Bitcoin Forum

My answer: No!

My argument: By definition, bitcoin is a solution to the double-spending problem:

The way Satoshi puts it in the very first line of the white paper, as a solution, bitcoin is immune against, rather than resistant to, double-spending. Double-spending makes digital cash absolutely worthless because of its potential to suffer from unregulated inflation. Bitcoin is safe against such inflation inherently and it is not because of PoW on top of or game theory behind bitcoin. In its most vicious (and ignorant) way of malfunctioning, a majority of hash power could defraud single users and won't be able to create bitcoins out of nowhere.

Misinterpretation: A majority of hash power collided is claimed to be a double-spending threat to bitcoin because of the sole power of chain-reorgs that let them defraud users. Yet it is not a proper classification of this threat as such practices are bound by cost/incentive tradeoffs according to the game theory employed by bitcoin.

My take (which is a surprise somehow):
Unlike what is said ever and ever, one could put trust in miners as long as there is proof that:

• Miners are not inflating the supply illegally,
• The costs involved in defrauding him/her (personally) by re-org attacking the bllockchain are orders of magnitude higher than the assets he/she has put in stake.
  

This is the fundamental principle behind a hierarchical sharding scheme which I'll propose later.

Bitcoin is not a perfect solution to the double-spending problem, so there is always a threat.

The security of Bitcoin depends on financial incentives, specifically the assumption that the participating parties try to maximize their financial gain and that they act rationally to achieve that goal. The security can fail in cases where that assumption does not apply. A double-spend via a 51% attack can never be dismissed as impossible.

Two plausible examples:

Bitcoin could be doomed if a country decides that Bitcoin is a threat to national security and is willing to spend whatever it takes to dominate the hash rate and destroy Bitcoin via double-spends and DOS.

In 2014, ghash.io achieved more than 50% of the hash rate and could have performed a double-spend. Normally, a pool would not do that because it would mean the end of the pool as miners would desert them. But suppose ghash.io decided that they wanted to become famous for being the only pool to successfully execute a double-spend via a 51% attack regardless of the consequences. In the end, it turns out they really had nothing to lose because they lost all of their miners anyway. They didn't do a 51% attack, but they could have and they might have been motivated.

Specifically financial stability or long term financial plan. Double-spend via 51% attack could have good short term financial incentives if :
1. Network hashrate is relative low
2. Attacker have access to 51% or more hashrate (compared with network hashrate), either by own or rent mining hardware.
3. There's vulnerable exchange/service with relative low minimum confirmation and fast time to process withdraw request/send digital goods.

51% attack on BTG is the prime example.

There is absolutely no double-spending threat, bitcoin is an ultimate solution to this problem. let's elaborate more:


What is the double-spending problem?
For a digital token to be used as peer-to-peer electronic cash, a medium of exchange, it is absolutely necessary to have an inflation regulatory mechanism because digital streams are reproducible trivially bu consuming almost zero resources. Owners of digital assets have full incentives and sole power to send multiple copies to different users. Electronic signatures are of negligible relevance to help with mitigating this issue and trusted third parties gain too much power. A decentralized, trustless, permissionless, open solution is the only acceptable solution to this problem.

How bitcoin solves the double-spending problem?
The most critical game-changing innovation of Satoshi and bitcoin is the core idea of using a distributed ledger, synchronized by consensus. PoW and game theory are used in bitcoin as instruments to prevent spamming and adversary behavior by establishing a fair voting mechanism. As long as the distributed ledger is balanced and there is no inflation we have the solution and whether the instruments used are perfect or not is irrelevant. They are secondary problems.


Is bitcoin perfect?
Hell no! Bitcoin is just a first attempt to implement the solution, besides there is no such system in the universe, a perfect system! The most important flaw in bitcoin, which I've been investigating/trying_to_address  (https://bitcointalk.org/index.php?topic=4687032.msg42296802#msg42296802) for a long time is the infamous pooling pressure flaw and its 51% consequential threats.


Is the 51% problem a cloned form of the double-spending problem?
No! The 51% problem is secondary and has nothing to do with double-spending because it has no irregular inflation consequence. The main concerns with 51% are fraud and censorship/DoS vulnerabilities.

Is there any built-in countermeasure to mitigate 51% problem?
Yes, there is, PoW plus game theory, the former is flawed (pooling pressure)but working now and the later is not flawed.  

Is the "rational behavior assumption" in the way game theory is employed in bitcoin is a flaw?
No, it is not. There is no version of game theory without such assumption and it has been used in economics and politics exactly the same way as bitcoin is using it.

What's the point?
The point is about the infamous "Don't trust, verify" and how it is exaggerating the situation with miners in bitcoin. Putting trust in miners is discouraged too much and in a vague and confusing way. It is a major obstacle in the development scene of bitcoin IMO.

To be even more clear:
Defrauding people by re-org attacks on blockchains is not double-spending because it doesn't inflate the coins in circulation, it is just a fraud!

- Collided miners/pools could be spotted and being put behind bars!

- Smart people should wait for enough (weeks maybe) confirmations before releasing large amounts of assets in exchange for digital tokens as long as they are concerned about such a threat.

what exactly do you mean by "put trust in miners" here?


it may be possible to cause some short term drama and maybe some small damage to bitcoin but it is extremely hard for a 51% attack to destroy bitcoin.
such attacks must be accompanied by scamming of a large number of bitcoin users out of a very large sum of money to be able to damage bitcoin. the scenario you describe requires that  country to start trading with other bitcoin users and then scams them by reversing the transaction! the cost of such scam is too huge which includes legal problems for that government.
otherwise just finding the same blocks that were mined and ending up with a longer chain could not "destroy" bitcoin.

There are many proposals and ideas being abandoned or lack support in the community because of slogans like "Don't trust, verify" and wrong narrow assumptions about the criteria in which one can count on PoW and miners. For instance:

- We have UTXO commitment proposals that could help with the insane "sync form Genesis" policy but are not getting support because of a general hesitation of relying too much on PoW.

-  We have Drivechain and sidechains scaling solutions being left in darkness and confusion because people are arguing about how miners can steal all funds deposited there overnight.

- Most importantly, sharding schemes are being criticized for their too much reliance on PoW and mining.

The problem with this paranoia about mining is its lack of theoretic transparency. The advocates representing such paranoia have never established a reasonable framework to specify in what aspects and by what extent one can rely on PoW and where it is not a reliable source of trust.

