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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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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 setup a hybrid PoW + PoS or PoA ethereum based blockchain. ...
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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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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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Calculate or obtain the TargetDifficulty for Ethereum

So I am trying to create or obtain the TargetDifficulty of a Block. This is so that I can then later proof that the Block was mined at a specific difficulty. I found this, but I could not figure out ...
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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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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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This contract does not implement all functions and thus cannot be created In PosToekns

I have try to run the run PoSToken in remix compiler, So I am getting the the following error, Please help me to solve my problem. "This contract does not implement all functions and thus cannot be ...
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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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Is the cost of attacking POS (e.g. Casper) higher as compared to attacking POW?

I've recently read about Vitalik's (and others) arguments on the cost of attack and cost of defense in POS vs POW. Is it really true that attacking POS costs more than POW? This sounds counter-...
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99 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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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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62 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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Using Custom PoW Algorithm with Parity?

If I wanted to create a PoW alrorithm to replace ethash on a private blockchain, how would I tell Parity to use it?
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In Proof of Stake, how can we prevent party owning large portion of stake want to attack?

In Proof of Work, there is this so called 51% attack. But lets say, in Proof of Stake, one day, Google and US government teamed up and owns 75% of the stake. Then they can do whatever they want right?...
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148 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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In the proof of stake world, does the person holding the most coins have the advantage? [duplicate]

In attempting to understand how proof of stake is different (and potentially better) than proof of work, I'm curious about if one stakeholder holds twice as many coins as another stakeholder, does ...
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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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How is the Two Generals Problem solved with proof of work?

Here is an email where Satoshi Nakamoto explains how PoW solves the Byzantine Generals' problem http://satoshi.nakamotoinstitute.org/emails/cryptography/11/ The proof-of-work chain is a solution to ...
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68 views

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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3answers
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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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1answer
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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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Mining equivalent in Proof of stake: What reward is there for betting?

Vitalik's post https://blog.ethereum.org/2015/12/28/understanding-serenity-part-2-casper/ outlines the process of the betting strategy. However it doesn't discuss the rewards to which a validator is ...
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Is it viable/possible to develop eth smart contract for hard processing task?

Let's assume there is a task, that should be reliably and correctly executed and there is no simple way to check if it's done correctly, without actual execution, e.g. 1. Download image/video from ...
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1answer
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Proof Of work (with real world example needed)

I have understood the sha256 algorithm example . But how does a node in a network decide if a transaction is valid or not .
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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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How can I prove `sha256^1000000000(X) = Y` for a verifier that can't perform that much computations?

Suppose, for example, I want to write an Ethereum contract that pays 1 ETH for whoever gives me the right answer to sha256^1000000000("good boy"). That amount of computation would be much higher than ...
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2answers
264 views

From Proof-of-Stake to Proof-of-work

Have any (cryptocurrency + blockchain)s switched from proof-of-stake to proof-of-work?
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389 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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3answers
129 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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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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Is POW required for a private blockchain?

PoW is a mechanism to keep block chain incorruptable from malicious nodes. Now in a private block chain where all nodes are supposed to be honest, what purpose PoW would serve? Would it not be just a ...
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What's the difference between Nakamoto consensus vs Proof-of-Authority vs BFT

Documentations all around the internet are filled with these terms to categorise consensus protocols. What is the difference between them. For example: many call parity's tendermint as a BFT type ...
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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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272 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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2answers
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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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1answer
681 views

Has proof-of-stake been formally proved?

From my understanding Bitcoin solves the Byzantine's Generals Problem under the assumption that there's no attacker that control more than 50%+1 of the mining power and this has been studied and ...
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1answer
129 views

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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1answer
433 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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3answers
4k views

PoS, how will it prevent 51% attack?

Wouldn't it be possible for a government seeking to destroy the blockchain just "print out" the money for getting 51%? if they plan to bring the network down then the printing wont effect the fiat ...
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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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1answer
1k views

Does next hard frok (initial PoS implementation) remove difficulty bomb?

To my understanding, we now started something called ice age period where difficulty bomb becomes harder exponentially and this was implemented to make sure everyone switches to new PoS chain when it ...
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1answer
25k views

Is Ethereum ASIC resistant?

I've heard that Ethereum mining is ASIC resistant since it requires memory-hard hashing algorithms. However, why can't miners buy large DRAM and devote the memory to ASIC mining? What prevents miners ...
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2answers
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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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1answer
1k views

How is the 1GB dataset generated, which is used by the Ethash algorithm?

I want to understand algorithmically how the 1GB dataset is generated and how it is updated based on block data in Ethash. I also would like to see, where in the code it is implemented in Go-Etherum. ...
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0answers
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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1answer
3k views

Are miners eliminated in Proof of Authority?

According to this blog post by Vitalik on April 1st 2017, Ethereum will move from Proof of Work to Proof of Authority in 2018. He states: We have decided that the problem is too hard, and secure ...
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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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1answer
961 views

Could I mine on Ethereum without storing any of the blockchain?

If a reference node provides an API so that I can read from their copy of the blockchain, could I run Ethash, do proof-of-work and claim rewards while not storing anything?
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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 ...