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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Is it always possible to find a number whose hash starts with a certain number of zeros?

As I understand it, proof of work requires nodes to "scanning for a value that when hashed, such as with SHA-256, the hash begins with a number of zero bits" ([bitcoin paper])1. Specifically,...
Benjamin Grange's user avatar
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2 answers
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Are the blocks produced by different nodes in the network comparable in terms of the order of transactions contained in them?

Having a transaction from person A to B and another transaction from person C to D that both took place in more or less the same time I assume that there might be a situation in which different nodes ...
bridgemnc's user avatar
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What are the differences between POW, RPOW and hashcash?

What are the key differences between Satoshi’s Proof-of-Work, Hal‘s Reusable Proof-of-Work and Adam Back‘s hashcash?
BitcoinFanatic's user avatar
1 vote
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51 views

How does mining work on a technical level?

I want to make a scrypt/sha256 miner for Bitcoin and altcoins in C to learn more about how mining works in Bitcoin, altcoins and learn more C. getblocktemplate gives some data that is needed for ...
IdotMaster1's user avatar
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1 answer
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Bitcoin network: data-intensive or compute-intensive system?

Is it more accurate to consider the Bitcoin network a data-intensive system due to the massive amount of data that must be stored by miners, or instead, a compute-intensive system due to the PoW and ...
Questioner's user avatar
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1 answer
161 views

What is the nBits field in the CBlockHeader class?

In the source code for the CBlockHeader class, there is a field called nBits. /** Nodes collect new transactions into a block, hash them into a hash tree, * and scan through nonce values to make the ...
Amir reza Riahi's user avatar
1 vote
2 answers
203 views

Why is Bitcoin inefficient? Would other cryptocurrencies do better if they were as popular?

I'm new to blockchain stuff. I have few questions. Why are Bitcoin fees are so high compared to Litecoin or other currencies? Why does Bitcoin use so much computing power (more than Ireland)? I heard ...
Garbarius's user avatar
2 votes
1 answer
259 views

What does `log2_work` in Bitcoin Core's output mean?

I have a question. Does the "log2_work" finally is a "proof de work" ? :) Do you know what does it mean ?
Romain's user avatar
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Is solo mining solve block as same as pool mining?

Guys i want to ask tht if solo mining has the same strategy as same as pool mining I mean the way they guess the block hash is it the same or not?
just.callme.client's user avatar
0 votes
1 answer
69 views

Is it easier to reverse the entire blockchain than to guess a private key?

If I am not mistaken you could in theory revert the entire blockchain, by producing nonces which probabilistically speaking required more work. So the (hypothetical) question is: if I wanted to steal ...
MManke's user avatar
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4 answers
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Why does an attacker need 51% mining power to overtake the blockchain?

I am really struggling to understand this thing about the 51% attack. Usually whoever mines a block first wins. My understanding is that mining is like a race. In a race, an athlete does not need to ...
Shariq Hasan Khan's user avatar
1 vote
1 answer
137 views

Proof of work: comparing computed hash with target hash

According to the source code here is where the hash computed by a miner is compared with the target hash: bool CheckProofOfWork(uint256 hash, unsigned int nBits, const Consensus::Params& params) { ...
smartmouse's user avatar
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0 answers
27 views

Estimate hashrate from block info [duplicate]

Hi for POW is it possible to estimate hashrate for that block using only available info from getblock rpc ( difficulty , timestamp, etc ) ? Is there a correlation between difficulty and block found ...
wpsd's user avatar
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3 answers
76 views

Relation between PoW and integrity?

I'm pretty new to the Blockchain technology. In a video that I watched, the lecturer talked about Consensus Algorithms and said that they're used for maintaining the integrity of the blockchain.  Then ...
BooRuleDie's user avatar
0 votes
1 answer
60 views

Trusting only the proof of work to receive payments

I understand that a pruned node needs to download all the blockchain in order to verify the blocks and construct the UTXO set. But wouldn't be possible to download the headers only? Let's say if the ...
leslie's user avatar
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Why is randomness needed in Proof-of-Work?

In Proof-of-Work (PoW) mining, a miner that contributes 10% of the network hash rate will on average receive 10% of the mining rewards. "On average" means that 10% of blocks are mined by ...
arni's user avatar
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1 answer
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Would a consensus algorithm like the one I describe work?

