KR20190078668A - Apparatus and Methods for Verifiable Lottery - Google Patents

Abstract

Disclosed are an apparatus for a verifiable lottery, which solves a trust problem between participants and organizers by introducing a block chain in a lottery system, and a method thereof. Provided are the apparatus for a verifiable lottery implementing query, subscribe, check, verify, open transactions in a smart contract form by using Hyper-ledger Fabric v1.0-alpha, which is a private block chain platform, and the method thereof.

Description

[0001] Apparatus and Methods for Verifiable Lottery [

The present invention relates to a computer software apparatus and method for raffling a lottery system in which a trust problem between a participant and an organizer is solved by introducing a block chain.

Existing lottery programs are implemented along a centralized basis and run on a single computer. The fairness of the lottery system is determined according to the irregularity of the random value used in the lottery, and when all the information is centralized and the administrator has authority, all the information can be arbitrarily modified, raising the reliability problem of the lottery system. The technology that guarantees the irregularity of the random value can be coped with using the public random service beacon provided by the NIST in the United States, but the problem that it has to depend on the centralized server manager still can not be solved. In order to solve these administrator rights problems, it is necessary to devise a technique that enables anyone to verify the lottery result. In other words, by constructing a lottery system that uses random values generated at a time that everyone expects and agrees while maintaining irregularity of the random value, the lottery result can be verified while supporting the fairness of the lottery system.

The bit coin block chain is basically a block miner node distributed around the world competing cryptographically hash puzzles, thereby forming a chain between blocks. The process of solving a cryptographic hash puzzle for this block chain construction basically involves many irregularity-based processes, and it is similar to generating a new random value each time block minors generate a block. By utilizing these features, a lottery system that can be verified based on block chain can be constructed by constructing a lottery system operation itself as a program executed on a block chain called a smart contract.

The block chain type is classified into a public block chain, a permissive block chain, and a conscious block chain. In the present invention, a block chain of a specific type is not assumed, but for convenience of explanation, do.

Hyperledger Fabric, an open source block-chain platform under the Linux foundation, enables transparent transactions between companies using a licensed block chain.

Conventional centralized lottery systems involve reliability problems, and these lottery systems have three major problems.

* Predictability

* Modifiability

* Information hiding

Predictability means that the winner can be predicted in advance, and operability means that the information related to the lottery can be modified arbitrarily, and the confidentiality of the information means that the information related to the lottery is not disclosed to the participant.

In order to solve this problem, the present invention has devised a reliable lottery system apparatus and method, and the present invention has been made to solve the above problems by providing a lottery system having fairness, immutability, transparency, and verifiability attributes Solves three major problems of existing lottery systems.

Impartiality means that the winner can not be predicted in advance. Invariance means that the random information can not be modified later, and transparency means that information related to the lottery should be disclosed to the participants. And verifiability means that the lottery system should be able to verify that it meets the above attributes.

Reflecting this, the present invention is to develop a reliable lottery program having fairness, invariance, transparency and verifiability properties by implementing a conventional centrally implemented lottery program using a block chain platform. More specifically, it involves developing a reliable lottery program based on a block chain that provides a lottery service.

The present invention proposes a reliable lottery device and method with fairness, invariance, transparency, and verifiability attributes using a block chain platform.

In the present invention, the random value used for realizing the fairness is divided into two types. It is a random value generated by a block hash of the bit coin block chain to be generated in the future and a cryptographically secure pseudo random number generator. The winner is determined based on the combination of the two.

Transparency and invariance are realized by a distributed replicated ledger implemented as a block chain. Transactions related to the lottery are recorded in distributed peer nodes, ensuring transparency, and stored in block chain format, thus ensuring consistency.

The result verification of the lottery system proposed in the present invention relates to a smart contract executed by peer nodes operating in a distributed environment. A smart contract running independently at each peer node verifies the lottery result by recreating the generated verification key at the time the winner was determined and comparing them.

Smart contract is a program that performs input / output with a distributed replicated ledger. In the hyper leisure fabric used in the present invention, this is also referred to as a chain code.

It provides a mechanism to ensure participants' anonymity by separating participants into hashes of public keys assigned by the CA.

The present invention solves the problem of newness by introducing a block chain to propose a decentralized lottery system that is not a conventional centralized system.

It provides a web-based program that provides services related to the lottery using Hyperledger Fabric, an open source block-chain platform under the Linux foundation.

The present invention proposes a reliable lottery system and by adopting a block chain it can reduce the social cost of dishonest lottery events.

Techniques have been proposed to make existing centralized lottery systems reliable, but they still have problems such as a single point of failure, which makes their implementation complex and difficult. However, using a block-chain platform, the reliability problem is easily solved and efficient implementation is possible.

1 is a schematic diagram of the entire system proposed in the present invention.
FIG. 2 is a conceptual diagram of a state change of a lottery event and an available chain code (smart contract) according to a time sequence.
3 is a block diagram of a verification key derivation process used for verification.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, A, B, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of the entire system proposed in the present invention.

In Figure 1, the block-chain network is implemented as a container-based container, and consists of two organizations and two peers per organization. The peer runs the transaction in smart contract format (chain code) and writes the record to the block chain. The chain code is also implemented as an independent container and is executed by the peer node. DB uses couchDB and stores and manages a block chain, which is a kind of distributed database. The Orderer orders transactions from the Web server (SDK), forms blocks and passes them to the peer node. A certificate authority (CA) in a hyper-leisure fabric manages the identity of components that make up a block-chain network. And the identity of the participants for the lottery is also managed by the CA.