In this topic, instead of vague and political ideas about how reliable are miners in bitcoin, I'm establishing a criteria-based measure:

Miners are reliable as far as:
1- Provably, they are not inflating the supply of bitcoins by breaching the regulations built into the protocol.
2- There is proof that any incoming fund to a wallet approved by miners, comes with an equal deduction from the ledger maintained by them.
3- There is a safe threshold for the number of confirmations where the costs of rewriting the blockchain outperform any criminal incentive for defrauding users by orders of magnitude.

I see what you mean. When you restrict the meaning of double-spending in that way, then can I agree with you.

But what you call a "misinterpretation" is really a different understanding of the word's meaning. If you modify your approach, you could reduce the confusion about your point.


I agree that those are major challenges  to sharding. I look forward to your solution.

Ambiguity and loosely defined terms circulating around in the community have bad consequences. In my previous post, I've presented some examples.

Accusing proposed schemes and improvements to bitcoin of being vulnerable to double-spending (because PoW is kinda suspicious to be 51% attacked by colliding pools/miners) is nothing less than cutting them out forever.

I'm not much of a conspiracy theory believer but I see a lot of bad incentives and I wouldn't be surprised if it found to be a deliberately implanted confusion. Anyway, it is time to get rid of this ambiguity and move forward, imo.

It's actually because of the full nodes. They secure the network, to make sure the miners are following the rules, and make sure to mine the type of blocks that the full nodes demand.

Plus, https://twitter.com/bitcoinmagazine/status/1197161029832265729

8)

You are rehashing the same argument the old "Don't trust, verify" thing which has fed the community up. It'd be a good occasion to make a re-assessment, I suppose and will do my best to help.

look, God is dead, and with him the absolute, eternal, big picture view of the universe. There is no highly privileged point of view, nobody is in charge of everything, Satoshi is gone and there are only millions of users, individual users and they should take care of their security, one by one, there is no community, we are not members of a sect.

Your notion about full nodes and how they are securing the network is misleading, full nodes are not securing anybody other than themselves, their own wallets and their own mining resources (for solo miners), this is it!

Now, please read my 3 above conditions and tell me from YOUR very own personal point of view: IF a hypothetical system could be able to fulfill all three of them do YOU or do YOU not feel absolutely secure?

Well, you are right and I did it above thread and by striking through the wrong perception and bolding the correct one in your comment.

As I've mentioned in my latest reply to @odolvobo, it is very critical to distinguish between the two nowadays because the ambiguity leads to unjust assessment of most improvement proposals.

Interesting read.  I see it as a term which has become adulterated.  I can't speak of a specific double-spend, but there have been plenty of 51% attacks, especially with alt coins, having low hash rates on their networks. Bad guys were successful in controlling the network and adding a longer chain with fraudulent transactions.  Exchanges were victimized with this as BTC-alt transactions cleared, the BTC was withdrawn and when the breach was discovered, the exchanges lost BOTH coins!

@AbernathyFray, welcome to bitcointalk the original bitcoin forum founded by Satoshi Nakamoto,

Defrauding people is always a threat in any financial transaction and cryptocurrency is no exception. For short-range 51% re-org attacks it is always users' responsibility to stay safe by waiting for enough confirmations depending on the volume of the transaction at stake.

You forgot the "Conclusion" part of Bitcoin's whitepaper, Bitcoin only has a "proposed solution" for double-spending but was never guaranteed by Saotoshi himself aside from that Satoshi is also aware that a 51% attack is possible that is why he is talking about PoW on transactions on how should it be "computationally impractical" so that it would be "impractical" for an attacker to infiltrate the network. But Satoshi didn't even dived in to the possibility of a 51% attack from happening in Bitcoin's network, I know it would require a lot of resources for an individual or a group to pull through and control 51% of the hash rate but if we are only talking about the chances of this happening I know we all know that a 51% attack has a chance to happen.

One doesn't need to scroll down to the conclusion part of the white paper to understand how confused was Satoshi about his work, he made the same mistake in the first paragraph of the abstract section I quoted above thread, as well . Satoshi was a terrible technical writer, brilliant software designer but not much of a writer. I mean look at the white paper as a whole for the starter.

It looks to be my fault starting this thread by quoting from Satoshi and the white paper but it was the right decision because it doesn't matter how Satoshi presented his work, it matters how he had to present it: as a solution to the double-spending problem!

If bitcoin was not such a solution it wouldn't get any attention, leave alone surviving for more than a decade and surpassing a whopping 120+ billion dollars market cap now in its worst days. We have pooling pressure flaw in bitcoin PoW since the first few months after the Genesis and we have pools and all this 51% threat around since late 2010. Bitcoin didn't survive because polls didn't practically do anything bad as the result of some fragile game theoric analysis. People don't trust a system that is half an inch away from a total failure.

The way Satoshi implemented PoW for bitcoin is flawed inherently it is based on a naive winner-take-all approach deemed as being vulnerable to pooling presuure (https://bitcointalk.org/index.php?topic=4687032.msg42296802#msg42296802), still we are fine, bitcoin is working, why? Because bitcoin is not about making 51% collision hard to achieve and irrational to carry on, it is about keeping the pace of inflation regulated.
As far as there is no way to print bitcoins out of thin air for miners (collided or not) the double-spending problem is solved, once forever by a genius named Satoshi Nakamoto who was not able to present his brilliant work thoroughly.

Now, and please stay focused, if the double-spend is solved in the first place regardless of what is happening in the mining scene, what's actually driving the anti-PoW/anti-miner propaganda/instincts in this community? I'm asking about the rationale behind this phobia and the way it is blocking so many scaling ideas and proposals? If double-spending is not going to happen and bitcoin supply won't ever exceed the cap, what else is at stake that makes people nervous about trusting in PoW?  

Are people concerned about pools to collide and defraud few Satoshis from reckless users who release their assets with one or two confirmations? Please! Just give me a break.

Actually I didn't focused on what Satoshi said of Bitcoin's whitepaper, I merely just touched your argument about it which is clearly stated before you quoted Bitcoin's whitepaper. My answer/post basically was just touching all the arguments you have laid on how Bitcoin is the "solution" for double-spending just because Bitcoin's whitepaper has said it so. So I'm sorry if I got off-topic with your new topic, I was basing it in your OP.


