隨著區塊鏈的技術和越來越成熟，人們可以更容易地在區塊鏈上部署智慧合約或開發應用。組織或公司可以根據自己的需求來更改區塊鏈的框架和管理方式，但與其他組織或公司的區塊鏈會因爲框架的不同而難以同步或共識。目前不同的組織和公司要透過區塊鏈共識必須要大家都加入同一個區塊鏈，違背了各個組織或公司要因應各自的需求來自訂區塊鏈，形成了兩難的處境。爲了滿足不同自訂區塊鏈之間可以傳遞資料的需求，跨鏈的技術現在處在開發和研究階段。
本篇論文提出了動態生成虛擬區塊鏈網絡的分散式跨鏈交易機制可用於各種異質區塊鏈之間，以不犧牲太多效能的前提下讓雙方的區塊鏈可以在跨鏈交易中取得共識，並且儲存跨鏈交易的記錄以便日後可以驗證交易的有效性和可追蹤性。由於模組化的設計讓這項機制能夠用於任何的區塊鏈網絡上。最後實驗環境下得證本機制可以在33秒內完成跨鏈交易，適合可以在實際環境下運作，並和側鍊的方法相比起來有更低的運算成本。本機制適合給不常有跨鏈需求的區塊鏈。

With the rapid development of blockchain techniques and support services based on blockchain conceptions are generally stabilized, people can easily implement fintech, smart contracts, and other decentralized applications with blockchain. To achieve long term usage of blockchain technology, organizations and companies should customize their management strategies according to their specific culture and goals. Though blockchain enabled the possibility to work as a platform for multiple parties to participate with, integrated blockchain frameworks are still under development and research.
This thesis proposes a heterogeneous blockchain mechanism for decentralized cross-chain transactions. By utilizing dynamically generated virtual blockchain mechanism, both consensus of cross-chain data and perpetuation of evidence issues, traceability, can be achieved without sacrificing too much computational resource. Due to the modular design, this mechanism is ably implementable to any blockchain. The experiment result show that a cross-chain transaction finished in 33 seconds, feasible in real world scenario, and had lower computational cost than side/relay chain approach, more suitable for blockchain that not always has requirement for cross-chain transaction.

Table of Content

摘要 I
Abstract IV
Acknowledgement V
Table of Content VI
List of Figures VIII
List of Tables IX
Chapter 1 Introduction 1
Chapter 2 Preliminary 6
2.1 Blockchain 6
2.2 Blockchain Projects 9
Chapter 3 Related Work 11
Chapter 4 Proposed Framework 21
4.1 System Structure 22
4.2 Message Queue Channel 25
4.3 Service Registration 26
4.4 Cross Blockchain Transaction Preparation 28
4.5 Cross Blockchain Transaction 30
4.6 Dispute Resolving Process 33
4.7 Smart Contract and Decentralized Application 35
Chapter 5 Experiment and Analysis 37
5.1 Performance Experiment and Analysis 37
5.2 Security Analysis 43
5.3 Discussion 46
Chapter 6 Conclusion and Future Work 48
Appendix 54

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