JP7579041B2 - Points Trading System - Google Patents

Description

The present invention relates to a points trading system.

Low-power wide-area networks (LPWANs) have become a key technology for accessing the IoT in recent years due to their characteristics of low cost, low power consumption, long distance and multiple connections. At the same time, point trading systems, as a typical application technology for third-party payment, have attracted increasingly extensive attention from academia and industry. Therefore, the research and development of LPWAN point trading systems is of great practical importance.

For example, Non-Patent Document 1 describes how LPWAN is a communications technology that meets the requirements for IoT to access networks.

Ministry of Internal Affairs and Communications, “Key Points of the 2017 Information and Communications White Paper, Part 1, Special Feature: Data-Driven Economy and Social Change, Section 3: IoT-Oriented Information and Communications Industry (2) LPWA”, [online], [Retrieved January 14, 2021], Internet <URL: https://www.soumu.go.jp/johotsusintokei/whitepaper/ja/h29/html/nc133220.html>

With the rapid development of mobile IoT, many application-oriented third-party payment technologies are creating new IoT finance. As a typical application technology of third-party payment, the point trading system for application-oriented LPWAN has attracted wide attention.

However, current point trading systems basically use centralized data storage to maintain accounting data to ensure the integrity of the system. Centralized data storage can be a single point of failure, and insufficient data access performance can cause the server to become unavailable. Therefore, how to ensure data security is a major concern.

Ledger-based technologies are used to generate electronic currency and can be a good solution to the problem of centralized security. Specifically, a ledger is a database of assets that is shared across multiple sites, different geographic locations, or a network of multiple organizations. Furthermore, distributed shared ledgers are guaranteed by cryptography to be tamper-proof and impossible to forge. That is why distributed shared ledgers are most widely used in IoT finance.

However, the computing power of IoT terminal devices is generally low and they cannot perform large-scale computational processing.

In view of the above, the present invention provides a points trading system using a lightweight ledger for application-oriented LPWANs that fully guarantees data security and is suitable for IoT devices with low computing power.

The present invention comprises a point trading terminal and a low-power wide area communication network composed of a plurality of nodes, the point trading terminal transmits transaction data indicating the contents of a point transaction between users to a window node, which is one of the plurality of nodes, the window node refers to a ledger stored in the device, and when it confirms the validity of the transaction data, generates a candidate block to be added to the ledger in order to reflect the contents of the transaction data in the ledger, and after attaching a signature of the device to the candidate block, broadcasts it within the low-power wide area communication network, and among the plurality of nodes, broadcasts it from the window node. A node that receives the broadcasted block candidate verifies the signature attached to the block candidate, and if the validity of the block candidate is confirmed, it attaches its own device's signature to the block candidate and then broadcasts it within the low-power wide area communication network, and each of the multiple nodes collects at least a predetermined number of block candidates each attached with a signature of a different node, verifies the signature attached to each of the collected block candidates at least the predetermined number, and if it confirms that the contents of the block candidates at least the predetermined number match, it adds the contents of the block candidates at least the predetermined number to a ledger stored in its own device as correct increment blocks.

The present invention enables points transactions between IoT terminal devices within an LPWAN.

1 is a diagram showing an overview of the configuration of a points trading system according to an embodiment of the present invention. A diagram showing an overview of the ledger processing process performed in a points trading system according to one embodiment of the present invention. A diagram showing an example of an algorithm for a ledger processing process executed in a node within an LPWAN constituting a point trading system according to one embodiment of the present invention. FIG. 2 is a diagram illustrating a transaction flow when a user pays points to a store using the points transaction system according to one embodiment of the present invention.

According to market research firm Gartner, the number of IoT devices will reach 20.4 billion by 2020. As the number of IoT devices grows, managing them through traditional centralized models becomes costly and poses security risks. In contrast, the decentralized nature of ledger-based technology provides a means to achieve IoT autonomy.

When an IoT device is connected to a network, it needs to be authenticated to confirm the identity of the device. Applying ledger-based technology to IoT device authentication without using third-party devices can effectively reduce authentication costs, provide security for IoT devices, and prevent unauthorized device impersonation. It can also protect IoT devices from external attacks. In addition, by modifying the consensus mechanism of the ledger, it is possible to build a consensus network that is applied to IoT devices.

In an IoT environment, smart device nodes do not perform data computational tasks or proof of workload mechanisms, but only perform data encryption and transfer. That data transfer is broadcast to the entire network as a ledger transaction. Ledger-based technologies can build a way to track the unique history of each individual device by keeping a ledger of data exchanged between devices and users or network services. Ledger-based technologies can also make smart devices independent agents and manage their transactions separately.

In short, the application of ledger-based technology to IoT can establish a self-sustaining system that provides low-cost and secure operation for large numbers of IoT devices.

However, ledger-based technology has two serious problems. The first problem is that low system throughput leads to an infinite accumulation of unprocessed transactions in the network, increasing the average transaction processing time. In that case, ledger-based technology cannot be used in situations where real-time processing is required.

