Why exactly is Bitcoin clinging to PoW?

[TangentC]

A double spend has never happened because it is simply not possible. Only one transaction or block made it through, there was a reorg, or something, but it was not spent twice.

Dude,
really.

A double spend is exactly that ,
User send btc, merchant accepts btc after in OKPAY case , Six freaking hours of confirmations,
blockchain is reorged to a new chain without that specific transaction.
So those coins were spend twice. ie: double-spend
Once with OKPAY and after the reorg with someone else.

That is the whole point to waiting for 1-3 confirmations, that a reorg should be impossible after 3 confirms in btc,
so in the case mention,  their was a doublespend with bitcoin.
Sorry if that hurts your bitcoin cultist beliefs, but it is absolutely true.

FYI:
https://www.reddit.com/r/Bitcoin/comments/1lhwcu/has_there_ever_been_a_successful_double_spend/

yes,
during the last fork a guy skrewed OKpay out of 10grand by reloading his keys and submitting a transaction into the new chain.

FYI2:
If you want blockchains that have never had any doublespends occur,
look no further than 3rd generation blockchain tech using Proof of Stake coins, Cardano & Algorand.   

[Lee_Mire]

First of all. I don't agree with MarsMan and I think what he is doing is straightforward market manipulation.

But one thing is o/c right in this whole mess. Proof of Work can't be Bitcoins destination. First of all one question is if it really still fulfills its function for decentralization. Is a system truly decentralized or distributed when there is already just a handful of groups that would just need to agree on common terms?

Energy might be another factor and important as well, so a less power hungry solution might be great, on the other side it could be very healthy to the renewables industry if all miners would be forced to use only green energy, since this would generate a significant amount of money flowing into those industries. But I don't see any technical way to really enforce that.

I am a long term user since Bitcoins inception, but I stopped following the development for some years now and hold most of my assets I bought for a few cents years ago and just do some trading from time to time. So I might be not up to date if there are efforts to move away from PoW. Can someone give me an update on this? If Bitcoin is not considering to move and evolve, what are your takes on this and why would one cling to much to PoW, just b/c of the hard fork it requires? Or are the alternatives still not mature enough?

POW is the only proven way to secure the network. Read the whitepaper and read into older implementations of fully decentralized e-currencies. Securing the network in a decentralized way and solving the byzantine problem is nothing short of a nightmare but somehow the genius that is Satoshi and the early devs solved it.  Anything else (POS, DAG, etc) is gravely experimental and bitcoin is nearly a $1 trillion network. It's not worth the risk. POW can be improved with greener mining solutions and increasing transaction throughput through L2, L3, etc. Overall POW is not a problem, it is a beautiful conception that has worked near flawlessly for over a decade.

[PrimeNumber7]

A double spend has never happened because it is simply not possible. Only one transaction or block made it through, there was a reorg, or something, but it was not spent twice.

The inability of someone to double-spend inputs is due to blockchain technology, not due to PoW, or Proof of whatever.

There have been many double-spends with unconfirmed transactions, in fact, RBF is a feature of bitcoin that allows users to double spend unconfirmed transactions. There have also been a handful number of double-spend transactions when there is a reorg, but this was due to the randomness of the timing of finding blocks, and that it just so happened that two miners found a block at the same height at approximately the same time that just so happened to include competing transactions.

I would argue that PoS blockchains have not seen as many double spends resulting from reorgs because 1) they see lower transaction volume, and 2) it is more difficult to get a double-spend transaction of an unconfirmed transaction to propagate throughout the network.

[NotATether]

User send btc, merchant accepts btc after in OKPAY case , Six freaking hours of confirmations,
blockchain is reorged to a new chain without that specific transaction.
So those coins were spend twice. ie: double-spend
Once with OKPAY and after the reorg with someone else.

Actually, it's not a double-spend in this case. Because the spending inputs are included in one transaction, but there is no second transaction to different outputs the spending inputs are in. A reorg is not transaction spending, because there is no spending initiated - the transaction inputs are still valid as if the first transaction never happened, in other words the first transaction was deleted. There was no second transaction at all, hence no double spend.

A double-spend would be if you submit a transaction to one miner, and then the same transaction but with different outputs to another miner and the two miners don't sync fast enough before a large number of nodes on both side have one of the different chain forks.

[TangentC]

**** No Double-Spends can ever happen in BTC. *****
       {The Bitcoiner Cult is strong with this one.}

Whatever floats your boat.  

[topcoin360]

User send btc, merchant accepts btc after in OKPAY case , Six freaking hours of confirmations,
blockchain is reorged to a new chain without that specific transaction.
So those coins were spend twice. ie: double-spend
Once with OKPAY and after the reorg with someone else.

