近年來由於區塊鏈技術以及智能合約的誕生，各式各樣的應用場景也越來越多，而這些應用已不再只是如同比特幣的單純轉帳如此單純，任何涉及資料儲存以及資產轉移的相關應用皆可透過區塊鏈進行實作，而區塊鏈技術最大的優點在於其能在去中心化的條件之下，依然保有資訊透明化、不可竄改且一致的特性，這不但對傳統的資料管理系統帶來了衝擊，也引起了人們對中心化管理系統的安全性有所反思。
目前二手車市場中的車輛資訊仍是中心化的發展模式，也就是車輛資訊皆掌握在中心化的二手車業者手上，並無法有效改善二手車之車輛資訊不對稱的情況，而一般消費者在接觸二手車買賣時，所獲得的車輛資訊仍是二手車商提供的二手數據，這些車輛數據並不透明且沒有竄改成本，因此這些二手數據的真實性、準確性、公平性就值得商榷。
為了解決上述的問題，本篇論文藉由區塊鏈技術打造一個可信任的車輛資料來源系統，此系統借助於可信任的第三方即時記錄包含事故事件、里程數、維修以及保養紀錄等車輛資訊到我們的平台上，再利用我們的平台將資料寫入區塊鏈中，透過區塊鏈其透明化以及資料不可竄改的特性來保持車輛資訊的完整性，使用者或買家可以輕易地透過我們的系統介面查詢相關車輛資料，避免接收到不實的車輛資訊，並消除在高單價的二手車市場中的交易紛爭。

Due to the emergence of Blockchain technology and smart contract, more and more application scenarios are available in recent years. These applications are no longer as simple as the transfer of Bitcoin, any application related to data storage and asset transfer can be implemented through Blockchain. The advantage of Blockchain technology is that it can keep the transparency, consistency and tamper-proof of data under the condition of decentralized environment, which not only brings impact on the traditional data management system, but also causes people to reflect on the security of the centralized management system.
The vehicle information in the market of second-hand vehicles is still centralized at present, that is to say, the information is all in the hands of the centralized second-hand vehicle dealers, and it cannot effectively improve the inconsistency of vehicle information in second-hand vehicles. The vehicle information obtained by customers is still the second-hand data provided by the second-hand vehicle dealers, and these vehicle data are not transparent and have no tampering cost, so the authenticity, accuracy and fairness of these second-hand data are worth discussing.
In order to solve the above problems, this paper builds a trusted vehicle data source system based on Blockchain technology. With the help of trusted third-party (e.g., maintenance plant and government branch) to record vehicle information (e.g., accident events, mileage, maintenance and other vehicle information) to our platform instantly, and then use our platform to write these data into Blockchain so the integrity of vehicle information can be maintained through the property of Blockchain, users or customers can easily query the relevant vehicle information through our system interface, avoid receiving fake vehicle information and eliminate the transaction disputes in the high unit price second-hand vehicle market.

Table of Contents i
List of Figures iii
1 Introduction 1
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Contribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Background 4
2.1 Introduce to Blockchain . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1 Decentralization . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.2 Transparency . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.3 Tamper-proof . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 History of Blockchain and Smart Contract . . . . . . . . . . . . . . . 7
2.2.1 Blockchain 1.0 - Primitive Blockchain Originated from Cryptocurrency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.2 Blockchain 2.0 and after - Ethereum: A Blockchain Platform with Smart Contract . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Decentralized Application . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3.1 Traditional Data Management System . . . . . . . . . . . . . 10
2.3.2 Decentralized Application System . . . . . . . . . . . . . . . . 13
2.3.3 Comparison between Traditional Data Management System and DApp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3 Related Works 16
4 System Design 19
4.1 Design Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1.1 Transparency of Vehicle Condition Information . . . . . . . . 20
4.1.2 Access Control of Smart Contract and Tamper-Proof of Blockchain Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1.3 User Friendly of Operation . . . . . . . . . . . . . . . . . . . 21
4.2 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.2.1 Vehicle Manufacturer . . . . . . . . . . . . . . . . . . . . . . . 22
4.2.2 Maintenance Plant . . . . . . . . . . . . . . . . . . . . . . . . 22
4.2.3 Government Branch . . . . . . . . . . . . . . . . . . . . . . . 22
4.2.4 Customer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2.5 Second-Hand Vehicle Dealer . . . . . . . . . . . . . . . . . . . 23
4.2.6 Authority Node . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.3 Life Cycle of Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5 System Implementation 26
5.1 System Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.1.1 Private Chain Setup . . . . . . . . . . . . . . . . . . . . . . . 27
5.1.2 User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2 System Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.2.1 Log-in Process . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.2.2 Operation of Customer . . . . . . . . . . . . . . . . . . . . . . 29
5.2.3 Operation of Vehicle Manufacturer . . . . . . . . . . . . . . . 30
5.2.4 Operation of Maintenance Plant . . . . . . . . . . . . . . . . 31
5.2.5 Operation of Government Branch . . . . . . . . . . . . . . . . 31
5.2.6 Operation of Second-Hand Vehicle Dealer . . . . . . . . . . . 32
6 System Evaluation 33
6.1 Gas Limit and Transaction Throughput . . . . . . . . . . . . . . . . 33
6.2 Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7 Conclusion 36
7.1 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.2 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Bibliography 38

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