Topic: Is 51% attack a double-spending threat to bitcoin? - page 2. (Read 914 times)

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..

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.

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'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.

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.

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

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.

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 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 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.

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.

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).

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.

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 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!

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?

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.

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.


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.