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Attestations don't have a real world economic cost that can be validated trustlessly within the system. If you compromise or coerce enough validators, you can r

Attestations don't have a real world economic cost that can be validated trustlessly within the system. If you compromise or coerce enough validators, you can rewrite the history for no cost. That's what PoW provides that PoS just doesn't. Immutability. In fact, I would argue that one of the most important products of bitcoin, is providing the hardest, most immutable database human civilization has ever created. We could theoretically lose it and we could control and manipulate what goes into it going forward, but once a piece of data gets confirmed and buried under a few days worth of bitcoin's PoW, it can never be changed or removed from the blockchain. This is a severely undervalued use case in my mind. I suspect that most PoS coins will eventually decide to periodically peg themselves into bitcoin's blockchain to timelock their blockchains and provide some immutability to their users. Having said that, humanity probably only needs one PoW blockchain. Bitcoin.

pshc 5y ago
I have to say I appreciate your transparency in directly Bitcoin shilling. > If you compromise or coerce enough validators, you can rewrite the history for no cost. If you can. You would need to compromise thousands of randomly selected validators just to forge one block. That impossible task nonwithstanding, the validators are selected with maybe five minutes’ warning. PoW doesn’t even offer absolute immutability, it’s just longest fork wins. Which is secure because of the economics, not because of a notion of perfect immutability. Likewise, ETH2 provides a definition of finality that’s backed by economics.
- deleted 5y ago
  [deleted]
- vesinisa 5y ago
  Exactly. These PoS FUDers fail to realize that largely the same, even if not stronger, economical factors protect the PoS as does the PoW blockchain. Both fundamentally rely on that 50% of validators need to be honest. With PoW, anyone with sufficient computational resources can execute a 50% double spending attack. I am sure that if few of the largest BTC miners conspired, they could right now execute a 50% attack. That's not in their best interest however, as it would permanently ruin the reputation of BTC and they'd be left with whatever proceeds the attack yielded, but also millions of USD worth of mining equipment that'd be rendered largely useless. With PoS exactly the same works. Most of the holders should be honest, and a successful attack would require spending at least 50% of the market cap of the coin to successfully execute - and then losing that stake as the reputation of the coin is soiled.
tylerhou 5y ago
> but once a piece of data gets confirmed... it can never be changed or removed from the blockchain. But it can, in the exact same manner as described in this article: have an 51% attacker build up a long chain and hide it from the world; then publish it. PoW is vulnerable to exactly the same type of attack described in this article. In order to build a longer chain with non-negligible probability, you need to stake at least 51% of the pool.
- disiplus 5y ago
  no the difference is, to build a side chain you have to produce the work, work that has a real cost and takes time, remember in POW the chain with most work wins.
ciphol 5y ago
"once a piece of data gets confirmed and buried under a few days worth of bitcoin's PoW, it can never be changed or removed from the blockchain." Could someone put child porn in the blockchain? Would that have legal consequences for anyone using Bitcoin in places that have laws about such porn?
- paulgb 5y ago
  Some researchers found some legally questionable content already in there. https://fc18.ifca.ai/preproceedings/6.pdf https://fc18.ifca.ai/preproceedings/6.pdf

pshc 5y ago

I have to say I appreciate your transparency in directly Bitcoin shilling. > If you compromise or coerce enough validators, you can rewrite the history for no cost. If you can. You would need to compromise thousands of randomly selected validators just to forge one block. That impossible task nonwithstanding, the validators are selected with maybe five minutes’ warning. PoW doesn’t even offer absolute immutability, it’s just longest fork wins. Which is secure because of the economics, not because of a notion of perfect immutability. Likewise, ETH2 provides a definition of finality that’s backed by economics.

deleted 5y ago
[deleted]
vesinisa 5y ago
Exactly. These PoS FUDers fail to realize that largely the same, even if not stronger, economical factors protect the PoS as does the PoW blockchain. Both fundamentally rely on that 50% of validators need to be honest. With PoW, anyone with sufficient computational resources can execute a 50% double spending attack. I am sure that if few of the largest BTC miners conspired, they could right now execute a 50% attack. That's not in their best interest however, as it would permanently ruin the reputation of BTC and they'd be left with whatever proceeds the attack yielded, but also millions of USD worth of mining equipment that'd be rendered largely useless. With PoS exactly the same works. Most of the holders should be honest, and a successful attack would require spending at least 50% of the market cap of the coin to successfully execute - and then losing that stake as the reputation of the coin is soiled.

tylerhou 5y ago

> but once a piece of data gets confirmed... it can never be changed or removed from the blockchain. But it can, in the exact same manner as described in this article: have an 51% attacker build up a long chain and hide it from the world; then publish it. PoW is vulnerable to exactly the same type of attack described in this article. In order to build a longer chain with non-negligible probability, you need to stake at least 51% of the pool.

disiplus 5y ago
no the difference is, to build a side chain you have to produce the work, work that has a real cost and takes time, remember in POW the chain with most work wins.

ciphol 5y ago

"once a piece of data gets confirmed and buried under a few days worth of bitcoin's PoW, it can never be changed or removed from the blockchain." Could someone put child porn in the blockchain? Would that have legal consequences for anyone using Bitcoin in places that have laws about such porn?

paulgb 5y ago
Some researchers found some legally questionable content already in there. https://fc18.ifca.ai/preproceedings/6.pdf https://fc18.ifca.ai/preproceedings/6.pdf