One having fear/worry on something they believe in won't really go away. The presence of just a possibility of a 51% attack happening alone just put some fear in a lot of people, seeing that there is a possible flaw on how Bitcoin transactions work and how they can be erased, reversed, and be double-spended is something that can cause fear in both the consumer and the producer side of things. Not until we reach a certain level of miners really dominating the network I guess this fear from a 51% attack won't just disappear instantly. 

I quoted the white paper to highlight what Satoshi has opened his paper with: A solution to the double-spending problem. Nobody would ever bother reading his paper if he was starting by saying: "hey, I got an idea about how to resist against double-spending!"
Money, digital or conventional, is not about just resisting such a huge problem:  being potentially re-producible by spending ever and ever! Satoshi needed to show-up with a solution and it was what he did. The fact that he was somehow confused about the role of PoW, doesn't change anything.

It is not a fear of doubles-pending, take care of the terminology, the sole presence of any kind of fear about double-spending would make bitcoin void. It is just about how a short fraudulent re-org attack can disturb people and this fear has a mitigation measure: wait for more confirmations for more valuable transactions. That simple.

Yea, but that double-spending problem can solve with bitcoin supporting payment cards or applications on phone.
 ;D

Hello aliashraf. I have seen you be a long time proponent of scaling ideas on bitcoin. I read a lot of your posts about proposing a rigorous solution and the code for some of your ideas but I don't know if you are actively pursuing them in terms of code. Point me in a direction if you are. I don't think there is any anti-PoW/ anti-miner propaganda in this community. Everyone loves PoW. The concern about miner centralization is only related to the fact that you cannot let a specialized group of people be the sole controlling-stakeholders in a decentralized system that we all hope will continue and flourish long after we have gone. Don't you feel it is a genuine and valid concern considering the vision and magnitude of such a system.

That is why Bitcoin community insist on the throughput constraints for full nodes when business interests are going wild with their 128 MB and 1 GB blocks. The concept that base layer with billions of dollar of value should continue in its robust, widely-accessible form is a worthy goal. What is wrong if real scaling solutions that can enable day-to-day payments come as Layer-2 solutions like LN? Bitcoin has a robust roadmap, in as much as a decentralized roadmap can be. The insistence on scaling the base network by crowding out full nodes and using the "Nodes don't matter" argument does not hold much water. There are more than one way to do a thing right.

What exact scaling solutions do you think the community is not thinking of? We had segwit. Then there is Schnorr and Taproot (https://bitcointalk.org/index.php?topic=5220436.msg53814136#msg53814136) which bring more functionality and a bit of scaling. I think the community is doing great. Your thoughts and comments on the thread i linked would be welcome.

BUT, it isn't wrong. Full nodes do secure the network FROM bad-actors. Including if the bad-actor is a miner.


The entities who want to co-opt Bitcoin are fed up, not the community. "Don't trust, verify" is, and SHOULD always be part of Bitcoin's ethos.

Hello, thank you for reading my comments, appreciate it.

About coding, it is complicated, some ideas have been coded for experimental purposes and approval of consistency because nothing is consistent if you just can't translate it to code elegantly but there is no public domain code release for the time being.

To be honest, I'm a bit short of budget right now to do anything more than part-time research and it has been a while since I've exhausted almost all my resources digging literature, writing, ... I'm not a fan of ICO and crowdfunding campaigns myself so it is gonna take a bit more for me to pull more resources together for supporting more serious projects.

There is good news though, as much as jumping to the coding phase is delayed the idea is growing stronger and stronger and I'm absolutely satisfied with the situation right now, no rush.
No, I don't feel so. I've presented a series of proposals above-thread which are abandoned because of such arguments and concerns.  Blocksize debate was a legitimate debate from the Core side not because of the way they were presenting their argument but because of the proximity premium flaw in bitcoin that makes blocksize increase a centralization nightmare for mining itself. Cenralization of mining is a legitimate concern but centralization because of relying too much on miners? No, it is not!

Sidechains, UtXO Commitment, Hierarchical Sharding schemes to name few. I started this topic purposedly because all these ideas are pushed back for their legitimate reliance on miners and PoW and right now and in the meantime, taking advantage of Corona situation, I'm doing my best to get some more free time and publish a proposal including all the above fantastic ideas in a package as a scaling proposal for bitcoin. It is not a typical brand new altcoin proposal, neither a two-way pegged sidechain nor a hard/soft fork and it is an ultimate solution for both centralization of mining and bitcoin scaling IMHO. Stay tuned  ;)

Who says?
...

Actually, I don't care.

I don't care that you don't care, BUT without it, and without full nodes, INDEPENDENT of the miners, Bitcoin would be a slow, boring, centralized ledger. Or the Federal Reserve all over again. Bitcoin would be pointless.

I believe that 51% (or more) is more of a centralization situation rather than being called as an attack for the purpose of double-spending. I've got many reasons to say this, one of which is the fact that at some time when we just began with crypto a decade ago, BTC mining had been both, easier and controllable due to least hash and many companies even tried and did rule the crypto mining industry, and trust me that there will be group of miners who, once all gather at one place (pool) some day, we'll definitely be noticing a drop in number of other mining groups as this single group will be ruling it up to the mark by getting almost all the blocks on its name and others will stop by seeing them gaining everything.

that is simply not possible without having 90% of the hashrate and the cost of such gigantic hashpower is ridiculously high even if divided among a small group of mining farms. besides even if one pool had that much hasr power it still wouldn't force the 10% to leave because that 10% can still mine 10% of the blocks no matter what. unless that 90% starts performing 51% attacks in which case we will switch to another mining algorithm to brick their billion dollar investment.

the thing about pools is that you may not notice it but their seemingly big hashrate comes from a very large number of miners connecting to them. which means if a pool starts being a little shady, they will all leave.

What if such pools start giving higher rewards per each miner (obviously after dividing their distributed amount of hash power) just to grab a big number (or almost all the miners in the market switch to them due to their competitive business and some contests)? Why won't the miners join them and start gaining even a few bits more than what they get from their ongoing mining group?

@Stedsm, @BrewMaster
Centralization of mining is a bad thing, no doubts, and a real threat since 2011, undisputable and it is really a hell of a problem to solve considering the sophisticated situation we are dealing with: so many strong and divergent stakeholders and groups present in bitcoin scene nowadays. But ] got two points to mention here:

1- It is hard but not impossible to mitigate, we need to get rid of centralized pools.

