Siddiqui Shoeb Khaled received his MS in Computer Science and Engineering (CSE). His research work was supervised by Dr. Sujit Prakash Gujar. Here’s a summary of Siddiqui Shoeb Khaled’s MS thesis, Blockchain: Ecosystem, Security and Performance.
Blockchain technology has been one of the most disruptive innovations in the last decade. Blockchain is a decentralized, append-only trustworthy distributed database. It was invented to build Bitcoin — to democratize financial systems, in particular, currency. However, soon the researchers learned the power of blockchain to build smart contracts, programs that can execute and validate contracts, which otherwise were traditionally done through legal contracts. Since then, a plethora of applications have been envisioned using blockchain.
At the backend, miners are the ones who maintain the blockchain in anticipation of fair rewards. Bitcoin offers two types of rewards for the miners: (i) block rewards that halve every four years and (ii) transaction fees. Halving block rewards is done by making currency inflation-free. Transaction fees are optional. This can lead to stagnation of transactions and unprofitability for miners. Another challenge with Bitcoin or many other blockchains, to build real-world applications, is performance. Many times, improving performance in blockchain leads to different security issues.
In this thesis, we address both research challenges: (C1), how to configure the Bitcoin reward structure to maintain its ecosystem healthily as well as inflation-free. (C2), how to design a blockchain that is performant as well as secure. Towards C1, we propose BitcoinF, a simple modification to Bitcoin rewards that ensures fairness to the miners. We analyze it game theoretically. Towards C2, we propose QuickSync, a novel blockchain protocol that is faster than most of the secure blockchain protocols such as Bitcoin and Ourborous and retains all the security properties. We do security analysis for different attacks such as Sybil attacks and prove the robustness of QuickSync towards the attacks we studied.