with each lottery participant among the plurality of lottery participants, and a lottery process execution unit that executes a lottery process based on the random number.

[0007] According to this aspect, since the lottery is conducted based on the fragments associated with each lottery participant, for example, it becomes difficult for a specific lottery participant to manipulate the lottery result. In addition, each fragment is encrypted using an encryption key issued by one or a plurality of corresponding key generation devices associated with each lottery participant among the plurality of time key generation devices, and is decrypted using a decryption key issued by these one or a plurality of corresponding key generation devices after the specified time. Therefore, it becomes difficult for the fragment to be read by other lottery participants or the like until the specified time. Further, since each fragment is recorded in the distributed ledger database in an encrypted state, it becomes difficult to falsify. From the above, the fairness of the lottery is improved.

Effect of the Invention

[0008] According to the present invention, it is possible to provide a lottery system or the like capable of conducting a lottery with improved fairness.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0010] Referring to the accompanying drawings, preferred embodiments of the present invention will be described. (In each figure, those with the same reference numerals have the same or similar configurations.)

[0011] (1) Overview FIG. 1 is a schematic diagram showing an example of the configuration of the lottery system 1 according to this embodiment. The lottery system 1 according to this embodiment is, for example, a system for conducting a lottery among a plurality of lottery participants. The type of lottery to which the lottery system 1 according to this embodiment is applied is not particularly limited, but may include, for example, IPO (Initial Public Offering) and the like. The lottery system 1 according to this embodiment includes, for example, a blockchain management device 10, a blockchain 20, a lottery management device 30, a time key generation device 40, and lottery participant terminals 50.

[0012] The blockchain management device 10 is a device for managing a blockchain 20, which is constituted by, for example, one or more computers. The blockchain 20 is an example of a distributed ledger database, which is a database that distributes and records arbitrary information to a plurality of computers connected as nodes. The lottery management device 30 is a device for managing a lottery, which is constituted by, for example, one or more computers. The time key generation device 40 is a device for generating and publishing a predetermined encryption key and decryption key, which is constituted by, for example, one or more computers. The lottery participant terminal 50 is a device for participating in a lottery, which is constituted by, for example, one or more computers.

[0013] Among at least some of the components (the blockchain management device 10, the blockchain 20, the lottery management device 30, the time key generation device 40, and the lottery participant terminal 50) included in the lottery system 1, they may be connected to be able to transmit and receive information to and from each other via a communication network n such as the Internet.

[0014] The lottery system 1 according to the present embodiment is a system for conducting a lottery among a plurality of lottery participants, for example, using a multiple-type time-release cipher described later. Here, the lottery system 1 may have N time key generation devices 40 used by N (N is a natural number of 2 or more) time key generators X (natural persons, corporations, etc.). In the present disclosure, in order to distinguish individual time key generators X and time key generation devices 40, they may be referred to as "time key generator X i " and "time key generation device 40 i " (where i = 1, 2, ···, or N), etc.

[0015] The lottery system 1 may have M lottery participant terminals 50 used by M (M is a natural number of 2 or more) lottery participants Y (natural persons, corporations, etc.). In the present disclosure, in order to distinguish individual lottery participants Y and lottery participant terminals 50, they may be referred to as "lottery participant Y j " and "lottery participant terminal 50 j"(where j = 1, 2, ···, or M) may be referred to as such."

[0016] In the present disclosure, the administrator of the blockchain management device 10 and the blockchain 20 may be referred to as "BC administrator" or the like. The BC administrator may be, for example, a consortium participating company in the case where the blockchain 20 is of the consortium type. In the case where the blockchain 20 is of the public type or the like, the lottery system 1 does not necessarily have to have the blockchain management device 10, and the functions of the blockchain management device 10 described later may be possessed by the lottery management device 30 or the lottery participant terminal 50 j may also have them."

[0017] In the present disclosure, the lottery administrator using the lottery administrator device 30 may be referred to as "lottery administrator Z" or the like. When applying the lottery system 1 according to the present embodiment to an IPO, for example, the BC administrator corresponds to a predetermined business company, the lottery administrator Z corresponds to an underwriting securities company, and the time key generator X i corresponds to a predetermined consortium participating company, and the lottery participant Y j may correspond to an applicant for the IPO. Note that these are merely examples, and the BC administrator, the lottery administrator Z, the time key generator Xi, and the lottery participant Yj are not limited to the above-described entities. For example, when the issuer of the IPO itself can lead the lottery due to regulatory relaxation or the like, the issuer of the IPO may assume the role of the lottery administrator Z."

