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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187 views

Can I find the address of my Bitcoin in the debug.log file?

I cannot download the entire block chain (I’ve tried four times now and failed) so I can’t replace my encrypted old wallet.dat file into the blockchain and do the rescan to check my coin balance. My ...
0 votes
1 answer
21 views

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(...
1 vote
1 answer
45 views

What to look for in Bitcoin-core logfile when something bad happens

About a week ago I was trying to reorganise my file structure with Bitcoin Core, I accidentally moved the file before listing it as a backup so when I opened Core, it didn't work. I tried returning ...
0 votes
3 answers
57 views

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 ...
-1 votes
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' ...
0 votes
1 answer
59 views

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 ...
0 votes
1 answer
440 views

Create wallet address on user registration for trading platform

I am creating a crypto-trading platform . I wanted to know how to create wallet address dynamically for all new registered user and also create new address for every transaction. I am using bitcoind ...
-2 votes
0 answers
32 views

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 ...
0 votes
2 answers
212 views

Does a trusted blockchain import from BitcoinCore require that chainstate and blocks be from the same source?

Can the chainstate folder from a pruned node be used with the blocks folder from a full node to provide the full blockchain? Assume that both nodes have been running for months. If the blocks folder ...
37 votes
10 answers
29k views

How is it possible to launder bitcoins?

Some services, such as bitcoinlaundry.com, claim that they can launder your bitcoins. Since all bitcoin transactions are publicly logged, how is this done? Wouldn't it be possible to trace back the ...
-1 votes
0 answers
53 views

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?
1 vote
1 answer
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How much on-chain activity is to and from exchanges?

Are there any data services which provide metrics that show how much of the transactions on the Bitcoin blockchain are to and from exchanges?
2 votes
3 answers
52 views

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 ...
-1 votes
0 answers
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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
1 vote
1 answer
68 views

What are bitcoin Pool APIs?

I contacted a website and asked them where they get their data for crypto like Bitcoin, as I am trying to find the place for the most up to date and reliable data on Bitcoin and other crypto. They had ...
3 votes
3 answers
185 views

Does descendant size affect transaction fees?

While calculating the transaction fee miners usually take ancestor size into the account. But does the descendant/output also affect the transaction fee calculation? Is descendant count correlated to ...
0 votes
1 answer
9k views

Blockchain wallet showing 0 however app showing balance

So my blockchain desktop wallet is showing 0 balance whoever if o go in to the app i can see my bitcoin wallet balance. When again i click on the wallet it goes back to 0 in the app for some reason. ...
1 vote
1 answer
61 views

How transactions or wallet balance are retrieved from bitcoin blockchain?

Using different blockchain explorers one can retrieve the wallet balance or transactions of address. My question is how does this query works do they search the whole blockchain for the related ...
2 votes
1 answer
106 views

Blockchain linking algorithm

Why does new block include only parent's block hash instead of hash of it's all previous blocks calculated using e.g. merkle tree algorithm?
1 vote
2 answers
206 views

How much data does it take to prove a given transaction exists on the blockchain?

As I understand the SVP protocol, a client can be reasonably certain that a transaction has been accepted on the blockchain if they know it is a member of a certain block, via the Merkle path, and a ...
1 vote
1 answer
45 views

Why do we need 2F prepare certificates instead of just F+1 in PBFT?

I started reading PBFT and I could not understand: why do we need 2F prepare certificates? The client needs only F + 1 replies, not 2F, so why can't the same rule be applicable in the prepare phase of ...
1 vote
1 answer
25 views

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') ...
1 vote
1 answer
45 views

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 ...
1 vote
2 answers
1k views

What happens when a transaction is included in more than one block?

What happens when two miners include same or set of transaction in their block, mine it and then broadcast it at same time? Can the transaction be included in two separate block like this OR a fork ...
-1 votes
1 answer
83 views

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 ...
2 votes
1 answer
3k views

How do you import Block Chain from bitcoincharts?

