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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Exploiting the use of signature?

I've just learned signatures and why they're used in blockchain. As I understand there is a key pair that consist of one public key and one private key: Private keys are used to sign a message(...
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How are newly generated key-pairs kept unique to a single cryptocurrency?

As an extension to this question and some quick searches on software crypto wallets - my understanding is that any newly generated key-pair is unique to a specific cryptocurrency. Assuming this is ...
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Support dev work [closed]

I need around 2 BTC in testnet coins. Can someone on this forum please spare some coins, I will return them once I have finished with my dev work. my address: misquBy87Jvs5j2bysab5fq5m4FXD4N2Pt Thanks ...
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Are all wallets always considered nodes?

Likely a duh question, but are all network participants (or wallet holders here) always considered nodes? Am I right to say that the answer might depend on what the wallet is capable of doing in terms ...
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1 answer
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are the hubs on the internet the only hackable 'computer'?

Context here: I'm a newbie on internet&blockchain, but I read some article and they said on the internet, computers are connected through hub(s). So, It seems to me that there's no other 'users' ...
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Who can give me an analysis of the current situation of Bitcoin and the future development trend? [closed]

Do Bitcoin Miners Bring Profits? Can Bitcoin continue to rise?
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I cant mov my blockchain to my wallet. And at the end of it it has a "change" symbol [closed]

What does change in a little blue box in my blockchain? I can't transfer to my wallet
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Relation between PoW and integrity?

I'm pretty new to the Blockchain technology. In a video that I watched, the lecturer talked about Consensus Algorithms and said that they're used for maintaining the integrity of the blockchain.  Then ...
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1 answer
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Wrong hashes for blocks when parsing from blk

Hello I'm using a python script to actually retrieve information from a blk file and to read data. import datetime # Read block ! file = open("REDACTED\blocks\\blk00000.dat", 'rb') ...
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1 answer
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Why is Bitcoin core deleting my blk files while downloading blockchain?

I want to download the bitcoin blockchain to actually be able to parse it using the blk files, but as I'm seeing right now while installing, bitcoin core is deleting them and keeps downloading newer ...
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1 answer
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Could you clarify the definition of bitcoin, that is "coin", which Nakamoto defined as "a chain of digital signatures"(details below)?

Say Alice buys 1 BTC and Bob 100 BTC. Nakamoto defined coin(BTC) as a "chain of digital signatures", so Alice bought 1 such chain, and Bob 100 chains. That makes no sense to me, so could you ...
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Double spending: Do miners generally adhere to the RBF-Flag (replace by fee) in on-chain transactions and the FSS-rule (First Seen Save)?

I've been reading some articles about 0-conf scams happening, where someone accepts bitcoin on-chain without waiting for even a single on-chain confirmation. In this blog post, it is described that ...
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How can I take a "snapshot" of the bitcoin blockchain and analyze it?

What I want to do: Download the copy of bitcoin blockchain Select from it all those addresses that have bitcoins (> 0.05 BTC) and they have not been active for > 7 days Display statistics on ...
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1 answer
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What prevents miners from removing transactions when validating a node? [duplicate]

Simple question: when a miners receives a block of transactions, he can't add fraudulent transactions because they need to be appropriately signed, but what prevents him from erasing a tx? If he ...
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BLOCKCHAIN CIRCULATOIN IF COIN NOT RECEIVE? [duplicate]

UK Company send some bitcoin in my wallet address but after 100 of confirmation bitcoin not showing in my Binance Account. So Depositer saying that recipient have to send half of actual value of ...
1 vote
1 answer
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Restarting the bitcoin chain in a land far away, after a global total collapse disaster

So I've been thinking about this scenario, you are a survivor of a global disaster. Years later you find a running solar powered bitcoin node and want to restart the chain. You have a few running ...
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BlockCypher API signature bitcoin transaction Error

I'm trying to make a bitcoin transaction using the BlockCypher API and I'm getting an error when I try to sign the transaction. This function creates an unsigned transaction: def buildTransaction(...
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Error `settings.json file has no read or write access` - but permissions OK

I was downloading the whole Bitcoin blockchain and the download stopped and I got an error message that the settings.json file has no read or write access, but I checked the permissions of the file, ...
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How is crypto Mining actually validating the block?

As far as I understand in crypto-mining you are trying to find the nonce such that the hash starts with some amount of zero's. I do not understand how this nonce is used to actually validate anything.
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bitcoin TransactionBuilder is not a constructor

I'm trying to send bitcoin with the bitcoinjs-lib library and I get the following error: TypeError: bitcoin.TransactionBuilder is not a constructor at sendmoney (/Users/....../bitcoin.js:53:18) at ...
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Why my node1 can's sync from the other node through RPC command "addnode IP:port onetry"?

I'm using bitcoin core 22.0 to start two nodes in two different containers in the same VMware ubuntu18.04, with network mode using Host-Only(I will talk about the reason later). What my aim to do so ...
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Can Bitcoin Core Blockchain initial sync time in BitcoinQT be sped up?

Given the following platform hardware and internet data speed (provided below), what settings are recommended for fastest possible blockchain download and sync? This is the hardware I'm running: Note:...
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3 answers
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How 2 chains co-exist together?

I am not able to understand, how 2 chains co-exist together, like these were the observations which are ambiguity for me: In one reading I have read, Only longest chain is valid and and rest chains ...
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Whats it called when two blocks are solved at the same time and create their own chain?

I'm trying to find more information on this topic but I can't remember what this is called in order to look up more information on it. Is there an easy way to see the "trusted" amount of ...
3 votes
2 answers
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Why anonymity is important in blockchain, what are the core reasons?

