以太坊智能合約並行化執行模型

自從2008年比特幣問世以來，以區塊鏈 (Blockchain) 技術為核心的去中心化帳本系統蓬勃發展。最初，在比特幣的世界中用戶可以自由的轉移他們的資產 (比特幣 Bitcoin) 在沒有中心化機構的情況之下，比特幣建立了虛擬世界中最可靠的金融系統，在互不信任的網路中，依然可以基於這樣的系統進行資產轉移。到了2013年，Vitalik Buterin 提出了新一代的去中心化帳本系統以太坊 (Ethereum) ，以太坊基於區塊鏈核心概念之上加入了圖靈完備的虛擬機，讓人們可以開發應用程式，並讓其在去中心化的環境下運行，這樣的程式也被稱為智能合約 (Smart contract)。如今的以太坊作為智能合約的執行平台已經十分成熟，各式各樣的去中心化應用程式 (Decentralized application, dapp) 都在以太坊上運作的非常好，但仍面臨著現行所有去中心化帳本系統都存在著的瓶頸，那就是可擴展性 (Scalability)。去中心化系統的可擴展性代表系統處理交易請求的能力，直觀上可以視為系統的效能或是產能，可擴展性也是區塊鏈技術目前最重大的課題之一。本論文主要目標為，在不更改現有以太坊架構的前提之下 (保留區塊及交易格式)，透過並行執行智能合約的方式提升以太坊智能合約的執行效率，以提升以太坊系統的可擴展性。

關鍵字

以太坊；智能合約；虛擬機；平行化；區塊鏈

並列摘要

Since the advent of Bitcoin in 2008, the decentralized ledger system, based on blockchain technology, has flourished. Initially, in the world of Bitcoin, users are free to transfer their assets (Bitcoin) without a centralized organization. Bitcoin built the most reliable financial system in the virtual world. In the network, that the users are not trust in each other, asset transfer can still be performed based on such the system. In 2013, Vitalik Buterin proposed a new generation of decentralized ledger system, Ethereum. Ethereum added a complete programming language based on the core concept of blockchain to enable people to develop applications on it. Users can develop their own application and let it run in a decentralized environment, such a program is also known as a smart contract. Today's Ethereum as a smart contract implementation platform is very mature, a variety of Decentralized applications are operating very well in Ethereum, but still face the bottleneck of all current decentralized ledger system, that is scalability. The scalability of the decentralized ledger system is mainly to describe the ability of the system to process transaction requests. It can be regarded as the performance or throughput of the system intuitively. The scalability is also one of the most important topics of blockchain technology today. The main goal of this thesis is to enhance the efficiency of Ethereum's smart contracts through parallelization without changing current Ethereum architecture (The block and transaction format remain the same). By this way, we can enhance the scalability of the Ethereum system.