Questions tagged [consensus]
Questions about the consensus system of Bitcoin and the protocol rules that are consensus critical.
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Does everything of a Blockchain Network rely on its underlying “Consensus Protocol”?
I have been reading about and researching on Blockchain Technology for quite a while now, and what I can comprehend from the very primitive architecture of these "Distributed Databases" is that ...
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16 views
How is the fault tolerance measured?
“If the number of nodes that agree exceeds 2/3, the blocks or transactions of clients will be accepted”
Practical Byzantine fault tolerance (pBFT) : (n - 1) / 3
I read those 2 things in a PDF that a ...
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14 views
Byzantine fault tolerance and blockchain: Can this work? Feedback [on hold]
I’m a software developer and I was wondering if this can work (According to my point of view it could work but I’d like to get some feedback)
Two types of Nodes: Proposers, Validators.
1) Proposers ...
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16 views
Byzantine Fault Tolerant - what a benefit? [duplicate]
According to wiki, if we had m generals, than we need 2m+1 to meet consensus.
So it's about 66.6% + 1 generals
But what the reason to use consensus like BFT?
Why we can't get result of the most (50%...
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14 views
Private Blockchains: Blocks’ validation
I’m a software developer and I’m trying to understand blockchain at a code level
I have the following issue:
There’s a private blockchain, this private blockchain does not have any relation to ...
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1answer
20 views
Private Blockchains: Validation
I'm a software developer, and I have some questions about private blockchains, I'd like to have technical answers since I'm trying to understand blockchain at a code level. I'm going to write a ...
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1answer
26 views
Proof for “Is an immutable, decentralized blockchain possible without economical incentives?”
Bitcoin is immutable because of economical incentives. Those who are able to 51% the network can't do it, because it'll result in the value of the currency to drop tremendously, which causes waste of ...
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1answer
23 views
Bitcoin Pluggable Consensus with Algorand? [closed]
Algorand is an extremely promising consensus protocol -- Could Bitcoin be configured to use Algorand?
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27 views
On blockchain scalability bottleneck
It is often said that the major bottleneck of blockchain scalability is that every (honest) node has to process every (valid) transactions. But the progress of a blockchain is how fast it reaches ...
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83 views
Did the introduction of VerifyScript cause a backwards incompatible change to consensus?
My question is about the changes to bitcoin done by commit range [a75560d8, 6ff5f718], and their effect on consensus.
Out of this range of four commits (all attributed to satoshi) during the dates ...
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30 views
Why is PoW 51% attack resistant?
I was trying to understand why PoW makes the blockchain 51% attack resistant. From my understanding, we can think of PoW as a way to assign a leader who would decide what the next block is. I can see ...
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What is the best way to test new consensus protocol?
I wanted to test a new consensus protocol. However, the bitcoin core is a large codebase (>100k lines). Is there any small codebase which is designed to test new consensus protocols and includes only ...
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Why Spectre has a “weak” liveness?
According to this article: (https://medium.com/@avivzohar/the-spectre-protocol-7dbbebb707b5) written by one of Spectre's author (Aviv Zohar), it is mentioned that Spectre has weak liveness.
What is ...
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2answers
77 views
Exact definition of “Liveness” and “Safety” properties in a consensus?
Two main properties of a consensus are "Liveness" and "Safety".
What are the exact and precised definition of "Liveness" and "Safety" properties in a consensus ?
Are the following definitions ...
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1answer
41 views
Is there a max number of tx outputs allowed by consensus? [duplicate]
It seems good for preventing an UTXO bloat by restricting max number of outputs of TX(or block) can have.
Is there such a restriction? if there is, which part of source code should I read? If not, why ...
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15 views
Does the BFT solution from lamport guarantee liveness?
Solution: https://people.eecs.berkeley.edu/~luca/cs174/byzantine.pdf
Although there is a lot of material about this, I am still not sure what the answer is. I found two different statements:
Yes, it ...
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1answer
23 views
Bitcoin economic nodes, concensus, and historical nodes
With regards to the recent dos + inflation bug, and seeing that most nodes on the network have still not upgraded with the patch (lukedashjr's chart here: https://luke.dashjr.org/programs/bitcoin/...