The Web server and the HyperLayer / Fabric Software Development Kit (SDK) interact with the user (web client) and the block-chain network. In other words, upon receiving the user's request, it passes the implemented protocol to the constituent nodes of the block-chain network and informs the user of the result. It also fetches the target block number to be used as a random source from the bit coin based random beacon.

Web clients and users are divided into participants and organizers according to actual users. There are five types of transactions that can be performed. The participant consists of a query transaction for inquiring a lottery event list, a subscribe transaction for participating in a lottery event, a check transaction for confirming lottery result (winner decision), and a verify transaction for performing lottery verification. The organizer may register the lottery through an open transaction. All of the above transactions are implemented in a smart contract format in a block-chain network.

The bit coin block chain serves as a beacon that provides a random number. The blocks of bit coins have hash of each previous block and the hash value is almost impossible to predict based on the hash characteristic. Therefore, the algorithm for determining the winner uses the hash of the future block which is not yet formed as a random source.

FIG. 2 is a conceptual diagram of a state change of a lottery event and an available chain code (smart contract) according to a time sequence.

FIG. 2 shows state changes and available chain code operations according to the time sequence of the lottery event.

The lottery event is divided into issue date (date), due date (date), and announce date (time). The issue date is the day of the lottery. Between the issue date and the deadline, participants can participate in the registered event. The results can be verified and verified after the date of publication. Query, one of the chain code operations, is omitted from the figure because it can be called at any time regardless of time order.

The open transaction registers the lottery. Input the event name, issue date, deadline, announcement date, target block number, number of participating members, winner number, random key, member name, and register the requested event on the lottery network. The target block number is selected by predicting the block number adjacent to the release date by calculating the latest block generation rate of the bit coin block chain. The random key provides a unique number to distinguish each event.

The subscribe transaction adds the participant to the participant list of the selected lottery event. The subscribe transaction also registers the enrolled participants in the CA's database before invoking the associated chain code and is assigned a public key from the CA. The hash value of the public key is used to distinguish participants. Anonymity can not be guaranteed by the one-way nature of the hash function, and if the result is true, the winner can prove that the winner is safe.

The check transaction can be called when the current time is the release date, and calls the chain code to determine the winner. When the check transaction is called, the target block to be used as a random source must be issued. Otherwise, it fails. If the target block is issued, the hash value of the block is read and the winner decision algorithm using the random source is called. The winner decision algorithm operates in a deterministic manner if a random source is specified. In this implementation, the following winners are determined.

1. Assign a random hash value (X _i ) to each integer in [0, 1, ..., number of participants - 1]. In a (key, value) pair, the key corresponds to an integer, and the value corresponds to a hash.

2. X _i of 1 is calculated as follows. Let Y be the value calculated by using the random key and the target block hash assigned to the lottery event as keys and data of each SHA256-HMAC. The hash value computed using the concatenated value of the index (i) of the integer value as the input of SHA 256 is assigned to X _i at the end of the Y-converted string value.

3. Sort by the assigned (hash) value. And stores the result in an array.

4. It scans the ranking of the winners by the index sequence number of the array. For example, if there are two winners, the first index number is 1, the second index number is 2, and so on.

5. Participants are assigned a number in the order in which they first joined.

If the winner is determined in this manner, the Smart Contract will record the winner in the winner field of the lottery.

The check transaction also generates a verification key for further verification.

3 is a block diagram of a verification key derivation process used for verification.

3, for the integrity of the random source and the lottery information, the hash value of the three blocks immediately before the target block, the random key provided at the time of lottery registration, and the hash value of the SHA256 function Creates a hash of concatenated values. Then, the generated verification key (VerifiableRandomKey) is recorded in the verification key field of the lottery information and used by the verify transaction.

The verify transaction reproduces the integrity and lottery results of the recorded lottery information and verifies whether the winners match.

The verification key is generated according to the verification key derivation process of FIG. 3 and the verification key recorded in the check transaction is compared.

The verification key is finally constructed by concatenating the result string of HMAC and SHA256. The key of the HMAC is an initial random key, the hash function is SHA256, and the data to be used as a message may be three hashes immediately before the target block. Lottery information includes the name of the lottery event, the random key used to register the event, the date of issue, the date of registration, the date of registration, the number of winners, the list of winners, the number of participants, the list of participants, the target block number, .

The operation of the method according to an embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. The computer-readable recording medium may also be distributed and distributed in a networked computer system so that a computer-readable program or code can be stored and executed in a distributed manner.

Also, the computer-readable recording medium may include a hardware device specially configured to store and execute program instructions, such as a ROM, a RAM, a flash memory, and the like. Program instructions may include machine language code such as those produced by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like.

While some aspects of the invention have been described in the context of an apparatus, it may also represent a description according to a corresponding method, wherein the block or apparatus corresponds to a feature of the method step or method step. Similarly, aspects described in the context of a method may also be represented by features of the corresponding block or item or corresponding device. Some or all of the method steps may be performed (e.g., by a microprocessor, a programmable computer or a hardware device such as an electronic circuit). In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

In embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functions of the methods described herein. In embodiments, the field programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. Generally, the methods are preferably performed by some hardware device.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that it is possible.

Claims (1)

An apparatus and method for verifiable lotteries that satisfy fairness, transparency, invariance, and verifiability,
A device and method for a verifiable lottery that implements query, subscribe, check, verify, open transactions in a smart contract format using Hyper Leverage Fabric v1.0-alpha, a private blockchain platform.

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