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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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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How can one blockchain with the same block heigth as another, have more Proof-of-Work

I am reading Andreas M. Antonopoulos's book and In chapter 10 - Assembling and Selecting Chains of Block he writes: Under most circumstances this is also the chain [main chain] with the most block ...
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57 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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96 views

What happens to the blockchain after the miner wins the puzzle?

I have some problems understanding the flow of consensus mechanism, so far I know, In PoW when validating a transaction the miners will compete with each other to solve a puzzle, the miner who find ...
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How often should a mining pool be notifying workers about new work (cancelling current jobs)?

I'm trying to get a handle on the Stratum mining pool protocol. If I set up a mining pool client, I will initially get something to work on. Let's say it takes me a while (e.g. an hour) to solve the ...
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58 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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456 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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How to protect the early stages of a proof-of-work application?

For a given cryptocurrency or other blockchain application, proof-of-work provides intrinsic security in the algorithm itself that makes it unlikely that someone can attack the network unless they ...
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265 views

What was the first transaction which resulted in the very first bitcoin being mined [duplicate]

OK, so I understand that bitcoin in introduced into the system when mining is performed. And mining is a process of adding transactions records to the bitcoin chain of blocks. And transaction (...
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45 views

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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441 views

Is Proof-Of-Work simply a decentralized clock?

I have not seen anyone explain Proof-Of-Work this way, so I thought I'd share it here, I'd be curious to know if I'm completely off. It seems to me that PoW is simply a distributed decentralized ...
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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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203 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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166 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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Does every nonce really have an equal chance of winning?

I set out to test the claim: "Every nonce has an equal chance of winning." Time Evolution So, I plotted, with gnuplot, the nonce values vs. hashes for all the valid blocks in the blockchain:(Also, ...
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In what sense does the security model of proof-of-stake require users to “log on to the internet every few months”

This is primarily a question about something I heard Vitalik Buterin say in an interview the other day. (Unchained podcast's January 9, 2018 episode, at 34 minutes, 15 seconds) I quote: As far as ...
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778 views

Why you need to rehash each block after a changed block when changing data in a blockchain?

Maybe my question is stupid, but, why you need to rehash each block after a changed block when changing data in a blockchain? Each block contains a hash of its data and hash of previous block. If I ...
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905 views

Implementing NiPoPoW algorithm

Hello, We, a small team, have implemented about 95% of a breakthrough scientific proposal that is describing the NiPoPoW Non-Interactive Proofs of Proof-of-Work. You can find our source code ...
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As a miner, why would I forward transaction with high transaction fees to other miners?

Miners receive transaction and broadcast it to other nodes. Node that solves the puzzle will add that transaction into the block it mined. But as a miner why would I broadcast a transaction with very ...
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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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125 views

What dead simple algoritm can be used for generating checksums by pen and pencil?

I'm holding a course on Bitcoin and blockchain technology. On my agenda I have an exercise where I'm going to let the attendees create their own blockchain on the wall using post-its. I'm in search ...
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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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51% attack and rewriting to the latest checkpoint

This is not a question about the consequence of a 51% on the price nor as to the motivation of the attacker. Let say we don't care that it's not realistic and we don't care that the attacker wouldn't ...
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What other whitepapers are there for coin distribution models like POW (proof of work) and POS (proof of stake)?

I'm looking for other types of distribution models for crypto coins that are like POW (proof of work) and POS (proof of stake). I'm assuming these are a type of distribution model for coins, or is ...
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207 views

How finding a working nonce says anyting about the validity of an initial transaction

I am by no means an expert, nor a cryptographer, but I would be interested in knowning a little bit more than what happens at the end of the following chain of events. What happens at the end of the ...
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How does the bitcoin transaction fee get paid to miner(s)?

According to https://bitcoinfees.info/ The current "cheap" rate for a bitcoin transaction is $22. How does this get paid to the miners? Is it just one miner that verifies the transaction, puts it ...
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What's so special about six blocks for confirming transactions?

