Presentation in PriTEM workshop, March 22-23, 2023, by Thiago Garrett from IFI, UiO
Abstract: Since Bitcoin's inception in 2008, blockchain technology has gained traction, sparked hundreds of cryptocurrencies, and received billions of dollars in investments. The most famous and widely adopted blockchain system, Bitcoin, is still based on Proof-of-Work (PoW), which is famous for its inefficiency and wastefulness. Proposing a block requires an enormous amount of computing power spent on finding a PoW solution that has no value outside of the blockchain ecosystem. However, due to the economic reward, this computing power has grown steadfastly over the years. Despite numerous attempts to replace wasteful cryptopuzzles with useful work and take advantage of the vasts amounts of computing power available in Bitcoin's network, no such system has been deployed yet. Where does state-of-the-art fall short, and can we still hope for such a replacement? Our work addresses this question systematically. We identify several PoW-based block proposal properties that are important to ensure a correct system operation. Our analysis reveals that usefulness directly conflicts with many important blockchain properties. Moreover, no alternative task or system design has been identified to satisfy all properties and completely replace cryptopuzzles.
Bio of Thiago Garrett: Thiago Garrett is a Postdoctoral Research Fellow at the University of Oslo, Norway. He has been working on various aspects of Distributed Ledger Technologies, from network to consensus and applications. He is also involved in projects related to low-latency Stream Processing in the Edge. More broadly, his research interests include Computer Networks, Distributed Systems, Distributed Ledger Technologies, and Experimentation Frameworks.