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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My transaction is in review for over 24hrs on blockchain, I want to cancel it

Please I want to cancel my in review transaction on blockchain. How will I go about it. Please help me,I need answers as soon as possible.
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I sent a token to trust wallet from binanve and after some time i sent the same token to binance that was given by trust wallet and didnt get it? [closed]

I sent a token to trust wallet from binance and after some time i sent the same token to binance that was given by trust wallet and didnt get it?
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Binance: How to check BTC value by USDT at time of arrival after blockchain disabled it

Let's say that i received an amount of BTC to my Binance wallet like one week ago. How can i know the value of it By USDT at time of arrival. Usually, i was check that from blockchain.com directly ...
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If the prices of virtual currencies on multiple platforms are different, can you buy low and sell high to make a profit? [duplicate]

I have observed that the prices will be different, can I earn the difference?
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Does Bitcoin-core support creating a new Bitcoin blockchain?

My goal is to add a new feature to Bitcoin, which requires changing the structure of the Bitcoin blockchain. So I was wondering if Bitcoin Core supports having a new/own Blockchain? If so, how to do ...
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Help analyzing this color coded hexdump of the Bitcoin blockchain

Sample of genesis, growth, and current height Sample of the latter part and the end of blk02655.dat. This probably covers parts of the last 10000 blocks. Process here: https://twitter.com/...
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Nothing-Up-My-Sleeve BTC Addresses [duplicate]

I've been researching some crypto related concepts and came across "Nothing-Up-My-Sleeve Numbers" and from what I understand I can generated a Bitcoin address that basically comes with an ...
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How can i import my wallet with old address

I had a bitcoin wallet and I have seed phrase but when I use it I can't access all my old wallet's addresses I read that I can use this site: https://iancoleman.io/bip39/ I actually used it and ...
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Suppose crypto is adopted globaly, and 100 years pass. Where would 100 years worth of global transactions/smart contracts be stored?

To my novice understanding the blockchain is stored on all participating computers in the network. is this to say each computer has the entire chain downloaded onto the hard drive? Or do we merely ...
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Bitcoin BTC wallet receive addresses

I want to create 100 to 500 to 1000 BTC receive addresses. It should not expire. Is it possible ? Is it possible in Bitcoin core ?
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What if a pool of computers are used to attack a blockchain and modify it in 51% of the network? [duplicate]

I mean if a large computer pool is used to attack a blockchain and modify the copy of the blockchain in 51% of computers in the network. Then due to consensus, the faulty blockchain will be replicated ...
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TRACING A TRANSACTION [duplicate]

Thanks in advance for your answers. In 2017 I invested in bitcoin without any experience or knowledge of the processes involved. I have records of the transactions through Coinjar but don't know where ...
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Says “confirmed” but never received [duplicate]

I sent someone bitcoin through cash app and it says confirmed but the recipient said they never received it, is there a reason this could be happening? Or is there a way for me to get it back from the ...
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Blockchain not letting me send all of my bitcoin (Please help) [closed]

I've been using blockchain for the past couple years and i have received lots of transactions (daily) for the past time. Today i decided to have them transferred to a Trading app which I've always ...
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Noob question: Why is there not a limit of the number of blocks in a chain revision?

I have a noob idea and I want to understand where I'm going wrong :) Say nodes agreed on a block revision limit, say, 6. This would mean that if they see an incoming chain that is longer than the ...
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fatal error using Win Bitcoin core to create node

It ran about 10 hours, loaded 70% of blockchain, now always this error in debug.log on restart 2021-06-21T14:11:58Z ERROR: ReadBlockFromDisk: Errors in block header at FlatFilePos(nFile=1801, nPos=...
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Python code error : Hash greater than Target

While trying to run a reference code from GitHUb i am getting an error "Cannot Mine-Hash is greater than Target". As i am just a beginner with coding i am not able to figure this out. Kindly ...
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Should I share my seed phrase to earn airdrop tokens?

Someone on Face Book said I could earn free crypto by appying for an airdrop. He told me to download Blockchain from app store to my phone. I did this and created my account with a password. I also ...
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Scenario: What would happen to Bitcoin if the internet would crash - world wide [duplicate]

What would happen to Bitcoin if the internet or power would be shut down for a moment, all over the world? Would this destroy Bitcoin or other block chain based money or technology?
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Are multiple parents/children possible in a block?

I always learnt/thought bitcoin blockchain is like a linked list and it can have only one parent and one child at max
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How to make a block given transaction ids, fee ,weight, possible parents

I have a list of transactions in this form 6c665f1d784d2032a13fa0986f08a3306bb1a4430049787cb1b692ed0d5d9bde,302,1136,cbf57b4e77708a6d920a63e9584cb482b03c42374b6a49e6057170a9354a89c5 txid, fee, weight, ...
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Can I merge blockchain downloads?

I downloaded the most recent 15GB of the Bitcoin blockchain. But I also have a back up from a year ago when I downloaded some more. Can I merely copy the old blockchain files into ~/.bitcoin and have ...
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Delay of a revocable transaction in the Lightning Network

The Lightning Network Whitepaper describes the concept of Revocable Sequence Maturity Contracts (RSMC), which allows a commitment transaction to be revoked during a predefined delay after the channel ...
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Isn't burning bitcoins a kind of fraud?

