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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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Can you send a Bitcoin transaction to a Bitcoin address that does not exist?

Say I arbitrarily pick an address "abcdefg" (for example's sake), which does not exist in the network; no one "owns" the address. What happens when I attempt to make a transaction to this address? ...
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1answer
24 views

Can you create multiple transactions per block in chronological order?

Say I buy a coffee mug, a box of tea bags, and a half liter of honey in the span of five minutes using Bitcoin. Since the Bitcoin network creates a block every ten minutes or so, these transactions ...
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2answers
83 views

What do we mean by honest nodes?

In his recent paper, Vitalik often mentions the term "honest nodes". What do we mean by that exactly?
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1answer
21 views

are all nodes validate each transaction added in a new block?

are all nodes validate each transaction added in a new block? Because what if someone said I have completed block and added invalid transaction? and if others node just accepts a block without ...
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1answer
26 views

Action taken when data of a block gets tampered with

Let's say we have a Blockchain consisting of 10 blocks, indexed from 0(Genesis Block) to 9(The last block). If the data of a block, say block 5, is changed(maliciously), the data stored on the block, ...
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0answers
12 views

“consensus over state” vs. “consensus over events”?

Does someone know what is difference between "consensus over state" and "consensus over events" ? I found just title of a reference i.e. "Ian Grigg, blog post “The Message is the Medium,” 2017." ...
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1answer
36 views

how to achieve transaction info of all the blocks

I use https://chain.api.btc.com/v3/block/date/20151215 to achieve list of blocks and also use https://chain.api.btc.com/v3/tx/0eab89a271380b09987bcee5258fca91f28df4dadcedf892658b9bc261050d96?verbose=3 ...
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1answer
35 views

Why are miners allowed to not announce their mined blocks to the network?

My question relates to a 51% Attack. As far as I understand, for this to work the miner must have a secret fork of the main blockchain, which he will later announce, whenever it becomes longer than ...
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21 views

blockchain-based transactins

I need 5 sets of transactions that includes events of nodes. I 'm going to cluster this data. I had searched in this site and found the list of blocks, but unfortunately couldn't find transactions ...
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0answers
194 views

Iquidus Explorer showing incorrect balance for given address

I tried to fork Iquidus Explorer to build my own block explorer for one of my altcoin. My coin was forked from Dash which it's Hybrid coin instead of PoW. The problem I had with Iquidus Explorer was ...
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1answer
45 views

Delegated Proof of Stake (DPOS) vs. Proof of stake?

What is the main difference between Delegated Proof of Stake (DPOS) vs. Proof of Stake? Is there any significant advantage for security? (since PoS in general suffers security problems.) And which ...
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2answers
56 views

Is it possible to get the standard private key from a too long private key?

We know the private key should not be longer than 256 bits. But if I choose one longer key X, for example 300 bits key, and use it generate a pub key and address. Can I use X to generate the standard ...
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1answer
105 views

How are nonces decided in mining?

I know that when I create a new block in a Bitcoin network, I change the nonce value to generate a block. The question is, do you randomly assign the values you assign to nonces? Or do you start with ...
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1answer
145 views

Difference between wallet,accounts and addresses

I know this question has been asked several times, But it never made any sense reading each of them. Can Anyone really explain deeply by using technical language so that I could really understand pros ...
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1answer
20 views

Can transaction data be altered before creating a block?

I'm a novice and had this thought. I understand that data in an existing block can't be altered, as it changes the hash. But what if, before creating the block, I take transactions from the pool, ...
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0answers
8 views

Synchronize bitcoin up to N blocks

Just my curiosity, I would like to synchronize Bitcoin blocks up to N(e.g. 10000) blocks. But I have no idea to stop(or limit) synchronizing at exactly N block. Is it possible to do that? Bitcoin ...
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0answers
62 views

How do I get bitcoin cash wallet balance in bitcoinj?

I have using this method to get balance. kit.wallet().getBalance().toFriendlyString(); But it only gives me refreshed address balance. and it also 0 BTC.
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1answer
232 views

Can we reset or forgot second password of the blockchain account via backup phrases or any other tricks?