Given n nodes(miners/validators), Every unspent transaction output is broadcasted to all n nodes. Each node will select a batch of transactions and add it to their block. The specific mechanism of ...
rasputin's user avatar
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3 answers
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Finding Hash with 11 leading zeroes

For an exercise, I'm trying to find a sha256 hash with 11 leading zeroes. For this reason, I wrote a Python script that basically tries all intergers from 1 to N and brute forces the hash. Now my N is ...
Howdy's user avatar
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2 answers
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alternative definition of Proof of Work

If the goal of PoW is only to have a single truth verifiable by all to which to converge. Is it correct to say that PoW is only a method that serves to make it very unlikely that many solutions ...
Stef's user avatar
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1 answer
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is possibile to fork the bitcoin blockchain and change it checking if the pow is created from a clean energy?

is possible to Clone the Bitcoin blockchain and in the calculation, it does for the difficulty, instead of the global hash power given by the ASICs, put it the global production of clean energy ...
Mat's user avatar
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2 votes
1 answer
105 views

What's the logic behind the way block proofs (in GetBlockProof) is calculated?

Bitcoin Core uses GetBlockProof() function to determine the contribution of a block to the total difficulty of the current chain, aka, nChainWork in CBlockIndex. I'm having trouble understanding the ...
The Quantum Physicist's user avatar
1 vote
2 answers
265 views

Where does this 2^32 come from?

Several months ago I was doing research into calculating mining revenue for several crypto currencies. When trying to calculate BTC revenue I found this value 1/2^32 which was described somewhere ...
Joe's user avatar
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1 answer
132 views

Probability of mining maximum of 3 block in next 20 minute

I know that block interval in bitcoin blockchain is exponential distribution. Now I want to know what is the probability that maximum of 3 block will be mined in the next 20 minute?
ali-sezar's user avatar
3 votes
2 answers
179 views

Is there a consensus as to what is meant by 'Nakamoto Consensus'?

I sometimes hear that bitcoin's key innovation was the Nakamoto Consensus, which solves the double-spend problem without the need for trusted third-party intermediaries. I take Nakamoto Consensus to ...
StatsScared's user avatar
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1 answer
62 views

Is it correct to refer to hashes found through proof of work as "proof of work numbers"?

I've seen come commentators refer to 'proof of work numbers'. I suppose these are the hashes found through proof of work, but not entirely sure. EDIT** Regarding where I got the 'proof of work numbers'...
StatsScared's user avatar
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1 answer
55 views

What stage of the bitcoin protocol deals (or 'solves') the double-spend problem?

I understand that a key innovation in bitcoin is that it solves a key problem faced by previous attempts at a digital currency: the double-spend problem. In addition, I also understand that the ...
StatsScared's user avatar
1 vote
1 answer
130 views

Proof that blockchain converges to the longest chain [duplicate]

Is there a mathematical proof that shows that blockchain converges to the longest chain? It seems not obvious to me how a scattered group of nodes and transaction signals will eventually converge to a ...
James Park's user avatar
0 votes
1 answer
47 views

Is it correct to differentiate between a validated bitcoin transaction and a confirmed bitcoin transaction?

From my understanding, a transaction is first 'validated' by nodes once a transaction is propagated - so in the early stages. These validated, but unconfirmed, transactions are then collected by ...
StatsScared's user avatar
0 votes
0 answers
16 views

Mining against candidate block hash or previous block hash? [duplicate]

When mining...; a) Is the block header hash of the candidate block used b) OR the block header hash of the previous block + noonce used? If it is a), which I presume, is it then correct that the ...
BOH's user avatar
  • 1
4 votes
3 answers
290 views

Can you get the longest chain by keeping a constant low difficulty?

I'm struggling with this question that should be easy to answer. If the truth is the longest chain, what if I redo all the work from Block 1 until I have the longest chain by keeping a constant low ...
SadPepo's user avatar
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1 vote
1 answer
92 views

How does PoW ensure that all the transactions are recorded and that all the transactions are valid?

I just started to study blockchain and bitcoin yesterday and came up with some questions. If miners can select transactions when creating a block, how is it ensured that all the transactions over ...
Donghwi Min's user avatar
1 vote
1 answer
122 views

Can a proof of work chain have finality?

My understanding is that finality is just a rule in the consensus which says any block that gets buried X block deep will be considered unchangeable by the consensus. This has nothing to do with proof ...
Kyrielight's user avatar
0 votes
2 answers
141 views

Why is PoW even necessary?

So I understand the concept behind PoW (that if someone wants to overturn the current chain, they'd have to do all that work again). But why is it even necessary since transactions are confirmed only ...
user131438's user avatar
1 vote
2 answers
116 views

Will we have blocks with hash 000...000 (all zeros) in the year ~2070 if hashrate will increase with the same rate?