2- It is not an existential threat to bitcoin as a whole because it is irrational to leverage huge mining resources for long-range attacks against bitcoin as @BrewMaster correctly mentioned above.

Plus,

3 - What Andreas Antonopoulos said, https://twitter.com/bitcoinmagazine/status/1197161029832265729

Thanks to the full nodes validating everything for themselves, and securing the network as an after-effect. I am very confident that that prevents the miners to become dishonest.

Have you forgotten how Bitcoin works yet again?  

I know you spend a lot of time playing with that staking rubbish, but that's not really a legitimate excuse for being woefully ill-informed.  But since you clearly need it explained to you like you were still a newbie, I'll happily oblige:

Miners would be jeopardising their income (not to mention their entire business model) if they tried to enforce higher fees.  Users include a fee to effectively bid for priority inclusion in a block.  The miners will naturally select the highest bids first, but it's not practical for them to attempt to force people to bid larger sums.  That's just something people choose to do when the network is congested.  When fees rise, that's the result of users trying to out-bid each other.  It's not the miners causing it.

If miners began en-masse to reject transactions based on lower fees, they're effectively just "leaving money on the table".  It's basic supply and demand.  

@Khaos77
I'm not used to saying this but @Doomad is right (exceptionally tho  :D) ...
Centralization of mining is a nightmare but not an existential threat for bitcoin: neither short-range nor long-range attacks are feasible in bitcoin because of the game-theoretic force behind the scenes.

The problem with @Doomad and guys like him (including @Wind_FURY) is their paradoxical positions:

Firstly they incorrectly believe that it is because of decent full nodes and not the game theory that mining centralization is not a serious threat to bitcoin. It is a totally wrong assumption and is nothing more than blindly repeating baseless rumors and slogans. For instance, I could imagine a bitcoin ecosystem solely consisted of SPV wallets and yet immune to such attacks in the real world. Any dishonest move from miners would trigger panic and drop the price drastically and ruin the mining business in the first place, wouldn't it?

Secondly, they follow the same miner-phobic discourse when it comes to advanced scaling proposals that need a bit more reliance on PoW and miners at the same time that they say there is no practical threat because of the centralized situation with miners!

Thirdly, they don't feel any obligation to engage in any project or support it by any means or at least remaining neutral about any proposal that involves changing the situation with mining and pools in bitcoin, instead, these guys are among the firsts to show up trying to shut down any serious idea by accusing it of being disruptive, out of the holly road map, requiring hard-fork, blah, blah, ...

Such a complex type of people our friends are  :D

He's trolling. Allow him. It helps open the newbies eyes to the truth.


Plus newbies, miners will also NEVER "delay transactions for fun", or waste energy to double-spend. Any dishonest miner will be kicked out of the network by the community of full nodes, and Bitcoin will continue moving along.

What the dishonest miner could have done was mine Bitcoin, and receive a block reward. 8)

The troll overlooked the game theory.

The troll is also saying that LN will steal the majority of transaction fees from the miners. Does he want Lightning to be successful? OK! Hahaha.


I never said that they were not a threat. I said, the entities that actually secure Bitcoin are the full nodes.

In your imagined Bitcoin ecosystem, the full nodes are centralized towards the miners? They can change the rules without community consensus?

You don't need a zillion of full nodes to beware of frauds, illegal inflation, ... one full node suffices: It could publish a proof for any malfunction in the press and everybody would be informed! It is game theory, its basic "rational behavior" assumption, that is saving bitcoin right now.

It is fragile and weak, I do agree, but it is how one could explain the price not being high enough and the lose of stem we experience.

One full node may be sufficient for one person, but if each user wants certainty that all the information they have is valid, they will each require a full node.  Anything short of that introduces a requirement to trust a third party.

Nope. We don't live in the Middle Ages, once there is proof that some entity is playing dirty, it is doomed, forever. We have the press, social media, etc. we don't need to do the test on our own behalf. It is how the real world works.

My point: A full node keeps its own user from being defrauded (and become the example of a victim for the press) not bitcoin as a whole. Pools are not afraid of full nodes, they are afraid of losing funds because of the obvious social penalties like price falling near zero as a consequence of any misdemeanor.

Trust the press?  In this day and age?  When the number of page impressions are clearly prioritised over maintaining even the slightest semblance of journalistic integrity and the articles generally appear to give the impression that the given publication is merely a mouthpiece for the vested interests of whichever billionaire owns it?  It's likely that very few people become genuinely informed of anything by absorbing modern media content, aside from perhaps what the 1% would prefer the herd to think.  As such, I think I'll stick to form and say that this is yet another one of your ideas I won't be lending my support to.   ;)



Pools don't have to be "afraid" of nodes, they just have to know unquestioningly that should they choose to build a chain upon a block which the full nodes won't validate, they'll be forked off the network and mining a worthless chain.  Blocks are either valid or invalid.  Binary outcome.  That's what full nodes keep in check, which prevents certain types of misdemeanour.  Not hashrate attacks, though.  For the purposes of the OP, I'd say it's likely you are correct in the assertion that it's mainly game theory keeping that part in check.  But that shouldn't in any way be interpreted to mean we don't still need a healthy node-count.

Sure there are limitations to the extents and the aspects but we don't live in absolute darkness, do we? For deciding to go short on a digital asset, sometimes even rumors are enough.
Actually, it is part of the sectarianism, I'm not comfortable with. We don't live in such a terrible world in which you just can't be informed that people are getting defrauded by a bunch of stupid collided pools, it is just absurd, having such a presumption as serious design criteria for any real-world system.

Believe it or not, there is no, zero, long-range reorg threat to bitcoin in foreseeable future and it has nothing to do with the cardinalit of full nodes.

you should reconsider, because it is the right thing to do, seriously. :)


And should be afraid of being forked-off, yes? NO!

BUT, that isn't a reason to discourage the community from running a full node in a permissionless system. If they want to run a full node for themselves, then they should a full node.

PLUS, your opinion is debatable. There's rational behavior BECAUSE of full nodes securing the network.


It's not weak, it's centralized, and it's not secure FOR the community. More full nodes = more security, and it's better to overshoot security.

in your scenario, it's easy to attack the network. users would have to coordinate out-of-band and fork the network every time that happens.

with a robust network of full nodes, such attackers would just be ignored.

how could your scenario possibly be preferable for bitcoin users? even if you are right about the game theory, why give miners that opportunity?

