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Comment by jordigh | Hacker News Reader

So what is going to replace miners? What incentive will people have to verify the integrity of this new blockchain? Is it still vulnerable to 51% attacks?

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When you know the participants PoW is just a waste. You can use something like round robin to determine who gets to add the next block. That means that no it's not.

Why do you even need blocks? If you trust each other, what's wrong with signed messages?

Less overhead in distribution and signed messages between individual parties doesn't allow third party(within the system ) auditing.

I can sign a message saying I am giving you $10 of Bank B's debt but there is no way with just signed messages for you to know I still have ownership of that debt.

That's not even a little true. Have you worked on finance code before?

What part isn't true?

I've worked in ETL at Morgan Stanley. So not only finance code. But their data systems.

The part about downloading entire databases to view your subset of the data. If this were an efficiency - SMTP would have blocks. Additionally, I am doubtful of your claim because information is the product of all hedge funds and investment banking operations - and to hand out your information to your competitors gives them tradable information at your expense. (Which youd know if you worked with any non-trivally finance operation)

>The part about downloading entire databases to view your subset of the data.

You're not doing this though you're downloading the entire database to verify the subset is true and you're using blocks because adding single transactions at a time when you need to have known ordering amongst a lot of participants leads to a lot of overhead that is removed by batching.

The type of information we're talking about isn't sensitive though(unless your going down the drain and trying to hide it). And yes I just made up that I worked in ETL at MS a department pretty much no one that hasn't worked in knows exists.

https://www.stellar.org/blog/stellar-consensus-protocol-proo... ?

But seriously, "OBC currently offers two implementations of PBFT (Practical Byzantine Fault Tolerant) consensus, as a means to validate transactions".

For consortium chains, one possible solution is mining diversity which enforces round-robin mining/creation of blocks.

http://www.multichain.com/qa/13/multichain-blockchain-mining

https://en.wikipedia.org/wiki/Proof-of-stake ?

https://en.bitcoin.it/wiki/Altcoin#Proof_Of_Stake

  Because these attacks exists, including Peercoin[3] and Blackcoin[4] proof of stake cryptocurrencies have "master" public keys that control the blockchain.

I wonder who would control that ;)

  This class of cryptocurrency is either insecure or centralized, however proof of stake (based on a PoW currency) is useful in some systems because gaining stake is costly, but it isn't workable for bootstrapping distributed consensus.

This would be an interesting though experiment. If they implemented proof of stake based on a proof of work currency, like Bitcoin, what would happen if the new currency took off and Bitcoin started to die? Now there's a threat model that requires unmotivated miners to still secure the network, both networks.

The pessimist in me says nothing, but we'll see.

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