Questions tagged [proof-of-work]

This tag should be used for questions regarding how Proof of Work works and Proof of Work algorithms. Proof of Work is a scheme where a 3rd party can verify that someone performed at least a certain amount of work to produce something. This is used in Bitcoin mining.

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184 views

Does 4 byte Nonce enough to proof of work?

Is it always possible to find an hash value of a block, smaller than the current difficulty, just using 4 byte (Nonce) ? How can we be sure about it ?
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Zero-BTC transaction fees, service-specific mining pools and external compensation

Bitcoin is a network that is proven to be stable, but if you want applications on top of Blockchains you have to play by the rules of the system. For notary use cases (for example), where you would ...
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458 views

Abrupt increase in difficulty of proof-of-work

I am simulating a private bitcoin network that I started with the initial difficulty set to (1/2)^16, however after about 20 blocks of mining on the network it increased to 1 and has been constant ...
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57 views

Proof-of-Stake: How to ensure immutability of the blockchain?

In Proof-of-Work, a miner tries to solve PoW puzzle based on the hash of previous block, such that in case of changing block B_i, all blocks after that (blocks B_i+1, B_i+2, ...) are no longer valid ...
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How to check that Genesis Block has valid proof of work using CheckProofOfWork() function?

I have been learning the ins and outs of the bitcoin source code over the past 3 months but I can say I have not fully mastered it yet. I wish to understand how the genesis block is validated using ...
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altcoin debug.log shows ERROR: CTxDB::LoadBlockIndex() : Failed stake modifier checkpoint height=0

What I have done so far: Generated new Genesis Block Generated new MerkleRoot Updated MerkleRoot Updated Genesis block values Commented out these lines Compiled on CentOS 6 Created altcoin....
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What's a good repo to fork if you want to create a blockchain like a “Math” coin or Curecoin. (mining equations, not hashes)

I want to create my own crypto currency and I want to know what's the best github repo to fork when it comes to making a blockchain that's based off of getting the miners to do mathematical ...
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159 views

Limit of Proof of Work [duplicate]

I do not have a complete understanding of bitcoin, but I feel that the PoW concept will not do it in the long run, so I need you to explain to me if I'm wrong. First of all, all this work force is ...
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104 views

What are bitcoin miners actually solving? [duplicate]

I've read all other answer, but nobody really gives an answer. Whom for are they solving, and what entity outside BTC community has benefits from all the electric energy wasted in the process of doing ...
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588 views

Where can i find proof of work in bitcoin core source code?

does anyone knows which part of the bitcoin core source code contains the proof of work for mining, creating of block and adding to blockchain? what are the files and functions involves? https://...
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168 views

Projects built on the Tendermint platform?

The Tendermint project sounds like a very promising proof-of-stake implementation. What public projects are being built on this platform?
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557 views

Why miners solve a puzzle in proof of work

I am new to block chain, In PoW, I know a puzzle is given to the miners to solve and the miner who solve the puzzle and find the nonce first will create the block. But I don't understand why there is ...
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Why have proof of work?

As far as I can tell, PoW allows multiple parties who don't trust each other to agree on an order of transactions. The fact that every transaction has a hash of the previous block means that you can ...
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3answers
51 views

What is resource of mining rewards

How the coins must be paid miners for mining process is provided? One of resources may be transactions fee. Is there any other resources for proving reward of miners?
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79 views

group proof of work

Right now, every node in a Proof of Work system, solves the POW puzzle independently. Is there any concept of group proof of work, where everyone in the group needs to solve part of the puzzle.
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5answers
166 views

Application of proof of work in bitcoin

Proof of work in spam I understand very well how proof of work is used to prevent email spam for example. Reasoning is since computing the right hash (e.g. with predefined number of zeros for example)...
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23 views

What is meant with 'the highest PoW'?

What is meant when the nodes select the chain with the highest cumulated PoW? How is the highest highest PoW calculated? I thought the concept itself is called PoW.
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72 views

Permissioned or Permissionless blockchain? Which one is PoS more adapted for?

Since in proof-of-stake (PoS) there is no mining process, according to functionality of permissioned and permissionless blockchains, which type is PoS more adapted for? In the other words, is a PoS-...
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36 views

is the proof-of-work for safety or efficiency?

i am reading the proof-of-work (aka: pow, target threshold, difficulty, etc.); my understanding is that pow adds a requirement to validate block headers, so that both benign and malign nodes need a ...
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41 views

Ethereum's PoW difficulty

Bitcoin's block time is about 10 minutes while that of Ethereum is 15 secs. Both are using PoW at this moment, right? How come Ethereum's block time is so short compared to Bitcoin? Is hashing a lot ...
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1answer
97 views

Is the bitcoin blockchain really non-corruptible? [duplicate]

Some people say that proof of work is better than proof of stake, because it's not possible to rewrite the whole blockchain on-spot. One would need to "re-mine" everything. But I think this is not ...
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2answers
182 views

Why are blocks in a permissioned blockchain linked together?

My question: Do the blocks in a blockchain without proof-of-work (i.e. a permissioned blockchain) have to be linked together via a cryptographic hash? Longer version of my question: (Please correct ...
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1answer
49 views

What are the hashes that miners need to do to create a block? [duplicate]

I’m bit stuck in the concept of mining. What are the hashes that need to be created in each block and the chain? Let’s say that we have block A - B - C forming a chain. One source said that we need ...
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1answer
89 views

When does a node mark a transaction as confirmed or unconfirmed?

