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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How Bitcoin mining contributes to confirmations?

Based on my knowledge I know (maybe wrong) when a miner is doing hash, he is inputting any arbitrary values, in order to get a value that can be hashed into something with certain preceding zeros. ...
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1answer
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How can I print these information using this library?

I want to know how through using this library I can print information about the current block that the world mine right now and I mean by that: Version, Previous Block, Merkle Root, Time, Bits, and ...
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1answer
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Is the ordering of blocks in the rev*.dat files same as the blk*.dat files?

I understand that blk*.dat files save the blocks in the order it gets them from it's peers. Is the rev*.dat files in the same order as the blk*.dat files? For example, would the 400th magicbyte in ...
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What can blockchain do that normal databases systems won't?

Aside from cryptocurrencies, what advantages may blockchain(either public or private) have and real life use cases that can be more useful implemented in blockchain over traditional databases based ...
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Is it possible to generate a BitMessage-Vanity address?

I want to generate a vanity BitMessage address to receive and send message from. I this is possible for Bitcoin itself, but what about BitMessage?
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0answers
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How to verify an BlockChiain transaction using python?

Find all details from the link: https://www.blockchain.com/btc/tx/94ec7186e39fd9a2fda11d67fde158ba956dea421b23bb3cdefb2cc008ad1440
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1answer
33 views

Understand double spending through an example

Let’s suppose you have 1 BTC which you try to spend twice. You made the 1 BTC transaction to a merchant (Transaction T1). Now, you again sign and send the same 1 BTC on another Bitcoin address to try ...
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1answer
37 views

Fork and Longest Chain Rule

At the same time, A and B succeed in resolving the "Proof of work" challenge and both add a new block to their local blockchain, then they propagate the new blockchains to other nodes. I have 2 ...
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1answer
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Mining process in a blockchain

Let's consider a blockchain. They mining nodes are listening to transactions and every one is building is own block. Due to latency and other issues, every miner is probably building a different block,...
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2answers
354 views

Does every node has a whole copy of the blockchain?

As i read here, in a blockchain "each node the has a copy of all transactions ever made". This to me seems impossible, bitcoin exists for a long time, and the memory size of the intere blockchain ...
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How to desgin blockchain with following properties? [closed]

How to design blockchain with following properties? a. I should be able to generate coin b. Anyone should be able to verify c. Owner should be able to spend
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1answer
28 views

When exactly do the transactions get validated?

I have some gaps in my understanding to the life cycle of the transaction that I want someone to help me fill them specially with the validation. What I understand about the life cycle with my ...
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1answer
32 views

Is trading cryptocurrency in india illegal or legal? [closed]

Is btc trading legal ? how to proceed into this business if this is legal in india! Please share your views and suggestions. how this business works and whether this business is profitable or not. ...
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0answers
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Blockchain unconfirmed transaction script to hack the unconfirmed transactions [closed]

Please do anyone here have the blockchain unconfirmed transaction script, please help me with it, it is a type of script that is used to send the unconfirmed transaction to your blockchain wallet, ...
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1answer
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Can bitcoind and btcd share a datadir?

I've already fully synced the blockchain with btcd, can I point bitcoind at the same datadir and use its contents?
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4answers
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How do I recover from a cryptocurrency scam?

I lost about $45,000 to crypto investment scam just recently. The company posed as an investment company that could deliver a certain percentage in returns if you deposit your Bitcoin with them. At ...
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1answer
66 views

Is mining a fair mechanism in blockchain network?

As we know, propagation of a new block in blockchain network has some delay and many nodes receive the new block later. so if it is that the first one who finds the nonce properly wins the block can ...
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1answer
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Does getblockcount return the correct block count when running in prune mode?

I am currently running a bitcoin node with prune=550. The getBlockCount from $ bitcoin-cli getblockcount does not match https://blockexplorer.com/api/status?q=getBlockCount. As I understand it, the ...
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2answers
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Bitcoin mining process

Can someone please explain these fuzzy understanding? I am trying to implement my proper demo application of blockchain, but now I discover that many concepts are not that clear.. 1- how do miners in ...
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0answers
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Which Bitcoin simulator can i use where changes in nonce size is possible?

I want to run a Bitcoin simulation in which I can have double nonce running in a loop on the block header, and I can also change the nonce sizes. which simulator can I use for this?
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2answers
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Configure esplora to point to the bitcoind servers ip address

I have 2 servers running: Ubuntu 18.04 running bitcoind daemon (v0.18.1 full blockchain synchronized) Ubuntu 18.04 running esplora (the local single page website works, but it has no data from the ...
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1answer
51 views

Why one miner can dig out many blocks continually in one moment?

I am new to bitcoin and blockchain, I browed the website just now. There is a question confusing me, I find that one miner dig out blocks many times even in one hour. For example, this miner dig out ...
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1answer
56 views

Why Block Chain not Transactions Chain?

I believe that, for some people, the term Block is a sort of holy notion. However, there exist yet some block-free blockchains such as Libra (Sometimes referred to as Zuck Buck). Unlike previous ...
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1answer
57 views

How to verify virgin bitcoin

I am willing to acquire bitcoin without transaction history (virgin bitcoin) at a premium. How do I tell that the bitcoins I receive do not have any prior transactions (except of the mining one)? What ...
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1answer
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1answer
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What are some other uses for blockchain instead of money? [closed]

What has blockchain been used for aside from money in the 10 years its been around? I know things like etherium exist, but They don't seem be going anywhere, most of its value seams to come from the ...
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2answers
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Wondering about the viability of a Hardware Wallet

I want to roll my own hardware wallet using a USB stick. I have some concerns: Do I need to download the entire blockchain in order to create a new wallet? Do I need to download and store the entire ...
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1answer
101 views

Why Block Chain not Block Tree?

