Blockchain is a decentralized and immutable append-only ledger. Smart contracts, the self-executing programs on blockchain, help build the Decentralized Finance (DeFi) markets. Front-running is the practice of benefiting from advanced knowledge of pending transactions. It impairs the fairness of DeFi ecosystem, leading to huge losses of honest participants. In this thesis, We present Flash Freezing Flash Boys (F3B), a blockchain framework that mitigates front-running with threshold cryptography. In F3B, transactions are encrypted with symmetric keys, which are collaboratively kept by a decentralized secret-management committee (SMC). Once the transactions are committed and immutable, the keys are reconstructed to execute the transactions. F3B hides the content of pending transactions so that adversaries cannot acquire information about them, thus mitigating frontrunning. Previous work using threshold encryption mitigates front-running with per-block encryption, which would fail when a transaction is not included in the expected future block. F3B solves this issue by adopting per-transaction encryption, ensuring that any uncommitted transaction remains encrypted and private, even when a huge network delay occurs. F3B is an execution layer front-running solution, meaning that it is independent of the consensus algorithms and compatible with existing blockchain networks and smart contracts. F3B is evaluated on a simulated Ethereum network, and proved to be a practical low-latency solution. F3B presents a negligible (0.026%) latency overhead with 128 SMC members, compared with the unprotected blockchain. / Blockchain är en decentraliserad och oföränderlig bilaga-endast reskontra. Smarta kontrakt, de självutförande programmen på blockchain, hjälper till att bygga decentraliserade finansmarknader (DeFi). Front-running är praktiken att dra nytta av avancerad kunskap av pågående transaktioner. Det försämrar rättvisan hos DeFi-ekosystemet, leder till enorma förluster av ärliga deltagare. I denna avhandling presenterar vi Flash Freezing Flash Boys (F3B), ett blockchain-ramverk som dämpar frontkörning med tröskelkryptografi. I F3B krypteras transaktioner med symmetriska nycklar, som hålls i samarbete av en decentraliserad hemlig förvaltningskommitté (SMC). När transaktionerna väl är genomförda och oföränderliga, nycklarna rekonstrueras för att utföra transaktionerna. F3B döljer innehållet i pågående transaktioner så att motståndare inte kan få information om dem, vilket minskar frontrunning. Tidigare arbete med tröskelkryptering minskar körning i förväg med kryptering per block, vilket skulle misslyckas när en transaktion inte ingår i det förväntade framtida blocket. F3B löser det här problemet genom att använda kryptering per transaktion, vilket säkerställer att alla oengagerade transaktioner förblir krypterade och privata, även när en enorm nätverksfördröjning inträffar. F3B är en exekveringslagers frontrunning lösning, vilket innebär att den är oberoende av konsensusalgoritmerna och kompatibel med befintliga blockchain-nätverk och smarta kontrakt. F3B utvärderas på ett simulerat Ethereum-nätverk och visade sig vara en praktisk lösning med låg latens. F3B presenterar en försumbar (0,026%) latensoverhead med 128 SMC-medlemmar, jämfört med den oskyddade blockkedjan.

The rise of cryptocurrencies has brought with it new math problems with new sets of constraints. The MEV problem entails solving for the ordering of pending trades that maximizes a block creator's profit. In decentralized finance, time is a big constraint, so an exhaustive search of all possible orderings is impossible. I propose a solution to the MEV problem that gives a near optimal result that can be solved in a reasonable amount of time. I layout the method and the formulas required for my solution. Additionally, I test my solution on synthesized data to show that it works as desired.

期貨交易法，事實上即為衍生性商品交易法，隨著衍生性商品發展推陳出新，在其高隱蔽與高槓桿的特性下，對於市場之波動甚至更甚於傳統基礎證券商品，而有管制之必要。我國於民國86年間訂定期貨交易法第107條內線交易禁止之規定，嗣又於105年11月9日為首次之修正，惟修正後仍有諸多疑慮，例如就連結至有價證券之期貨交易乙節，是否即已完全排除法規套利之誘因？而不區分連結之商品類型，一概適用期貨交易法是否妥適？又期貨交易法第107條部分體例如獲悉、消息成立等節，係採與證券交易法第157條之1相異之用語，適用上應如何解釋？就此，本論文交互對照證券交易法第157條之1之規定及比較法上美國之立法例，建議期貨交易法第107條在近期修正之目標上，應可就連結至有價證券之期貨交易增訂準用證券交易法內線交易禁止之規定，或將之參諸證券交易法第157條之1規定自期貨交易法第107條抽出獨立規範；另就諸如消息成立時點、定義、主觀要件等體例設計上與證券交易法統一，俾同時解決法規套利、法規漏洞以及規範解釋適用等疑義。 / With the frequent business and finance development, the concealment and leverage of derivative commodities are obviously higher than before. This shows the necessity and importance of the legal governance. Article 107 of the Futures Trading Act regarding the forbidden of insider trading was promulgated in 1997, and revised firstly in 2016. However, is the aforesaid amendment enough to eliminate the incentive of insider trading for the commodities derived from securities? Is the amendment which directly governs all kinds of futures trading without distinguishing by the nature thereof proper?And how to interpret the terms of “knowing”, “the establishment of information” of the Futures Trading Act since they are inconsistent with the Article 157-1 of the Securities and Exchange Act? For those aforementioned doubts, referring to the Securities and Exchange Act and the United States law system, this study suggests that the Futures Trading Act may adopt the following revisions: 1. The futures trading derived from securities and commodities shall be governed respectively. 2. Those terms such as “knowing”, “the establishment of information” which are irrelevant with the nature of futures trading shall be consistent with the Securities and Exchange Act.