Fair question. Before proceeding to it let's have a comparison between the role of game theory and full nodes (supposedly millions of them) in securing bitcoin:

Full nodes have no power to mitigate the real attacks a hypothetical 51% collided pools can carry out, no matter how many of them are present:

- Short-range chain rewrite attacks are not detectable by full nodes, they just bend the knee to the more difficult chain, forget about resisting against such attacks.

- Long-range attacks are the same as it is just a relative concept.

- Full nodes can't resist censorship/blacklisting attacks against peoples/institutions/nations.

- Full nodes can resist against protocol breach and most importantly double-spending/illegal-inflation attempts very well.

Game-theory addresses all those problems vigorously with the exception of censorship attacks: There is a hole.
It is possible for an aggressive coalition of governments to push for blacklisting groups of people by pools/big-miners and convince other people not to care as long as they feel somewhat/somehow safe (wrongfully). Pools/miners might conclude the negative impact as being tolerable compared to the legal penalties they have to bear otherwise.

The last point tells us why we should take care of the centralized situation we are in with pools and ASICs as well as centralized exchanges they are all part of compromise threat to bitcoin resistance agenda (https://bitcointalk.org/index.php?topic=5066769.msg47759875#msg47759875) against tyranny and greed.

Back to your question:
Answer: To use their power for implementing excellent features and solving crucial problems where it is needed.

Right now, bitcoin needs mobile secure wallets, doesn't it? A simple UTXO commitment enhancement could provide the opportunity for having elegant full nodes to be set up in a few minutes on an ordinary low-end mobile. The argument, if it deserves to be called an argument at all, is the vulnerability of this proposal to stupid miners who are susceptible to run a 500 blocks rewrite attack on bitcoin!

Fear has nothing to do with it.  I'm not sure I understand your insistence to introduce an emotion to such a simple equation.  Either miners build on blocks that conform to consensus rules or they cannot continue to contribute to securing the network.

If there is a legitimate argument to counter my assertion that a healthy nodecount prevents certain attack vectors, I certainly haven't heard it yet.

Apart from the 51% attack mitigation, I think you are ignoring the fact that full nodes run by normal users are essentially what make bitcoin collapse/ takeover resistant. A system comprised only of miners (if there are no non-mining full nodes) or entities with the ability to run specialized hardware (for chains with large blocks and enormous throughput requirements) can never be as takeover resistant due to centralized points of failures.

A system with millions of user maintained full nodes will just trudge along, no matter what. That is a worthy feature to ensure robustness in the face of calamity (natural or man-made).

It is not a fact, just a false assertion. Bitcoin is resistant to collapse/takeover because of the game theory behind the scene.

There is no party named "full nodes coalition" or something, established to keep bitcoin safe and secure. As a single user, I don't care about anything other than my own security and I won't pay a penny to keep you or "the community" secure.

If there are no full nodes, then won't the network stop existing in case of a takeover of centralized pools/ miners?  On the other hand, user run full nodes with a geographic diversification the world over, serviced by different ISPs etc. can keep running under even such conditions. Its a worst case scenario which needs full nodes plus home miners.

That is also the original peer-to-peer network and it can survive no matter what; but only if the block chain rules continue to allow full nodes to run.

Home miners plus full nodes is not a backup plan for D-day, it is the original plan which failed in 2011-2012 after pooling pressure falw (https://bitcointalk.org/index.php?topic=4687032.msg42296802#msg42296802) showed its power and pools started to dominate the mining scene of bitcoin. Since then we are running plan B: Centralized mining, no home miner, less full nodes AND game theory.

If the transactions, and blocks are not valid/doesn't follow the consensus rules. Those transactions/blocks won't be relayed by full nodes. The energy spent will be wasted. That's the game theory.


Then the more we are required to verify things for ourselves.

Plus if you truly believe that your one node network will be adversarially safe from a collusion by a cartel of miners, because "game-theory", and that users shouldn't run nodes, then what are we in Bitcoin for? Remove POW too, and make it cheaper.

I had last month a 0.25 btc double spent while having a trade. It still can be done, be aware!

Hahaha.

Newbies, ask him at what cost to the miner, and if it was worth double-spending the 0.25 Bitcoins, with the full nodes validating EVERYTHING in the network.

Nope.
That's the game theory.

Firstly, I don't say users shouldn't run nodes, on the contrary I'm thinking of and advocating for mobile full nodes: every user one full node! I'm saying it is not helping bitcoin security to have a zillion full nodes, it is just about every single user to avoid being the one whose name is supposed to go first to the news. Full nodes do not form an institution to keep bitcoin safe! I'm just wondering: How people have managed to deduct such a stupid argument?

Secondly, PoW is essential for the game theory behind bitcoin and it is why PoS is shit.

That WAS the game theory BEFORE the cartelization of mining. Satoshi did not fully know future. How could the community express themselves if their ability to run a full node was taken away?

Full nodes create demand for blocks for the miners to supply, and relay them only if valid/follows consensus rules.


But full nodes do secure the network. Any block/transaction that isn't following the consensus rules, won't be relayed. Bitcoins is actually a network of validation.


Not if the network is centralized towards the miners, and could collude to co-opt Bitcoin's development WITHOUT community consensus. Maybe they should remove POW, to remove costs. Haha.

Nope. That is Plan B: What if "a greedy attacker is able to assemble more CPU power than all the honest nodes"?
"The community" would come here, start a topic and warn about the shit, it gets viral and the attacker and his coins are doomed in a few hours. Full nodes aren't helpful in most attack scenarios anyway.

Relaying blocks is not a big deal. Your argument is not qualified enough to be discussed here, sorry, blocks get relayed anyway, e.g by collided pools. Plus, full nodes are not able to detect mal-incentivized reorgs and censorship the most practical threats due to mining centralization.

We are arguing on the basic premise that having a healthy full-node count is a desirable situation or not. Your argument is that full nodes are useless in terms of keeping miners in check because the game theory will keep the rational miners in check. Those of us who think that full nodes aren't completely useless say so because  of two reasons:

1. Bitcoin network is equally a network of users/ businesses running full nodes that validate and propagate well-formed transactions, which of course is the only thing they can watch out for and not double spends. (You said in reply to @Wind_Fury that block propagation is not an issue. Is it because in a hypothetical 'miner-collusion scenario' propagation will any way happen between their own full-nodes over relay networks like FIBRE ?)
2. Having this network of full nodes is the best way to remain vigilant. If we depend on, say, a few guardian nodes and then media to keep the game theory going then you are again dependent on centralized authorities as DooMad had been saying.

