[Proposal] Solution for BWA(Block Withholding Attack) - Proof of Online

ABCbits

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Quote from: yangchigi on September 27, 2018, 10:43:34 PM

it's same way too 51% attack and withholding attack.

if attacker can withholding block ,how attach network without 51% hashrate ?
if attacker can 51% hashrate , how attack without withholding block ?

two word looks like different , but two word same way attack network.

It's true that both of them are ways to attack network, however there are few major difference

51% attack

Require at least 51% of total hashrate

Can be used invalidate recent transaction/block

Mainly used to trick merchant

holding block/selfish mining

No minimum %, but the higher is more effective

Can't be used invalidate recent transaction/block

Mainly used to make other miners waste their time/resource

P.S. The table on post and preview totally different, gonna fix it later.

More info :
https://bitcointalksearch.org/topic/m.45110560
https://en.bitcoin.it/wiki/Majority_attack

Quote from: yangchigi on September 27, 2018, 10:52:25 PM

how make checkpoint every n block in blockchain software?
if make checkpoint every n block in reference site , how trust reference site.
trust foundation work only insert trust block, it's not reason to turn back to centralized system.

It's just random thought after saw how bad this PoO proposal. But basically, each nodes make their own checkpoint every n blocks and outdated nodes will ask checkpoint from other nodes (as opposed from asking block header first) before send blocks/block headers.

It's not practical/really useful anyway since it's only useful for nodes that online 24/7 and most client already set their own checkpoint.

HeRetiK

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Quote from: yangchigi on September 27, 2018, 10:43:34 PM

it's same way too 51% attack and withholding attack.

No.

51% attacks may involve withholding blocks, but they not necessarily do.

Withholding blocks is more effective with the majority hashrate, but is not a prequisite for such an attack.

Quote from: yangchigi on September 27, 2018, 10:43:34 PM

if attacker can withholding block ,how attach network without 51% hashrate ?

Selfish mining (an economical attack on fellow miners):
https://bitcoinmagazine.com/articles/selfish-mining-a-25-attack-against-the-bitcoin-network-1383578440/

Finney Attack (a double-spend attack):
https://bitcoin.stackexchange.com/questions/4942/what-is-a-finney-attack

Quote from: yangchigi on September 27, 2018, 10:43:34 PM

if attacker can 51% hashrate , how attack without withholding block ?

An attacker that has the majority hashrate does not even need to bother with withholding blocks. They have full control over which transactions make their way onto the blockchain and can ensure that blocks found by their competitors always end up orphaned due to being able to outmine the minority hashrate for as long as they control more than 50% of the hashing power.

Quote from: ABCbits on September 28, 2018, 12:15:12 AM

holding block/selfish mining
[...]
Can't be used invalidate recent transaction/block
[...]

The Finney attack mentioned above is a block withholding attack that can be used to invalidate the recent block without running majority hashrate.

For the most part it seems to be rather uneconomical though and is easily thwarted by waiting for at least 1 confirmation.

yangchigi

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how make checkpoint every n block in blockchain software?
if make checkpoint every n block in reference site , how trust reference site.
trust foundation work only insert trust block, it's not reason to turn back to centralized system.

Quote from: ?? on ??

So basically solve a problem with another problems (trusting a foundation) Tongue

Automated checkpoint every n blocks (between 144 - 2016 should be good) is simpler and more effective (for 51%+ attack and history manipulation, not selfish mining).
Besides by trusting a foundation, there's no point of consensus method or even decentralized system. We might as well turn back to centralized system (e.g. bank).

yangchigi

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it's same way too 51% attack and withholding attack.

if attacker can withholding block ,how attach network without 51% hashrate ?
if attacker can 51% hashrate , how attack without withholding block ?

two word looks like different , but two word same way attack network.

Quote from: HeRetiK on September 27, 2018, 03:06:09 AM

The title is not only clickbait, but also utterly wrong.

Block withholding attacks and 51% attacks are two entirely different things.

51% attacks by definition always include the majority hashrate, block withholding attacks not necessarily do.