I have searched a lot about this topic, but couldn't get a perfect answer. Why is anonymity is important in blockchain if the transactions are legit, What are the core reasons for importance of ...
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How do we know a new transaction is not corrupted/manipulated? [duplicate]

let's say I want to send a certain amount of bitcoin to a certain client, but my computer is connected to a public wifi, how do I make sure there is not a man in the middle altering the transaction ...
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3 answers
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How does Bitcoin prevent double-spending without penalizing miners?

In the network nodes below as shown in picture: Let's say A is trying to double spend by sending bitcoins to B,C (A->B) and (A->C) and let's say A tried to relay (A->B) transaction to honest ...
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Are transactions included in a block or is only the Merkle-root hash included in a block

Before broadcasting block into bitcoin blockchain, Does a Block transactions are included in a block or only the hash of them are included in a block. While I am surfing through net, I came across two ...
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1 answer
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How to obtain transaction-ID for a payment?

I'm trying to create a transaction and send it to the blockchain. The goal is to get an address from which the money comes and an address to which the money will go, send the transaction to the ...
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3 answers
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What Exactly is Blockchain?

I am trying to learn blockchain technology but I could not find clear answers. I will appreciate your help. ^^ Is blockchain a specific algorithm or software? As I know, blockchain is the ...
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Online resources to learn bitcoin from basic to Advance (might be building whole network) from scratch [duplicate]

I am new to bitcoin network, I want to learn the bitcoin from basic to advancev ( might be building whole bitcoin network from scratch including cryptography, wallets, codes, etc) from scratch. Kindly,...
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Why txindex breaks my partition?

Why Bitcoin Core -txindex breaks my partition? For three or four times, I have undoubtedly synced the chain up to 2017 or 2018, until it errors, then it crashes, upon unmounting the partition, ...
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Bitcoin blockchain verification on download

I would know what does Bitcoin verify when you download a block. Are the transactions verified too, or not? If they are, will it be the case for their signatures? Best wishes.
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How to decipher Bitcoin Hex code?

I have this hex code: ...
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How can I search blocks for transactions in which an address was used as output without knowing complete address?

Can I scan the blockchain for transactions if I remember first and last few characters of a bitcoin address which was used in a transaction?
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What's the logic behind the way block proofs (in GetBlockProof) is calculated?

Bitcoin Core uses GetBlockProof() function to determine the contribution of a block to the total difficulty of the current chain, aka, nChainWork in CBlockIndex. I'm having trouble understanding the ...
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How are validity flags in block index set in concurrent blocks when one of them is chosen?

I'm trying to understand block validity flags, and what happens when a branch occurs. I found a block status flags in the bitcoin core source code: enum BlockStatus : uint32_t { ...
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4 votes
1 answer
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Does local blockchain database (blkXXXXX.dat) contain abandoned forks forever?

When my node realizes that the given block needs to be abandoned - does it leave it in the database or replace the block with a valid one? And if "invalid" block remains: is it somehow ...
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1 answer
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Old Blockchain Wallet App Not Working (android)

I have the Blockchain wallet app most recent version (yet, years old) everytime I try to login it says "error connecting to server" And I have the internet and 4 digit pin, and this app is ...
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1 answer
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How does blockchain decide the complexity of proof-of-work [duplicate]

I heard that the complexity of proof of work in blockchain can vary. On what factors does it depend? Is it possible that that proof of work i.e. the required hash starting with certain number of zeros ...
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2 answers
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Where does this 2^32 come from?

Several months ago I was doing research into calculating mining revenue for several crypto currencies. When trying to calculate BTC revenue I found this value 1/2^32 which was described somewhere ...
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Searching The Blockchain Based on Transaction Amount and/or Date

I know there are a lot of services to look up if I have the wallet address or transaction ID. But, let's say I have no idea who the sender or receiver were nor a transaction ID but I know ...
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1 vote
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Blockchain app won't let me send bitcoin because it says there's nothing in the wallet, yet I have $40 in there [closed]

Like the title says, it won't let me send any bitcoin through the "Send" function of the blockchain app, and only prompts me with the "Buy Crypto" button, but I have $40 in the ...
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Isn't the power of blockchain coming from decentralization instead of immutability of blocks?

I've only started exploring the working of blockchain. So what I've gained from guides on Google has me into thinking that what makes blockchain records resilient to corruption is distributed storage, ...
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1 answer
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How do transactions get into the mempool?

I was tracking a transaction using a Bitcoin Core command. I was able to extract info on whether the transaction had entered the mempool. Among the information I got were details such as "the ...
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What is the reason for unusual stuck bitcoin transaction?

I have my bitcoin wallet and there is the following situation: There is a strange transaction with 200+ inputs to the wallet A which I don't know (with low amount and very low fee). These ...
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Imported Address

I had some btc in a hardware and I transferred to my new blockchain account. But now it shows in a imported address. Do I have access from my blockchain? Can I sell, exchange … or watch only?
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Same blockhash that appears more times in a bitcoind’s rpc call listsinceblock transaction returned json

Let's suppose that listsinceblocks return a json like this: { "transactions": [ { "involvesWatchonly": true, "account": "", "...
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Consider only deposits in a bitcoind’s RPC call listsinceblock transaction returned JSON

I have a JSON result of a bitcoind’s RPC call listsinceblock. There are 4 categories of transaction: "send" means transactions sent "receive" means non-coinbase transactions ...
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Can a receive transaction be 0 in a bitcoind’s rpc call listsinceblock transaction returned json?

Suppose that I want to check all the valid deposits of the results of bitcoind’s rpc call listsinceblock transactions, can I found a ‘receive’ transactions with ‘amount’ as 0? Should I consider that ...

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