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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117 views

Are the mining incentives of bitcoin compatible with the existence of a competing Proof-of-Work chain? [closed]

Scenario A: A chain split occurs due to a bug or contentious rule change (i.e. the miner incentives aren't changed in any way). Both coins initially start out with the same difficulty (and won't ...
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1answer
9k views

What happens when there are no Bitcoins miners anymore [duplicate]

So if I'm not wrong, the proof of work is the way to validate all the transactions in a Block. The miner gets (at the moment) 12,5 Bitcoins as a reward for each validated block. So my question is: ...
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0answers
329 views

Probability of Orphaned Blocks

This is a question regarding the probability of orphaned blocks depending on the block interval. I am using Bitcoin vs Litecoin as an example. Assuming equal hash rate and number of transactions, ...
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41 views

What's a good repo to fork if you want to create a blockchain like a “Math” coin or Curecoin. (mining equations, not hashes)

I want to create my own crypto currency and I want to know what's the best github repo to fork when it comes to making a blockchain that's based off of getting the miners to do mathematical ...
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0answers
116 views

Zero-knowledge/Arthur-Merlin Proof-of-Work for NP-like problems with coin flips hashes of recent transactions [closed]

On a previous answer to a question about making proof-of-work more useful, two challenges were provided: "1. The work must be much, much easier to verify than to do, and 2. The work must in fact ...
2
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1answer
453 views

why verification of transaction after proof of work?

I have question about bitcoin protocol. In Satoshi's paper it is mentioned that: New transactions are broadcast to all nodes. Each node collects new transactions into a block. Each node works on ...
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2answers
110 views

Would an optimization proof-of-work problem where the entity with the lowest hash wins have any security weakness or other disadvantage?

I am wondering if there would be any security deficiencies if cryptocurrencies such as Bitcoin were to change their proof-of-work problems to optimization contests. For example, suppose Bitcoin were ...
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2answers
2k views

How proof-of-work detects Sybil attack in Bitcoin?

I read in several paper that PoW deters Sybil attack in Bitcoin. However, there is no enough explanation about how proof-of-work detects Sybil attack in Bitcoin?
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0answers
161 views

Limit of Proof of Work [duplicate]

I do not have a complete understanding of bitcoin, but I feel that the PoW concept will not do it in the long run, so I need you to explain to me if I'm wrong. First of all, all this work force is ...
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0answers
109 views

What are bitcoin miners actually solving? [duplicate]

I've read all other answer, but nobody really gives an answer. Whom for are they solving, and what entity outside BTC community has benefits from all the electric energy wasted in the process of doing ...
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2answers
216 views

Is the purpose of proof-of-work the immutability of the blockchain?

I have a disagreement with a person: I believe that the primary and most important goal of including proof-of-work (and therefore the nonce) in a block is to make it hard for an attacker to change ...
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1answer
114 views

How are miners prevented from doing too much work?

I understand that scripts can be written within transactions that make the miners do some work. How does Bitcoin ensure that scripts that make miners do too much work are prevented?
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6answers
6k 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 ...
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1answer
66 views

Proof of work: optimal number of transactions?

I've been struggling with this Q for a while: My initial understanding was that miners start to work on PoW for new block immediately after the previous round's block is confirmed. My Q is this: ...
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3answers
6k views

How does Proof of Burn work?

I have been trying to make a comparison between PoW, PoS and Proof of Burn. While I understood the other two, I want to know how exactly Proof of Burn helps in attaining the consensus. One burns ...
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1answer
199 views

Does 4 byte Nonce enough to proof of work?

Is it always possible to find an hash value of a block, smaller than the current difficulty, just using 4 byte (Nonce) ? How can we be sure about it ?
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1answer
285 views

The 51% assumption

I am new to understanding how bitcoin works but reading up a little on PoS and PoW, I understand that anyone with over 50% of the network resources (bitcoins or computing power respectively) can ...
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1answer
69 views

separating proof of work from mining possible?