[0018] (2) Features of the lottery method according to the present embodiment Hereinafter, the features of the lottery method by the lottery system 1 according to the present embodiment will be described."

[0019] (2-1) Determination of the fragment r by the lottery participant j of The lottery system 1 according to the present embodiment may, for example, aim to enable lottery participants to be confident that they are fairly selected. For this purpose, in the present embodiment, for example, a plurality of lottery participants Y jEach lottery participant Y determines on their own, etc., j and the fragment r associated with j is obtained by the lottery administrator Z. Then, for a plurality of lottery participants Y j based on each of their fragments r j a random number may be obtained, and a lottery process may be executed based on the random number. Specifically, in the lottery system 1 according to the present embodiment, for example, the lottery participant terminal 50 j obtains the fragment r associated with the lottery participant Y j in response to an operation by the lottery participant Y j and then transmits the fragment r j to the lottery management device 30 used by the lottery administrator Z. j

[0020] The lottery management device 30, for example, generates a random number based on the fragment r j obtained from each lottery participant terminal 50 j and executes a predetermined lottery process based on the random number. The random number may be calculated by a predetermined operation based on the fragment r j . The predetermined operation is not particularly limited as long as it is based on the fragment r j , but for example, it may be the multiplication of the fragments r j with each other. That is, when the number of lottery participants Y j is M people, r 1 ×r 2 ×···×r M is obtained as the result of the operation (multiplication). The lottery management device 30 inputs the obtained operation result as the seed r (r = r 1 ×r 2 ×···×r M ) into a predetermined random number generator, obtains the random number output from the random number generator, and then executes a lottery process by an arbitrary algorithm based on the random number.

[0021] In this way, in the lottery system 1 according to the present embodiment, since the lottery is conducted based on the fragment r j associated with each lottery participant Y j , for example, for a specific single lottery participant Y j ​It becomes difficult to manipulate the lottery result, and the fairness of the lottery is improved.

[0022] (2-2) Recording of fragment r by blockchain 20 j thereof In the lottery system 1 according to the present embodiment, for example, the fragment r j obtained from the lottery participant terminal 50 j (as will be described later, the fragment c j encrypted by a predetermined encryption key) may be recorded on the blockchain 20 by the blockchain management device 10. The format of the blockchain 20 is not particularly limited, and for example, it may be a public type, a consortium type, a private type, a combination thereof, or other formats.

[0023] As a result, it becomes difficult to forge the fragment r j provided from each lottery participant Y j to the lottery administrator Z. Therefore, for example, each lottery participant Y j has difficulty forging the fragment r j of other lottery participants Y j and operating their own fragment r j after checking it, or operating the final random number seed r.

[0024] (2-3) Encryption of fragment r by time key j thereof The lottery system 1 according to the present embodiment may encrypt the fragment r j with one or more predetermined time keys so that it cannot be decrypted until a predetermined time. The encryption and decryption of the fragment r j may be performed, for example, with one or more time keys generated by one or more time key generation devices 40 i used by one or more time key generators X i .

[0025] Time key generation device 40 iFor example, it generates a time key for a time-release cipher. A time-release cipher means, for example, performing encryption such that decryption becomes possible at a predetermined time. The time key for a time-release cipher may include, for example, a key for encryption (encryption key P i ) and a key for decryption (decryption key Q i ). The time key generation device 40 i generates and publishes the encryption key P i at, for example, the time when the time key generation device 40 i is configured. The method for generating the encryption key P i is not particularly limited. For example, it may be the product s i of a master key s i unique to the time key generation device 40 i and a base point p, i.e., s i ·p as the encryption key P.

