Guy Goren

Guy Goren, Jorge M. Soares

In this paper, we analyze the finality of the Filecoin network, focusing on dynamic probabilistic guarantees of tipset permanence in the canonical chain. Our approach differs from static analyses that consider only the worst-case scenario; instead, we dynamically compute the error probability at each round using the live chain history, providing a more accurate and efficient assessment. We provide a practical algorithm that only requires visibility into the blocks produced by honest participants, which can be implemented by clients or off-chain applications without any change to Filecoin's consensus mechanisms. We demonstrate that, under typical operating conditions, the sought-after error probability of $2^{-30}$ is achievable in approximately 30 rounds, a 30x improvement over the 900 rounds that the network currently encodes as a fixed threshold. This finding promises to expedite transactions and enhance network efficiency, and lays the foundation for further analysis of other DAG-structured blockchains.

Guy Goren, Alexander Spiegelman

In this paper we revisit the mining strategies in proof of work based cryptocurrencies and propose two strategies, we call smart and smarter mining, that in many cases strictly dominate honest mining. In contrast to other known attacks, like selfish mining, which induce zero-sum games among the miners, the strategies proposed in this paper increase miners' profit by reducing their variable costs (i.e., electricity). Moreover, the proposed strategies are viable for much smaller miners than previously known attacks, and surprisingly, an attack performed by one miner is profitable for all other miners as well. While saving electricity power is very encouraging for the environment, it is less so for the coin's security. The smart/smarter strategies expose the coin to under 50\% attacks and this vulnerability might only grow when new miners join the coin as a response to the increase in profit margins induced by these strategies.