As new transactions are broadcasted, the nodes keep them in a pool of unconfirmed transactions. One node will add it to a block as soon as it finds a proof of work. At the same time many other nodes ...
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40 views

The “work” in proof of work

How does proof of work function? Why does the "work" in proof of need to have zero utility for the economics of the cryptocurrency to be viable.
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169 views

How does bitcoin implement checkpoint mechanism to finalize the blockchain history?

I read in Peercoin whitepaper that to prevent large blockchain reorganization, bitcoin also implements checkpoint mechanism which finalizes the blockchain history. Can you explain how exactly bitcoin ...
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71 views

Source of entropy for PoW hash

How does bitcoin do it to generate an (upredictable) hash in each new block with sufficient randomness so that no one can precompute it?
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33 views

When does client decide to stop/cancel proof of work algorithm?

I have been reading about bitcoin and blockchain in the last few days, but I have something I don't clearly understand. The "proof of work" may take a long time for a simple node to guess, but if we ...
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1answer
88 views

How many proof-of-work algorithm exists for crypto currencies?

How many proof-of-work algorithm exists for crypto currencies ? We know PoW in Bitcoin and Etherium are different. Is there any other algorithm used for crypto currencies ?
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1answer
702 views

Steal proof-of-work answer from a miner [duplicate]

Is it possible to steal proof-of-work answer from a miner who has insecure machine? Consider a miner who has insecure machine found correct answer of proof-of-work and an adversary steals this it and ...
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1answer
348 views

Is there any link between Bitcoin's PoW and BFT?

As per Bitcoin's documentation, the consensus mechanism in Bitcoin Blockchain is based on PoW. Thus, any miner node successfully computing the hash as per difficulty is eligible to mine a block and ...
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1answer
62 views

Proof of work: optimal number of transactions?

I've been struggling with this Q for a while: My initial understanding was that miners start to work on PoW for new block immediately after the previous round's block is confirmed. My Q is this: ...
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1answer
752 views

What prevents a miner from faking nonce hash

What exactly prevents a miner from presenting a random nonce hash of the block with enough zeroes at the start to get chosen? How is the new hash verified by the other nodes? Since as I understand ...
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1answer
621 views

Bitcoin Mining Computational Power [duplicate]

1/ I do not understand why bitcoin mining is random when hashing is deterministic. reference : https://en.bitcoin.it/wiki/Nonce Can the mining pool with the most mining power always win? What value ...
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3answers
1k views

Difference (if any) between proof-of-work in mining bitcoin vs verifying transaction

I'm trying to understand the proof-of-work idea for verifying a transaction. I think I understand why proof of work is needed to verify transactions (essentially to prevent spoofing/double spending ...
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1answer
44 views

If all Proof of … systems use mining

I understand how Proof of Work (PoW) works now, and am beginning to look at different Proof of ... systems like these: Proof of Stake Proof of Ownership Proof of Existence Proof of Space From what I ...
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2answers
19 views

Is it possible to accurately map hashing power to network size?

Let's say we have a network with n nodes in it. Is it possible, when the hashing power of the network is calculated after a proof-of-work, to accurately estimate n with an algorithm taking the ...
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1answer
27 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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74 views

What is the reason to pay miners “monetary rewards” for mining process?

Is it correct to say that: In Bitcoin, it is crucial to incentivize miners by monetary reward, because mining process has significant monetary cost (energy/electricity cost). ? otherwise, mining ...
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52 views

What would happen if PoW cost were drastically reduced or eliminated?

Assuming Bitcoin had a different method for selecting winning nodes and controlling block time creation, please describe step-by-step how the Bitcoin network would be vulnerable to various attacks. ...
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66 views

Proof of Work: email versus bitcoin

I have read "Hashcash is a proof-of-work algorithm that requires a selectable amount of work to compute, but the proof can be verified efficiently. For email uses, a textual encoding of a hashcash ...
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23 views

What other proof methods are there? [closed]

I am familiar with the proof of work method and a little with the proof of stake method. Is there any more methods that are out there and how do they work?
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49 views

How do offchain transactions get validated/confirmed whilst using Lightning network?

How do offchain transactions get validated whilst using Lightning network?
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How is mining associated to blockchain transactions?

I know how mining works and how transactions are added to the blockchain. What I don't understand is the association between the two...if any. I've read a few times about how a cryptocurrency ...
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1answer
487 views

Block Hash and Nonce generated by GenesisH0 python script is incorrect

After running GenesisH0 python script to generate the Genesis block for a local testnet (using v0.15.1), I got the following results. merkle hash: ...
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1answer
132 views

Proof of Work and Proof of Stake - Competitive advantage

It is said that Proof of Stake will be the mainstream consensus mechanism in the long run. Regarding the nature perspective I totally agree. But it has been rumoured that Proof of stake is more ...
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24 views

randomly assigned pow?

in Bitcoin, every node solves the POW puzzle. instead, are there cryptocurrencies where a random group of nodes is chosen (before block creation), and only that group solves for the puzzle?
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139 views

Where can i find proof of work in Electrum(light weight bitcoin) source code?

Hi does anyone knows where can i find electrum's proof of work in the source? https://github.com/spesmilo/electrum
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2answers
80 views

Review of “equitable” proof-of-work systems

One major criticism against usual SHA-based proof-of-work systems in main cryptocurrencies (except the ecological concerns) is the fact that, years after years, it's more and more dominated by a ...
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Miner modify pending block (not yet on chain) and successfully solve the PoW

For example, I pay a cup of coffee with bitcoin, and later remove that transaction from the pending block that is not yet on chain. After 10 mins, I successfully and luckily solve the PoW problem, and ...