Questions tagged [blockchain]

This tag should be used for questions pertaining to the blockchain. The blockchain is a list of all transactions that have occurred using the Bitcoin currency. It consists of blocks which are linked to each other, and each block consists of transactions. DON'T USE THIS FOR THE SERVICE NAMED 'blockchain.info'!

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1answer
260 views

How do merkle trees ensure credibility to blockchain, when full node wrongly denies a presence of a txn in a block?

How can Merkle Trees ensure that a full node doesn't lie to a thin node that a txn t is not present in a block B if infact B contains t? How can a thin node tell if the full node is lying if the full ...
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Bitcoin balance vanished when transferring from bitcoin trading wallet to bitcoin wallet balance on blockchain app

I tired to move my full bitcoin balance from my bitcoin trading wallet to my bitcoin wallet balance on the blockchain app, but when I transferred it to my bitcoin wallet balance it never gave me ...
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1answer
29 views

Does cryptocurrency ETF use block-chain technology?

As you know, one of these days trends is cryptocurrency ETFs that the CES doesn't approve it yet. But there are some questions about them and their functioning. Is it necessary to build them over ...
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2answers
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How to count the provably unspendable UTXO in the blockchain?

As far as I understand, one can count the UTXOs by iterating through the blockchain starting at block height 0 and counting the number of outputs and subtracting the number of inputs for each block ...
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1answer
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I sent bitcoin and put low tx fee (4sat/b). Unconfirmed for 3 days. Can it be forever? [duplicate]

I just want to withdraw bitcoin and put a low fee. It's been 3 days and nothing happened with it - Unconfirmed. So, can it be forever? Or how much time it may take to be confirmed? Or what should I do ...
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26 views

How do mining pools fetch and retrieve blockchain data? How could one start their own?

I was just wondering how the various cryptocurrency mining pools are fetching the live transaction data, such as merkle trees, block hashes, etc. I am new to mining, but a great programmer, so I had ...
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9 views

Automate Bitcoin Sell Transaction within a website

I recently built a web application for a client where users can buy and sell BTC, I have integrated the wallet but am having still trying to figure out the best way to automate the buy orders and sell....
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Is there actually such a thing as “blockchains” being used right now for actual things? [closed]

In the last few years, I've heard "blockchain" and "blockchain 2.0" and many other such buzzwords repeated so many times that I'm beginning to wonder if I've missed out on ...
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1answer
47 views

How come the bitcoin blockchain is only 285gb only?

I found some statistics that the bitcoin blockchain is 285gb. https://www.statista.com/statistics/647523/worldwide-bitcoin-blockchain-size/ Bitcoin has been around for how long? 10 years? with 1mb ...
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3answers
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Is blockchain.com the only place where you can see the blockchain?

I've been investigating Bitcoin and when I would try to find out where the blockchain is stored, I was told that it is stored on everyone's computer. Then I would ask where was the blockchain stored ...
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1answer
24 views

Can you have a cryptocurrency with a single source of truth?

Can you have a cryptocurrency that's based on TRUST? (how dare I use this dirty word haha) Everyone who participates in the system agrees to trust this 1 party only, because they find them trustworthy....
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2answers
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What is the best free iOS wallet out there? [closed]

I only ask this question because there's so many kinds of wallets out there and I understand the difference between wallets(hardware wallets, iOS and Desktop wallets). But what is the best wallet in ...
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1answer
39 views

What would be an example for an insertion into the blockchain?

I'm reading the paper The Bitcoin Backbone Protocol: Analysis and Applications. On page 21, definition 8 reads: An insertion occurs when, given a chain C with two consecutive blocks B and B, a block ...
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Is there a real case where a very long blockchain got overtaken? [duplicate]

The longer the longest blockchain is, the harder it is to get overtaken by new blockchain with different sequence of transactions. But is there a case where it happened? What happened afterwards if ...
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177 views

Abandon transaction in Bitcoin Core with -zapwallettxes (transaction isn't online in mempool yet)

EDIT: I have found another solution for my problem. I've started Bitcoin Core with my wallet.dat backup, which I have saved before doing the transaction. If I am right and Bitcoin Core hadn't send the ...
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1answer
38 views

How's Blockchain like “magical Smart Contract”?