The second problem is that each validator node needs to independently maintain a complete ledger of historical data and corresponding state information, thus consuming a large amount of storage resources.

A variety of scaling techniques have been proposed to address the issue of low system throughput. However, most of these scaling techniques are unable to simultaneously address the three challenges of ledgers: security, decentralization, and scalability.

In response to this, fragmentation technology is considered to be an effective method for solving the three issues with ledgers.

To address the problem of consuming large amounts of storage resources, a pruning technique has been proposed. In this technique, historical data that is not useful for verifying transactions and blocks is deleted (prune) from some nodes, and only the verification state information is maintained. This method can effectively reduce the overall ledger size and the synchronization problem of historical data. However, although the ledger pruning technique can solve the problem of insufficient disk capacity due to historical data, it cannot solve the problem of insufficient memory capacity.

[Embodiment]
As a system for solving the above problems, we propose a lightweight ledger-based points trading system for LPWAN (hereinafter referred to as "points trading system 1") as one embodiment of the present invention.

The points trading system 1 achieves the following:
(1) Points can be easily traded between tags.
(2) The ledger strictly manages the balance of points. Since points can be used as a special currency for transactions under certain circumstances, it is important to be able to strictly manage the balance of points.
(3) By using LPWAN, points can be transferred even when a failure occurs. When a failure occurs, the Internet may be partially interrupted. Even in such a case, the LPWAN-based points trading system 1, which does not require physical contact, will operate normally.

The points trading system 1 can be operated in the following environment.
(a) The functionality of tags is limited. Tags in the system are battery-powered, and the frequency of battery replacement is low.
(b) The functionality of LPWAN nodes is also limited. LPWAN nodes have very low computing power and very small storage capacity.

The points trading system 1 is a payment system that functions both in normal times and in times of disaster. In the points trading system 1, point transactions at each event can be traced using a distributed ledger. In the points trading system 1, the construction of a ledger prevents transaction data from being tampered with, ensuring high reliability.

Figure 1 is a diagram showing an overview of the configuration of a points trading system 1. In the points trading system 1, various tags can be connected to a points trading terminal (e.g., a smartphone) via Bluetooth. In the points trading system 1, an LPWAN window node is also connected to the points trading terminal via Bluetooth.

In the points trading system 1, in order to ensure the immutability and security of the entire system ledger, and taking into account the low computing power of LPWANs, a consensus with a low processing load that is a simplified version of PoA (Proof of Authority) is adopted.

The points trading system 1 provides services to external business systems through an open API. In general, users of the business system are divided into business administrators and general users (hereinafter simply referred to as "users"). Users can obtain points (e.g., community promotion points, disaster compensation points, etc.) from the business administrator.

The user carries a tag and a points trading terminal. The tag functions as an identifier for the user. The points trading terminal (e.g., a smartphone running a points trading app) has the ability to search the points balance in the user's account and make payments with points.

Users can use the search function on the points trading terminal to check their points balance, details of points transactions, and the history of orders they have been involved in.

Users can place various orders using the ordering function of the points trading terminal. Points trading begins with the registration of an order. When a user completes a series of operations for registering an order in the business system, the business system calls the transaction system API to create an order indicating information such as the user's ID to be paid, the recipient's ID, the points for the transaction, the order time, and the expiration date. The transaction system verifies each parameter included in the order, confirms its validity, and then assigns a unique order ID to the order.

When the user performs an operation to instruct the payment of points for an order created as described above, the business system receives the order ID and causes the transaction system's payment page to be displayed on the points transaction terminal. After the user confirms that the points to be paid on the payment page are correct, the user performs an operation to execute the payment, and the payment is completed.

When payment is completed, the transaction system displays a specified page of the business system on the points transaction terminal. The payment result is sent to a pre-set URL as an asynchronous notification. Payment can also be made at offline shops where order processing is not performed.

Business administrators are organizations that provide a point system to users. Business administrators are divided into network administrators and point system administrators. Network administrators have the authority to add new legitimate nodes to the system.

The distributed ledger-based network system used in the points trading system 1 has an interface prepared so that it can be used for services other than the points trading service.

In the point trading system 1, all nodes hold a ledger containing the same data, just like the Bitcoin blockchain. In the Bitcoin blockchain, PoW, which requires high-load calculations, is adopted as the consensus protocol, but PoW is not suitable for resource-limited environments. Therefore, the point trading system 1 uses a new consensus protocol that is similar to PoA (Proof of Authority) but is lightweight (light in calculation load, communication load, storage load, etc.) by making a nearby trusted node the authority.

Figure 2 is a diagram showing an overview of the ledger processing process carried out in the point trading system 1. When a window node (N0000) confirms the validity of transaction data (hereafter referred to as "transaction"), which is data indicating the contents of a transaction received from a point trading terminal, it refers to the existing ledger and generates incremental block candidates (hereafter referred to as "block candidates") to be added to the ledger in order to reflect the received transaction in the ledger, and broadcasts the block candidates after assigning its own device's unique signature.

