The blockchain is a list of all transactions that have occurred using the Bitcoin currency. Please don't use this tag for the service named 'blockchain.info'.

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need advice for building bitcoin miner from scratch

Ok so I've been studying bitcoin for a while now and would like to start up my own rig. I know it's pointless now to mine bitcoin because it's not worth it but I'd like to learn for fun and start with ...
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1answer
29 views

Is there any relation between the block version field and the one of the transaction?

I am struggling to validate my custom miner against the testnet network and I can't seem to add a block of mine to the chain. I've noticed that all the other miners are appending version 2 blocks, so ...
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2answers
36 views

How often does a block have only one transaction?

I was looking at blocks on blockchain.info, and came across this one with only one transaction in it: (the mining reward one) ...
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2answers
56 views

Help me understand Bitcoin analytics

I'm trying to use the Blocktrail API to look at the oldest Bitcoin addresses to create a info graph piece - besides looking at historical transactions, what else would be good for me to analyze? \\ ...
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3answers
80 views

How are transactions broadcast to the rest of the network?

If a person sends a transaction to another person, and Bitcoin is a peer-to-peer application, how will the transaction get to the rest of the Bitcoin community? How does everyone have the same ...
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1answer
259 views

Best way to anonymize bitcoin transactions?

https://en.bitcoin.it/wiki/Mixing_service How do sites like this work? "Mixing services". I know it can be broken and traced back with coinsuduko but how exactly does it wash your coins. I doubt they ...
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6answers
22k views

Can I download the whole block chain from somewhere?

Every time I turn on the Bitcoin client it takes days to catch up with the block chain. Are there alternatives to getting it trickling through the peer-to-peer network? Can I just download it ...
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0answers
15 views

Armory can't find blockchain files produced by bitcoin-qt

Armory is telling me to restart the application using --satoshi-datadir=[path] But I don't understand how to do this? I'm running MacOSX. I know where the blockchain is. How do I start Armory with ...
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1answer
31 views

Remove address from sequence in HD wallet

Is there a way to eject an address out of the sequence of an HD wallet? Lets say an address was used for a political donation to a regime in Namibia that may get international condemnation a few ...
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1answer
177 views

Trust Less Database Design?

I'm a young developer and have been following the bitcoin community for some time now and have wanted to contribute to a project. Have not fully read through the bitcoin protocol, but from my ...
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2answers
2k views

Why does the initial blockchain download get stuck part way through?

I am trying to get Bitcoin up and running on a fairly underpowered laptop and Windows Vista using bitcoin-qt 0.5.0.1 . After installing and starting the program I am stuck at at the syncing stage at ...
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1answer
62 views

Bitcoin 101, need some knowledge [closed]

I am new to bitcoin. How do I check if my blockchain is working? I have tested some free bitcoin sites but neither of them have worked.
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1answer
267 views

Bitcoins Stuck?

This morning I attempted to send BTC to my Bter account from my Mt Gox account. I sent them and they seemed to reappear. I sent them again and there was a little left over, I sent that. Now the ...
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3answers
151 views

Blockchain programming books C#?

EDIT 1: It seems that what I really want to learn is how to create software which makes use of a distributed hash table. ORIGINAL QUESTION: I want to learn about coding my own blockchain based ...
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2answers
897 views

Does the block reward get halved every 4 years regardless of hardware advancements?

Is the invention of a faster computer (let's say a quantum computer) or the lack of advancements in computing power (let's say it takes a decade to make any progress greater than incremental increases ...
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1answer
39 views

My balance gets sent back to me [duplicate]

I'm using the blockchain API to make a "send to many transaction". In the recipients I only put other people addresses, but somehow the API sends the remainder of my balance back to me. For example: ...
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3answers
189 views

Blockchain API support - receive payment IPN

I'm having some real trouble setting up the Blockchain API on my server First off is it possible to test it offline with local host? Secondly, how do I set it up so when a tx is made through my ...
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1answer
41 views

Lower confirmation time schemes: any requirement between confirmation time and the probability to find a block during that confirmation time?

Bitcoin, the first blockchain-based cryptocurrency, set a 10 minute confirmation interval time; LiteCoin set a 2 minute confirmation interval time; DogeCoin set it at 1 minute; QuarkCoin set it at 30 ...
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1answer
100 views

If more than one coin did the “mini-blockchain” proposal, would that make the weaker coin vulnerable?

So, I was reading this paper as a proposal to the ever growing blockchain problem. In summary, it's security is provided without a full blockchain by having a proof chain with these fields: Previous ...
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1answer
442 views

Armory client shows transaction unconfirmed

I am new to btc and am using the Armory client. Yesterday I transferred some btc to wallet from my MtGox account. The wallet showed the btc received within minutes, but, after 12 hours it still shows ...
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1answer
30 views

Safely interrupt -reindex?

My database became corrupted and I had to reindex: bitcoind --daemon -reindex It takes my computer quite some time and CPU power. It's been running for an hour but it will take at least 4 more ...
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2answers
111 views

How to fork an Altcoin Which has 0 Reward Block to continue mining after the LAST POW BLOCK

Im trying to learn how is it possible to Hard Fork an Altcoin Blockchain to Continue the Mining Phase after the LAST POW BLOCK. The Block Reward is already 0 and the LAST POW stops at Block 8000. And ...
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1answer
27 views

Query Blockchain: Reference previous transaction in “txin”

I'm currently working with a postgresql database I've downloaded here which has the following schema and has probably been parsed using Bitcoin-ABE (I added some indexes and redundant columns): Now ...
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2answers
451 views

How to experience the thrill of mining?

