Caspar Schwarz-Schilling, Joachim Neu, Barnabé Monnot
Aditya Asgaonkar, Ertem Nusret Tas, David Tse
2021 · arXiv
Recently, two attacks were presented against Proof-of-Stake (PoS) Ethereum: one where short-range reorganizations of the underlying consensus chain are used to increase individual validators' profits and delay consensus decisions, and one where adversarial network delay is leveraged to stall consensus decisions indefinitely. We provide refined variants of these attacks, considerably relaxing the requirements on adversarial stake and network timing, and thus rendering the attacks more severe. Combining techniques from both refined attacks, we obtain a third attack which allows an adversary with vanishingly small fraction of stake and no control over network message propagation (assuming instead probabilistic message propagation) to cause even long-range consensus chain reorganizations. Honest-but-rational or ideologically motivated validators could use this attack to increase their profits or stall the protocol, threatening incentive alignment and security of PoS Ethereum. The attack can also lead to destabilization of consensus from congestion in vote processing.
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I don't think we'll see practical attacks against it until one of the important ones goes PoS. I definitely agree with that. I think that's where PoS has some real weaknesses Sure, attacks and mitigations for them are actively being researched. A couple of examples: https://ethresear.ch/t/change-fork-choice-rule-to-mitigate-b... https://arxiv.org/abs/2110.10086
I don't know why you were flagged, but if your question was in earnest: Bitcoin almost certainly won't move. Because those touted energy efficient protocols come at the cost of much weaker security guarantees which undermine a key point of Bitcoin. Proof of stake, the forerunner of energy efficient protocols, may work better for networks that have different aims, although smart contract oriented blockchains still need good security to be trusted. The stupendous levels of complexity involved in trying to hammer out proof of stake into a viable method of energy efficient mining make the approach look ever more unpromising. Ethereum keeps delaying the switch and the touted…
2022 migration has once again been kicked into the long grass after this paper from a few weeks ago: https://arxiv.org/abs/2110.10086 Lead to: https://nvd.nist.gov/vuln/detail/CVE-2021-42764 https://nvd.nist.gov/vuln/detail/CVE-2021-42765 https://nvd.nist.gov/vuln/detail/CVE-2021-42766
More recently Vitalik has said Ethereum PoS is at least a couple of years away, likely due to new attack vectors that require further research https://arxiv.org/abs/2110.10086, one of which enables an attack with only 0.09% of the total staked. It would have been foolish to fork knowing attacks like these are still being discovered. "with more than 99.6% probability, an adversary with 0.09% of total stake is in a position to execute a 1-reorg for any given day." Another which could prevent the chain moving forwards indefinitely. "an adversary controlling 15% of stake can stall PoS Ethereum"
"Recently, two attacks were presented against Proof-of-Stake (PoS) Ethereum: one where short-range reorganizations of the underlying consensus chain are used to increase individual validators' profits and delay consensus decisions, and one where adversarial network delay is leveraged to stall consensus decisions indefinitely. We provide refined variants of these attacks, considerably relaxing the requirements on adversarial stake and network timing, and thus rendering the attacks more severe. Combining techniques from both refined attacks, we obtain a third attack which allows an adversary with vanishingly small fraction of stake and no control over network message…
propagation (assuming instead probabilistic message propagation) to cause even long-range consensus chain reorganizations. Honest-but-rational or ideologically motivated validators could use this attack to increase their profits or stall the protocol, threatening incentive alignment and security of PoS Ethereum. The attack can also lead to destabilization of consensus from congestion in vote processing." https://arxiv.org/pdf/2110.10086.pdf
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