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
2
votes
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
votes
1answer
361 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?
2
votes
2answers
60 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
2answers
745 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 ...
1
vote
2answers
278 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 ...
1
vote
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 "...
1
vote
1answer
48 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 ...
1
vote
1answer
193 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 ...
1
vote
1answer
175 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 ...
1
vote
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?
1
vote
3answers
504 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 ...
1
vote
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?
1
vote
1answer
194 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 ...
1
vote
2answers
110 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
67 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
44 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, ...
1
vote
1answer
86 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 ...
1
vote
1answer
190 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 ...
1
vote
1answer
62 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 ...
1
vote
1answer
370 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 ...
1
vote
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 ...
1
vote
2answers
607 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 ...
1
vote
1answer
672 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 ...
1
vote
1answer
68 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 ...
1
vote
1answer
49 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). ...
1
vote
1answer
40 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 ...
1
vote
1answer
99 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 ...
1
vote
2answers
324 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 ...
1
vote
1answer
713 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 ...
1
vote
3answers
69 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 ...
1
vote
1answer
158 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 ...
1
vote
2answers
658 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 ...
1
vote
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 ...
1
vote
2answers
101 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 ...
1
vote
1answer
278 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 ...
1
vote
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 ...
1
vote
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 ...
1
vote
2answers
152 views

Are there any stochastically dependent proof of work algorithms?

In bitcoin, the probability of discovering a block on the X-th hash is the same1 as it is on the Y-th hash. As such, the probability of discovery is stochastically independent. Are there proof of ...
1
vote
2answers
80 views

Theoretical security of mining bitcoins

Is it possible to change rules of mining bitcoin division? rewrite P2P bitcoin client (or write maleware) which will be pretending that fake bitcoin client is legal, original client distribute ...
1
vote
1answer
769 views

Confirmation limit

When seeing transactions I see that the number of confirmations keeps increasing without any limit. I wanted to know if there is any time limit on including a already confirmed transaction in a block ...
1
vote
4answers
883 views

Is mining the unfair part of bitcoin in the same way banks (or rather, fractionary reserve systems) are to current monetary system?

I've been reading a lot about bitcoin lately and I'm very interested. Especially, when it comes to making a currency that is way more fair, because it avoids a centralized control of it. However, in ...
1
vote
1answer
39 views

How to model randomness in validators selection in PoS?

I searched a lot here and on the Internet to figure how how randomness selection of validators in PoS works? I understand it is a random selection based on fraction of stake a validator has, similar ...
1
vote
2answers
68 views

What is entropy mean in this context?

"The Bitcoin nonce forms part of the block header, which is used by miners to provide entropy as part of the Proof of Work process, to try and find a hash meeting the difficulty requirement." Quote ...
1
vote
1answer
84 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 (...
1
vote
1answer
31 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
1answer
149 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-...
1
vote
4answers
109 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 ...
1
vote
1answer
143 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 ...
1
vote
1answer
277 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 ...
1
vote
2answers
112 views

How does the network know the legitimate chain in a double-spend attempt?

Apologies if this has been covered, but there's one area of the Bitcoin network that is not clear in my head, and it's intimately linked to the double-spend problem. Suppose Person A is purchasing an ...