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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Why is the block limit so low?

The Ethereum block limit is currently 30M gas. From what I have read elsewhere, this limit has been ostensibly chosen so as to ensure that processing transactions remains feasible for consumer grade ...
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Block hash in Ethereum vs block hash in Bitcoin [duplicate]

The hash of a block in bitcoin has several leading zeros, and I understand that's how proof-of-work is done, finding a nonce that leads to a number with so many zeros. On the Ethereum network, however,...
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Transaction order in Ethereum Proof of Work

My Question is: How does picking and ordering transactions connect to Proof of Work Consensus Let me explain a little bit more: I'm confused about a concept in Proof of Work (PoW) on Ethereum. I ...
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How can a smart contract deployed on Mainnet know if it is running on PoW or (in the future) PoS?

I'd like my smart contract to know if it's running on PoW or (in the future) PoS in Mainnet. Does checking for block.difficulty solve the problem? If so, what will be the value of block.difficulty ...
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What is the incentive for people running execution clients in eth2

If I understand correctly, in the coming proof of stake version of Ethereum, there would be the beacon chain, with blocks on it created by validators. These validators will get compensated for doing ...
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Michael Saylor explains POW(proof of work) is superior to POS(proof of stake). Can we PHW(prove him wrong)? [duplicate]

In this video Saylor explains why he thinks POW is superior to POS. He says a lot of things but the summary of his thinking is that since POS doesn't require as much energy, that makes it much less ...
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publishing blocks with delay

this is rather a simple and fundamental question but nevertheless i couldn't find any solution for it and now I'm worried if it can cause real attacks to slow blockchains. imagine in a form of ...
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What controls the inter-block interval in proof-of-stake?

In proof-of-work, the interval between 2 blocks is controlled by the mining difficulty: in Bitcoin, at all times, it must take roughly 10 minutes to mine a block, so every two weeks we adjust the ...
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High Block Validation

Suppose node A is running on height 2000. Node B sends to node A block with height 2002. Node A is not able to validate the block without having a block with height 2001. How does node A behave in ...
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How to reverse engineer ETH POW

If I store 10 blocks from Ethereum, with the block difficulty, mixHash and nonce etc. Transactions etc. Is it possible for me to back trace that the information I have stored is actually correct and ...
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Does a Proof of Authority network consume much less energy than a PoW/PoS one?

One of the main problems of PoW networks like Bitcoin or Ethereum is its energy consumption. Question 1: does this get solved with PoA networks?(without taking in account that these are not really ...
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Is there a mistake in this passage about the requirements on the block header nonce?

It says that PoW evaluates to an array with the first item being the mix-hash, and the second item being a pseudo-random number. However, from equation 49, it would seem it is the second item, m, ...
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Even if I own 51% of stake (or have 51% computational power) and try to cheat, can't others still see that my block is invalid?

I'm thinking about how proof of stake works exactly. As I understand, here is how it is secure: I cannot forge a tx where random A pays me X amount because I would need the private keys of A. ...
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Ethereum2.0 Shard chains will be PoW or PoS

I'm sorry if this is a basic question. But will the new shard chains for Ethereum2.0 be PoW or PoS? I know the plan is for Eth1 mainnet to "dock" onto the beacon chain eventually and be its ...
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Why don't blockchains use simple voting based consensus algorithms?

Suppose we have an malicious agent Bob with account balance of 100 units trying to double spend a coin by broadcasting two messages simultaneously: A: Bob sends Alice 100 units B: Bob sends Emily 100 ...
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How are difficulty of finding a proof of work dynamically regulated without a central body? [duplicate]

The probability of a miners to mine a block dynamically changes so that blocks are mined at regular intervals.How does block chains accomplish this without a central regulating body,
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“Universal Proof of Work” with SNARKs?

If SNARKs are able to prove computations of arbitrary complexity and difficulty were executed correctly, would it be possible to use them to create a Proof of Work system where ANY computation can be ...
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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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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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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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