Author Topic: Any thoughts on this criticism of DPOS?  (Read 4283 times)

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Offline arubi

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But then can't the malicious 51% ignore these votes (they are transactions, right?)?

They can ignore them, but they will be stuck with 51 delegates while the honest chain with the majority of shareholder approval will move up to 100% participation and eventually be longer.

Exactly what I was getting at.
This is also the reason why I said you can only "take over" the network with 100% delegates.
Even an honest 49% can still recover.

This is perhaps a topic for a future blog post.   You can "recover" from any attack as long as the attackers never gain more than the long-term average delegate participation rate.   The reality is that you would recover with a developer released hard-fork / check point.   

Only an idiot would trust "the longest chain" metric on its own.   The longest chain is just a "short term" consensus building approach, it is not the basis of long-term consensus.

Right, so a 51% attack is not viable in the long term.
A hardfork/checkpoint is more or less "cheating" (requires a human factor) but still a viable solution.

It seems that as more malicious delegates are voted in (or just turn malicious), it's harder for the network to "naturally" recover, but it can still easily recover from a 51% attack.

A lower % of an honest network can still recover, and that's where Bitshares wins with DPoS.
With Bitcoin, a "Longest chain" isn't really longer than any other chain, but the difficulty is higher.
With Bitshares, the "Longest Chain" is asserted because any other (malicious) chain has fewer blocks, because malicious delegates ignore honest blocks that vote them out.
A malicious delegate can't just vote in another malicious delegate because she needs enough stake in the chain for that to happen.
Having stake in a malicious chain goes against the very premise of "zero stake".


Man, I love Bitshares :)

Offline bytemaster

But then can't the malicious 51% ignore these votes (they are transactions, right?)?

They can ignore them, but they will be stuck with 51 delegates while the honest chain with the majority of shareholder approval will move up to 100% participation and eventually be longer.

Exactly what I was getting at.
This is also the reason why I said you can only "take over" the network with 100% delegates.
Even an honest 49% can still recover.

This is perhaps a topic for a future blog post.   You can "recover" from any attack as long as the attackers never gain more than the long-term average delegate participation rate.   The reality is that you would recover with a developer released hard-fork / check point.   

Only an idiot would trust "the longest chain" metric on its own.   The longest chain is just a "short term" consensus building approach, it is not the basis of long-term consensus.   
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Offline arhag

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But then can't the malicious 51% ignore these votes (they are transactions, right?)?

They can ignore them, but they will be stuck with 51 delegates while the honest chain with the majority of shareholder approval will move up to 100% participation and eventually be longer.

So theoretically, even if there was only one honest delegate, it would be possible (perhaps after a few rounds) to get enough vote changes into the 1% participation chain to make it into a 100% participation chain that grows to have a larger block height than the 99% chain (likely after several rounds) and cause everyone to fork over to that chain?

What are the limits on chain reorganization? Isn't it far worse for the users to do a chain reorganization at a fork point of say 1 day old (with a huge potential of old transactions that they thought were valid becoming invalid) than it is to just let the majority chain of corrupt delegates win until the point that stakeholders collectively decide a hard fork is necessary to reset the delegates to a new set of honest delegates?

Offline arubi

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But then can't the malicious 51% ignore these votes (they are transactions, right?)?

They can ignore them, but they will be stuck with 51 delegates while the honest chain with the majority of shareholder approval will move up to 100% participation and eventually be longer.

Exactly what I was getting at.
This is also the reason why I said you can only "take over" the network with 100% delegates.
Even an honest 49% can still recover.

Offline bytemaster

But then can't the malicious 51% ignore these votes (they are transactions, right?)?

They can ignore them, but they will be stuck with 51 delegates while the honest chain with the majority of shareholder approval will move up to 100% participation and eventually be longer.
For the latest updates checkout my blog: http://bytemaster.bitshares.org
Anything said on these forums does not constitute an intent to create a legal obligation or contract between myself and anyone else.   These are merely my opinions and I reserve the right to change them at any time.

