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.

Filter by
Sorted by
Tagged with
0
votes
2answers
84 views

group proof of work

Right now, every node in a Proof of Work system, solves the POW puzzle independently. Is there any concept of group proof of work, where everyone in the group needs to solve part of the puzzle.
2
votes
1answer
235 views

Who decides what the next, correct Nonce is?

As I understand finding the correct Nonce is the basis when hashing transactions for Proof of Work. How and where is this decided in the ecosystem what the next Nonce is? In my limited understanding ...
2
votes
1answer
208 views

What hash algorithm is used in Bitcoin Cash?

I know that bitcoin uses hashcash as PoW algorithm, Ethereum uses EtHash and Litecoin uses Scrypt. But I didn't found anywhere the PoW algorithm used in BitCoin Cash, does it uses hashcash too?
26
votes
3answers
80k views

The bitcoin mining algorithm from a programmer's viewpoint

This page: Blocks said mining is actually to solve a mathematical problem, but reading Block hashing algorithm doesn't give much help. I also tried reading bitcoind source code, but reading code takes ...
1
vote
4answers
120 views

Use of proof of work in bitcoin

I am trying to understand what problem in bitcoin proof of work solves and came to this somewhat helpful quote: So, for instance, if a miner controls one percent of the computing power being used ...
2
votes
1answer
114 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 ...
0
votes
1answer
43 views

is the proof-of-work for safety or efficiency?

i am reading the proof-of-work (aka: pow, target threshold, difficulty, etc.); my understanding is that pow adds a requirement to validate block headers, so that both benign and malign nodes need a ...
191
votes
8answers
112k views

What exactly is Mining?

I have heard that mining is for people with ready hardware and blah blah blah... But what exactly is it? Does it operate like real mining? I mean, people talk about it like you are physically mining.
1
vote
1answer
286 views

Partial Proof of Work in Pools

Technically speaking a full PoW solution is one whose hash value is below a certain threshold value say V. It is not equivalent to saying that the hash value must begin with say X number of zeros (...
2
votes
1answer
302 views

Is this calculation of mining probability using the Bernoulli trial formula accurate?

I'm trying to understand the formulas for successfully mining a block (without a pool) based on hashrate over time (i.e. to chart the probability of finding a block at various historical points ...
3
votes
7answers
386 views

Justification of usage of Blockchain by banks

After learning a bit about Bitcoin and Blockchain Technology, I do not understand how any bank is going to use it. My understanding is that the blockchain is useful in an environment of mistrust. In ...
2
votes
1answer
222 views

Can Bitcoin(PoW) work under partial synchrony?

This paper rigorously proves that Bitcoin can achieve consensus under the assumption of bounded message delivery time: Messages in a mailbox may be delivered in any order, and at any ...
4
votes
1answer
115 views

POW based blockchains systems Majority Attack

TL;DR: With only 30% of network power a Majority Attack is possible and profitable. Am I missing anything? Generally speaking, blockchains based on Proof-of-Work authentications are using amount of ...
2
votes
1answer
79 views

Proof of work: average number of tries to create a block

First, I'm sorry if I'm asking a stupid question. I'm just trying to understand bitcoin. I'm reading the Ethereum white paper, and I couldn't understand this sentence about proof of work: At the ...
8
votes
1answer
1k views

What prevents similar time-warp attacks in Bitcoin as happened to Verge?