[0026] In this embodiment, for each lottery participant Y j , one or more (for example, N) of the plurality of time key generation devices 40 i may be associated as a corresponding key generation device. One or more time key generation devices 40 i associated with the lottery participant Y j (corresponding key generation device) may be, for example, those selected by the lottery participant Y i himself / herself from the plurality of time key generation devices 40 j , or those designated by the lottery administrator Z from the plurality of time key generation devices 40 i as the time key generation devices 40 j to be used by the lottery participant Y i , or may be determined by any other arbitrary method. i

[0027] The lottery participant terminal 50 j performs operations according to, for example, the lottery participant Y j , and for one or more time key generation devices 40 j associated with the lottery participant Y i(One or more corresponding key generation devices) obtain one or more encrypted keys P i After that, by specifying a predetermined time, the fragment r j is encrypted by these one or more encrypted keys P i to obtain an encrypted fragment c j The predetermined time may be, for example, a time (designated time) specified by the lottery administrator Z in relation to the lottery, and specifically, it may be the closing time of the lottery application, etc. And the lottery participant terminal 50 j specifies a time and transmits the fragment c i encrypted by one or more encrypted keys P j to the lottery management device 30.

[0028] The encryption method with a specified time is not particularly limited. For example, the hash value H 1 (T) obtained by inputting the specified time T as a character string into a hash function, each encrypted key P i , and a random number generated by the lottery participant Y j etc. are combined to generate a blind, and the encrypted fragment r j is encrypted by taking the exclusive logical sum (XOR) of the blind and the fragment r.

[0029] The time key generation device 40 i issues and publishes a decryption key corresponding to each time, for example, after a periodically arriving time (for example, every few hours, every few minutes, every few seconds). As described above, when encryption is performed by specifying a predetermined time using the encryption key P i , among the decryption keys issued after each time, the decryption key Q i issued in association with the predetermined time after the predetermined time can be used to decrypt the encryption. That is, among the keys generated by the time key generation device 40 i , the encryption key P i used for encryption with a specified predetermined time and the decryption key Q i issued in association with the time after the predetermined time form a pair.

[0030] Decryption key Qi The method for generating i is not particularly limited. For example, the master key s i unique to the time key generation device 40 i and the time T associated with the decryption key Q 1 are input as a string into a hash function, and the resulting hash value H i (T) is multiplied by s 1 ·H i (T) may be used as the decryption key Q

[0031] The lottery management device 30, for example, in response to an operation by the lottery administrator Z, when the predetermined time (designated time) has elapsed, one or more time key generation devices 40 j associated with the lottery participant Y i (corresponding key generation device) to obtain one or more decryption keys Q i associated with the designated time. Then, the lottery management device 30 uses the one or more obtained decryption keys Q i to decrypt the encrypted fragment c j to obtain the fragment r j .

[0032] Thus, in the lottery system 1 according to this embodiment, the fragment r j associated with each lottery participant Y j is encrypted by one or more encryption keys P j generated by one or more time key generation devices 40 i (corresponding key generation device) associated with each lottery participant Y i . Then, after the predetermined time, the one or more decryption keys Q j associated with the predetermined time, which are publicly disclosed by the one or more time key generation devices 40 i (corresponding key generation device) associated with the lottery participant Y i , are used for decryption. Therefore, the fragment r j provided by each lottery participant Y j to the lottery administrator Z is difficult for other lottery participants Y j and the like to read until the predetermined time, improving the fairness of the lottery.

[0033] In particular, the lottery system 1 according to the present embodiment may include, for example, a plurality of time key generation devices 40 i and may include one or more time key generation devices 40 j associated with the lottery participant Y i (corresponding key generation device) may be selected from these plurality of time key generation devices 40 i . As a result, for a plurality of fragments r j provided by a plurality of lottery participants Y j , one or more encryption keys P j published by one or more time key generation devices 40 i for each different combination of these fragments r i are encrypted, or all of the plurality of fragments r j are encrypted by a plurality of encryption keys P i published by the same combination of a plurality of time key generation devices 40 i . In such a case, for example, it becomes difficult for a single time key generator X i to illegally decrypt all of the fragments r j , and the fairness of the lottery is improved. In the present disclosure, in this way, a method using a time-release cipher by a plurality of one or more time key generation devices 40 i may be referred to as a "plurality type time-release cipher".

[0034] (2) Functional configuration (2-1) Blockchain management device 10 FIG. 2 is a block diagram showing an example of the functional configuration of the blockchain management device 10 according to the present embodiment.

[0035] The blockchain management device 10 can be composed of one or more computers as its hardware configuration, including, for example, computing elements such as a CPU (Central Processing Unit) and a GPU (Graphical Processing Unit), volatile memory elements such as SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory), non-volatile memory elements such as NOR flash memory, NAND flash memory, and HDD (Hard Disc Drive), and communication means such as a bus for connecting these. In the non-volatile memory element, for example, a computer program for executing each process shown in this embodiment is stored. The volatile memory element temporarily stores at least a part of these computer programs and arithmetic processing results, etc. However, at least a part of these computing elements, non-volatile memory elements, etc. may be installed in a remote location connected to a communication network n such as the Internet. For example, the computing element may be configured to acquire a computer program or necessary data via the communication network n.

