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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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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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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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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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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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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Rewriting the blockchain?

The main bitcoin blockchain (the chain that miners choose to work on) is the chain with the most proof of work ("heaviest" chain). Currently, the cumulative proof of work on the bitcoin main ...
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bitcoin block time after halving? [duplicate]

I would like to know why the bitcoin block time is taking longer than 10 minutes, I know that bitcoin halving had decrease reward and increase difficulty but according what I read the blockchain ...
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54 views

Unable to make custom Bitcoin command

I'm writing a thesis on Bitcoin system and as a part of my assignment i have to explore Bitcoin-core source code. I 've downloaded the code, compiled it and manage to run it. However, I wanted to ...
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Replace-by-fee issue

Ok so i recieved a 50$ transaction and it was on my account ( the bottom transaction) and 2 days later i have 0 $ on account and all funds from that transaction apparently got replaced by fee, am i ...
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Can an unsynchronized node create a valid transaction?

I'm trying to understand how bitcoin transactions work. From what I understand, in the Bitcoin network nodes hold different versions of the Blockchain and after some time the different chains start ...
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Corrupt block database

I activated the core with bitcoin-qt as I always do. What can be the cause of the database loss? Synchronization is restarted from the genesis block. I use the testnet with Pruned mode activated.
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Problems Setting a Transaction Fee on a Per Transaction Basis Bitcoind

I've spent hours and hours trying to find a solution to this problem, with no success. Using Bitcoin Core on a Linux machine, so using bitcoin-cli to process commands back to the daemon. Here's what ...
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How does a miner identify himself

There has been a new mining pool appearing after the halving called Lubian.com cf https://www.cryptoglobe.com/latest/2020/05/new-bitcoin-mining-pool-comes-out-of-nowhere-already-5th-largest/ How does ...
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Is there any method to extract transactions for an bitcoin address which is not in my wallet using bitcoin core?

I have setup Bitcoin core and trying build an API to fetch all transactions under an address ( not in my wallet ). Bitcoin core RPC documention says that an address which is not in my wallet needs to ...
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How can there exist businesses that “specialize in blockchain analysis looking for patterns of usage that reveal how money is being used”?

I read this today in a SE comment for an unrelated question: there are businesses that specialize in blockchain analysis looking for patterns of usage that reveal how money is being used. To me, ...
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How Bitcoin avoids double spending?

If someone is sending bitcoin with low transaction fees and then sends the same bitcoin with higher transaction fees before the previous one is confirmed, so it is obvious that miners will pick the ...
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Problem with data redundancy in block chain

Since the copy of same data is storedon each node in network. Does it use storage space to store same data on each node? If yes then how the data is decentralised. It is just a large network of ...
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Why raw Bitcoin transaction are in hex format?

Why are Bitcoin raw transactions in hexadecimal format? I am looking for scientific articles / books on this topic and I can't find anything, so my question is: why are they in hexadecimal and can ...
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How to calculate z and z1 from ecdsa signature [duplicate]

Can anyone explain me any clearly answer or code in python with examples how we can calculate z and z' value fromECDSA Signature order? I search in google and youtube and i not saw any correctly ...
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101 views

How can i calculate z and z1 from ecdsa signature

Can anyone explain me any clearly answer or code in python with examples how we can calculate z and z' value fromECDSA Signature order? I search in google and youtube and i not saw any correctly ...
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What is being done to avoid 51% consensus attack given 80%+ of miners are Chinese and that government could centralize all mining operations? [duplicate]

What is being done to avoid 51% consensus attack given 80%+ of miners are Chinese and that government could centralize all mining operations? / Can the consensus % be incremented to a higher more ...
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48 views

How does the network verify previous transactions when transferring BTC between two users?

When transferring BTC between two users, the new transaction will consist of references to previous transactions. For example, if I user A wishes to transfer 1 BTC to user B, he will need 'n' ...
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41 views

Is it possible to use Bitcoins from an old or changed adress confirmed on the blockchain?

I sent & Confirmed bitcoins from my Luno Wallet using the adress from a binary miner. Next day the Binary miner said they received the Bitcoins BUT are UNABLE to use them to facilitate payment due ...
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How can i import a btc wallet into blockchain api v2

Hello I will use the bitcoin wallet api v2 to make payment from my website. My problem is i need to import my electrum wallet into blockchain wallet api v2, in the documentation i see that can be ...
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1answer
35 views

How to be assured a wallet is on a blockchain?

How could I check that a wallet or any app I download from Google play or Apple store or a website is truely runs by a blockchain and be certain that producing company can not manipulate the private ...
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484 views

Why am I receiving an email from Blockchain about receiving a payment?

I do not own bitcoin and do not belong to Blockchain but received an email from Blockchain about receiving payment... Incoming Payment You just received 3.86655869 BTC from an external Bitcoin ...
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How does hard fork lead to a double spending attack?

I read some article mentioned that hard fork may lead to a double spending attack. I wonder how? And i have one more question: will the bitcoin wallet address change after the hard fork?
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Could something like proof of work be provided in the form of human creativity voted on by other humans?