Right now (may 2018), Verge (an altcoin with proof of work) was attacked by time-warp attack. More can be read here https://blog.theabacus.io/the-verge-hack-explained-7942f63a3017 What exactly ...
3
votes
1answer
111 views

Why haven't a large number of cryptocurrencies copied Primecoin's mining algorithm? [closed]

According to my understanding, generating an ever-growing list of prime numbers benefits mathematics and society in some mysterious way. Given this, why have more recently created proof-of-work ...
1
vote
2answers
4k views

altcoin debug.log shows ERROR: CTxDB::LoadBlockIndex() : Failed stake modifier checkpoint height=0 [closed]

What I have done so far: Generated new Genesis Block Generated new MerkleRoot Updated MerkleRoot Updated Genesis block values Commented out these lines Compiled on CentOS 6 Created altcoin....
1
vote
1answer
285 views

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 ...
0
votes
3answers
57 views

What is resource of mining rewards

How the coins must be paid miners for mining process is provided? One of resources may be transactions fee. Is there any other resources for proving reward of miners?
0
votes
1answer
61 views

How is the amount of proof-of-work invested in a chain calculated?

The bitcoin whitepaper (page 3) states The majority decision is represented by the longest chain, which has the greatest proof-of-work effort invested in it. I could not find how exactly this ...
0
votes
2answers
155 views

Where can i find proof of work in Electrum(light weight bitcoin) source code?

Hi does anyone knows where can i find electrum's proof of work in the source? https://github.com/spesmilo/electrum
0
votes
2answers
92 views

What is the reason to pay miners “monetary rewards” for mining process?

Is it correct to say that: In Bitcoin, it is crucial to incentivize miners by monetary reward, because mining process has significant monetary cost (energy/electricity cost). ? otherwise, mining ...
0
votes
2answers
73 views

What would happen if PoW cost were drastically reduced or eliminated?

Assuming Bitcoin had a different method for selecting winning nodes and controlling block time creation, please describe step-by-step how the Bitcoin network would be vulnerable to various attacks. ...
0
votes
1answer
53 views

Ethereum's PoW difficulty

Bitcoin's block time is about 10 minutes while that of Ethereum is 15 secs. Both are using PoW at this moment, right? How come Ethereum's block time is so short compared to Bitcoin? Is hashing a lot ...
19
votes
6answers
8k views

Why do we need Proof of Work in bitcoin?

I know that proof of work shows that the person has put in some time and power into the processing. I also know that bitcoin mining is adding a transaction into the blockchain and then the miner will ...
2
votes
2answers
78 views

Blockchain validation process is linear?

I've read at a few places that the nodes validate transactions in a linear fashion, i.e. after node A validates, then node B, etc. (which is also the reason, as claimed by many, why blockchain suffers ...
1
vote
1answer
45 views

Security via Proof - of - Work

I am reading Satoshi's original paper, merely for the sake of understanding the concept. I have minimal computer science background (some), mostly just mathematics. In Section 4. Proof of Work of ...
1
vote
2answers
185 views

What happens if full nodes don't check for double spends or deliberately lets a double spend TX pass and then this full node relays the transaction?

I am studying about Bitcoin and Blockchain tech via the Princeton crypto course, and it mentions that Full nodes do the following checks : i)transaction is valid with the current blockchain, ii)...
1
vote
1answer
80 views

Why not to mine more efficient?

I'm a kinda newbie here. But this is what I completely can not understand. If every single miner have to 'arrange' transactions and then compute a SHA-256 function of a given memory chunk, and if ...
1
vote
1answer
47 views

Is it a problem that miners participate in a pools? [duplicate]

I am talking about miners centralization with large pools. Is it a problem? I think there are some possible ways to prevent miners from pooling. For example add miner signature to the block header, ...
2
votes
1answer
63 views

On a low level, how are long chains kept secret and later broadcast during 51% attacks?

I've been reading about the vulnerabilities of PoW crypto, and there's a part of it that I don't understand. Suppose I wanted to stage a 51% attack on Bitcoin (not really feasible, but bear with me). ...
0
votes
2answers
98 views

Proof of Work: email versus bitcoin

I have read "Hashcash is a proof-of-work algorithm that requires a selectable amount of work to compute, but the proof can be verified efficiently. For email uses, a textual encoding of a hashcash ...
28
votes
1answer
12k views

What is proof-of-stake?

