Questions tagged [proof-of-work]

A proof-of-work (POW) system is an economic measure to deter denial of service attacks and other service abuses such as spam on a network by requiring some work from the service requester, usually meaning processing time by a computer.

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157 views

How is difficulty used by mining clients?

I understand how it's calculated and what its intent is. I'm unsure of how the value is being used in practice.
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556 views

What is the set number of Ether in existence during POW and then POS? [duplicate]

How many Ether exist during POW and then POS? Is it unlimited inflation?
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257 views

Transaction throughput: POA vs POW in private blockchain networks

I know that proof of work is resource intensive, while proof of authority is much faster as no consensus is required since the network is validated by the proper authorities. But in terms of the ...
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1k views

Transaction confirmation time with proof of stake [duplicate]

With proof of work and the associated mining process, transactions must wait till the block verifying the said transaction reaches enough depth within the blockchain to avoid relying blocks generated ...
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How to make atomic swap between Ethereum and POS chain?

There's simple way to make atomic swap for smart-contact chain and any POW chain. For example for Ether <> BTC: Alice sends some Ether to the swap smart-contact which locks this money. While ...
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what does memory hard mean in ETH POW? [duplicate]

I came across the term memory-hard while ready about ETH POW algorithm. What does it mean when someone says that POW is memory hard?
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Scalability of a scientific computing proof of work token

Say I want to create a contract that rewards miners with an ERC20 token for discovering solutions to a certain mathematical problem where the following points apply: The problem is well defined and ...
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3k views

Does Ethereum has halving or anything equivalent?

Bitcoin has a halving which will likely happen around June 2020. Is there anything similar for Ethereum? If not, why?
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1k views

How does Ethhash compare to mining algorithms used in other blockchains?

When it comes to mining, I'm more or less aware of how Bitcoin's simple SHA256 mining works, how Litecoin & similar attempted (and failed) to introduce ASIC-resistance with Scrypt, and how ...
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176 views

Public-of-chain using proof-of-authority, where authority is defined as the amount of work on your public key

I'm wondering if there would be benefits to create a public blockchain based on the same algorithms used for private, proof-of-authority blockchain, except replacing the concept of authority by the ...
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4answers
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Why is my proofOfWork() working on every nonce?

I am running proof of work function from my deployed contract in ethereum wallet by providing any random number as nonce. As per my understanding the PoW() shouldn't work on every nonce, but in my ...
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395 views

How blocks are calculated in POS

In POS people bet on the blocks to be added to chain and the honest block wins and the people who have voted for honest blocks get a share in the rewards. But one thing i am still confused is, who ...
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Why is ethereum's mining function is safe as bitcoin's proof of work?

bitcoin's mining time is about 15 minutes while ethereum's mining time is 10 seconds. Is not it bad for ethereum's mining time to be too short? (from security aspect). Why is it so important for ...
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How are transactions ordered in POS?

With POW, the miners who finds the block chooses the order of transactions in that block. How will this work with POS?
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I don't really understand how mining works, anyone can help?

I am currently studying Ethereum all by myself, and am struggling to understand how mining and Proof of work work. I have read many posts and books about it but still hard to understand how the ...
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218 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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1answer
125 views

How many blocks can a cache of 1gb (1024) hold tentitively?

If I use a command geth --cache=1024, how many blocks it will hold runtime in cache. And what will be the size of each block. Is there any calculation? And is there any way using which we can force to ...
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Disable proof of work in Whisper

I have a private network and am looking to disable Whisper's required Proof of Work when sending a message. This issue talks about how the source prevents this, but I'm wondering if there's another ...
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146 views

What do the parameter in sha3() in Proof of Work implementation of Ethereum mean

sha3(nonce, currentChallenge, block.blockhash(block.number-1)) In this line I get it that blockhash is a random number, but why are we taking it from the previous block, any hard and fast rule here ? ...
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How do I use the proof of work function given in here: https://www.ethereum.org/token#proof-of-work?

I am creating a cryptocurrency contract, which rewards the miner a proof of work generated. To get the reward you will need to call proofOfWork(uint nonce). If the nonce is correct, the miner is ...
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Who generates the mathematical problem for miners?

In POW miners solve an problem for successfully mining a block, who provide the question to the miners ?, does all miners work on same problem ?, and how the miners verify the answer ?, if the problem ...
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345 views

During the POW/POS transition, why would a POW miner choose to mine on the chain with the POS consensus algorithm?

As the title says, what incentive does a POW miner have to mine on the hybrid POS chain? They would, effectively, be removing their own economic incentive from the consensus mechanism. I understand ...
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1answer
380 views

How were the “dynamically adjusted target” in mining expressed in the Yellow Paper?

The one validity condition present in the above list that is not found in other systems is the requirement for "proof-of-work". The precise condition is that the double-SHA-256 hash of every block, ...
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How feasible it to combine Proof of Work and Proof of Elapsed time consensus to create a custom blockchain?

I wonder if it feasible to create your own custom consensus by combining Proof of Work and Proof of Elapsed time? How would I approach it? Any tools or frameworks to build it? I appreciate all the ...
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How nonce is calculated EthHash POW?

So I get that Ethereum POW is different from Bitcoins POW, I dont get the calculation of nonce from the pseudo random nodes from the data set to serve as POW, can somebody elaborate on this ?
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Does every node execute contracts in Proof of Stake? If yes, why?

