金融機構在對顧客做Know-Your-Customer(KYC)流程的第一步就是蒐集及驗證顧客資料來確認顧客的身份。傳統的做法不僅耗時而且成本昂貴，雖然目前有多個基於區塊鏈提出的解決方案可以重複利用顧客資料，但大部分都會在過程中透露金融機構和顧客的關係。這個原因會影響到參加共享KYC資料平台的意願，因為在現實世界中金融機構之間具有業務競爭關係，他們都不希望在過程中洩露資訊使得自己的競爭力降低。

本論文提出雙盲KYC資料共享區塊鏈框架。框架中結合區塊鏈與IPFS技術。利用公會在聯盟區塊鏈中運行代理節點，並代理多家銀行執行區塊鏈交易，以便混肴銀行在區塊鏈上的身份。讓銀行間可以互相分享資料，而且在過程中不揭露身份，達成雙盲資料分享。授權分享過程和授權請求過程中利用授權書，保證經過顧客授權同意，銀行和公會才能執行資料分享，另外在過程中會有審計員進行自動化稽核。最後，我們針對不同銀行個數做授權請求流程的效能實驗，以及針對框架進行安全性分析。結果顯示，本框架能以安全且高效率的方式幫助銀行取得顧客在其他銀行留下的KYC資料。以總銀行數為32家的實驗來說，銀行以平均每個5MB檔案花費1.63秒的速度來取回32個KYC資料。

The first step in a financial institution's Know-Your-Customer (KYC) process is to collect and verify customer data and identify the customer. The traditional approach is not only time consuming but also costly. While several blockchain-based solutions can reuse customer data, most of them reveal the relationship between the financial institution and the customer during the process. This affects the willingness of participating in KYC data sharing platforms because, in the real world, financial institutions have a competitive business relationship with each other and do not want to be less competitive by revealing information.

This thesis proposes a double-blind KYC data sharing blockchain framework. The framework combines blockchain and IPFS technologies. It uses associations to run proxy nodes in consortium blockchains and execute blockchain transactions on behalf of multiple banks to mix the identity of banks on the blockchain. This allows the banks to share data without revealing their identities in the process and enables double-blind data sharing. The authorized sharing and requesting protocol utilize warrants to ensure that banks and associations can only perform data sharing with the customer's authorized consent. In addition, an auditor will conduct automated audits during the processes. Finally, we ran performance experiments of the authorized requesting protocol with different numbers of banks and performed security analysis on the framework. The results show that our framework helps banks to securely and efficiently get customer KYC data from other banks. In an experiment with 32 banks, the bank obtained 32 KYC files at an average speed of 1.63 seconds per 5MB file.

摘要 I
Abstract II
Acknowledgement III
Table of Contents IV
List of Figures VI
List of Tables VII
Chapter 1 Introduction 1
1.1 Background 1
1.2 Objective and Contribution 3
Chapter 2 Related Work 5
2.1 Preliminaries 5
2.1.1 Blockchain Technology 5
2.1.2 Smart Contract 7
2.1.3 InterPlanetary File System 8
2.2 Literature Review 9
Chapter 3 Proposed Framework 16
3.1 Framework Architecture 16
3.2 Smart Contact Design 21
3.3 Proposed Protocols 22
3.3.1 System Setup Protocol 23
3.3.2 Authorized Sharing Protocol 24
3.3.3 Authorized Requesting Protocol 27
3.3.4 Automated Auditing Protocol 36
Chapter 4 Experiment and Analysis 41
4.1 Experimental Environment and Prototype Implementation 41
4.2 Performance Analysis 43
4.3 Security Analysis 45
Chapter 5 Conclusion and Future Work 47
References 49

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