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57 views
Byzantine Fault Tolerance Threshold of Bitcoin: 1/2 or 1/3?
According to this answer: https://bitcoin.stackexchange.com/a/58908/41513 a Byzantine Fault Tolerant (BFT) consensus threshold is 1/3, that is contrary to belief that the Bitcoin network is secure (...
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2answers
65 views
Do miners become temporary dictators of blocks they mined?
This is something I've read here: https://blockgeeks.com/guides/bitcoin-forks-guide/
"When a group of miners discovers and mine a new block, they become temporary dictators of that block"
Can anyone ...
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2answers
262 views
Why didn't Bitcoin implement segwit in the first place?
Why didn't Bitcoin implement segwit in the first place?
Why and how does non-segwit Bitcoin enable a miner to change a transaction's txid?
From Mastering Bitcoin ch. 7 § "Transaction identifiers":
...
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3answers
117 views
Game Theory in Blockchain?
The blockchain consensus seems to be very related to the Game Theory, when each participant tries to achieve their "favorites", where defining "what favorites means" is not very easy, since a ...
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1answer
42 views
Tendermint consensus: Are validators “known” and “pre-selected”?
What are similarities and differences between Tendermint consensus and Proof-of-Stak?
For example, in both consensus, a validator is selected randomly (I think in Tendermint consensus they are ...
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29 views
Leader election-based Blockchains public?
Consensus protocols such as those of Tendermint, Red Belly Blockchain or Algorand can be of great help when dealing with the problem of Finney attacks, and similar sorts of abusing of excessive 'thing'...
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1answer
26 views
Bitcoin version conundrum
Given that the Bitcoin node software not centrally controlled (auto updated) and many different versions and implementations exist around the world, how would a core change be possible if it is not ...
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1answer
155 views
Is PBFT a consensus algorithm?
Can we consider PBFT (Practical Byzantine Fault Tolerance) as a consensus algorithm ?
And if yes, How does it work?
And is it similar to other consensuses such as PoW, PoS or PoA ? Or it is totally ...
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1answer
97 views
Is “Proof-of-work” a subset of “Byzantine fault tolerance (BFT)”?
Can we say that Proof-of-work is a type of Byzantine fault tolerance (BFT) ? In other words, is PoW a subset of BFT ? Or they are two different categories?
Please note that there is a similar ...
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1answer
45 views
Consensus roles for op_return
What is the validation rule, not policy, for op_return? What is the maximum length of the data that can be attached? Is it 514 bytes? As if the maximum script size was 520 bytes -1 byte for the ...
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1answer
67 views
How to select a leader in RAFT consensus protocol
Suppose a network of 5 nodes uses RAFT consensus protocol. Each nodes maintains a transactions log which consists of a list of the log entries. Each log entry again consists of index and term. All of ...
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1answer
87 views
the maximum possible entries a network can accept in RAFT consensus?
Suppose a network of 5 nodes uses RAFT consensus protocol. Each nodes maintains a transactions log which consist of list of log entries. Each log entry again consist of index, term and command. The ...
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1answer
23 views
How is the amount of proof-of-work invested in a chain calculated?
The bitcoin whitepaper (page 3) states
The majority
decision is represented by the longest chain, which has the greatest proof-of-work effort invested
in it.
I could not find how exactly this ...
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0answers
26 views
What is the “Oracle Problem” definition exactly and briefly?
What is the Oracle Problem definition exactly and briefly? Does it mean "trusting on a centralized Oracle" ? Or "How to reach a consensus between a group of Oracles" ? Is the matter "centralization" ...
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“consensus over state” vs. “consensus over events”?
Does someone know what is difference between "consensus over state" and "consensus over events" ?
I found just title of a reference i.e. "Ian Grigg, blog post “The Message is the Medium,” 2017."
...
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1answer
53 views
Delegated Proof of Stake (DPOS) vs. Proof of stake?
What is the main difference between Delegated Proof of Stake (DPOS) vs. Proof of Stake? Is there any significant advantage for security? (since PoS in general suffers security problems.) And which ...
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2answers
82 views
Do private blockchains need consensus protocols?
