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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1answer
128 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 ...
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2answers
167 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 ...
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1answer
171 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 ...
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1answer
440 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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1answer
568 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

Transaction verification vs block mining

I cannot clearly understand if the transaction verification is done over a single or double phase. This is my understanding. Once a transaction is completely assembled, its inputs and outputs ...
2
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1answer
116 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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0answers
115 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
377 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
66 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 ...
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6answers
2k views

Is proof-of-work required in Bitcoin?

It seems that the rationale behind the proof-of-work requirement in Bitcoin is that it creates trust in a decentralized trustless network by: helping to reach consensus on which version of the ...
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2answers
752 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 ...
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2answers
282 views

Why don't the miners just take profit from our coins and make the coin worthless?

You own a very valuable thing and you want to go to holiday without it, but there is nobody who you trust and who can look after the thing. So you take somebody unknown to guard it. You pay him a fee ...
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2answers
5k views

Who are you solving algorithms for and why?

I am sick to death of people responding to my question with logistics of "how to" mine data or just that you are solving "mathematical concepts" and "algorithms." What I do understand is this - some "...
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1answer
86 views

Consensius algorithm difference to PoW and BFT

I have a question on the consensus algorithms, in particular, what is the principal difference conceptual to the family algorithm od PoW(used to bitcoin) and BFT(used to Libra blockchain with the ...
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2answers
152 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 ...
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1answer
195 views

How finding a working nonce says anyting about the validity of an initial transaction

I am by no means an expert, nor a cryptographer, but I would be interested in knowning a little bit more than what happens at the end of the following chain of events. What happens at the end of the ...
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1answer
176 views

How the first succesful miner is ensured his reward

With my still rather limited knowledge of bitcoin, I was wondering how the correct origin of proof of work is ensured. Specifically, when a miner successful computes a valid hash and is to broadcast ...
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2answers
1k 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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3answers
508 views

Can the Bitcoin blockchain eliminate the need for Trusted Computing in Smart Contracts?

Let me preface this by saying that I'm a novice, but this is my rough understanding of how Bitcoin's blockchain works. (This is largely based on blog posts like this one.) If person A wants to ...
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4answers
356 views

What is the useful work done during the mining of Bitcoin? [duplicate]

What is the work that the computer performs while it does Bitcoin mining? Is it useful work in any case?
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1answer
141 views

A Blockchain that merges mining forks and could be more power-efficient? [closed]

I'm new to blockchain technology so I'm sorry if I'm using wrong terminology. This is not a Bitcoin question, but a general blockchain question. Imagine a theoretical blockchain that uses gradual ...
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3answers
57 views

when a miner solves the problem in less than one timestamp then what does it do with its extra capacity?

If a miner solves the problem in less than one second then how does it use the extra capacity.
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1answer
43 views

Chain Race: How to know chain-length of competing chain?

If a fork happens, miners mine on the block they receive at first. Further, they only forward the block they received first (so the block they will use to mine)! So it can happen that 10% of the ...
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1answer
228 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 ...
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2answers
123 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)...
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1answer
73 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 ...
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1answer
45 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, ...
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1answer
89 views

What happens to the blockchain after the miner wins the puzzle?

I have some problems understanding the flow of consensus mechanism, so far I know, In PoW when validating a transaction the miners will compete with each other to solve a puzzle, the miner who find ...
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1answer
747 views

How does the bitcoin transaction fee get paid to miner(s)?

According to https://bitcoinfees.info/ The current "cheap" rate for a bitcoin transaction is $22. How does this get paid to the miners? Is it just one miner that verifies the transaction, puts it ...
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1answer
201 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 ...
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1answer
65 views

Bitcoin Proof of work puzzle inconsistency

At this time, I am really confused about the Proof of work puzzle because as I have seen in some documents, there are 2 different ways to talk about them. The first one I have seen is from some ...
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1answer
390 views

Chain with most proof of work - hash target or block header hash?

What is calculated towards the sum of PoW of the chain? Is it the target difficulty that has been met or is it the actual block header hash? Say the target is 000000ABC00000000... and I mine block ...
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1answer
113 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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2answers
613 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
689 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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1answer
80 views

where in the source code is the the proof of work checking the blockheader hash and nonce?

Where in the source code do we check whether hash(blockheader*nonce) < Difficulty In fact, the line I found is as follows: https://github.com/bitcoin/bitcoin/blob/v0.17.0.1/src/pow.cpp#L87 My ...
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1answer
51 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). ...
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1answer
49 views

The “work” in proof of work

How does proof of work function? Why does the "work" in proof of need to have zero utility for the economics of the cryptocurrency to be viable.
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1answer
43 views

As a miner, why would I forward transaction with high transaction fees to other miners?

Miners receive transaction and broadcast it to other nodes. Node that solves the puzzle will add that transaction into the block it mined. But as a miner why would I broadcast a transaction with very ...
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1answer
102 views

What dead simple algoritm can be used for generating checksums by pen and pencil?

I'm holding a course on Bitcoin and blockchain technology. On my agenda I have an exercise where I'm going to let the attendees create their own blockchain on the wall using post-its. I'm in search ...
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2answers
344 views

What's so special about six blocks for confirming transactions?

I read that when your transaction is part of a block that has five other blocks on top of it, you can feel safe that your transaction is not in danger of being orphaned because someone else would come ...
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3answers
71 views

What are the chances that Bitcoin changes its proof-concept one day?

Is it realistic/possible that the bitcoin core team make a new Bitcoin Improvement Proposal (BIP) on day in which they propose to change Proof of Work (POW) with something else (proof of stake for ...
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1answer
163 views

Creating blocks while more transactions arrive and proof of work mechanics

I am having a hard time understanding the details of how blocks are getting created by miners while many transactions are being received by various nodes at slightly different times and what ...
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2answers
709 views

How many nonces on average do I need to try in order to get n leading zeros?

Assuming 256-bit hash output, how does the (average) number of nonces I need to try (to solve the proof-of-work puzzle) grow with the number of leading zeroes required, n? Is there a bound on this ...
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1answer
3k views

How much “Proof of work accepted by server” needed to generate 1 bitcoin (or a part of it) [duplicate]

I am using Bitminter client, and I am confusing about how much I earn in one week while my system working overnight. https://bitminter.com/ says "Mining one bitcoin with just a PC now takes millions ...
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2answers
104 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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1answer
282 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
191 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
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 ...