[0036] As functional units realized by the above hardware configuration, the blockchain management device 10 includes, for example, a storage unit 11 and a control unit 12.

[0037] The storage unit 11 stores various computer programs, data, etc. The various computer programs may be installed in the storage unit 11 from a computer-readable portable recording medium such as a CD-ROM or a DVD-ROM using a known setup program, etc.

[0038] The control unit 12 includes, for example, an acquisition unit 121 and a recording unit 122.

[0039] The acquisition unit 121 acquires various information from, for example, the lottery participant terminal 50 j The acquisition unit acquires, for example, the lottery participant terminal 50 jFrom the lottery participant terminal 50 j Lottery participant Y who uses it j Fragment r associated with j May be acquired. Here, fragment r j Is "Lottery participant Y j Associated with", the fragment r j Is the lottery participant Y j May be a character string or number string arbitrarily input and determined by the lottery participant Y, or may be a random number generated in the lottery participant terminal 50 j Or the like, or may be information calculated by an arbitrary algorithm in the lottery participant terminal 50 j Or the like.

[0040] The fragment r acquired by the acquisition unit j For example, one or more time key generation devices 40 out of a plurality (for example, N) of time key generation devices 40 i Among them, lottery participant Y j One or more time key generation devices 40 associated with i (Corresponding time key generation device 40 i ) May be encrypted by one or more encryption keys P issued by i . One or more corresponding time key generation devices 40 i For example, lottery participant Y j May be selected by the lottery participant Y himself from a plurality of time key generation devices 40 i , or may be those designated by the lottery administrator Z from a plurality of time key generation devices 40 j To be used by the lottery participant Y, or may be determined by any other method. i As a plurality of time key generation devices 40 i From which the lottery administrator Z designates, or may be determined by any other arbitrary method.

[0041] The recording unit 122 records, for example, the encrypted fragment c j Acquired by the acquisition unit 121 from the lottery participant terminal 50 j On the blockchain 20. Specifically, the recording unit 122 records, for example, the encrypted fragment c jGenerate a transaction including it and send (broadcast) it to each node constituting the blockchain 20. Then, in the blockchain 20, a block including the transaction is generated by a predetermined algorithm, and the generated block is linked to the previous blocks stored in each node.

[0042] (2-2) Lottery management device 30 FIG. 3 is a block diagram showing an example of the functional configuration of the lottery management device 30 according to the present embodiment.

[0043] The lottery management device 30 can be configured as one or more computers including, as a hardware configuration, for example, an arithmetic element such as a CPU or GPU, a volatile storage element such as SRAM or DRAM, a non-volatile storage element such as NOR flash memory, NAND flash memory, or HDD, and a communication means such as a bus connecting these. A computer program for executing each process shown in the present embodiment is stored in the non-volatile storage element, for example. The volatile storage element temporarily stores at least a part of these computer programs and arithmetic processing results. However, at least a part of these arithmetic elements, non-volatile storage elements, etc. may be installed at a remote location connected to a communication network n such as the Internet. For example, the arithmetic element may be configured to acquire a computer program or necessary data via the communication network n.

[0044] The lottery management device 30 includes, as functional parts realized by the above hardware configuration, for example, a storage part 31 and a control part 32.

[0045] The storage part 31 stores, for example, various computer programs, data, etc. The various computer programs may be installed in the storage part 31 from a computer-readable portable recording medium such as a CD-ROM or DVD-ROM using a known setup program.

[0046] The storage unit 31 may store, for example, lottery rule information 311 which is information indicating the lottery rules. The lottery management device 30 may store the lottery rule information 311 in the storage unit 31 according to the operation of the lottery administrator Z or the like. At least a part of the lottery rule information 311 stored in the storage unit 31 may be disclosed to, for example, the lottery participant terminal 50 j and the like.

[0047] The lottery rule information 311 may include, for example, information regarding the method of determining the winners in the lottery. Specifically, for example, the lottery rule information 311 may include the type of random number generator used in the lottery, the format of the seed of the random number generator, and the algorithm or method for the lottery using the random numbers.