A node (e.g., N0001, N0002, N0003) that receives a block candidate from the window node (N0000) forwards the received block candidate to other nodes and verifies the signature of the window node (N0000) that is attached to the received block candidate. If the validity of the block candidate is confirmed, the node assigns its own unique signature to the block candidate and then broadcasts it.

A node that receives a block candidate (signed by N0000) broadcast from a window node (N0000) via another node also performs the same processing as a node that receives a block candidate (signed by N0000) directly from the window node (N0000).

When the window node (N0000) is able to collect block candidates, each signed by a different node, from a majority of all nodes (N or more), it confirms that the contents of the collected block candidates match, and then adds the block candidate to the ledger as a correct increment block. Similarly, when other nodes are able to collect N or more block candidates, each signed by a different node, it confirms that the contents of the collected block candidates match, and then adds the block candidate to the ledger as a correct increment block.

Figure 3 shows an example of an algorithm that causes a node to perform the above process.

Figure 4 is a diagram illustrating the flow of a transaction when a user uses the points trading system 1 to receive a service (or purchase a product) at a store and pays points to the store in return.

A user carries a portable device (IC tag) equipped with a display as a tag. When a user receives some service (or purchases a product) at a store and pays, for example, 10 points to the store in return, (1) the portable device first broadcasts its ID via Bluetooth. Next, (2) a smartphone owned by the store receives the ID broadcast from the portable device and identifies the user of the portable device. The identified user is displayed on the screen of the smartphone owned by the store and confirmed by a store clerk (service provider).

Next, (3) a transaction for a payment request of 10 points is sent from the store-owned smartphone to the portable device. (4) In response to receiving the payment request transaction, the portable device displays a screen on the display prompting the user to agree to the payment of 10 points. On this screen, the user performs an operation to agree to the payment of 10 points. (5) In response to that operation, the portable device affixes a signature to the transaction and then sends the transaction to the store-owned smartphone. (6) The store-owned smartphone registers the signed transaction in the LPWAN. (7) In response to the registration, the store-owned smartphone receives a notification of registration completion from the LPWAN.

[Modification]
The points trading system 1 according to the embodiment described above may be modified in various ways within the scope of the technical concept of the present invention. Examples of such modifications are shown below.

(1) In the above-described embodiment, block candidates are generated only by the window node (N0000). Alternatively, each of the multiple nodes may generate block candidates. In this modified example, for example, the window node (N0000) assigns its own unique signature to the transaction received from the points trading terminal and broadcasts it.

Each of the multiple nodes that receive a transaction forwards the received transaction to the other nodes and verifies the signature of the window node (N0000) attached to the received transaction. If the validity of the transaction is confirmed, the node refers to the existing ledger and generates a candidate for an incremental block (block candidate) to be added to the ledger in order to reflect the received transaction in the ledger. The node then assigns its own unique signature to the block candidate and broadcasts it.

When each node, including the window node, can collect block candidates with signatures from a majority of all nodes (N or more), it confirms that the contents of the collected block candidates match, and then adds the block candidate to the ledger as a correct incremental block.

In this variant, block candidates are generated by multiple nodes, so even if an error occurs in generating a block candidate, the erroneous block candidate will not be added to the ledger.

(2) In the above-described embodiment, if each node can collect the majority of block candidates (each with a signature from a different node) from all nodes, it adopts those block candidates with matching contents as incremental blocks and adds them to the ledger. When each node adopts a block to add to the ledger, the number of block candidates to be collected is not limited to the majority. For example, the threshold for the number of block candidates to be collected may be a number less than the majority (e.g., 40% of the total number of nodes).

Even if the number is less than half, if a certain number or more nodes recognize the same block candidate as valid, it may be acceptable in practice to consider the block candidate to be legitimate. In such cases, by reducing the threshold for the number of block candidates to be collected, processing delays are less likely to occur even in networks with constraints on communication speed, the amount of data that can be transmitted, etc.

1...Point trading system

Claims (1)

The present invention comprises a point trading terminal and a low-power consumption wide area communication network composed of a plurality of nodes,
the point trading terminal transmits transaction data indicating details of a point trading between users to a window node which is one node of the plurality of nodes;
the window node refers to a ledger stored in its own device, and when it confirms the validity of the transaction data, generates a candidate block to be added to the ledger in order to reflect the contents of the transaction data in the ledger, and broadcasts the candidate block within the low-power wide-area communication network after attaching a signature of its own device to the candidate block;
Among the plurality of nodes, a node that receives the block candidate broadcast from the window node verifies the signature attached to the block candidate, and if the validity of the block candidate is confirmed, attaches a signature of the own device to the block candidate and then broadcasts it within the low power consumption wide area communication network;
A points trading system in which each of the multiple nodes collects a predetermined number of block candidates, each of which is assigned a signature from a different node, verifies the signatures assigned to each of the collected block candidates, and if it confirms that the contents of the block candidates match, adds the contents of the block candidates as correct increment blocks to a ledger stored in the node itself.