What is the key difference between the Proof of Activity proposal and Proof of Stake?

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coblee (Litecoin creator) suggested a new Proof of Activity method, to complement Proof of Work, instead of using Proof of Stake (oh my!)

Can someone provide a tl;dr of what is the key problem in PoS that PoA is trying to solve, and how does it solve it?

ripper234

Posted 2012-09-17T08:15:53.897

Reputation: 25 192

Answers

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From what I understand, Proof of Activity and Proof of Stake are methods of preventing a 51% attack.

Proof of Stake basically means that the people that hold the most coins sign the blocks that will be part of the block chain. This means that the people that have the most to lose from a 51% attack will do their best to prevent it and not risk losing their money. However, this also means that the rich users can control the network.

Proof of Activity from what I gather is a method of selecting a random peer from the entire network to sign a new block that would be temper-proof. This would mean that a 51% attack could not execute too well, as it couldn't predict who the signing peer be in the future.

The latter idea appears to be better for preventing attacks on the network, providing there are no logical problems in there. However, I have not studied either of the two methods in greater detail so I might be wrong.

ThePiachu

Posted 2012-09-17T08:15:53.897

Reputation: 41 594

So would it be correct to say that "In PoA a single output/satoshi is selected every block that has the permission to sign it (but doesn't have to)" and "In PoS multiple signatures/votes are allowed every 'Stake block', and these votes are tallied to resolve conflicts" ? In PoA, we randomly appoint a dictator per block (by BTC ownership weight), while PoS uses a majority vote. If this is indeed the difference, I'm not sure why this difference makes PoA so much better than PoS.ripper234 2012-09-17T20:27:38.490

@ripper234 I guess that PoA is less centralised and doesn't rely on some key people to be present, whereas in PoS you put the future of the project in the hands of just a few individuals.ThePiachu 2012-09-17T22:42:56.907

Then I don't understand. What in PoS makes it more centralized?ripper234 2012-09-18T05:04:49.300

@ripper234 Relying on a few key users to be present to sign the new blocks. Those key entities could be targeted and if they all become compromised, your network could shut down.ThePiachu 2012-09-18T06:18:20.787

In what way does PoS "rely on a few key users" and PoA does not?ripper234 2012-09-18T06:25:26.423

@ripper234 From what I gather, in PoS the richest keypairs are used to sign new blocks (for example, StronCoin's "millionaire accounts"), whereas in PoA random active keypairs are used to sign the blocks. I might be wrong on this, however.ThePiachu 2012-09-18T06:54:13.770

let us continue this discussion in chat

ripper234 2012-09-18T08:06:04.480