Actually, it's not a double-spend in this case. Because the spending inputs are included in one transaction, but there is no second transaction to different outputs the spending inputs are in. A reorg is not transaction spending, because there is no spending initiated - the transaction inputs are still valid as if the first transaction never happened, in other words the first transaction was deleted. There was no second transaction at all, hence no double spend.

A double-spend would be if you submit a transaction to one miner, and then the same transaction but with different outputs to another miner and the two miners don't sync fast enough before a large number of nodes on both side have one of the different chain forks.

Reorganizing the blockchain to reverse a transaction is a fraud and it is possible to do it on btc's network. Definition of fraud by Google: wrongful or criminal deception intended to result in financial or personal gain.

[NotATether]

**** No Double-Spends can ever happen in BTC. *****
       {The Bitcoiner Cult is strong with this one.}

Whatever floats your boat.  

Nice paraphrasing with words I never said. I gave you a practical example of double-spending above.

Reorganizing the blockchain to reverse a transaction is a fraud and it is possible to do it on btc's network. Definition of fraud by Google: wrongful or criminal deception intended to result in financial or personal gain.

Yeah you're right about that. If miners knowingly include transactions inside a smaller chain when they are aware of a larger chain that exists, that is a perfect example of fraud against users (and also, buggy mining software that should be repaired ASAP) but from a metaphorical perspective to conventional fraud, in this case the fraud will also hurt the miners who will lose large sums of block reward BTC from submitting blocks to a shorter chain.

Because of the amount of money at stake and how difficult mining became, this is why you don't see miners pull of this kind of fraud. It would take a really dumb mining organization to risk millions of $$$ in block rewards just to play with people's transactions.

But normally the reason why a lot of temporary chain splits happen is because two miners who are far from each other on the peer graph find a block, broadcast it to their peers who are also far enough from the other set of peers such that they can't talk to each other quickly, and then one of the miners that are in these groups of peers finds a third block and extends one of the competing changes.

Since this type of occurrence can't be known in advance and is corrected by the network quickly, in no more than several minutes, it can't be described as fraud though. In this case, there's nothing a miner can do to prevent this kind of situation from happening except to connect to all the nodes which are attached to other miners. Whereas fraud is something that happens intentionally, as you said, not accidentally.

[PrimeNumber7]

User send btc, merchant accepts btc after in OKPAY case , Six freaking hours of confirmations,
blockchain is reorged to a new chain without that specific transaction.
So those coins were spend twice. ie: double-spend
Once with OKPAY and after the reorg with someone else.

Actually, it's not a double-spend in this case. Because the spending inputs are included in one transaction, but there is no second transaction to different outputs the spending inputs are in. A reorg is not transaction spending, because there is no spending initiated - the transaction inputs are still valid as if the first transaction never happened, in other words the first transaction was deleted. There was no second transaction at all, hence no double spend.

A double-spend would be if you submit a transaction to one miner, and then the same transaction but with different outputs to another miner and the two miners don't sync fast enough before a large number of nodes on both side have one of the different chain forks.

Reorganizing the blockchain to reverse a transaction is a fraud and it is possible to do it on btc's network.

A reorg to reverse a transaction is possible on any blockchain network. This is not specific to bitcoin. This remains true regardless of if PoW, or something else is implemented. A party wishing to reverse a transaction on a PoS blockchain for example would need to bribe a different set of stakeholders versus a PoW blockchain, but is still possible.

[Dabs]

So where is the double-spend again? I don't see it. Sorry. My boat already sunk. Lost all my bitcoins some time ago. We cultists always have boating accidents.

[TangentC]

So where is the double-spend again? I don't see it. Sorry. My boat already sunk. Lost all my bitcoins some time ago. We cultists always have boating accidents.

I showed you the double spend, the original article called it a double-spend, the reddit post called it a double-spend.

Everyone in the freaking universes calls it a double-spend, except for bitcoin cult members.

If part of being in the bitcoin cult makes you ignore reality, that is your problem , not mine.

I guess when the US bans bitcoin PoW mining in ~ 3 years for excessive power grid disruptions,
the bitcoin cult members will cry fud just like when China did for excessive power grid disruption.

[zbig001]

As a last resort, you can mine Bitcoin with totally ecological pencil and paper, reaching around 0.67 hashes per day 

http://www.righto.com/2014/09/mining-bitcoin-with-pencil-and-paper.html

But let's not be naive...
If the elite really cared about the environment, then they would order mining using only green energy sources instead of banning it completely, right?
I also think they know that in terms of DLT-based networks, Sybil-resistance and fault tolerance can quite well go hand in hand with centralization.

Bitcoin is still a resistance movement, not a cult.

[Dabs]

Where is the double-spend in the blockchain? It can not possibly be there. Can I see it on my own full node? I'm not a part of any cult, have no idea what you are trying to imply.

The reddit thread had these words in them:

Technically speaking the answer is no. No successful double-spend.

