去中心化數位貨幣交易記錄與查詢服務：設計與以太坊實作

Abstract

在這個數位崛起的時代，區塊鏈是這個時代所造就的新興科技。隨著區塊鏈的發展日漸成熟，該技術也逐漸在金融、物流、穩定幣等各個層面衍生出多樣化的應用與服務。它透過密碼學與分散式系統技術，使區塊鏈中的所有節點彼此交換訊息並共同維護鏈上資料（如交易帳本）。隨著時間的推進，區塊鏈中的資料與交易量不斷成長，因此，如何於龐大的區塊鏈中取得數位貨幣交易紀錄，已成為實務應用上必須面對的問題。為此，本論文設計一去中心化數位貨幣記錄與查詢服務。此服務實作於私有鏈之智能合約中，利用跨鏈技術（見證人模式與中繼者模式）存取於公有鏈上之交易資料，並於智能合約中使用Binary Search演算法，提升「區塊範圍查詢」、「時間範圍查詢」功能之效率。最後，本論文將透過Geth建構此去中心化數位貨幣記錄與查詢服務，並架設一網頁介面以呈現服務內容。

Blockchain is a novel technology, and it has diverse applications and services in various fields such as finance, logistics, and stable coins. Blockchain uses cryptography and decentralized system technology to enable all nodes in the blockchain to exchange messages with each other and jointly maintain chain data such as transaction ledgers. As time progresses, blockchain stores a massive amount of data. Thus, searching data has become an important problem. Therefore, we design a decentralized digital currency tracing service, which is implemented in private blockchain smart contracts. For private blockchain smart contracts to access blockchain that stores the transaction data, we use cross-chain technology such as notary schemes and relays. In addition, we apply binary search to improve the efficiency of our searching functions, including block range query and time range query. Finally, we have implemented our system on Geth, and setup a website to demonstrate our service.