# Paper Challenges Slashing As Sole Defense Against Proof-of-Stake Attacks

By Simon Yoon

Canonical URL: https://www.tokenpost.com/news/technology/25919
Published: 2026-09-30T17:14:59.000Z
Updated: 2026-09-30T17:14:59.000Z
Section: Technology

> A theoretical model lets validators coordinate before signing conflicting messages and proceed only if their combined stake reaches a required threshold.

A theoretical paper published Sept. 24 argues that proof-of-stake networks may not be able to rely on slashing alone to deter coordinated equivocation attacks, challenging a core assumption behind crypto-economic security.

The paper, titled “Too Late to Slash: Coordinating a Risk-Free Equivocation Attack,” was written by Hao Chung and Chen-Da Liu-Zhang. It examines whether validators can coordinate before signing conflicting blocks or messages and commit to an attack only after enough stake has enrolled.

Slashing is intended to make equivocation costly. Validators that sign conflicting blocks or contradictory attestations can lose part of their staked assets and be removed from the validator set.

Under the paper’s proposed protocol, validators first register their willingness to participate through a public smart contract. The registration does not itself involve signing conflicting messages. After a public deadline, the contract checks whether enrolled validator weight has reached a required “monopoly threshold.”

If the threshold is not reached, the protocol aborts without equivocation. If it is reached, participating validators proceed with the coordinated strategy described in the model.

The authors say the strategy can form an ex post Nash equilibrium under standard double-signing rules, even when validators do not know in advance how many others will participate. In other words, the strategy can remain rational for participants after the outcome is known. The paper says the result applies to any positive attack gain, represented as ε > 0, however small it is relative to bonded stake.

“We challenge this rationale by constructing a risk-free coordination protocol for rational validators under algorithmic slashing,” Hao Chung and Chen-Da Liu-Zhang wrote.

The result is theoretical. It does not demonstrate an attack against Ethereum or another live proof-of-stake network, and the paper does not establish that the proposed protocol has been deployed. Its conclusion depends on validator rationality, successful coordination, execution of the smart-contract mechanism and the ability to reach the required stake threshold.

Ethereum’s proof-of-stake system allows validators to be slashed for proposing two blocks for the same slot or submitting contradictory attestations. For a validator with 32 Ether (ETH), the immediate penalty is 0.0078125 ETH, followed by a 36-day removal period. In a large correlated slashing event, the maximum penalty can reach the validator’s full effective balance.

Ethereum requires agreement representing two-thirds of total staked ETH for finality, while its design makes coordinated attacks costly through fork-choice rules, finality thresholds and correlation penalties.

The researchers also examine reporting rewards and anonymous enrollment under broader slashing rules. They say the coordination result can persist when participants post sufficient collateral.

“Thus, slashing alone does not guarantee economic security proportional to the value of bonded stake,” Hao Chung and Chen-Da Liu-Zhang wrote.