I went to http://eu1.bitcoincharts.com/blockchain/ and downloaded the most recent build. Then I extracted it and was left with BLK0001.dat and BLK0002.dat. What is the next step? I tried replacing the ...
0 votes
1 answer
101 views

Can can I identify my deposits to a wallet on a BTC (or LTC) blockchain (using the blockcypher api)

I'm trying to reconcile my deposits to a wallet (happens to be LTC) on an exchange account with the data on the blockchain. I was using the logic: if tx_input_n is -1 then transaction is a ...
14 votes
3 answers
7k views

What is a step by step way to insert data in OP_RETURN?

I was following https://bitcointalk.org/index.php?topic=453086.0 for creating a message in OP_RETURN. I am able to decode my raw transaction, but on signrawtransaction it gives error: {"code":-22,"...
0 votes
0 answers
34 views

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 ...
0 votes
1 answer
860 views

Bitcoin transaction graph

I am trying to make bitcoin transaction graph, but I am not sure how to go about it. I have extracted the necessary data from blockchain like the sender, receiver, amount of bitcoins sent, transaction ...
2 votes
1 answer
1k views

bitcoind crashing due to insufficient memory?

EDIT 3 Bumping my VPS to 1GB of physical RAM stopped the crashing issue... UNTIL said VPS ran out of disc space. I added prune=10240 to my ~/.bitcoin/bitcoin.conf file such that the blockchain file ...
0 votes
1 answer
73 views

In the basic Wallet based in QT, How can i get by RPC the stored addresses and labels?

this question is for you to ask about the QT wallet, in the section to send coins, there is an address window, and it has the list of the stored addresses we save along the time. So using RPC, do you ...
8 votes
2 answers
2k views

What is the size of different Bitcoin transaction types?

I found this interesting take on Bitcoin transaction type trends from 2015. As that article is from 2 years ago, I am wondering: a. Are there any newer transaction types? b. What is the average ...
0 votes
1 answer
457 views

resilience to sybil attack - public vs private

it appears that although not totally water-proof to Sybil attacks, Bitcoin network seems quite resilient to these kind of attack Preventing Sybil attacks. Is it true to assert that permissioned or ...
3 votes
2 answers
3k views

Does every node have a whole copy of the blockchain?

As I read in this blog article, in a blockchain "each node has a copy of all transactions ever made". This to me seems impossible, bitcoin has existed for a long time, and the memory size of ...
0 votes
2 answers
125 views

How do cryptocurrency exchanges work with so many currencies at the same time?

To implement automated deposits/withdrawals of a single currency for a business there has to be a lot of code in place specific for that currency. For example if I want to automate sending and ...
0 votes
2 answers
53 views

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 ...
1 vote
1 answer
121 views

developing hd wallet using bip32 and bip 39

I'm developing a HD wallet using C#. I want to use this wallet for multiple blockchains like bitcoin, ethereum, dogecoin etc... I've read that I should use bip32 for my wallet. i know what's bip32 but ...
0 votes
1 answer
3k views

How to send bitcoins without the bitcoin client in PHP

Is there a way to send bitcoins programmatically without the bitcoin client using PHP?
0 votes
1 answer
116 views

Coinbase to Blockchain Transaction

Hello everyone! Recently i received a cryptocurrency to my Blockchain Wallet. The Bitcoin was sent from Coinbase to my address - I waited for about an hour. And i don't see the transaction and the ...
0 votes
1 answer
105 views

Error getting bitcoin block to process from DB

i am installing a full node on a linux server and i'm trying to connect to bitcoin with BIFROST(https://github.com/stellar/go/tree/master/services/bifrost) but i am getting the error below which ...
1 vote
0 answers
25 views

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, ...
0 votes
1 answer
68 views

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 ...
4 votes
1 answer
835 views

what is nMinimumChainWork?

I was trying to run my own private bitcoin network, so I downloaded the source and compiled it, then I started two bitcoind instances in two docker contains, and I made sure they did not connect to ...
1 vote
1 answer
41 views

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 ...
1 vote
1 answer
55 views

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 ...
2 votes
1 answer
88 views

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 ...
0 votes
0 answers
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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
88 views

Question Regarding Send_to_many function of blockchain wallet api

I am using send to many function of blockchain wallet api and i am facing issue. when upto 20 transaction done then after i get error in terminal that 1538652825520 - error: ERR_PUSHTX ...
0 votes
1 answer
76 views

How to decipher Bitcoin Hex code?

I have this hex code: ...

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