Disproof of Stake

Amoveo Editor
Sep 9, 2019 · 2 min read

Throughout the previous few weeks, Zack Hess has been on a mission to help PoS blockchains take steps to secure a critical flaw in their consensus design. Here is a summary of Zack’s campaign.

Those who have been around the cryptocurrency community are no strangers to the possibility of investing in projects that have the chance to fail catastrophically. Zack Hess has been streamlining a push to inform the blockchain community about the possible dangers of the increasingly popular PoS consensus mechanism.

Amoveo GitHub

Zack’s main argument for the vulnerability for the PoS consensus mechanism is found when a majority of participants establish control over a blockchain.

Using their combined ‘power’ through the stake they hold ‘the majority coalition can use soft forks to push through any changes to the consensus rules that they want, they can steal any money, they can raise the fees as high as they want.’ Zack’s argument is founded in mathematics, where he uses the tragedy of the commons as an argument to demonstrate his point.

The formula that Zack proposes could compromise a blockchain is straight forward:

LU = (how much the validators have to lock up)

#V = (how many validators are there)

Bribe = LU / (2 * #V)

Using this bribe, validators would be able to form a majority coalition, taking over a blockchain using a PoS consensus methodology, gaining the ability to steal from others on the network.

Zack has reached out to multiple projects looking to share his perspective on the vulnerabilities that Proof of Stake holds as a consensus mechanism. Some of the most prominent and popular projects include Cardano and Algorand both of which have tried to debunk Zack’s claims but have not been able to provide conclusive evidence against the vulnerability proposed by Hess’s model.

According to Zack, it would only take around $500,000 to corrupt a $1billion dollar PoS blockchain.

So far there has not been a project that has fully disproved Zack’s claims, but you can follow all of the counter-arguments here.

You can also read Zack’s thoughts on PoS and relevant blockchains on GitHub: Proof of Stake, Algorand, Ourobos.


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