I read that when your transaction is part of a block that has five other blocks on top of it, you can feel safe that your transaction is not in danger of being orphaned because someone else would come ...
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72 views

What are the chances that Bitcoin changes its proof-concept one day?

Is it realistic/possible that the bitcoin core team make a new Bitcoin Improvement Proposal (BIP) on day in which they propose to change Proof of Work (POW) with something else (proof of stake for ...
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170 views

Projects built on the Tendermint platform? [closed]

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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Who are you solving algorithms for and why?

I am sick to death of people responding to my question with logistics of "how to" mine data or just that you are solving "mathematical concepts" and "algorithms." What I do understand is this - some "...
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What are bitcoin miners really solving?

As with mining, what are the bitcoin miners really solving? I read they are solving hashes, but what does that really mean. Can we see what they are solving? Can someone give an example of what a ...
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371 views

Egoistic miners combined with large transactions destroy PoW?

EDIT There is a clearer description of some parts of the problem in the link questions. If there is a transaction value much higher than the payment for mining 10 new blocks, how can you trust this ...
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Is there a way to set up proof-of-work systems so they would be even more useful?

One of the arguments made against Bitcoin's design choices is that it wastes resources authenticating transactions. In particular, finding small hashes is completely useless for the world. Are there ...
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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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Bitcoin Proof of work puzzle inconsistency

At this time, I am really confused about the Proof of work puzzle because as I have seen in some documents, there are 2 different ways to talk about them. The first one I have seen is from some ...
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211 views

Hashcash proof of work bitcoin sha256

I'm looking for a program or something to run from the terminal in mac. That does the same thing as the program found here. http://www.blockchain-basics.com/HashPuzzle.html?nonce=221 What I'm looking ...
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126 views

How does the network know the legitimate chain in a double-spend attempt?

Apologies if this has been covered, but there's one area of the Bitcoin network that is not clear in my head, and it's intimately linked to the double-spend problem. Suppose Person A is purchasing an ...
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How proof of work prevents double spend

One article I am reading said that proof of work system is used in Bitcoin to prevent double spending. More particularly: Imagine we are protecting against double spending in following way. When Bob ...
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How is mining time validated?

New target is calculated from the T(new_block-1) - T(new_block-2016). Here T is the time miner mined the block. Miner itself sets this time for the block. Thus miner can falsify this time. I see a ...
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186 views

Creating blocks while more transactions arrive and proof of work mechanics

I am having a hard time understanding the details of how blocks are getting created by miners while many transactions are being received by various nodes at slightly different times and what ...
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92 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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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 ...
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920 views

How many nonces on average do I need to try in order to get n leading zeros?

Assuming 256-bit hash output, how does the (average) number of nonces I need to try (to solve the proof-of-work puzzle) grow with the number of leading zeroes required, n? Is there a bound on this ...
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1answer
273 views

Can the mining pool with the most mining power always win? [duplicate]

Suppose we have three mining pools, one with 40% of computing power, and the other two having 30% of computing power each. Will the node with 40% power, be able to solve the puzzle for each node ...
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858 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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How does Proof of Burn work?

I have been trying to make a comparison between PoW, PoS and Proof of Burn. While I understood the other two, I want to know how exactly Proof of Burn helps in attaining the consensus. One burns ...
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306 views

What is the downside of not using Proof of Work for validator selection?

Bitcoin uses Proof of Work for two things: one is to secure the blockchain with strong cryptographic signatures like a Merkle tree, and the other is to crown the validator which "mines" a solution as ...
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230 views

Is it possible to build mining reward pooling directly into Bitcoin?

Mining pools were formed quite early in Bitcoin's history. Since then, they have not been considered ideal because of more and more centralization creeping in. But it seemed the community has learned ...
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Transaction verification vs block mining

I cannot clearly understand if the transaction verification is done over a single or double phase. This is my understanding. Once a transaction is completely assembled, its inputs and outputs ...
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184 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)...