Offline arubi

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But then can't the malicious 51% ignore these votes (they are transactions, right?)?

Offline bytemaster

So we have a network where 49% of the blocks are missing.
Hardly a functional network, even for the malicious 51%.

Another question,
Does the next block in the round comes in the form of a transaction on the previous block?

It would quickly recover as people change their votes. 
For the latest updates checkout my blog: http://bytemaster.bitshares.org
Anything said on these forums does not constitute an intent to create a legal obligation or contract between myself and anyone else.   These are merely my opinions and I reserve the right to change them at any time.

Offline arubi

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So we have a network where 49% of the blocks are missing.
Hardly a functional network, even for the malicious 51%.

Another question,
Does the next block in the round comes in the form of a transaction on the previous block?
« Last Edit: January 02, 2015, 07:48:19 pm by arubi »

Offline Troglodactyl

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I'll edit my reply, though I still don't get how only 51% of delegates can censor transactions.

They can ignore blocks produced by the other 49 delegates.

So who is creating the rest of the blocks in the round?
No one. They're reported as missed blocks.

Offline arubi

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I'll edit my reply, though I still don't get how only 51% of delegates can censor transactions.

They can ignore blocks produced by the other 49 delegates.

So who is creating the rest of the blocks in the round?

Offline bytemaster

I'll edit my reply, though I still don't get how only 51% of delegates can censor transactions.

They can ignore blocks produced by the other 49 delegates.
For the latest updates checkout my blog: http://bytemaster.bitshares.org
Anything said on these forums does not constitute an intent to create a legal obligation or contract between myself and anyone else.   These are merely my opinions and I reserve the right to change them at any time.

Offline arubi

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I'll edit my reply, though I still don't get how only 51% of delegates can censor transactions.

Offline pc

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Just to reiterate, to "attack" Bitshares, you would need 100% honest-seeming delegates.

No, to attack BTS you must control >50% of the delegates. These can create their own fork of the chain, and suppress any block with transactions they dislike. Including transactions voting them out, which makes healing the network more difficult than for bitcoin.
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Offline arubi

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Quote
The cost of attacking Bitshares is extremely low.  It has already been done once.

I don't get it, What "attack"? Did his delegate not sign blocks? Censored transactions?
Spreading FUD is a human factor. I don't see how the network was under attack (I skimmed the post. I may have missed it).

Quote
Imo, PoW is evolving into a centralized system but it is still more decentralized than DPoS because it is mathematically provable through PoW that the chain is secured by a verifiable amount of hashpower.

Huh? How does centralization have anything to do with the network's hashpower and/or mathematical validity?
Sure, anyone can start a Bitcoin mining farm, but does that happen? On the contrary, mining is centralized than ever.

Quote
misleading people to think the system is "decentralized" and "Safer than a Swiss bank account."

Obviously any blockchain (if prototyped correctly) is more secure than a swiss bank account.
Neither Bitshares delegates or Bitcoin miners can steal your money, but a bank can since the ledger is only accessible to it and it has free reign over it.


It seems to me he's opposed to a non-POW network, whatever it is, Not Bitshares specifically.

edit:
Just to reiterate, to "attack" Bitshares, you would need 100% honest-seeming delegates.
To attack Bitcoin you'd need 51% (although less, bet meh) of the network's hashing power.


You can't know if a person owns more than one delegate - granted.
You can't know if a person owns more than one mining pool either.
« Last Edit: January 02, 2015, 05:52:38 pm by arubi »

Offline clayop

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With DPOS hiring people, voters will elect delegates by their product, not by fame or familiarity. It is very hard to produce multiple products at the same time lying his/her identity running multiple delegates.
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Offline matt608

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https://bitcointalk.org/index.php?topic=905385.msg10003476#msg10003476

While it's not easy to get voted in as 100% pay delegate, it is much easier to do so for a 3% pay delegate as voters are less careful.

Would it be better to have block signing/network security automated with POS and use DPOS to hire + fire employees? (not an original suggestion I know).
« Last Edit: January 01, 2015, 08:14:59 pm by matt608 »