[0048] The lottery rule information 311 may include information regarding the encryption of the fragment r j in the lottery participant terminal 50. j For example, the lottery rule information 311 may include correspondence information indicating which one of the plurality of time key generation devices 40 i is the one or more time key generation devices 40 i associated with the lottery participant Y j . The corresponding key generation device is the time key generation device 40 i that issues the encryption key P j used by the lottery participant Y i in the lottery. The corresponding key generation device may be determined by the lottery administrator Z from the plurality of time key generation devices 40 i , or may be determined by the lottery participant Y i from the plurality of time key generation devices 40 j . i

[0049] The control unit 32 includes, for example, a decoding unit 321, a random number generation unit 322, and a lottery process execution unit 323.

[0050] The decoding unit 321 decodes, for example, the encrypted fragment c j to obtain the fragment r jTo obtain. Specifically, the decoding unit 321, for example, selects one or more time key generation devices 40 j associated with the lottery participant Y i (corresponding time key generation device 40 i ) to obtain the decryption key Q i issued in association with the specified time after the specified time. Then, the decoding unit 321 decrypts the encrypted fragment c j provided by each lottery participant Y j recorded in the blockchain 20 using the one or more decryption keys Q i obtained, to obtain the fragment r j .

[0051] Note that when the lottery participant Y i himself / herself determines which of the multiple time key generation devices 40 i will be the one or more corresponding time key generation devices 40 i (the one or more time key generation devices 40 that are the issuers of the one or more encryption keys for encrypting the fragment r j ), in such a case, for the lottery administrator Z, it may be unclear which time key generation device 40 i is the one or more corresponding time key generation devices 40 j . However, in that case, for example, by trying decryption with the decryption key Q i of each of the multiple time key generation devices 40 i included in the lottery system 1 in all cases, it is possible to perform the decryption process. i The random number generation unit 322 generates a random number based on, for example, the fragment r i associated with each lottery participant Y

[0052] . Specifically, the random number generation unit 322 executes a predetermined operation based on, for example, the fragment r j associated with each lottery participant Y j . The content of the operation is not particularly limited as long as it is based on the fragment r j associated with each lottery participant Y j . For example, the operation is based on the fragment r j and is not particularly limited. For example, the fragment r jIt may be a multiplication between them. As a result, fragments r j the product between them (r 1 ×r 2 ×···r M ) is obtained. Then, the random number generation unit 322 inputs the result of the operation (e.g., the product between fragments r j ) into a predetermined random number generator as the seed r to obtain a random number.

[0053] The lottery processing execution unit 323 executes lottery processing based on, for example, the random number obtained by the random number generation unit 322. The lottery processing may be a process of determining a winner from lottery participants Y j . The winner may be single or multiple. Also, a predetermined type or rank may be set for the winner. The lottery processing may use any algorithm.

[0054] (2-3) Others The lottery system 1 does not necessarily have to include the blockchain management device 10 and / or the lottery management device 30. That is, as long as one or more computers included in the lottery system 1 have all or part of the above-described functional units of the blockchain management device 10 and / or the lottery management device 30, the configuration of the lottery system 1 is not particularly limited.

[0055] (3) Operation processing With reference to FIGS. 4 to 6, an example of the operation processing by the lottery system 1 according to the present embodiment will be described.

[0056] (3-1) Before lottery start FIG. 4 is a sequence diagram showing an example of the operation processing before lottery start by the lottery system 1 according to the present embodiment.

[0057] (S11) First, each of the N time key generation devices 40 included in the lottery system 1 i generates an encryption key P i and publishes it. For example, each time key generation device 40 i uses the master key s iAfter generating, it is multiplied by the base point p to obtain s i ·p may be used as the encryption key P i Note that each time key generation device 40 i stores, for example, the generated master key s i in the storage unit managed by each time key generation device 40 i . The timing for generating the encryption key P i is not particularly limited, and may be, for example, the time when each time key generation device 40 i is configured, etc.