Can we reset or forgot second password of the blockchain account ?
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37 views

gitian-builder fails when building a windows wallet

GItian-builder fails when I run deps-win32.yml. I am using bitcoin's earlier version so that to learn creating new coin. I'm using 0.8.7.4 and in that gitian-builder version there's a package ...
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2answers
226 views

Blockchain vs. Banks: which one has more affordable transaction fees?

Maybe one of the issues researchers are trying to solve in blockchain protocols like Bitcoin or Ethereum is removing / decreasing "transaction fees". However, if we compare blockchain transaction fee ...
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1answer
41 views

I am not able to send BTC in Blockchain

I have 0.98 BTC confirmed, but my wallet only lets me send 0.1 BTC. My wallet has received a lot of small payments, what can I do? Thanks
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1answer
38 views

When does a node start mining the next block?

Will a particular node on the Bitcoin network begin mining the next block after it has successfully been mined? Mine right away. When the node with the best computation power among the nodes ...
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1answer
43 views

With the strongest hardware today, how long does it take to brute force or generate 10^18 bitcoin address as fast as possible?

I see this kind of question before on this topics, but lots of them seems very old. Arcording to Moore's law, computer speed doubles every two year, so i wonder how fast have they archive these days. ...
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1answer
41 views

Do miners receive a reward when solving the hash for the next block or when validating the block, or both?

Let's say I want to make a transaction to my friend Bob. When I send 10 BTC to Bob, a transaction is signed with my signature and sent to the network. What happens next? Do miners check if this ...
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1answer
65 views

Understanding how validation of a transaction works

As far as I understood, a transaction works like this: Alice wants to send 5 BTC to Bob. Alice creates her digital signature that contains transcation info like id etc. She encrypts the signature ...
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1answer
66 views

When are Bitcoin transaction outputs generated more than two?

When are Bitcoin transaction outputs generated more than two? In my understanding, if my wallet has only UTXOs that have more values than i wanted to spend(send), then two outputs are generated which ...
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1answer
46 views

Funds disapprearance [closed]

I stored 0.0154 BTC in my blockchain for mining purposes and next morning I found my balance to be 000, what does that mean? Are my coins lost or stored somewhere else?
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1answer
37 views

Double transaction on same hash (transaction ID) - Loosing 0.01 btc each time [duplicate]

Each time I send some btc to another bitcoin wallet there is a second transaction on the same transaction ID (hash) and each times i am loosing around 75 USD. You can see by yourself here; https://...
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1answer
31 views

How do I know one transaction has confirmed?

I am running my bitcoind with -zmqpubhashtx optional, and I receive notification once a new transaction has broadcast to public chain! I can also parser it by getrawtransaction and ...
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1answer
97 views

Mining Theory: What would happen if a block hash collision occured? [duplicate]

To my knowledge, neither SHA256 or scrypt have ever had provable instances of hash collisions occur.. However, if this highly unlikely event was to happen, what would that mean for the state of the ...
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2answers
89 views

While calculating merkle proof, where are the other hashes being stored?

Consider that I have a merkle root made up of transactions a,b,c,d,e,f,g,h. The root is H( H(H(a)+H(b)) + H(H(b)+H(b)) ) + H( H(H(b)+H(b)) + H(H(b)+H(h)) ). Now, I have to verify whether transaction ...
5
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1answer
273 views

From where does the 2 hours limitation on bitcoin time stamp come?