My understanding is that in a private blockchain, the participating nodes verify and agree that the block is valid and only then add it to the blockchain.In this scenario, are consensus protocols (...
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3answers
805 views
How is Bitcoin governed by mathematics?
I keep hearing talks from Bitcoin evangelists that claim Bitcoin isn't governed by any central authority, rather it's governed by mathematics.
What exactly do they mean when they say "governed by ...
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1answer
63 views
What is the “main” difference between consensus mechanism of Bitcoin and Ethereum?
Bitcoin and Ethereum both use proof-of-work (PoW) consensus mechanism. One of differences between Bitcoin Pow and Ethereum PoW is difficulty level, meaning that while in bitcoin block generation rate ...
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2answers
80 views
Is it logical to use “Proof-of-Authority” for a “public” blockchain?
According parity.io website:
Proof-of-Authority is a replacement for Proof-of-Work, which can be
used for private chain setups.
And also:
The chain has to be signed off by the majority of ...
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3answers
350 views
PoW 51% attack vs. BFT 1/3 attack?
So from what I understand, Bitcoin's PoW is prone to 51% attack, but as a distributed system it is also prone to BFT's 1/3 attack right? I think it's mathematically proven that in a distributed system,...
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1answer
38 views
Distributed Consensus
"Distributed" means operating on more than one devices which dont share physical memory and perform their task (which might be storage or computation) to perform one single task (which in our case ...
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3answers
141 views
Has PoS really been proven secure under comparable assumptions as Bitcoin?
I am just reading this paper which claims to be a formal proof that Cardano's latest Ouroboros PoS protocol ("Genesis") gives similar security guarantees than Bitcoin's PoW protocol. Unfortunately, it ...
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1answer
104 views
Why was BIP34 (Block v2, Height in Coinbase) not implemented via the coinbase tx's locktime or nSequence?
At some point in 2011/12 miners started using custom mining algorithms ignoring the best practise to mine to a different new public key (hash) for each subsequent block. This lead to a lack of ...
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1answer
77 views
Hyperledger consensus protocol
I'm soo deep inside the consensus protocols like PoW, PoS, PoA or other variants used on permissioned/private blockchains such as JPMorgan's Quorum (Based on Raft), Istambul etc..
But I've not ...
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3answers
51 views
Why is a softfork unable to divide the network?
I was wondering why a soft fork cannot in principle divide the Bitcoin network as a hard fork can. I understand that a soft fork, by definition, involves only tightening the consensus rules, but the ...
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1answer
102 views
Would nine 1MB transactions potentially create havoc on the BitcoinCash network
It appears that the BitcoinCash chain is still on its original BCH main chain, and non-upgraded mines/exchanges/wallets can still transact there.
What then would happen if nine (or more) 1MB ...
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1answer
38 views
How can one full node know whether other full nodes added certain block to their blockchain?
How can one full node know whether other nodes agreed a block suggestion of a miner (so it will know whether to add the block to its blockchain too)?
thank you
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1answer
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How to: Check whether or not transaction inputs have been previously spent
Maybe I have overlooked it, but I think the "Bitcoin Developer Reference" does not specify how a miner has to check whether or not transaction inputs have been previously spent.
How is it done?
And ...
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How Ripple ledger behaves in a cross border transaction
While I was reading on Ripple, the following part of in cross border payment handling confuses me.
If it's between two banks, it says that once the participating parties agree on exchange rates, the ...
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2answers
221 views
Do all consensus algorithms aim to solve the Byzantine generals problem?
Can I clarify my understanding:
Byzantine Fault Tolerance is a characteristic of a system to tolerate a class of failures belonging to the byzantine generals problem.
Byzantine Fault tolerance is ...
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49 views
DPOS vs tendermint in Ethereum
what is the difference between DPOS and tendermint?
and which one can be used for partially decentralized blockchain ?
note i will use ethereum
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2answers
56 views
Has a consensus algorithm where temporary authorities are fairly “elected” via PoW been discussed?
In the usual proof-of-work consensus system, miners constantly compute hashes (“wasting” resources). What if hashing were restricted to a certain time window, e.g., 1 hour per day?
This could act as ...
