My definition of "blockchain" is a distributed ledger in a entirely trustless p2p network. To which PoW is the most widely deployed mechanism in use to secure against the double spend problem. Pow being a mechanism that remains un-superseded inspite of significant efforts to do so. All this making PoW hardly orthogonal.
Of course this definition of a "blockchain" can be loosened. One of two tweaks and suddenly we need to label prosaic everyday items such as a git repos as "blockchains".
At which point it becomes difficult to even have conversation about "blockchains" since our industry has yet to bring to bear a sufficient amount of focus to even define the term with any sort of useful precision.
Also, by saying "blockchain is a terrible solution", I assume you mean "there are other better solutions [to the problem of creating a decentralized ledger, or whatever]". What are those better solutions?
Proof of stake at this time is purely theoretical. It lacks strong proof that it solves the problem it sets out to solve. I personally doubt it is a viable solution and my belief it is a dead end avenue of research. Notable there are no large scale implementations yet, even eth rolled back the clock on POS.
Never heard of XRP before. Very briefly scanning, looks like a distributed consensus type protocol, which isn't anything new doesn't attempt to solve the core concern about decentralised trust. Realise am being a bit flippant here, I need to study more which I will, but this is my initial impression.
>> I assume you mean "there are other better solutions [to the problem of creating a decentralized ledger, or whatever]". What are those better solutions?
No I am not saying this at all. Why is it incumbent on me to solve this problem merely because I advance a critique of the current solution? Does my failure to bring an alternative to the table make my critique invalid? I don't think so. I have been puzzling over this problem space and exploring some ideas for alternatives. The problem is hard and honestly I am probably not smart enough to solve it. But the problems are interesting so I'll keep turning it over.
In terms of my thinking right now, I am not even confident that problems solved blockchains are even problems worth solving, that blockchains provide us, as a society, anything of value at all. Too much is given up: notably for example dispute resolution. Look at all the long parade of thefts and errors that have happened on Eth, the legacy to date of the idea of "the code is law" is problematic at best. To date I can only think of one real use case that has made me think blockchain/bitcoin is actually even useful : when US DoJ leaning on Visa/Mastercard to cutoff funding to Wikileaks, bitcoin provided good stopgap technical solution to this grotesque legal excess.
To save you some googling, it _does_ try to solve decentralized trust. It goes for a more traditional scheme, a variant of Byzantine agreement.
However, there was a dispute wherein David Mazières (of Kademlia fame) claims that Ripple's design has a flaw, that he fixed in SCP (Stellar Consensus Protocol), by designing FBA (Federated Byzantine Agreement) as described in his paper: https://www.stellar.org/papers/stellar-consensus-protocol.pd... (which features a comparative description with Ripple and Bitcoin).
Proof-of-work is designed to be inefficient -- to consume exactly as much power as the bitcoins produced from it are worth. The more efficient PoW is, the less energy it requires to rewrite history, which is exactly what we're trying to avoid.
That's not even vaguely close to true. Are you basing that on blockchain.info's retracted estimate?
All of them acknowledge difficulty in computation. It's like trying to solve the drake equation. Unless you know all the terms in the equation accurately the number at the end isn't terribly useful.
Many different computations seem to be in same order of magnitude.
The result of high energy consumption is unsurprising and intuitive, given the design principal of PoW. It's all about who is prepared to do the most work, up until economic limits set by current BTC rate.
(12.5 * 6) BTC/h * 2000 USD/BTC * (1/0.02) kWh/USD = 7.5 GW
Ok, that is a lot. Energy usage is on the order of a few million Americans. Sorry, I based my first reply on a debunk that doesn't sound accurate!
Firstly Proof of Work is incredibly energy inefficient, to extent that electricity consumed to append to public blockchains is comparable to electricity used by nation states.
Secondly POW by its inherent design recentralises trust. When mining evolves to deploying on ASIC and deploying it where electricity is cheap you are recentralising trust to a tiny few who are willing and able to fulfil the ever higher and steadily increasing bar that POW, by design, demands. The trust model at this point has evolved from technical difficulty of fabricating & maintaining long duration forked chains to one where key block creators are too financially invested in success of the chain overall to allow fraud to happen. At this point, when your trust model is essentially too much to loose to cheat, there are scant distinguishing features between a blockchain ledger and a traditional centralised clearing house.
To steal a line from a good book I read recently about blockchains: "The good bits of blockchain are not original, and the original bits of blockchain turn out to be much good."
[Edit: grammar / readability]