Bitcoin wiki says that: A timestamp is accepted as valid if it is greater than the median timestamp of previous 11 blocks, and less than the network-adjusted time + 2 hours My question is why 2 ...
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0answers
41 views

Different balances in API block explorers for BTC

BTC.com block explorer shows bigger balance than for example Insight or Blockchair. For example: https://btc.com/1FLDCfr9iG7n6bAdGsqBXmhaLgC4aSze72 https://insight.bitpay.com/address/...
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1answer
309 views

Why A Block have a Merkle root hash? [duplicate]

That is the question, why a block needs to have a Merkle root hash, as Iundestand, once a block is mined the hash value of this block is stored at the header of the next one so, it generates the chain....
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2answers
48 views

Why are my Signature Scripts Different from my professors?

bob_addr = "1NWzVg38ggPoVGAG2VWt6ktdWMaV6S1pJk"#"1FMb8Jnn1jSh7yjDFfonC8xCCH3ittoEzB" bob_hashed_pubkey = base58check.b58decode(bob_addr)[1:] bob2_hashed_pubkey = b'\xec\x06\xb2\xbf\x18\xc8\x97\x06\...
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2answers
65 views

Is it logical to use “Proof-of-Authority” for a “public” blockchain?

According parity.io website: Proof-of-Authority is a replacement for Proof-of-Work, which can be used for private chain setups. And also: The chain has to be signed off by the majority of ...
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3answers
120 views

How do I know that a node provides the accurate blockchain

When I connect with a wallet to the bitcoin network, how is the balance actually retrieved? One node? Or more? I understand it is a sum of all transactions. But when I load my wallet I assume I ...
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1answer
35 views

Who set the rules for validating a block in blockchain?

Who set the rules for validating a block in blockchain? The rules can be set the creator of the blockchain network. There might be some rules on the application that uses the blockchain network. Is ...
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1answer
29 views

How transaction manipulation handles in Blockchain?

I'm new to Blockchain and would like to understand few concepts in a detail. After reading about basics of Blockchain, one thing is unclear to me about tx. manipulation. For instance, A has some (i....
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0answers
37 views

“state channel” v.s “micro-payment channel” : are they the same?

We use "micro-payment channels" such as "Bitcoin Lightning Network" or "Duplex Micro-Payment Channels" for saving transaction fee, accelerating payments, supporting better micro-payment and scaling ...
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1answer
43 views

How are blocks accepted in bitcoin?

These are steps to run the network quoted from the Bitcoin white paper (https://bitcoin.org/bitcoin.pdf): New transactions are broadcast to all nodes. Each node collects new transactions into a ...
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1answer
46 views

While attempting to fetch a particular block my node just gets disconnected by peers?

A system at an office has its testnet node stuck at a particular block. The logs report "requesting block" over and over again for the same block and after each one reports "socket recv error" and ...
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2answers
38 views

Could mining centralization be countered by checking if the node connects to many ASICs instead of one?

In a mining pool, many ASICs and GPU/CPU from all around the world connect to the pool's node. Is it possible to force every node's client software to check if a node is connected to just one ...
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1answer
38 views

Distributed Consensus

"Distributed" means operating on more than one devices which dont share physical memory and perform their task (which might be storage or computation) to perform one single task (which in our case ...
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2answers
260 views

Why aren't block hashes used directly as scores for difficulty purposes?

Why does Bitcoin apply a difficulty function to block hashes and then use the output of this function to add up and determine the "longest" chain? Why not just e.g. add together all block hashes (as ...
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1answer
30 views

terminology and conceptual question about progress of PoW

what is wrong about thinking prbobability of attacker increases with time t that goes into PoW since they have more time to secretly mine their alternate blockchain ? This refer to double ...
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1answer
22 views

is target a 256 bit field or a 32 bit field

first, do we talk about fields or values. is it correct to say that it is a 32 or 256 bit value ? or should we call it a 32 or 256 bit field ? Why do some authors like say that the size is 32 bit . ...
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1answer
268 views

Template of a DAO?

Where can I find a simple smart contract template of a DAO? not The DAO, but a Decentralized Autonomous Organization, rules, codes, bylaws, responsibilities, etc.
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2answers
110 views

Does it make sense to design a mutable blockchain?

I work in a large consulting firm which is marketing a mutable blockchain solution to its clients. But I personally fail to grasp any advantage of using a blockchain design if you are discarding ...
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2answers
77 views

Is it possible for there to be a virus in the blockchain?

can a blockchain ever get a 'virus', that continually replicates itself, continues paying for gas (if on the ethereum network) and survives/self-replicates through the blockchain, similar to viruses ...