Keeping the ability to maintain and run full nodes should always remain a low-barrier activity not just because of fear of miner collusion/ attacks but because a lot of properties of bitcoin arise from it, namely decentralization and being your own bank, even in the D-day situations, even if media becomes dishonest, even if a concerted attack targets miners in some jurisdictions rendering the miners disconnected. If we just accept that all of this is paranoia and in reality, such attacks are not possible then of course there is no need for full nodes.
 
Thanks for the link to your topic on PoCW. It aims to solve the problem of pooling because i guess you do believe that centralized pools can coordinate and they reduce decentralization.(??) Yet, if miners are to be trusted and no full-nodes are needed then doesn't that create the same problem?? Huge mining farms can coordinate. Instead of debating about need of full-nodes, i will go and read about these proposed scaling solutions you think are being ignored due to the love of full-nodes..

I think there is a deep, deep, misunderstanding: Actually, I am the one who is in favor of having millions of full nodes and the guys like @DooMAD and @Wind_FURY are the ones who are against it, practically!  :D

How? Let's dive in:
There is a very efficient, secure way of running a bitcoin full node on commodity mobile devices very efficiently in economic mode, called UTXO commitment. According to this model miners would have to commit to the UTXO (state of the bitcoin machine) by somehow including its hash in their blocks and a light full-node could besides synchronizing headers like a usual SPV wallet continue to downloading the full state of the machine as of latest couples of hundreds of blocks and act like an ordinary pruned full node thereafter. Right?

For this to happen, you need a simple soft fork which is not getting support, why? Because people are paranoid about miners being susceptible to commit to bad UTXOs for say 500 blocks!

Are we clear? This full-node, full-node propaganda is totally fake and misleading. It is not a campaign in favor of empowering bitcoin users by giving them an opportunity to run a full node, it is just a trick to relying less and less on miners in a baseless and paranoid way: Who in the hell can imagine a scenario in which miners are colliding for 3-4 days to inject a few false UTXOS in bitcoin blockchain? A paranoid or a politician.

The full nodes validates, that every transaction/block follow the consensus rules. If a miner mines an invalid block, it won't be relayed be the nodes.


I don't see how this part of your post is right. That is simply wrong, and I doubt you truly understand how the Bitcoin network works.


Then why haven't they tried it?


If "that" doesn't validate and relay transactions/blocks, then it's not doing anything for the network, and therefore not part of the network.

Blocks are relayed to any client, being a mining full node, a full node wallet, an SPV wallet, a blockchain explorer, ...) who connect to a pool/solo-miner and/or any full node that accepts inbound connections. What do you mean by accusing me of being ignorant about bitcoin relay network? It is not so complicated and I've been discussing it on many occasions in this forum.

You guess! It is not a rational move, simple game theory.

"That" is an ordinary bitcoin pruned full node and does everything an ordinary full node can do other than uploading the ancient history of blockchain for the current (stupid) bootstrap process.

aliashraf,

Your original question and discussion in your thread is a total mess. You are using very unclear terms, and you are bending Bitcoin terms in a way that shows that you do not understand Bitcoin's security model.

You don't understand what a "full node" is (as you confuse it with SPV), and you don't understand its role in the network.

It's a headache to read what you write as you appear to be ranting and make half-points all along the way.


Confusion..
Here is only one example of your confusions:
Here is more confusion:
Even more confusion:
Even more confusion:

I started out reading your thread coming from a place of being willing to help and to clarify how Bitcoin works, but after reading your responses, I'm not convinced you are interested at all.


Bitcoin safe to double spend, based on fully validating nodes
Just to start somewhere, Bitcoin does solve the double spend problem. This is achieved by that participants run fully verifying nodes, and each such node enforce Bitcoin's consensus on every transaction of every block, and this will mean that in one node's view and perception, no double-spend ever occurs.

Miners are then free to mess up with blocks as much as they like, but they do so at their expense, so as long as the value of your transactions are insignificantly small compared to the Bitcoin miners' electricity expenses, you're safe - it's highly unlikely that someone will want to play appear-disappear reorg games with your 100USD transaction when it costs 10,000USD to mine a block.


UTXO commitments discussion
Regarding UTXO commitments, again you discuss these without understanding Bitcoin.

I'll share with you here that UTXO commitments are somehow similar to Ethereum 1's blocks' merkleized state snapshots.

What happened in the Ethereum community then was that, they fell for the temptation of validating blocks at all - when the Ethereum network is too busy, it will trig a feature that they call "fast forward", where a fully validating node will skipover one or more blocks, and thus simply blindly trusts the other nodes and the miners that they didn't forge anything. This is extremely risky and a viable attack vector for attacking their blockchain.

Further discussion of Bitcoin's security model, the definition of decentralization, and of that, here: https://hackernoon.com/the-ethereum-blockchain-size-has-exceeded-1tb-and-yes-its-an-issue-2b650b5f4f62


UTXO commitments infallible as you suggest is not correct
Your assertion that "UTXO commitments would always be valid because the miners are always attentive, correct and would never want to trick anyone" does not hold.


Again, this reads confused, you need to be more specific and clear.


A 51% attack would not let through a double-spend
Last to respond to your question in the thread's title, "Is 51% attack a double-spending threat to Bitcoin?", I guess you have the answer already: It is not.


Asterisk

I think this is again pretty much a question of what you think bitcoin is. A lot of people out there think a lot of things about what bitcoin is and there are claims from con-marketeers about "Real Bitcoin" "True Vision" etc etc.  If you feel that we CAN trust miners, media can be believed to disseminate trustworthy information, full nodes are not needed etc etc. then there are plenty of other centralized scaling approaches out there.

If we take all these issues on privacy, trust on miners, media etc for granted then you are not in agreement with the privacy and security model of bitcoin made possible because of full nodes.