Granted, block withholding attacks such as selfish mining are at their most effective with the majority hashrate, but then again every attack on PoW is. In the end once a miner achieves majority hashrate they can attack the network whatever way the like, regardless whether they decide to withhold blocks or not.

Apart from attacks on the incentive structure of PoW such as selfish mining, block withholding attacks are usually thwarted by... waiting for confirmations. That is, by using the protocol the way it was meant to be used.

That being said:

Quote from: qcitycoin on September 27, 2018, 02:42:59 AM

A particular signer is an account owned by a foundation or organization that initially designs the block chain or operates the block chain, and is called a verifier.

So the solution to block withholding attacks is.... federated trust.

...

*slow clap*

AGD

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So much work destroyed with 2 answers. Sorry for your loss of time...

HeRetiK

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The title is not only clickbait, but also utterly wrong.

Block withholding attacks and 51% attacks are two entirely different things.

51% attacks by definition always include the majority hashrate, block withholding attacks not necessarily do.

Granted, block withholding attacks such as selfish mining are at their most effective with the majority hashrate, but then again every attack on PoW is. In the end once a miner achieves majority hashrate they can attack the network whatever way the like, regardless whether they decide to withhold blocks or not.

Apart from attacks on the incentive structure of PoW such as selfish mining, block withholding attacks are usually thwarted by... waiting for confirmations. That is, by using the protocol the way it was meant to be used.

That being said:

Quote from: qcitycoin on September 27, 2018, 02:42:59 AM

A particular signer is an account owned by a foundation or organization that initially designs the block chain or operates the block chain, and is called a verifier.

So the solution to block withholding attacks is.... federated trust.

...

*slow clap*

qcitycoin

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Proof Of Online - Solution for BWA(Block Withholding Attack)

Proof Of Online is used as a supplement to the Block Withholding Attack (BWA), a type of 51% attack on the block chain.
BWA (Block Withholding Attack) is a process that creates a longer malicious block in the off-line state and then invalidates the normal transaction.
All PoW-based coins, including Bitcoin, are potentially at risk and therefore suggest a way to fundamentally block off-line block generation.

[Contents of technology]

The height % n == 0 block of the block chain (eg, every xxx00, xxx10, xxx20, ..., xxx90 when n = 10) is called a PoO block.
Always include a signature signed by a particular signer, and the signature information is recorded by adding a VchBlockSig field to the header.
A particular signer is an account owned by a foundation or organization that initially designs the block chain or operates the block chain, and is called a verifier.
They sign the PoO block with the private key of the public address to provide that the block is synchronized to the network.
All other nodes accept the block by confirming that the PoO block has been signed with the public address of the foundation.
A node with a public key of a verifier is called a verifier node to distinguish it from an ordinary mining node.
It records the verifier public key list operated by the Foundation like the SeedNode operation method in the program source, and the block addition operation for online certification grants authority only to the verifier node.
With this logic, an attacker can only have fewer than the number of blocks defined by %n, so even if he seizes the network hash power, he can not get enough time to do a malicious double spending attack.
The miners of all blocks can be identified as the corresponding block with the seed node operated by the foundation.
For this reason, the name of this algorithm is called Proof Of Online.

[The way of operation]

In order to minimize the repulsion of existing miners, mining compensation for PoO block is limited to the commission of the transaction and the appropriate n value is set.
In the case where all of the verifier nodes stop operating, if the block time is more than twice the normal block time, the nth block will also enable mining of general miners.
If a verifier node is added or a transfer of authority is required, it is approved by a co-signature of more than a majority of verifiers, and the new verified verifier is managed in the client's internal database of each node

[Application of technology]

The PoO solution will be the first to be applied to the QCity Coin, and a detailed description of the technology will be replaced by the corresponding technical white paper.
Qcity coin technical white paper : http://www.qcitycoin.org/img/qcitycoin_tech.pdf

[Notoce]
We changed the subject of this post because there was a difference in views on 51% attack.

Topic: [Proposal] Solution for BWA(Block Withholding Attack) - Proof of Online (Read 283 times)