Please keep everything like I'm 5. I don't know computer science or programming. Please help me understand this ELI5 comment? I simplified names. Bob opens a candy shop called BCS (Bob's Candy Shop). ...
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What is the current growth rate of the bitcoin blockchain size month by month in 2020?

I'm looking to get a VPS to host a btc full node and would like to know how much space I should get and what is the current Bitcoin blockchain growth rate on a monthly basis?
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1answer
65 views

Where is the actual data stored in blockchain?

I know that the blockchain stores the transnational data and it is immutable but where is the actual data stored? If there is a use case to replace a centralized data center solution with a blockchain ...
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0answers
28 views

Hash160 and Hash key [duplicate]

I can not find a way to get hashkeys. How do I get HASH160, HASH KEYS I have tried several options but no result or way forward.. I know both are wallet related. A friend is building a private ...
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26 views

What are the potential causes for the “block not found on disk” error?

We run several bitcoin core nodes and load balance requests across them all. We occasionally hit the error "Block not found on disk" shortly after a new block gets confirmed, when looking up ...
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0answers
54 views

My unconfirmed BTC transaction on blockchain just disappeared [duplicate]

I had an unconfirmed BTC transaction on blockchain.com for about 2 days plus and now I log in and there's no transaction again. I checked blockchain.info using the hash; all wiped nothing is showing, ...
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0answers
33 views

Who generates the Bitcoin mathematical puzzles? [duplicate]

I would like to know how it is generated and who generates the mathematical puzzles within bitcoin, and how is its generation mechanics and how it also verifies transactions.
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1answer
405 views

Pending Unconfirmed Transaction for 5 days

I have been waiting on this transaction to confirm since July 16th when I made it. I have no idea as to why this transaction is not being fulfilled. Here is the blockchain of the transaction. https://...
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0answers
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Why do we need 2F prepare certificates instead of just F+1 in PBFT?

I started reading PBFT and I could not understand: why do we need 2F prepare certificates? The client needs only F + 1 replies, not 2F, so why can't the same rule be applicable in the prepare phase of ...
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2answers
42 views

I received an email that says someone sent me bitcoin

I was sent bitcoin through email, but I am being told to pay a fee first so that I can receive the funds. What should I do and I don't have the fees?
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2answers
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missing transaction not received

I transfered 0.013 mBTC into Bitoincore.org wallet.on the 07/07/2020. As yet I have not received Hash:- 13290114c5e1fe381c707e5f67b246cd0260f5bd24c9a1fc1aed0eab08dd2521 Address:- ...
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1answer
39 views

Where does “Included in Block” value comes from?

I was exploring transactions inside of a blockchain using this site, and inside of a transaction I noticed there is attribute called Included in Block and its description is: block this transaction ...
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2answers
51 views

Blockchain transaction change output

I'm very new to this. It’s hard to know for sure, but what’s most likely the case with the below transaction: Someone sent 25.99 bitcoin to another person/organization Someone sent 1 bitcoin to ...
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1answer
42 views

Blockchain transaction unspent [duplicate]

This is a bitcoin transaction as shown in a blockchain explorer. What does ‘2 confirmations’ mean here? Sorry for the picture quality. Which one is the best answer? 2 confirmations by miners are ...
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1answer
36 views

how to find the block height from merkle root?

I have the merkle root, using this value, how to get the block hash or its height? There is this merkle root available in getblock RPC output: ./bitcoin-cli getblock ...
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0answers
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Can one consider that the interest of other actors/stakeholders would change something about the concept of “blockchain”?

I am new to the Bitcoin world and am trying to get an overview within a research project. I see that Bitcoin was born out of a certain motivation to decentralize money and that decentralization, open ...
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4answers
4k views

Does blockchain without currency make any sense?

I keep reading about private companies building blockchains for stuff like supply chain management, and about the billions of dollars that are going to be invested in blockchain over the next 5 years, ...
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0answers
42 views

How Do I Fix This Error Without Loosing Stored Blocks On Pc?