Asterisk,

Welcome back to the bitcoin discussion forum as a newbie, I was waiting for you and I hope you expect nothing less than full hiding here (just kidding  :D)

Meanwhile, please behave and do not make an embracement out of this brand new id too. I know who you are, and I understand it is a shame for the bitcoin community to watch an important figure being humiliated because of his own reckless manner of debating. I understand too, it is hard for you to get rid of your own malicious discourse. But come on, just give this fake id a shot and think out of the box if you may.
 
I see no confusion in what you have quoted from me. It is crystal clear: Your claim about full nodes playing such a crucial role in bitcoin is simply wrong and baseless. As I've extensively discussed up-thread, full nodes have nothing to do with the network security, they are just useful for the entities who own them as a single body to keep them somewhat more secure against some attacks that are not considered realistic anyway.

So, I skip the embracing confusion part of your post if you don't mind.

What is called UTXO commitment is radically different from Ethereum's snapshots. The latter is vulnerable to short-range attacks UTXO commitment is not! I read the article you've linked, the day it was published, good statistics about Ethereum but nothing new for bitcoin, the same blind enthusiasm about current bitcoin. Put some real meat on the table, please. :D

In the scheme that I'm advocating for, nodes do not accept (and relay) a single block without full validation. Guys like you are worried about malicious UTXOs being forged by miners and committed to for hundreds up to thousands of blocks and exploited thereafter, which is really a stupid paranoia. It could also be considered a forgery of concepts to spread FUD about the mining scene of bitcoin for political reasons, again, stupid.

Why? According to you, it is because full nodes won't allow it but my argument is more solid: It is not gonna happen because it will be revealed anyways and destroy the attacker completely beforehand. Bitcoin inflation rules are currently parts of a social contract, rather than some lines of code, it is hard to understand but you should try.

Cheers,

I think you are now somehow agitated by the previous embracing post of the fake Asterisk id, aren't you? it is what they do, they trigger anxiety and push buttons, be careful.

Bitcoin is what it is and presented in its white paper. The "Full-node! Full-node!" screams are fake and a canonical part of a made-up discourse. Bitcoin is dependent on PoW,  ways far beyond what they are presenting and it means there are lots of opportunities for utilizing PoW to help with crucial problems like the one I suggested above, without compromising a single bit of the security or decentralized nature of bitcoin as far as we are speaking of a world that game theory is applicable the way Satoshi has put it.

Alienating scaling/mass-adoption/decentralization proposals by spreading FUD about PoW is an alien discourse and has nothing to do with bitcoin white paper.

No, I am actually trying to understand the argument you are making and seems to me that you take a lot of things on good faith for the game theory to work. In the replies above, you have repeatedly said that miners will be kept in check because "community", "media" will know as soon as anything happens. But this has to be detected right? That is what a full node does and in a decentralized system we need more of them.

You then say that SPV nodes are sufficient for this which they clearly are not. SPV nodes themselves rely on full nodes for consensus verification. The only case that possibly stands is that of the network relying on pruned nodes rather than archival full nodes. I am still reading on this pruned nodes vs archival full node comparison in how one is better than the other for the network.

When we are talking about benefits of propagation among non-mining nodes in case mining nodes become unreliable, you said that full nodes are not necessary for propagation too as SPV nodes can provide the network service. But, the important thing is they DO NOT validate. We can agree that SPV nodes aren't much use to the network per se, except for being an easy way to provide wallet services to individual users without downloading the full blockchain.

I am also convinced that in its present state, the network of full nodes is still the best D-day option we have. You took a tangent to your old proposals in denying that but well, an idea is just an idea. It cannot be used to refute the actual requirements for bitcoin network.  

This is a loaded political statement regarding the bitcoin developers and i personally don't agree with it, whatever my opinion counts for. IMO, there is no "True Vision" in bitcoin whitepaper that needs a zealous following. Satoshi wouldn't have shared his humongous work on a public forum to cypherpunks all over the world in an easy to modify repository if he thought that "his whitepaper" is the end-all for everything.

---

PS: I think it'd be good if we can continue this somewhere other than "Technical Discussion". I just don't feel qualified enough for this sub in discussing these basics.. :P

For getting rid of a false discourse, one should absolutely remain focused.

1- There is just one hypothetical threat that full nodes can ever detect: illegal inflation of bitcoins. There is no other threat to bitcoin that full-nodes are capable to detect not mentioning their inability to mitigate.

2- Illegal inflation of bitcoin is possible either by allowing multiple copies of a coin to circulate around (double-spending) or by printing bitcoin out of thin air.

3- Both threats are considered existential. A single instance of such a catastrophic event will destroy bitcoin and the whole cryptocurrency ecosystem practically. We are talking about 2 hundred billion dollars being at stake at the time of this writing.

4- In bitcoin, PoW is designed as the solution for this threat with game theory as the backup solution for the centralization possibilities and 51% problem.

5- With the centralization of mining we experienced soon after less than a couple of years from the Genesis, we are existing in the edges of a 51% attack for almost a decade now. Fortunately, game theory is doing well and we are good, for now, and probably for a long time.

6- Centralization of mining because of pools is bad and should be addressed somehow.

7- In the meantime, we have a scaling problem and some other less critical ones like privacy issues, they are to be addressed, as well.

Now here is the problem:
Core devs of bitcoin somehow have become convinced that bitcoin is what it is and there is no hope to do anything disruptive about the two BIG problems: Centralization of Mining and Scaling. They've gone that far to adopt Buterin's stupid Trilemma assertion about denouncing feasibility of solving the two at the same time (with a fake third factor, security, he has added to emulate something he has read in high school, the Combined Gas Law :D).

This give-up strategy was first triggered by the embracing raw scaling proposals like th one gave birth to bcash after the scaling debate. People went all-in on the idea of every scaling idea is somehow related to a suspicious centralization agenda, just like bcash.

Well, it was obviously just a stupid and naive generalization, but it got viral and became a part of the culture and now it is time to get rid of it, ok?

One important part of this give-up strategy is the exaggerated and artificial distinction between full nodes and miners. Originally, bitcoin does not make such a distinction between the two, right now bitcoin client code has a built-in mining feature and every full-node is officially (not practically) a mining node too!

The give-up strategy is primarily a give-up on PoW. By advertising full-nodes as the superheroes of security and decentralization, other than getting off-track from bitcoin's most important innovation, Proof of Work, the most revolutionary phenomenon in the 21st century for the least, this strategy is neutralizing any opportunity to improve the situation.

