Judmayer, A., Stifter, N., Schindler, P., & Weippl, E. (2022). How much is the fork? Fast Probability and Profitability Calculation during Temporary Forks. In WWW ’22: Companion Proceedings of the Web Conference 2022 (pp. 467–477). ACM. https://doi.org/10.1145/3487553.3524627
Estimating the probability, as well as the profitability, of different attacks is of utmost importance when assessing the security and stability of prevalent cryptocurrencies. Previous modeling attempts of classic chain-racing attacks have different drawbacks: they either focus on theoretical scenarios such as infinite attack durations, do not account for already contributed blocks, assume honest victims which immediately stop extending their chain as soon as it falls behind, or rely on computationally heavy approaches which render them ill-suited when fast decisions are required. In this paper, we present a simple yet practical model to calculate the success probability of finite attacks, while considering already contributed blocks and victims that do not give up easily. Hereby, we introduce a more fine grained distinction between different actor types and the sides they take during an attack. The presented model simplifies assessing the profitability of forks in practical settings, while also enabling fast and more accurate estimations of the economic security grantees in certain scenarios. By applying and testing our model in the context of bribing attacks, we further emphasize that approaches where the attacker compensates already contributed attack-chain blocks are particularly cheap. Better and more realistic attack models also help to spot and explain certain events observed in the empirical analysis of cryptocurrencies, or provide valuable directions for future studies. For better reproducibility and to foster further research in this area, all source code, artifacts and calculations are made available on GitHub.
Verbesserung der Sicherheit von Informationsprozessen in Produktionssystemen: CDL SQI (CDG Christian Doppler Forschungsgesellschaft; CDG Christian Doppler Forschungsgesellschaft)
Austrian Federal Ministry for Digital and Economic Affairs National Foundation for Research, Technology and Development FFG FFG Horizon 2020
878835 878736 grant agreement No 826078 (FeatureCloud)
Computer Engineering and Software-Intensive Systems: 50% Information Systems Engineering: 50%