導入區塊鏈於票交所ACH業務系統

Design and Implementation of ACH Blockchain

林柏安(Po-An Lin)

指導教授 ： 廖世偉

國立臺灣大學/電機資訊學院/資訊網路與多媒體研究所/碩士(2017年)

https://doi.org/10.6342/NTU201702395

摘要

隨著區塊鏈技術的興起導入區塊鏈於金融交易變成金融科技裡很重要的題目之一。本研究係以票交所底下的ACH業務媒體交換業務為標的，導入區塊鏈系統。基於央行利用區塊鏈系統發行數位貨幣的前提假設下，研究新技術所帶來的系統、流程、業務模式之改變和與現行系統之比較分析。並藉由導入區塊鏈系統於票交所ACH業務之研究，試圖了解區塊鏈應用於金融交易時所可能面臨之困難與挑戰。
在本研究過程發展出兩種設計架構，分別為：使用Gcoin原生區塊鏈金流系統的交易即清算架構（設計架構一），和利用智能合約將清算和隱私進一步優化的混合清算架構（設計架構二）。以這兩種架構開發概念驗證之系統雛型，導入ACH歷史交易資料進行研究。並在最後提出現行業務與兩個設計架構的比較、導入區塊鏈系統之可行性分析以及若導入區塊鏈後票交所的營運模式之轉換建議。
導入區塊鏈後，原先需要T+1日才能完成清算的交易，變成可以在T日內即時完成。 並且交易帳本之安全性因為區塊鏈之不可篡改性而提升保障，系統在部分功能亦能提升至拜占庭容錯。然而，本研究亦發現，導入區塊鏈於ACH業務亦有一些問題：效率、隱私與導入區塊鏈之必要性。因區塊鏈之特性，對於交易需要較多的驗證，且為分散式系統，交易處理速度上較一般中心化系統慢。而交易隱私與速度亦有取捨，所以當需要有較好的隱私保障時，交易速度又會進一步下降。最後，本研究僅導入區塊鏈於單一業務與單一中心之系統，似乎較難發揮區塊鏈之優點，若有跨業務或多中心之應用場景，似乎是較適合區塊鏈應用之領域。

關鍵字

區塊鏈 ； 票交所

並列摘要

With cryptocurrency attracting the crowd’s attention, the underlying technology — blockchain has become one of the hottest topic in fintech field. This research focuses on introducing blockchain into the “Automated Clearing House (ACH)” business of Taiwan Clearing House (TCH), aiming to design an ACH blockchain system and to implement a POC (proof of concept) of it. Under the premise that the central bank would issue digital currency into blockchain system, the research should show what and how would introducing blockchain technology into ACH system change the current ACH business and system design. Meanwhile, with the research of introducing blockchain into ACH system, we hope to get a clearer picture of the benefits and concerns of using blockchain in financial transactions.
Two architecture are designed and developed during the research, with one using Gcoin tokens to handle near real time gross settlement (architecture 1) and the other using smart contract to improve privacy and to realize hybrid settlement model (architecture 2). To proof both architectures’ designs, historical ACH data are settled into the POC system, ensuring the system could transfer the original transaction format data into blockchain transactions. In the end, comparisons of models (including current ACH model and two research models), analysis on feasibility of ACH blockchain, and suggestions on role changes of Taiwan Clearing House are shown as main results of the research.
Current ACH system settles transactions at T+1 day. Under the design of this research, it can be done within T day, enabling faster settlement which takes only around few minutes (for blockchain confirmation) for each transaction. Meanwhile, with blockchain consensus, some part of the system can tolerate byzantine failure.
However, there remains several issues about introducing blockchain into ACH system: efficiency, privacy, and essentiality. Due to the nature of blockchain consensus, the system would not be as efficient as a centralized system when handling an abundance of transactions. The TPS (transactions per second) is usually slower than a centralized design. Secondly, blockchain shares all data around all nodes in the network, making privacy an issue of blockchain. Though one of our architecture design handles this with hybrid encryption, the overhead of the encryption further decreases the TPS of the system. Finally, it is doubted that is it essential to apply blockchain to a single business. It is hard to show the real value of blockchain under single business, such as being the trust platform. A scenario with multiple business sharing a blockchain platform might shines more light on value of blockchain and gain the essentiality of introducing blockchain into the system.

並列關鍵字

blockchain ； auto clearing house ； ACH

參考文獻

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