All that's necessary for a proof system in a blockchain, as far as I know, is that mining be hard to do and easy to validate. Creating works of art is hard to do, but determining their value is ...
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How does the mathematical problem get harder for bitcoin mining over time?

How does it become harder for miners to extract bitcoin as time passes (excluding increasing computer capabilities and the competition between miners accordingly)? Is related to the amount of bitcoins ...
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1answer
126 views

How do miners earn partial bitcoins?

I know that the miner who has the hash matching with the bitcoin's root software gets to stamp the block and put it onto the blockchain (correct me if I'm wrong). Accordingly, that miner takes the ...
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How did lose my bitcoin?

I met this guy online and he wanted to teach me trading. so he said I needed to log in my wallet in my wallet which I did then he sent a link of team viewer (https://www.teamviewer.com/en/download/...
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46 views

Are Core's blockchain reads parallelized?

Does Core have a mutex allowing one read at a time from the blockchain, or can reads be parallelized? If multiple reads from different threads is possible and there's no single mutex, it is advised to ...
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1answer
71 views

Is This a Bitcoin Scam? [duplicate]

Is this a bitcoin scam? He is not asking for my username and is having me change my password before sending him the link to my mining wallet. A bitcoin miner on LinkedIn wants to mine for me. He ...
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Configure esplora to point to the bitcoind servers ip address - Part 4

Continuing on from this post: Configure esplora to point to the bitcoind servers ip address - Part 3 The indexing now works, but quickly runs out of space on the local drive. I have a second drive ...
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Can I rely on my full node to always have the most recent blocks?

I have a full node running and I am using ZMQ to let me know when new blocks arrive. How can I make sure that this block that my node received is a valid block written in the blockchain ledger and it ...
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1answer
65 views

How to connect the Blockchain to the Network without IP Address?

I would like to know how do we connect the blockchain to the network when there is no IP? Indeed we all use bitcoin core (for bitcoin) to connect and retrieve information and update. However the ...
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1answer
77 views

Is there such a service as an unlimited Bitcoin wallet with an API?

Well, I did tons of research and currently I'm using bitcoinlib for python to have a wallet which should be able to hold over one million addresses and occassionally broadcast transactions. It has ...
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1answer
57 views

Transaction not complete for two days now

I sent bitcoins to a wallet using the QR code in order to be very sure of the address. It shows in my wallet that it has been sent. But the receiver haven't seen it in his wallet. I checked it online ...
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50 views

Api to automatically check the status of a BTC transaction

My team is working for a community of members who make donations in BTC to support a cause from time to time. The donations the details are stored in a database and displayed on their personal ...
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Trying to locate my bitcoins

I was working with a broker, now my "bitcoins" are in "blockchain", and I have no trace. How do I find them? How do I find said blockchain and bitcoins ?
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How to sign Raw Transaction with Multiple Inputs

What is the procedure to sign a raw transaction with multiple inputs, i have some doubts, this is what i am doing: Step 1 First I serialize 1 unsigned tx for each input. INPUT 1 02000000 // Version ...
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1answer
24 views

Imported bitcoin address to block-chain un-spendable

I imported a bitcoin address to my block-chain wallet. The bitcoin shows as un-spendable in the wallet. The address was used previously by me and worked fine. How do i fix the problem to make the ...
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743 views

How to find Reused R values

I use software from https://github.com/ca333/rng-scanner , I try to find r that is reused. from the software I found results Bitcoin Address : 1GQdrgqAbkeEPUef1UpiTc4X1mUHMcyuGW In Input NR : 141 ~ ...
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51 views

How do bitcoin nodes agree who first mined ablock?

Once transactions are broadcast and a node starts working on a proof of work, and finds it, it broadcasts it to all other nodes for that block to be verified and added onto their blockchain. All nodes ...
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Bitcoin stuck in bitcoin core

Anaware of the fact that Bitcoin Core has to sync 800gb of data before showing up my coins, I transferred some money on a wallet created with the application. Now my money is stuck. The files are too ...
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1answer
42 views

How a transaction is permanently accepted by the blockchain?

If a miner A creates a block containing a transaction A and a miner B creates a block NOT containing the transaction A about at the same time, then some of the other miners will first receive the ...
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Bitcoin Core wallet fails to load and requires reindex after I already did it

My Bitcoin Core is synchronized. But I can't open a wallet, it says that I might need a reindex. Though I already did it. Also I can't do dumpprivkey because it says that no wallet is loaded. How can ...
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1answer
60 views

How to create block height to UNIX time converter?

I want to create a converter that can be given a block height, human readable time, or UNIX time and then provide the correlated information for it. For example, if given a block height, the converter ...
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What’s prevents people from appending useless blocks to very old blocks in order to revert new transactions? [duplicate]

As far as my understanding goes, nodes in the network should accept the longest branch of blocks and disregard any other branches (excuse my terminology if it’s not what’s normally used - I hope it is ...
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Creating a Locking Script

What will be the script like for a situation like this: Lets say Alice and Bob are 2 parties. Alice has a password which Bob wants. Alice will only give Bob the password if Bob pays 5BTC to Alice. ...

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