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The Taub Faculty of Computer Science Events and Talks

Theory Seminar: Proof-of-Useful-Work Blockchains
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Ilan Komargodski (Hebrew University)
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Wednesday, 09.07.2025, 13:00
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Taub 201

The recent emergence of Proof-of-Useful-Work (PoUW) consensus protocols [Komargodski,Schen,Weinstein'25] enable participants to reuse their *native* workloads (arbitrary matrix-multiplications) to secure blockchains as in Nakamoto's original Bitcoin protocol, allowing miners to earn external rewards. PoUW blockchains thereby give rise to a new economy where *both* data and compute are needed to efficiently mine the network.

In the first part of the talk, we will briefly describe the longstanding challenges of PoUW and how the protocol of [KSW'25] overcomes them. We then investigate and discuss the market dynamics and decentralization of PoUW cryptocurrencies. We extend the model of Fiat, Karlin, Koutsoupias and Papadimitrious (2019) to include external rewards, and analyze the resulting equilibrium. Our findings suggest that in some cases, miners with access to external incentives will optimize profitability by concentrating their useful tasks in a single block. We also point out initial directions for predicting the amount of useful-vs-nonuseful work done on chain, which dictates the energy savings of the KSW Blockchain.

Joint works with Yogev Bar-On, Itamar Schen, and Omri Weinstein
https://arxiv.org/abs/2504.09971