I opened my Bitcoin Core program today on my Windows 7 PC via an external hard disk (1 TB) and I found the following error: MinGW Runtime Assertion Assertion Failed! Program: E:\Blockchain\bitcoin-qt....
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1answer
44 views

Bitcoincore wallet 0.20.0

Because on windows it is so difficult to load the blockchain into the BitcoinCore wallet. Arrives in 2016 the loading rate increases days. In ubuntu18.04 it is so fast and does not slow down after ...
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3answers
110 views

Basic question about transaction verification

I am fairly new to crypto and had some questions about how transactions are verified by the nodes Would it be correct to say that the full nodes check to see if the sender(Alice’s) signature is valid. ...
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0answers
35 views

Parsing transaction hash from rawblock data

I got block raw data next url https://blockchain.info/rawblock/00000000000000000002447735c7723ee9188322c0938e6587866a4458b9135f?format=hex Can I find transaction hash in url used python?
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0answers
32 views

Who was the originator of the term “Internet of Value?”

I am most familiar with the term "Internet of Value" as it is used by the company Ripple. The term is used as a parallel to the "Internet of Information." The idea being that money ...
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0answers
20 views

Can I get all block header data like the SPV node?

It hasn't been long since I studied Blockchain. I only need header data, not all block data, for study purposes. As far as I know, the SPV node stores only the block's header information. Can i get ...
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1answer
95 views

Would this alternative to Proof of Work work? [closed]

I'm fairly new to the subject, but I've read enough to figure out that Proof of Work has a problem concerning mining pools, and other alternatives don't seem to convince me either. I thought of my own,...
2
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1answer
48 views

How can I download a single Bitcoin block?

I just started studying bitcoin. I would like to be able to download a single block from the Bitcoin network. I referred to the following: https://blockchain.info/rawblock/...
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0answers
43 views

How to recover bitcoin wallet from messed up seeds [duplicate]

I have a ledger nano s wallet that is broken , when i tried to recover wallet from 24 recovery word i got error that says the recovery phrase is incorrect, i think the place of some words is incorrect ...
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1answer
20 views

Can we determine which one of the referenced outputs corresponds to a cashback transaction in BTC transaction scripts?

let me quickly elaborate the question. The structure of a BTC transaction script looks somewhat like the following example "...
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0answers
79 views

generating a private key for a blockchain wallet [duplicate]

I hired a broker to make forex and crypto profits for me. They did and put it in my broker account. the only method to get the profit out was to put it in a blockchain wallet. After they did this, ...
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3answers
91 views

Does descendant size affect transaction fees?

While calculating the transaction fee miners usually take ancestor size into the account. But does the descendant/output also affect the transaction fee calculation? Is descendant count correlated to ...
4
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2answers
114 views

Is that proved that for each block there is always nonce value which will make block hash to start by n count of 0

Sorry for the obvious question, but I'm looking for a mathematical prove. Block header is calculated as a concatenation of the following values. Version hashPrevBlock hashMerkleRoot timeStamp Bits ...
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2answers
59 views

Is a hypothetical Bitcoin network on Mars guaranteed to fork from the one on Earth?

Electromagnetic waves take between ~4 and ~24 minutes (mean: ~14 minutes) to travel a one-way trip between Earth and Mars. Suppose I set up a Bitcoin network on Mars. Is it guaranteed to eventually ...
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1answer
69 views

I transferred about 0.54 BTC and I cannot find this on Blockchain.com. Can anyone help? [closed]

I'm hoping someone more onto it can help me find or understand exactly what happened when I xferred my BTC from an exchange (Dasset) to my wallet. I transferred about 0.54 BTC to ...
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0answers
31 views

How to find the threshold of hash inequality at a given time?

For a miner to mine in bitcoin, he should find a nonce s.t the hash of block <= threshold. At a given time lets assume the total hash rate of the network be A hashes/sec and the mining rate be f ...
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0answers
35 views

What is the probability of mining a block by a miner controlling a fraction of hashing power?

Suppose a miner controls α fraction of the hashing power and the chain on which he is trying to mine has the mining rate given by f. How to find the probability of mining a block by the miner?
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34 views

Online BTC wallet implemention with bitcoin-core

I have written a php code to register users and create wallet for them on bitcoin-core full node.My question is how can i manage users wallets.if i use loadwallet to load USER A wallet and get address ...

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