BitCoin burning is the process by which digital currency miners and developers can remove bitcoins from circulation, thereby slowing down inflation rates or reducing the total circulating supply of ...
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I was stolen my ETH [closed]

hello I was recently the victim of a hack consisting in withdrawing me all my wallet without being able to do anything. Basically some paid me in ETH with my public key and then a few minutes later I ...
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Understanding paper bitcoin wallets [duplicate]

I'm doing a project on bitcoin and have no idea what is expected of me. The question asks to create a public address and private key to unlock, and then to move on to the private wallet (this is using ...
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Tracing Blockchain.com Wallet-ID from Receiver Address. Address Re-use

I am wanted to question related to blockchain.com ? If i have some one BTC to BTC receiver address can i trace name or wallet id or something? For example if i generate multiple btc to btc receiver ...
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Is Bitcoin a scam or safe to invest in [duplicate]

Is bitcoin a fraud/scam? If not, why are there people constantly calling it a Ponzi scheme, a pyramid scheme or other things similar? Does this indicate that these things have something in common in ...
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Bitcoinj Doesn't increase wallet value

this is the initialization of wallet and block and PeerGroup : Wallet wallet = new Wallet(params, KeyChainGroup.createBasic(params)); BlockChain chain = new BlockChain(params, wallet, new ...
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How do I find out where my bitcoins got sent to? [duplicate]

I withdrew bitcoin from my account in Binance in 2018 and still have the email they sent with address it said it sent to,18bVuA2FxDdz5gE4qf9MgbsNxp2F46PaLD The time and amount looked correct. Now I ...
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Where and how are raw transactions stored on the blockchain?

My understanding is that transactions are stored on the blockchain in double hashed format: ie SHA256(SHA256(rawtransaction)). But it is also possible to get access to the raw transaction. This means ...
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Developing a Bitcoin POS (Payment Page) - How do I identify the transaction

This is probably a basic question but I can not find an answer. We are developing a BTC payment process for a Point-of-Sale. We have managed to build this fine and can make requests (QR code) for a ...
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Bitcoin in wallet transactions but not on the blockchain (old wallet)

I've been checking old wallets and found an unconfirmed transaction that's on the wallet but not on the blockchain transaction id (missing from blockchain) ...
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I have 12 phrase recovery code for bitcoin wallet [closed]

I have 12 phrase recovery code for bitcoin wallet and I use it for purchased shop and for every deposit generate a new wallet now I restore my 12 word to blockchain and electrum and exodus and … but ...
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1answer
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what happens to low-fee or forgotten transactions

If a transaction has a fee that is too low then it is possible for the transaction to either age out of the mempool (14 days) or get removed because the mempool reaches its max size. So what happens ...
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What can I do if someone obtained control of my blockchain wallet?

I fell for a bitcoin scam and I would like to undestand what are the risk associated to it. i established contact with scammer on instgram he convinced me to join the mining pool i had to create a new ...
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Why do transactions have to be bundled in a block? Why not mine single transactions separately?

Why do transactions have to be bundled in a block? Why not mine single transactions separately? What is the advantage of bundling transactions in a block? Also are there any blockchains/decentralized ...
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How does Bitcoin verify that a user owns the bitcoins he/she spent?

I'm making my own blockchain based currency for a school project and kind of hit a roadblock. I have a wallet class which initializes with zero coins. What prevents the user from just sending a ...
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108 views

Money sent to wallet was removed in unexpected second transaction 30 minutes later

I got sent bitcoins to my cake address then the coins went into the account as unconfirmed for about half an hour then they were sent to another address, and the confirmations have finished and i dont ...
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3answers
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Why must the entire chain be included in calculations if it's already been validated. Why can't the validated portions be archived to save energy? [duplicate]

I'm new to this so don't laugh. If all of the previous transactions in a blockchain have been validated as authentic, why does the entire chain have to be carried forward in the calculations? Why ...
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How can one join and leave Blockchain network? [duplicate]

As a newbie, it seems a bit abstract for me to imagine how Blockchain works! I'm curious that how my friends and I can join a Blockchain network? When we don't want to stay, can we silently leave and ...
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What is the Optimal block size based on 90 percentile block propogation delay?

We can have pruned nodes that can verify blocks and transactions so the block size can be increased without leading to the centralization of block verification. But if we increase block size then ...
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What is the meaning of difficulty in Bitcoin mining?

I'm a beginner in Bitcoin and Blockchain technology, so I have a question after reading about the difficulty in Bitcoin mining: What does the difficulty actually mean? I read that A high difficulty ...
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1answer
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Some technical questions about Bitcoin [closed]

I'm a developer. I've read a lot about Bitcoin structure and how it works. But yet something confuse me. I would like to share them with you and read your answers: When a miner solves a block, how ...
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Forced fork of older, low difficulty blocks

Let’s assume main chain (A) height is 1000 and the difficulty adjustment is 50 blocks. At height 450, the difficulty is very small. By modifying timestamp of blocks 450-500, I mine a fork (B) such ...
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If nonce can change the hash then it should be changing the next block's previous hash?

I am studing blockhain and i know that a block hash is linked to the next block in previous hash and it cant be changed for valid reason. Reason is : because if someone have changed hash then then he/...
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Submitting new block to blockchain

Supposed that I have managed to mine a new block that meets all requirements successfully by building my own script that can collect transactions and add them to new block and hashing the new block ...
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163 views

Is there a way to change Bitcoin Open Source code to be more Environmentally friendly?

If Bitcoin is open source as proponents mention, why can't make Bitcoin as environmentally friendly as Ripple, Dogecoin, Cardono etc? Elon Musk tanked the market by mentioning Dogecoin is More ...
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What exactly is a “blockchain developer”?

Hello everyone. This isn't specifically a bitcoin thread but due to recent events I think it is important that people get an understanding of the real Elon Musk as I have no doubt he will try and ...

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