In Ethereum, for Proof of Work this sentence is true: "Every single operation that is executed inside the EVM is actually simultaneously executed by every node in the network. This is why gas exists" ...
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1answer
488 views

POS migration hard fork

when Ethereum will switch to the proof of stack consensus mechanism as i know it will get rid of the POW going through a hard fork. is it possible to have the similar scenario that happened before ...
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How do the miners prove to have actually run the contract code that they claim the gas fees for? [duplicate]

How is the fact of execution of the contract bytecode in the VM proven by the miner? Why can't a miner just say "uhm, the contract didn't do anything so I take all the gas"?
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Why 51% hash power require to control the network?

Why 51% is explicitly mentioned to get control over the network?. Why not 50 or lesser ?. Anyway there is no central authority to decide, whether 51% is attained or not?.
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How many nodes can confirm the correctness of the hash value by miner?

After mining the hash value for the new block, How many nodes can confirm the correctness of the hash value by miner? In one of blockchain paper, all other nodes must mutually confirm the correctness ...
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3answers
141 views

Blockchain Recent Scaling Proposals : (Sharding, blocksize , SegWit, GHOST, Lightning, multichains, sidechains, DAGs)

What are some of the most recent scaling proposals for Blockchain? Ie. various blockchain scalability topics including the blocksize debate, SegWit, GHOST, Lightning, multichains, sidechains, ...
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What are CUDA and OpenCL? How and why are they used for PoW Mining?

It is often suggested that, to practically participate in mining, one must obtain a graphics card and install CUDA and/or OpenCL libraries. From their wikipeda definitions: CUDA is a parallel ...
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Does the consensus going to fail if contract has “now” filed?

now keyword stands for current time. So if contract has now filed, peers may have different times leading to different data in blockchain.
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Why is PoW needed to confirm transactions and add new blocks [closed]

I have read and I vaguely understand about how Proof of Work works and what does it do. But why PoW? Or more bluntly, why do we need any algorithm at all to add new blocks. What would happen if ...
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259 views

how to setup hybrid PoW+PoS or PoA private network (geth)

I am aware about PoW and PoA setups of ethereum private networks but would like to know if anyone could help or point me the direction how to build a hybrid PoW + PoS or PoW + PoA ethereum based ...
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1answer
251 views

Nonce in proof of work

When a block is being mined nonce will be generated so that the nonce is appended with the previous block hash,data. Then the resulting hash of that appended value should be less than the target. The ...
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1answer
119 views

Can I use Ethereum to prove work? [closed]

I need to store pdf hash in blockchain to prove my pdf existence. I thought to use blockchain, but public blockchain required some fee ... I don't really understand if ethereum could be my solution......
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42 views

how transaction in block-chain is validated

Please explain complete procedure/journey how transaction in block-chain get validated by miners, From broadcast of transaction to become part of new block.
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62 views

What are the challenges involved moving Ethereum from POW to POS?

I'm aware of the idea to roll out the POS protocol by using a hybrid model of POS/POW. What are the challenges of such a change? This hybrid model would make mixed adoption(for legacy users and new ...
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3answers
72 views

Question on the security of forks

Reading the whitepaper of Ethereum I came up with the following questions on forks. Let me explain: Lets say that I send 1 ETHER to an address A1 to buy something and this transaction gets logged on ...
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Updating local variable across http efficiently [closed]

So a bad way to do what I want to do is this while(True): challenge_number = http(request) # where the value is subject to change miner(challenge_number) If challenge_number across http ever ...
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Resources of a miner's reward in Ethereum?

To compensate the miner who could solve the PoW as the first one, they will receive some coins as a reward for keeping them motivated due to the costs related to mining process (electricity and ...
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1answer
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PoW in Public blockchain Vs. PoW in Private blockchain

I am reading about consensus mechanisms in blockchain and it is stated that PoW (Proof of Work) requires longer confirmation time compared with voting-based mechanisms. But some things are not clear ...
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Problems trying to implement Nexus (NXS) Skein-Keccak (SK1024) in Golang

) I know this might not be the perfect place to ask, but as ETH is also a Blockchain Tech and also uses Go within their stack, I couldn't find a forum that seems more appropriate. My Problem: I'm ...
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Relationship between fault tolerance and network latency

I'm currently studying Ethereum's PoS and a sentence on the relationship between fault tolerance and network delays caught my attention in the Proof of Stake FAQ. Quoting Vitalik: In this model, ...
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1answer
320 views

Proof of work vs Proof of Stake [duplicate]

I'm newbie to Ethereum and trying to make things clear. I've read few articles about PoW(proof of work) vs PoS(proof of stake) and what I understood is, Proof of Work is nothing but the mining, in ...
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1answer
81 views

Can you use Ethereum to build a blockchain with a different proof mechanism? [duplicate]

This may be a silly question but is it possible to build a system that can use both the euthereum proof of work/stake and a custom built proof using the same ethereum nodes?
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35 views

Leverage short positions in decentralised PoW currencies

Hint I asked this question in a similar style already on bitcointalk and on bitcoin.stackexchange. But in these threads, there are no good answers and I thought maybe it would be better to ask the ...
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395 views

Is Casper implemented yet?

So as far as I understand, Proof-of-stake works by all nodes voting on what they think the correct next block should be and then recieving a small reward out of thin air if they guess correctly and a ...
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61 views

How and from where i can learn about Ethereum Mining algorithm(including PoW)? [duplicate]

How a transaction is mined to a block?