[0058] (S12) Further, the lottery management device 30 acquires lottery rule information 311, which is information regarding the lottery rules, and publishes it. The lottery rule information 311 may include, for example, information regarding the method for determining the winners in the lottery. Specifically, it may include the type of random number generator used in the lottery, the format of the seed of the random number generator, and the algorithm or method for the lottery using the random number. These pieces of information may be determined by, for example, the lottery administrator Z. Further, the lottery rule information 311 may include, for example, correspondence information (information indicating which one or more of the N time key generation devices 40 i are the time key generation devices 40 i associated with the lottery participant Y j (corresponding key generation devices)). One or more corresponding key generation devices may be determined by the lottery administrator Z from the N time key generation devices 40 i , or may be determined by the lottery participant Y i from the N time key generation devices 40 j . i

[0059] (3-2) From the start of the lottery to the lottery application deadline time T FIG. 5 is a sequence diagram showing an example of the operation process from the start of the lottery to the lottery application deadline time T by the lottery system 1 according to the present embodiment.

[0060] (S21) First, each of the M lottery participant terminals 50 j sends the fragment r associated with the lottery participant Y j ​​j Generate it. Each lottery participant terminal 50 j For example, lottery participant Y j May obtain the character string or number string arbitrarily input and determined by lottery participant Y as fragment r j Or may generate a random number according to the operation of lottery participant Y and use this as fragment r j Or may calculate fragment r by any algorithm. j j

[0061] (S22) Next, each lottery participant terminal 50 j Obtains one or more encryption keys P published by one or more time key generation devices 40 associated with lottery participant Y j For example, in response to receiving the operation of lottery participant Y who selects one or more time key generation devices 40 (corresponding key generation devices) from among N time key generation devices 40 i Each lottery participant terminal 50 may obtain one or more encryption keys P from the selected one or more time key generation devices 40. Alternatively, lottery participant terminal 50 i May refer to the correspondence information included in the lottery rule information 311 etc. stored in the lottery management device 30 etc., identify one or more time key generation devices 40 (corresponding key generation devices) associated with lottery participant Y among the N time key generation devices 40 j And obtain one or more encryption keys P from the identified one or more time key generation devices 40. When lottery participant Y selects one or more corresponding key generation devices i Lottery participant terminal 50 may transmit information regarding the selection to lottery management device 30 at an arbitrary timing. Lottery management device 30 may store the information in storage unit 31 as lottery rule information 311, for example. i (Corresponding key generation device) j i i j i j i (Corresponding key generation device) i i j j ​​​​​​​​​​​​

[0062] (S23) Next, each lottery participant terminal 50 j specifies the lottery application end time T and encrypts the fragment r j with the encryption key P i . Specifically, for example, each lottery participant terminal 50 j acquires the lottery application end time T from the lottery management device 30, and then obtains a hash value by inputting the time T as a character string into a hash function. Then, each lottery participant terminal 50 j generates a blind by combining the hash value, the encryption key P i obtained in step S22, and an arbitrary random number, and encrypts by taking the exclusive logical sum (XOR) of the blind and the fragment r j .

[0063] (S24) Next, each lottery participant terminal 50 j transmits the encrypted fragment c j to the blockchain management device 10. The blockchain management device 10 receives (acquires) the encrypted fragment c j from each lottery participant terminal 50 j . In the above-mentioned step S22 etc., when the lottery participant Y j selects one or more corresponding key generation devices, the lottery participant terminal 50 j may also transmit information regarding the selection to the blockchain management device 10 together. The blockchain management device 10 may transmit the information regarding the selection to the lottery management device 30. The lottery management device 30 may store the information regarding the selection in the storage unit 31 as, for example, lottery rule information 311.

[0064] (S25) The blockchain management device 10 records the encrypted fragment c j acquired from each lottery participant terminal 50 j on the blockchain 20. Specifically, the blockchain management device 10, for example, each encrypted fragment c jGenerate a transaction including it and send (broadcast) it to each node constituting the blockchain 20. Thereafter, in the blockchain 20, a block including the transaction is generated by a predetermined algorithm, and the generated block is linked to the previously stored blocks in each node. As a result, each encrypted fragment c j is recorded in the blockchain 20.

[0065] (3-3) After the lottery application end time T FIG. 6 is a sequence diagram showing an example of the operation process after the lottery application end time T by the lottery system 1 according to the present embodiment.

[0066] (S31) Each time key generation device 40 i generates and publishes a decryption key Q associated with the time after the periodically arriving time, and when the lottery application end time T arrives, thereafter, the decryption key Q associated with the time T i is generated and published. Specifically, for example, each time key generation device 40 i generates the product s of the master key s unique to the time key generation device 40 i and the hash value H i (T) obtained by inputting the lottery application end time T as a character string into the hash function, and generates and publishes s i ·H 1 (T) as the decryption key Q i ·H 1 (T) as the decryption key Q i and publishes it.

