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Comment by aakilfernandes | Hacker News Reader

I agree that lots of people who talk about blockchain don't understand how it works.

However, there is plenty of cool things to like about a blockchain without POW. A blockchain is just a database which broadcasts signed transactions over a p2p network.

Forging a blockchain requires a validator to sign two conflicting transactions. When that happens, you have undeniable proof of fraud which you can take to a judge.

Compare this to most databases where a sysadmin changes a few values and deletes the logs, no one would be any wiser.

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> A blockchain is just a database which broadcasts signed transactions over a p2p network.

That is certainly the definition some people seem to be using. However, that's not even remotely the innovative part of Bitcoin. If that definition of "blockchain" is acceptable, you might as well call git a blockchain.

What others consider to be the key innovation in Bitcoin is the combination into a self-feedback system of proof-of-work-mining (variable according to network power as determined by looking back at previous blocks), longest-chain-wins and the ever-growing-ledger with standard-rules-for-ledger-validity. The real genius is that this creates an incentive to mine while making double-spend impossible without 51% of the network (which is made difficult because others have an incentive to mine, and so it goes round).

The Wikipedia definition of "blockchain" appears to be a hashed chain of blocks (so basically git) with the addition of a selection-of-winning-branch algorithm. I'm not sure that's really generally accepted as the definition of "blockchain", though. The term seems to be suffering from inflation at the moment as everyone working on anything related to keeping a distributed ledger jumps onto the hype bandwagon.

This article is no better. It reduces the real innovation by referring to "known algorithms". Thus we don't even know what the author considers a definition of a blockchain to be!

> Compare this to most databases where a sysadmin changes a few values and deletes the logs, no one would be any wiser.

To me that screams "use off-site backups with different trust roots not sysadmined by the same sysadmin". Invoking "blockchain" here is unnecessary, and might unnecessarily confuse folks into adopting tech that doesn't solve their underlying problems.

But the average user has no idea whether a system is "using off-site backups with different trust roots not sysadmined by the same sysadmin." And even if it was like that at one time, they have no way of continually auditing the system to confirm that, at all times, that process is in place. And they have no idea that two sysadmins aren't in cahoots with each other.

That's not a good basis for a robust system.

The whole point of a blockchain is to prevent double spending by untrusted parties. If you have to go to a judge to resolve your transaction then you're kind of missing the point of this entire experiment.

> Compare this to most databases [...]

What this misses for me is that once we step beyond the conventional database, there are many, many things besides blockchains.

So I don't think the right question is, "Is this better than a normal database?" I think it's "Is there a way we can solve the particular user needs with something simpler than a blockchain?"

Given that most of the commercial blockchain uses I've heard of involve some sort of trusted party or legal arrangement, I ask that question a lot. So far, I've never gotten a persuasive answer that blockchains are needed.

  When that happens, you have undeniable proof of fraud which you can take to a judge.

Only if you maintain a node on that network. Which is unlikely since companies will need full control to reverse txns.

I was pretty excited about tamper evident logging from some work I was doing (medical records). I haven't delved into the P2P/consensus part, but I could see how that might be useful too.

Apart from the currency, I haven't thought of another use case for PoW.

A buddy keeps pestering me about blockchain-based voting schemes, which eliminates the secret ballot (meaning: non-starter), but I got curious any way.

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