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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Ethereum POA attack scenario

I am studying consensus algorithm. In the case of the proof-of-work algorithm, a double spending attack was possible by the miner making a transaction and presenting the longest block from which the ...
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Ethereum vs bitcoin technology [closed]

I have understood how bitcoin works (coinbase block, mining, links between transactions, hashrate, nounce, proof of work, ...) Now i want to understand how Ethereum works. Can we say it is the same ...
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When an Ethereum transaction event occurs, is there a case when it was not included in the main chain later due to a fork?

I know Ethereum is a POW blockchain where forks take place. The transaction event is issued after executing the transaction on the node. If a fork occurs, is there a possibility that the transaction ...
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Ethereum private network behaviour

I tried launching a private POW etherium blockchain. Following is what I observed. Attempt 1 2 node network. Node1 is a miner, node2 doesnt not sync Attempt 2 2 nodes network. Node1 is a miner, send ...
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Does successful mining require the block's transactions in advance?

Typically a miner decides which transactions go inside a block. But does this have to be so? Is the actual mining process just a process to find the right nonce regardless of block contents or does it ...
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What if difficulty exceeds the length of a fixed sha256 hash in proof of work?

Hello im a newbie in Blockchain, i got to know some basics, but im confused that what if the difficulty exceeds the length of a sha256 fixed length string example : The fixed length is here 64 (sha256)...
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Is Ethereum 2.0 (Sharding Ethereum) only PoS based? Or a combination of PoW + PoS?

Does Ethereum 2.0 (Sharded Ethereum) only use PoS (Proof-of-stake) for consensus mechanism ? Or Does it use a combination of PoW + PoS ?
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Why does proof of work targeted zeros always comes at the start of hash? why is it not in the middle or the end of hash?

My question is why always targeted zeros come at the start of hash of the block? I have never seen more than 2 zeros in middle or somewhere else in the hash of mined block... What's the reason?.... ...
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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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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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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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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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What should I prepare for the coming ETH 2.0 upgrade as a Dapps developer?

As announced, Ethereum is expected to be its upgraded version Eth2.0 probably from 2020. There will be several upgrades like PoW to PoS/Casper FFG eWasm integration sharding (Casper CBC) These ...
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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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When is a new block created?

I am currently reading an interesting book about solidity, and I'm reading about block creation. This gives a good overview: The book mentions that the maximum size of a block is determined by the ...
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Does the ETH blockchain have fundamentally more branching than BTC?

Intuitively speaking, ETH seemed to have simply increased the average block generation rate from one every 10 min in BTC to 1 every 15 seconds. There doesn't seem to be any other protection against ...
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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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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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How does the network validate a block in PoS

In general PoS, the forgers stake their coins and then a validator chosen in a pseudorandom fashion gets the chance to validate a block. But how do the whole network validate it? In PoW, for example, ...
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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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Deliberate Slashing: Don't slashing and leaking incentivize DDOS attacks on smaller nodes? Won't this centralize POS more than POW, even?

In Ethereum's proposed proof-of-stake algorithm (POS): A traditional node operator can't host a node themselves (e.g. on a home network), someone could just DDOS their node to bring them offline. ...
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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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Can't we incentivize miners to include more transactions in their block?

If you go to etherscan.io, you can see that each block has the different number of transactions. Can't we incentivize miners(e.g. give more rewards ) to include more transactions in their block so ...
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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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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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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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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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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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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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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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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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237 views

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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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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136 views

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 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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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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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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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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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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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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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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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 ...