[0067] (S32) The lottery management device 30 acquires, via the blockchain management device 10, the encrypted fragment c associated with each lottery participant Y j recorded in the blockchain 20. j is acquired.

[0068] (S33) The lottery management device 30 obtains one or more decryption keys Q associated with the lottery application end time T from one or more time key generation devices 40 j associated with each lottery participant Y i and ito obtain. The lottery management device 30 refers to, for example, the correspondence information included in the lottery rule information 311, and for each lottery participant Y j one or more time key generation devices 40 associated therewith i are specified, and one or more decryption keys Q i may be specified from the one or more specified time key generation devices 40. i

[0069] (S34) The lottery management device 30 decrypts the encrypted fragment c associated with each lottery participant Y j using one or more decryption keys Q associated with the time T obtained from one or more time key generation devices 40 associated with the lottery participant Y j j i i Thus, fragments r associated with each of the M lottery participants Y j are obtained. j

[0070] (S35) Next, the lottery management device 30 calculates the product r of the fragments r associated with each lottery participant Y j j That is, the lottery management device 30 calculates r = r 1 × r 2 × ··· r M .

[0071] Note that when the lottery management device 30 fails to correctly decrypt the encrypted fragment c associated with each lottery participant Yj using one or more decryption keys Q associated with the time T obtained from one or more time key generation devices 40i associated with the lottery participant Y j j it may calculate r excluding the r i when calculating r. Alternatively, if the decryption is successful but the obtained fragment r j is not in the correct format, it may calculate r excluding the fragment r j when calculating r, or, alternatively, the fragment r j j ​​​​​​​​It is also possible to convert it into the correct format according to certain rules.

[0072] (S36) Next, the lottery management device 30 inputs the obtained r as a seed to a predetermined random number generator, and obtains a random number output from the random number generator in response to the input. The lottery management device 30 may, for example, refer to the lottery rule information 311 stored in the storage unit 31 and use a random number generator defined in the lottery rule information 311.

[0073] (S37) Next, the lottery management device 30 performs a lottery using a predetermined algorithm based on the acquired random number. For example, the lottery management device 30 may refer to the lottery rule information 311 stored in the storage unit 31 and use a random number generator defined in the lottery rule information 311.

[0074] (4) Variations The blockchain management device 10 (e.g., the acquisition unit 121) acquires a plurality of time key generation devices 40 i Which of the time key generating devices 40 i Each lottery participant Y j One or more time key generating devices 40 associated with i For example, the lottery participant Y may further acquire correspondence information indicating whether the lottery participant Y is a j One or more time key generating devices 40 used for encryption i In the case of selecting the lottery participant terminal 50, for example, at the timing of step S24 described above, j The lottery manager Z may obtain the corresponding information from each lottery participant Y. j One or more time key generating devices 40 to be used for encryption i When determining the lottery rule information 311, the blockchain management device 10 may, for example, obtain corresponding information recorded as lottery rule information 311 from the lottery management device 30.

[0075] The correspondence information obtained by the blockchain management device 10 may be encrypted with an arbitrary encryption key. The correspondence information is, for example, one or more time key generation devices 40 j associated with the lottery participant Y i may be encrypted with one or more encryption keys P i issued by, or alternatively, one or more time key generation devices 40 j associated with the lottery participant Y i and different one or more time key generation devices 40 i may be encrypted with one or more encryption keys P i issued by. In this case, for example, at the timing of encrypting the above-mentioned fragment r j (step S23) or the like, the lottery participant terminal 50 j further encrypts, with the same encryption key P j used for encrypting the fragment r, the correspondence information indicating which one or more time key generation devices 40 i the lottery participant Y has selected. Then, the lottery participant terminal 50 j may further transmit the encrypted correspondence information to the blockchain management device 10, for example, at the timing of transmitting the encrypted fragment c i to the blockchain management device 10 (step S24) or the like. And the blockchain management device 10 may record the obtained correspondence information in the blockchain 20, for example, at the timing of step S25 or the like described above. And the lottery management device 30 may further obtain the encrypted correspondence information, for example, at the timing of obtaining the encrypted fragment c j from the blockchain 20 (step S32) or the like. And the lottery management device 30 obtains, for example, at the timing of step S33 or the like described above, the decryption key Q j associated with the lottery application end time T from each of the plurality of time key generation devices 40 j , and then, with each of the obtained plurality of decryption keys Q i , decrypts the encrypted fragment c i i jIt may also decrypt the encrypted corresponding information.