I'm advocating for both: decentralization of mining and scaling bitcoin at the same time but it is very important to note: a decentralized mining scene needs full nodes, many many of them, solo miners are full nodes, remember?
So, I'm the one who truly loves full nodes. The give-up strategist? No, he is just a fake lover.

This is another misunderstanding:
I said that in a context: A hypothetical scenario in which miners somehow could prove that they are not inflating the supply.

I needed this argument for showing the limits you can push PoW. We need to re-think the whole idea of ignoring PoW.

One point: I'm not the one who started it, and I'm not the one who continues it. People, dev or not,  should take care of their attitude and behave sanely. The one who starts a war is not always the one who ends it. Politicizing bitcoin development proposals is not my option, it is how you are treated when you are discussing critical issues in bitcoin.

Wrong.  There are numerous consensus rules that full nodes perform checks to ensure each blocks conforms to.  Please refer to this wiki article (https://en.bitcoin.it/wiki/Protocol_rules#Explanation_of_Some_Rules) for a list.  If ANY of those rules are breached, the node will reject the block.

Really? Bitcoin wiki? Interesting!

FYI: Besides ordinary transaction processing, bitcoin consensus rules serve just two canonical purposes:1) mitigating the double-spending problem and 2) regulating the rate of bitcoin issuance. You can look at the two as one big target: preserving the scarcity of bitcoin as planned by the protocol, i.e. inflation control. 

Because they are ONLY connected to a full node, that validates, the clients that ONLY connect to the full node DON'T DO anything for the network, and are NOT truly part of the network.


In the network's current form, Game Theory, because?


Listen, if it's not validating, and relaying blocks. It's not part of the network.

Either you are incorrect, or unclear, or both.


That's great, good for you.


Feel free to describe it.


It's a challenge to take you for serious when you write like this. It's unclear what you are trying to say, if anything.


Why did you make a thread with the title "Re: Is 51% attack a double-spending threat to bitcoin?" - a question to which the answer is no - to discuss a Bitcoin fork?

You suggest a "it (doublespends?) will be revealed anyways (now how, unlike how else?) and destroy the attacker completely beforehand (how?)" related to "Bitcoin inflation rules" in the "social contract, rather than some lines of code".

Are you trying to communicate a Bitcoin fork or protocol feature suggestion?

Anyhow this was my last post here.

I appreciate your effort in trying to convince me but I have thought for myself. For reasons i mentioned before, I do not think that this is a false discourse. In the current form of its implementation, Full Nodes are indispensable to the bitcoin network. Those that think otherwise are trying their own methods.

You are reading too much into the thoughts and minds of core devs. I think their sole motivation is infallibility and robustness of bitcoin which leads to a conservative approach, understandably so. The discussions that happen at the bitcoin mailing list and the activity in bitcoin repository are proof that it is open-to-all and everyone is trying to find a better way forward.

This idea assumes two things:
1.) Implementation, testing and adoption of fundamental changes to the block structures such that pools are no longer needed. Do you know of any such implementation? Working code, testnet, altcoin ?
2.) It also assumes that One node= One vote. This is no longer the case due to ASICs. The fundamental assumption that everyone running the core client would also own hashpower changed with ASICs. That is why, in the current reality, Full nodes are what they are, till of course we have alternative implementations.

I'll bow out of this discussion for now with one last word. Code speaks louder than words/ advocacy. 

How about, before you go spouting "FYI" at people, you could perhaps ensure that the "information" you are providing is accurate?

You are still talking nonsense.  What really would be interesting is if you actually read the wiki and made at least some attempt to understand Bitcoin before you delve down the path of espousing a solution which is still looking for a problem to solve.

Thank you very much guys for joining this conversation. Few points to answer some FAQ and I'll be discontinuing this thread. Feel free to add your comments if any but I won't follow anymore:

1- I started this thread for one simple purpose: Re-visiting some of the ideological standpoints of bitcoin community as of these days which has distracted us from PoW and its crucial role in bitcoin both conceptually and historically.

2- I did it because I see many occasions in PoW for improving the state of bitcoin which are ignored or denied after the shameful bch fork.

3- As of specific improvement proposals, I discussed UTXO commitment and reminded of Drivechain scaling proposals which are under attack because they seem to rely too much on PoW they are both examples of how a minor, tolerable soft-fork could help bitcoin to get in better shape and instead it is blocked because of vague anti-PoW assumptions, I tried to debunk here.

4- I've also another project under the hood, one would consider it as a decentralized mining pool based on a whole new technology other than what is perceived from this concept now. For such projects to be of any value for helping bitcoin mining to become compatible with the original design, we need to be more sensitive and serious about the mining scene of bitcoin and recognize such efforts as being legitimate and important instead of alienating them and insisting on mining as a fringe world.

Finally, I have to clarify that I'm not an anti-core warrior (or a big-block enthusiast or PoS trojan or something) who has nothing to do other than attacking Greg Maxwell or Adam Back or other nice people we all feel deep respect for, the thing is, sometimes they go politics too much and do not let themselves and people to think out of the box. I understand bitcoin is under attack from many sides and people run sophisticated schemes to fail bitcoin and to take advantage of such a failure and these guys have every right to be sensitive and sharp but we have to think and re-think and discuss as well and it is absolutely necessary to avoid sectarianism at the same time.

No one is alienating the miners. They are an important part of the community, BUT, don't expect the community to submit to their demands. They tried to politicize the use of BIP-9 once, and they had the UASF to crack them.

Good luck to your project, that you have been teasing us for a long time.

aliashraf, I thought of asking you in the other "51%" topic, but I believe it's better suited here.

Considering all your thoughts about what, and debates against the full nodes, would it be in your opinion that Bitcoin Cash is "potentially" a better network than Bitcoin?

To be short and comprehensive: No, I hate bcash, because they did what nobody should do ever with a great project such as bitcoin: worsening the problems. By increasing the block size they ruined any chance for solo miners to exist because of proximity premium consequences (https://bitcointalk.org/index.php?topic=4687032.msg42296802#msg42296802).

As of full nodes, I don't think the arguments made by the other side about Raspberry Pi nodes hold enough water. It was not is not about poor users who couldn't afford an average pc or VPS for running a full node, it is about the centralization of mining.

P.S.
I think revisiting the block size debate or your general concerns about full nodes is a good idea but as @ETFbitcoin has suggested it'd be better if you start a new thread for this.