I (think to) understand that proof-of-work is the process through which transactions are verified and the health of the network is being ensured. I also (think to) understand miners get bitcoins for ...
4
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1answer
347 views

What is the difference between PoW and PoS regarding computations when determining a new block?

According to Buterin there are 600 trillion computations done per second using SHA256. He and other sources say that PoS solves the issue of not requiring so many computations but I do not completely ...
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1answer
160 views

Zero-BTC transaction fees, service-specific mining pools and external compensation

Bitcoin is a network that is proven to be stable, but if you want applications on top of Blockchains you have to play by the rules of the system. For notary use cases (for example), where you would ...
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1answer
2k views

How does a time warp attack work?

I more or less understand how an attacker (with less than 50%+1 of the hashing power) can artificially lower the block difficulty by messing with timestamps. I also understand how such an attacker ...
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1answer
787 views

What prevents a miner from faking nonce hash

What exactly prevents a miner from presenting a random nonce hash of the block with enough zeroes at the start to get chosen? How is the new hash verified by the other nodes? Since as I understand ...
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1answer
631 views

Bitcoin Mining Computational Power [duplicate]

1/ I do not understand why bitcoin mining is random when hashing is deterministic. reference : https://en.bitcoin.it/wiki/Nonce Can the mining pool with the most mining power always win? What value ...
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1answer
376 views

Do multi-PoW currencies open up additional attack vectors on a blockchain?

I'm curious if there have been any technical evaluations of the vulnerabilities of cryptocurrencies that utilize more than one proof of work algorithm - for instance, myriadcoin or huntercoin. ...
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4answers
6k views

If SHA256 produces an alphanumeric hash, how can a hash be “less than a certain value”?

I was under the impression that Bitcoin's method for validating a hash involved making sure the hash started with a pre-determined number of zeroes. However, after reading the docs here, I see the ...
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1answer
193 views

Why was the chain with the largest work chosen as the metric of consensus?

There seems to be a myriad of ways to find consensus (PoW, PoS, PoD, PoE and various other methods and hybrid approaches). What was the reasoning behind bitcoin being PoW and treating the chain with ...
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2answers
227 views

Is it possible to build mining reward pooling directly into Bitcoin?

Mining pools were formed quite early in Bitcoin's history. Since then, they have not been considered ideal because of more and more centralization creeping in. But it seemed the community has learned ...
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3answers
21k views

What's the difference between PoW and PoS?

I'm looking for an explanation of the difference between Proof of Work algorithm and the Proof of Stake and how they relate to Bitcoin and the Blockchain. Also looking for a fairly simple, non-...
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1answer
122 views

Would miners have an advantage by proceeding randomly?

If most miners are looking for solving their proof of work in a prescribed order (perhaps preceded by a prescribed way to break down the search space, e.g. by dichotomy); is there not an advantage for ...
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1answer
886 views

Why change the nonce instead of just rehashing?

Why do miners increase the nonce to compute a block hash rather than just generating a random block hash? It seems to me that both approaches would have the same likeliness of finding a result that ...
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1answer
147 views

Hash-based crypto-currencies?

What are the most famous crypto-currencies which use repeated hashes as proof-of-work? What are the other proof-of-work methods?
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1answer
169 views

Projects built on the Tendermint platform? [closed]

The Tendermint project sounds like a very promising proof-of-stake implementation. What public projects are being built on this platform?
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1answer
263 views

Can the mining pool with the most mining power always win? [duplicate]

Suppose we have three mining pools, one with 40% of computing power, and the other two having 30% of computing power each. Will the node with 40% power, be able to solve the puzzle for each node ...
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1answer
747 views

Why was finding a hash beginning with a certain number of zeroes chosen as the proof of work?