Why is the Blockchain intended to be a chain and not a tree? Why do orphaned blocks get trimmed off? Would you please provide a detailed answer.
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1answer
42 views

How does Bitcoin utilize cryptography and secure hash algorithm (SHA) to link records in the blockchain?

I am wondering how Bitcoin uses cryptography and secure hash algorithm such as SHA256 to link the records in the blockchain. And if possible I think it will give me a better understanding if there is ...
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0answers
41 views

Lost Transaction from Blockchain.com to Electrum

This link, https://www.blockchain.com/btc/tx/a081d03519bc0f1dcf4ac391da6f54d4d6091c458530b620f96eca5c1c5a3511, shows the transaction was delivered to the address "1Mv4fi8UdVhbfm9iLx2Bf8xhDrMv9sZSyD" ...
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1answer
32 views

Does the chain become computationally more expensive to validate over time?

Since there is only one chain per coin, doesn't that mean it becomes computationally more expensive to validate the chain the older the coin is and the longer the chain becomes?
2
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1answer
26 views

Race attack with transaction fees

let's say I run a simple race attack (say in a restaurant). I transfer BTC to the restaurant but seconds before (or after) I send the very same coins to myself. To make this deal more likely for ...
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0answers
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Getting Started with a Hello World Node.js App making an API call to bitcoin.org

I have been reading around trying to find where/how you can attach a SHA256 or MD5 hash (i.e. a small chunk of data) to a Bitcoin transaction, which led to OP_RETURN, but I have yet to see exactly how ...
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1answer
59 views

Who can predict that a benign attacker has 51% hash rate of the system?

In the Bitcoin network, suppose that there is an attacker who has 60% hash-rate (hr) and then other users have 40% hr. Therefore, it is obcioust if other users generate any new block, attacker can ...
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1answer
43 views

How do miners determine if a wallet has sufficient funds

I have ready about 10 posts that are similar and none of them seem to answer my question so any help is appreciated. My question is how to miners technically determine if a "wallets" has the "...
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2answers
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Imported address:private key [duplicate]

Please I want to ask how can I get the private key so to withdraw from my imported address and is it possible that you get to pay a certain amount of btc to get the private key..thanks in anticipation
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1answer
24 views

Understanding getchaintips in terms of chain reorganisations

I'm trying to get an understanding of the chain reorganisations my node has experienced by looking at bitcoin-cli getchaintips. The "status" of the different branches tells me the following: 1. "...
3
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3answers
172 views

Can we shutdown the Bitcoin blockchain?

I maybe wrong but what I think is the blockchain ledger exists as long as there are active nodes in the network. So can the Bitcoin blockchain be shutdown by shutting down power supply across the ...
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1answer
25 views

What would be the effect on the number of leading zeros hash generation if bitcoin increase its nonce size from 32 to 60 or 100 bits?

If Bitcoin increases its nonce size from 32 bits to double or triple the size, how will it affect the speed of getting the right hash with the required number of zeros?
0
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1answer
66 views

Bitcoin i have been asked to send money for a private key [duplicate]

Hi i have been asked to send money for funds that are nonspendable to receive a private key to unlock it, it's from bitcoin investing. How safe is this as i'm worried i wont receive the payment. It's ...
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2answers
112 views

Blockchain Explorer says received but it's not received yet!

I sent some Bitcoin to my friends wallet since 2 days ago. It says approved and sent successfully on my end. And even on blockchain Explorer it says confirmed and received. But my friend says he hasn'...
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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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2answers
38 views

How can I know that my transaction has been confirmed on the longer chain?

This question is more on the theory of bitcoin. Let's say I receive a coin in a tx which has been confirmed with 6 blocks following the block that's been confirmed. How can I be sure that there's no ...
3
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1answer
75 views

Fundamentals: Addresses don't hold coins, wallets do?

In the beginning it was my understanding that: Every address has a private key Every address has a balance Every address may send and receive coins. This is simple. But now I am using more proper ...
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1answer
40 views

Is their any way to identify whether the miner is using renewable or non renewable energy for mining?

Is their any way to identify whether the miner is using renewable or non renewable energy for mining ? in decentralized way?
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1answer
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what is exact meaning of some field of response of `getBlock` rpc api

I refer to this document for using getBlock rpc api. https://bitcoin.org/en/developer-reference#getblock { "hash" : "hash", (string) the block hash (same as provided) "confirmations" : n, (...
2
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1answer
46 views

Is it possible to share blockchain data between multiple nodes?

I'm planning to create a Raspberry Pi Cluster in order to run several bitcoin nodes. Can I share parts of the ~/.bitcoin/ folder in order to not have to store the entire hundreds of GB for each of the ...
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1answer
40 views

Wallet forensic

Someone who scammed me used this wallet to receive the BTC 12fmomENb5SSxR54Bitua71CZrc4oVQtmB he hasn't moved them from there since July 31st I'm trying to figure it if that wallet belong to any ...
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1answer
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How to decode a coinbase transaction?

Below is block result of block height 200,000 { 'hash':'000000000000034a7dedef4a161fa058a2d67a173a90155f3a2fe6fc132e0ebf', 'confirmations':396774, 'strippedsize':247533, 'size':247533, ...
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0answers
26 views

how to know miner of each bitcoin block [duplicate]

Do you know from what kind of API I can get miner info per each block? I've run bitcoin mainnet, and I want to know who mines each block if possbile. I've googled and read many docs but I couldn't ...