[0076] The blockchain management device 10 may record the acquired corresponding information (including the encrypted corresponding information) in the blockchain 20.

[0077] The embodiments described above are for facilitating the understanding of the present invention and are not for limiting and interpreting the present invention. Each element included in the embodiments and its arrangement, material, conditions, shape, size, etc. are not limited to those illustrated and can be appropriately changed. Also, it is possible to partially substitute or combine the configurations shown in different embodiments.

Explanation of Reference Numerals

[0078] 1…Lottery system, 10…Blockchain management device, 20…Blockchain, 30…Lottery management device, 40…Time key generation device, 50…Lottery participant terminal, 11…Storage unit, 12…Control unit, 121…Acquisition unit, 122…Recording unit, 31…Storage unit, 32…Control unit, 321…Decryption unit, 322…Random number generation unit, 323…Lottery processing execution unit

Claims

1. An acquisition unit that acquires encrypted fragments obtained by encrypting, at a specified time, fragments associated with each lottery participant among a plurality of lottery participants with an encryption key issued by one or more corresponding key generation devices, which are the key generation devices associated with each lottery participant among the plurality of key generation devices; A recording unit that records the encrypted fragments in a predetermined distributed ledger database; A decryption unit that decrypts the encrypted fragments with a decryption key that is a pair of the encryption key issued after the specified time by the one or more corresponding key generation devices to obtain the fragments; A random number generation unit that generates a random number based on the fragments associated with each lottery participant among the plurality of lottery participants; A lottery processing execution unit that executes a lottery process based on the random number; A lottery system comprising:

2. The lottery system according to claim 1, wherein the random number generation unit executes a predetermined operation based on the fragments for each lottery participant among the plurality of lottery participants, and inputs the result of the predetermined operation as a seed to a predetermined random number generator to obtain the random number.

3. The lottery system according to claim 2, wherein the predetermined operation is an accumulation of the fragments.

4. The acquisition unit further acquires correspondence information indicating which of the plurality of key generation devices are the one or more corresponding key generation devices associated with each lottery participant; The lottery system according to claim 1, wherein the recording unit records the correspondence information in the predetermined distributed ledger database.

5. The correspondence information acquired by the acquisition unit is encrypted; The lottery system according to claim 4, wherein the recording unit records the encrypted correspondence information in the predetermined distributed ledger database.

6. The lottery system according to claim 5, wherein the correspondence information is encrypted with the encryption key issued by the one or more corresponding key generation devices.

7. The lottery system according to claim 5, wherein the correspondence information is encrypted with an encryption key issued by a key generation device different from the one or more corresponding key generation devices among the plurality of key generation devices.

8. The lottery system according to claim 1, wherein the predetermined distributed ledger database is a blockchain.

9. One or more computers, The step of obtaining encrypted fragments obtained by encrypting at a specified time, by means of an encryption key issued by one or more corresponding key generation devices, which are key generation devices associated with each lottery participant among a plurality of lottery participants, for each lottery participant included in the plurality of lottery participants; The step of recording the encrypted fragments in a predetermined distributed ledger database; The step of obtaining the fragments by decrypting the encrypted fragments with a decryption key that is a pair of the encryption keys issued after the specified time by the one or more corresponding key generation devices; The step of generating a random number based on the fragments associated with each lottery participant among the plurality of lottery participants; The step of executing a lottery process based on the random number, and a lottery method for executing the steps.

10. One or more computers, An acquisition unit that acquires encrypted fragments obtained by encrypting at a specified time, by means of an encryption key issued by one or more corresponding key generation devices, which are key generation devices associated with each lottery participant among a plurality of lottery participants, for each lottery participant included in the plurality of lottery participants; A recording unit that records the encrypted fragments in a predetermined distributed ledger database; A decryption unit that obtains the fragments by decrypting the encrypted fragments with a decryption key that is a pair of the encryption keys issued after the specified time by the one or more corresponding key generation devices; A random number generation unit that generates a random number based on the fragments associated with each lottery participant among the plurality of lottery participants; A lottery process execution unit that executes a lottery process based on the random number; A program for causing the above to function.

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