It seems to me that the reason the proof-of-work involves finding a hash beginning with a (temporarily) fixed number of zeroes is because one can easily check whether they have solved the problem by ...
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1answer
476 views

Abrupt increase in difficulty of proof-of-work

I am simulating a private bitcoin network that I started with the initial difficulty set to (1/2)^16, however after about 20 blocks of mining on the network it increased to 1 and has been constant ...
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2answers
876 views

Has anyone proposed a human only proof of work system?

There have been suggestions of proof of work requirements that exclude GPUs or ASICS (or try to) but I was wondering if anyone had suggested a proof of work that is not suited to being solved by ...
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1answer
218 views

In Proof-of-Stake, can a block creator fudge the block hash?

In Proof-of-Work, a block hash is costly to manipulate (say, wanting the hash to be even, or have the hash of the hash smaller than some number) since there is a lot of computing power put into ...
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2answers
1k views

How can a block be considered more difficult to solve/hash than another one?

In this answer: https://bitcoin.stackexchange.com/a/760/28219 It is said: Because of all this work, when a Bitcoin client signs on to the network it can trust the block chain that was most ...
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1answer
115 views

What are the chances of someone coming up with a new and simple/out-of-the-box solution for the double-spending problem?

The proof-of-work solution is simple but has many drawbacks (waste of time, energy and uncertainties about its security in the future). The consensus solutions proposed by Ripple/Stellar are too ...
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1answer
396 views

Where is the spec of HashCash so that I can implement it in Java from scratch?

I would like to implement HashCash in an efficient/fast/garbage-free way. Is there a spec to do so? How can someone go by implementing HashCash from scratch?
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2answers
623 views

What is the hash function used by Bitcoin proof-of-work?

Probably a simple question, but I believe it is important to state it clearly for the beginners like me out there. What is the hash function used for the Bitcoin proof-of-work? What implementations ...
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1answer
439 views

Challenge difficulty adjustments

Basically for this question I need a confirmation that all of my listed assumptions are fairly accurate. The bitcoin network measures how much time it took to create the last 2016 blocks in a ...
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1answer
708 views

Why is POW/POS absolutely necessary to run public distributed ledger?

my first question here, so please be patient with me. Thank you in advance. Q: Why exactly are POW/POS mechanisms needed to secure the blockchain (in bitcoin as well as in other alts)? + what is ...
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2answers
779 views

How does Peercoin (or other PoS) prevent timestamp forging effecting hash attempts or random minting?

I understand that every second the timestamp & potential transactions is hashed. I guess there exists a "start time" on the block chain we can't roll the clock before because transactions with ...
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2answers
349 views

Is there a PoW system that shows cumulative work without an ever-increasing proof size?

Let's say I have an output in the blockchain at height 100,000. At height 200,000, I want to prove that my output has the work of 100k blocks built onto it, securing it. In Bitcoin, proving that the ...
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3answers
5k views

What Value does mining provide?

After reading the O'Reilly book and perusing online resources, I'm still confused about the value that the actual mathematical mining provides to Network (I understand it does provide value, but not ...
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4answers
1k views

Why can't Bitcoin switch over to Gridcoin's proof of work system?

Gridcoin advertises itself as a "a mandatory competitive reward mechanism based on contributing the most towards BOINC projects on top of existing cryptocurrency technology." Is there a reason why ...
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1answer
577 views

What sort of calculations do the miners have your computer do? [duplicate]

I recently heard of a new cryptocurrency (or maybe it's not new and I'm just out of the loop) called Gridcoin which uses your GPU/CPU/ASIC to do research calculations rather than "meaningless" ...
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2answers
2k views

Generating blocks in regtest: “hash doesn't match nBits”

I'm getting this error in regtest mode after setgenerate RPC: ERROR: CheckProofOfWork() : hash doesn't match nBits After looking for error text in src I found a match in pow.cpp (obviously ...
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2answers
759 views

What is the most lightweight proof-of-work algorithm?

I know litecoin was created back in the day using Scrypt as to make it more lightweight but also harder to build ASIC hardware from - so everyday computers could mine. Are there other algorithms one ...