As we know one of the important mechanisms of Bitcoin is proof-of-work. How does the concept of proof-of-stake work? How does it differ from proof-of-work?
0
votes
1answer
748 views

Block Hash and Nonce generated by GenesisH0 python script is incorrect

After running GenesisH0 python script to generate the Genesis block for a local testnet (using v0.15.1), I got the following results. merkle hash: ...
0
votes
1answer
135 views

Is the bitcoin blockchain really non-corruptible? [duplicate]

Some people say that proof of work is better than proof of stake, because it's not possible to rewrite the whole blockchain on-spot. One would need to "re-mine" everything. But I think this is not ...
1
vote
2answers
169 views

Why have proof of work?

As far as I can tell, PoW allows multiple parties who don't trust each other to agree on an order of transactions. The fact that every transaction has a hash of the previous block means that you can ...
1
vote
1answer
198 views

My coin - Proof-of-Action

I am writing a project on cryptocurrencies. As a part of this project, I thought of a new token for web services exchange. I tried to combine PoW and PoS and here is what I have. I called it Proof-of-...
0
votes
1answer
127 views

When does a node mark a transaction as confirmed or unconfirmed?

As new transactions are broadcasted, the nodes keep them in a pool of unconfirmed transactions. One node will add it to a block as soon as it finds a proof of work. At the same time many other nodes ...
6
votes
2answers
2k views

What happens to extinct blockchains, and transactions inside of them?

While understanding the concept of block chain and proof of work, few things are confusing me. Miners always consider the longest chain(by difficulty) and work on expanding it. Now, lets say two ...
0
votes
1answer
25 views

What other proof methods are there? [closed]

I am familiar with the proof of work method and a little with the proof of stake method. Is there any more methods that are out there and how do they work?
5
votes
1answer
694 views

How does scrypt pow work?

Bitcoin's pow is sha256, the hash of header is taken and check against a given target to see whether it is smaller than the target, this can be easy seen as block hash starts with zeros. But how does ...
0
votes
1answer
48 views

Validation methods beside POW etc

Are there other concepts for the validation of the next added block to the blockchain beside POW, POS etc.? Of cource there are, but is there a methode that is shining out of the mass? A methode that ...
1
vote
1answer
146 views

Blockchain beyond bitcoin etc. - Who is mining?

People are praising the blockchain for use in all kinds of environments where a secure transaction history is required, e.g. logistics etc. My question: Let's say someone sets up a blockchain for ...
13
votes
4answers
8k views

Why can't we design a bitcoin that does useful work? [duplicate]

The bitcoin network, including every miner, is the biggest computing project that humanity has created. Thus I ask: why, instead of using it to generate useless data, don't we use it to generate ...
1
vote
1answer
299 views

A theoretical low cost attack scenario in PoW currencies

The scenario was designed by user:croraf and me in discussing a question of mine yesterday. To make it more clear, I want to present it here again in a stricter design. To do it in a clear way, first ...
2
votes
2answers
184 views

Can a Blockchain be Built Like This?

Can a Blockchain be Built Like This? 1) Alice sends Bob one X-coin. 2) The blockchain's protocol takes X and the next (say) 100 transactions and puts them in a block. 3) Distributed peer-to-peer ...
0
votes
2answers
241 views

Why are blocks in a permissioned blockchain linked together?

My question: Do the blocks in a blockchain without proof-of-work (i.e. a permissioned blockchain) have to be linked together via a cryptographic hash? Longer version of my question: (Please correct ...
0
votes
1answer
84 views

Source of entropy for PoW hash

How does bitcoin do it to generate an (upredictable) hash in each new block with sufficient randomness so that no one can precompute it?
10
votes
2answers
3k views

Will the proof-of-work system end when all bitcoins have been mined?

This article from ArsTechnica is claiming that Bitcoin is not such an environmental disaster, and one of the reasons they mention is that mining will come to an end. Ok, fair enough, there is an end ...