You are also saying the US will ban bitcoin mining in 3 years, just like China? I look forward to that. Maybe some things will change before then.

[TangentC]

Where is the double-spend in the blockchain?

Double-spends will Never show up on the Blockchain,
Because the Reorg overwrites the ORIGINAL transaction.
That is why it is a DOUBLE_SPEND!


FYI:
https://www.investopedia.com/terms/d/doublespending.asp

The greatest risk for double-spending comes in the form of a 51% attack, which can occur if a user controls more than 50% of the computing power maintaining the distributed ledgers of a cryptocurrency. If this user controls the blockchain they will be able to process transfer bitcoins to their wallet multiple times by
reversing the blockchain ledger as though the initial transactions had never occurred.

[Dabs]

Double-spends will Never show up on the Blockchain,
Because the Reorg overwrites the ORIGINAL transaction.
That is why it is NOT a DOUBLE_SPEND!

Fixed that for you. And yes, that is correct.

[TangentC]

(Clueless, just utterly clueless nonsense.)

Their is no hope for you.
You don't know anything.

 

[Dabs]

Their is no hope for you.
You don't know anything.

I have hope for you.

[franky1]

double spends:
the blockchain will never have 2 UXTO's (unspent transactions of the same parent)
block rejects/orphans ensure only 1 utxo is valid/remains

a double spend is not about onchain transactions existing in double..
but services that give away products at the sight of a zero-confirm/low confirm.. and then find that transaction disapears(never confirms, gets confirmed then orphaned).. so the service doesnt get paid

meaning the person(spender) has got the goods and kept the funds. via one version of his transaction dispearing

its about the service/retailer/recipient of funds not waiting for good confirms to guarantee they are paid before releasing goods/service.

[Dabs]

Yes, it would be wise to wait for a few or several confirmations. If you also know there is an upcoming hard fork or some other major upgrade, it would be wise to wait for a day or two worth of confirmations. Many exchanges suspend trading or withdrawals when everyone knew a fork or upgrade was going to happen, and not just to bitcoin but any other altcoin.

Double spent transactions will never exist on chain.

It's not that hard to understand. But, this is a little bit beyond the original topic already.

[DannyHamilton]

a double spend is not about onchain transactions existing in double..
but services that give away products at the sight of a zero-confirm/low confirm..

Nah.  That's no different than giving away products at the verbal promise of payment.

If I call you and say, I'll send you 0.01 BTC, please send me $300 worth of product, and then you send it without ever seeing the transaction that's not a "double-spend".  That's you making an assumption about how much you can trust my promise.

If I send you a transaction that isn't confirmed (or has very few confirmations), and then you send it without waiting for sufficient confirmations, that's not a "double-spend".  That's you making assumptions about how much you can trust an unconfirmed transaction.

The entire purpose of the blockchain (the only reason it exists at all) is so that the users of bitcoin can determine (among multiple transactions spending the same utxo) which transaction is the one-and-only "real" transaction. In other words, to eliminate the possibility of an actual "double-spend" where there are two (or more) transactions and no way to determine which is the real one.

If a transaction that is not in the blockchain is considered to be a "double-spend", then we can just get rid of the blockchain (and mining) entirely and move on with the acceptance that double spends happen.

Let's think about this in terms of cash.  It's impossible to "double-spend" cash, right?  If I give you a $10 bill, and you are holding on to it in your hands, there's no way for me to hand it to someone else at the same time and they believe that they are the sole possessor of that $10 bill.  However, if I deposit that $10 bill into a bank account and then write two people each a separate cheque for $10, does that mean that I "double spent" that $10?  No.  The bank will transfer the $10 based on whichever cheque clears first, and the other cheque will "bounce".  The $10 wasn't "double-spent", but the losing recipient of a cheque may have made a poor assumption about the trustworthiness of the cheque.

[TangentC]

Let's think about this in terms of cash.  It's impossible to "double-spend" cash, right?  If I give you a $10 bill, and you are holding on to it in your hands, there's no way for me to hand it to someone else at the same time and they believe that they are the sole possessor of that $10 bill.  However, if I deposit that $10 bill into a bank account and then write two people each a separate cheque for $10, does that mean that I "double spent" that $10?  No.  The bank will transfer the $10 based on whichever cheque clears first, and the other cheque will "bounce".  The $10 wasn't "double-spent", but the losing recipient of a cheque may have made a poor assumption about the trustworthiness of the cheque.

The double spend that we were originally reference had 6 hours of confirmations.

And yes Cash can be double spent,
If I give you a $10 bill for a soda, and you are holding on to it in your hands,
Then I slap you upside your head and Take the $10 back and keep the soda,
then walk down the street, and buy some candy with that $10 , I just double-spent that $10,
and the only proof I did so is that knot on your head.  


FYI:
Think of it as a 51% butt kickin.
As I was 51% stronger than you to take the cash back.