I have made an estimate on when the total hash rate will be high enough that we might observe blocks that have a hash with complete zeros. ...
phinz's user avatar
  • 121
0 votes
2 answers
135 views

Could one create an offline full node network mining node?

I'm curious if Bitcoin is vulnerable to this: Create thousands of virtual machines, all "networked together". Download the current full Blockchain and register each virtual machine as a ...
Christopher R's user avatar
1 vote
1 answer
121 views

When transactions of orphan block go back to the mempool?

Imagine there are two collision blocks A and B. These are mined at the same time. One miner created new block C on top of block A and longest chain happened. Do transactions of block B go back to ...
pepperoni's user avatar
0 votes
1 answer
50 views

When one miner created a new block and won the mining race, what other miner do next?

Imagine that wee have 10 indexed blockchain. Now, I start mining for index 11 block referencing index10's hash, I mean, the last hash data. Also, other miners starts too. When other miner finishes ...
pepperoni's user avatar
1 vote
1 answer
135 views

If malicious person(node) tampered withone block transaction, what's gonna happen?

I understand that if one bad person(node) tampered one block of his/her blockchain, the block hash data changed completely different. Let's say each node has 10 indexed blockchain and index4 block has ...
pepperoni's user avatar
0 votes
2 answers
173 views

how do nodes agree or disagree after new block is create?

I'm new to blockchain field and I read one article. article In this article of Authorization chapter, it is said that "For a public blockchain, the decision to add a transaction to the chain is ...
pepperoni's user avatar
2 votes
2 answers
203 views

Can we benefit from Collatz conjecture-based proof of work?

Can we benefit from Collatz conjecture proof of work to enhance bitcoin utility? F Bocart 2018:"Inflation Propensity of Collatz Orbits: A New Proof-of-Work for Blockchain Application" argues ...
Tabo's user avatar
  • 21
0 votes
1 answer
104 views

Changing the blockchain requires more than just recalculating all hashes..?

New here! I read this everywhere - "To change some data in a blockchain, the malicious user will have to recalculate hash for every block starting from that particular block". My doubt is - ...
Exter's user avatar
  • 103
0 votes
1 answer
320 views

Determination of Block Size Limit

In Bitcoin Mining, there is a limit on the size of any block added to the chain. What happens if, for instance, a block's nonce is so large that the block's size exceeds the limit? Secondary questions:...
kendfss's user avatar
  • 103
0 votes
3 answers
165 views

Does Proof Of Stake have any intrinsic scalability Advantage over Proof Of Work?

Is there any intrinsic scalability advantage to using proof of stake over proof of work? Ignoring the environmental impact issue, and ignoring sidechains, can proof of stake achieve higher TPS rates ...
Nick Sexton's user avatar
5 votes
4 answers
2k views

Would Bitcoin still work without a target difficulty?

Suppose that Bitcoin nodes had no target difficulty at all, and instead just accepted the block with the largest PoW every 10 minutes. Ignoring the increased bandwidth (since nodes would be ...
MaiaVictor's user avatar
0 votes
1 answer
279 views

How to get unconfirmed transactions

I am trying to learn how mining is done in bitcoin , wrote a simple mining code in python that works fine on sample data set of raw json coming from https://btc.cryptoid.info/btc/block.dws?693649.htm, ...
Shakti's user avatar
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0 votes
2 answers
287 views

How often does the "little man" win [mining]

I have read that long term we expect that the percentage of blocks mined to be forever converging to the percentage of hashpower possessed by the miner. This means if a particular miner has 20% of the ...
Prince M's user avatar
  • 340
0 votes
1 answer
102 views

Potential fork from genesis block using enormous computational power

51% attacks are commonly discussed where one entity could potentially mine blocks ahead of the network. The assumption is that the attacker manages to acquire 51% of computational power. However, ...
John Smith's user avatar
2 votes
2 answers
121 views

Making the block reward dependent on the difficulty?

I am looking for papers which discuss, if making the block rewards dependent on the difficulty could be used to curb excessive PoW growth. Idea is that BTC price roughly drives difficulty and energy ...
Nordic Mainframe's user avatar
0 votes
2 answers
140 views

Bitcoin: How does Proof of Work and single transactions align?

I'm reading papers since hours and still don't get one thing: A bitcoin transaction is an information like "Bob sends 2 BTC to Alice". This message is signed with Bobs private key and needs ...
user avatar
0 votes
1 answer
60 views

Appending txns to merkle tree on PoW efficiency, true hash rate

As I understand, when miners add transactions to their candidate block from their mempool, they append the txn to the merkle tree, which requires more hashing, as well as the hashing/maths involved ...
Matt Tainsh's user avatar

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