Bitcoins are hard to mine now. I've always wanted to actually earn them, but never actually gotten much of anything. I want to create my own blockchain, separate from any other networks, so that ...
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3answers
1k views

Where to place Bitcoin bootstrap.dat

I'm sure this has been asked many times before, but I've recently gotten into the whole cryptocurrency thing starting with Dogecoin, and I now want to use Bitcoin as well. I am on Windows 7. I found ...
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1answer
36 views

What happens to off chain transactions when the blockchain is reorganised?

Many companies seem to use off chain transactions to transfer bitcoins between their own customers. What happens when a side chain gains dominance and no longer contains a block with the underlying ...
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1answer
156 views

Retrieving all the funds from BIP32 derived wallets

An ecommerce site is using BIP32 wallets for receiving order payments from a tree of child keys where each leaf node is unique to one purchase transaction. Is it common for the site to immediately ...
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3answers
402 views

How to get current BTC rate for BRL(real) using php cURL or javascript

Is there anyway to get current rate of BRL = BTC. I saw the blockchiain ticker. But the value for BRL currency is not updated As listed here in preev. I want to get the current 1BTC= how much BRL ...
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2answers
624 views

What is the block maturation time?

I was reading the wiki article about the blockchain and I didn't understand the part in bold: When a block becomes an orphan block, all of its valid transactions are re-added to the pool of ...
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2answers
63 views

Block Chain API for BTC transactions

I want to fetch transactions for an address from the following api: https://blockchain.info/address/$btc_address?format=json The thing is understanding the json returned from the api, I don't ...
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1answer
79 views

getrawtransaction doesn't work for every transaction with -txindex=1?

i put txindex=1 in bitcoin config and reindex blockchain after that when i call getrawtransaction for some transactions didn't exist in my wallet and work well like: [Working] getrawtransaction ...
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2answers
113 views

Double Spending - Does each node maintain a list of unspent transaction references?

My Understanding Of How Bitcoin Prevents Double Spending Each transaction contains references to the input transactions and ever node has to verify all transactions from time immemorial to ensure ...
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0answers
40 views

Querying insight-api to dump all addresses with a positive balance

It's been some time I've been using 'insight-api' (https://github.com/bitpay/insight-api) and I couldn't find any documentation / anything helpful to query leveldb in a way that all addresses with a ...
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1answer
7k views

Can someone explain how the Bitcoin Blockchain works?

I'm trying to figure out how the blockchain works and how to read it via blockchain.info website. Is there a laymen way of explaining how the block chain works and how to read the blockchain to trace ...
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1answer
30 views

How do I change the default blockchain Database download location for NXT?

I'm testing out the nxt client and was wondering how do i change the default database download location? Its currently downloading to the current folder (nxt_db).
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2answers
64 views

What methods are currently used to embed additional data into the Bitcoin blockchain?

Yes, I do understand that it is inappropriate to pollute the already large blockchain with data not necessary to make the currency work. But I know people are using Bitcoin as an underlying system for ...
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1answer
80 views

how to get one address from two public keys?

Parsing an input script of a transaction, I’ve come across two public keys in the script. Either public key is 33 byte long. I know how to transform a single 33 byte long public into an address. ...
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3answers
768 views

When downloading the blockchain for the first time using bitcoind, how do I know when it's done?

I'm using bitcoind on Ubuntu, headless. So there's no GUI to tell me when it's done. So how do I know?
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3answers
2k views

How to check Bitcoind block chain download progress level

i have installed bitcoind on ubuntu server, and when i run screen -x for btc it says error -10 blockchain is downloading, How do i know the progress level, currently 125600 blocks are downloaded, how ...
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1answer
22 views

how to parse input script of a transaction in blkzzzz.dat file?

In data files, an input script of a transaction appears to be in this form: [funky byte 1][signature][funky byte 2][public key] Bitcoind displays an input script in this shape: [signature][blank ...
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2answers
95 views

How can I create a list of X richest bitcoin addresses?

I have looked around, but I can't find the code related directly to my question. I want to create a list in any format that contains the all accounts with balance over 0 for example. Thanks ahead for ...
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0answers
39 views

Calculating Account Balance [duplicate]

Is anyone familiar with how the standard Bitcoin client gathers account balances from the blockchain? I understand that the software will look through the blockchain to calculate the balance, but I ...
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2answers
84 views

Why wait for several confirmations before shipping?

Suppose customers pay me bitcoins for their purchases. As far as I understand, I could check block chain that the proper payment amount has been made to the address I generate for each customer, and ...
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2answers
471 views

How does a client decide which is the longest block chain if there is a fork?

Is it only the block height or is it the effort that went into the forks? In other words: does this decision account for different difficulties?
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3answers
631 views

How often forks occur?

How often do forks occur in the block chain? I'm interested in the small, one block forks that happen when two miners create a block at the similar time.
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3answers
111 views

If using Bitcoin core client am I constantly going to be downloading data from the blockchain?

I understand you have to download the entire blockchain and sync in the beginning but don't you also have to constantly keep the software on if you want to buy/sell stuff, which means more data being ...
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2answers
73 views

When miners are working on their block, do everybody's block have the same transactions in them?

In this webpage https://en.bitcoin.it/wiki/Blocks, it says this "Bitcoin transactions are broadcast to the network by the sender, and all peers trying to solve blocks collect the transaction records ...
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3answers
2k views

get Armory to use an existing blockchain?

I'm trying to set up Armory but it wants to download the whole blockchain. The thing is I already have the blockchain downloaded on the same machine for bitcoin-qt. Is there any way to get Armory to ...
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1answer
2k views

Can the blk0001.dat and blk0002.dat files be deleted?

I have a Bitcoin installation on an SD card, and the blockchain files (blk0001.dat specifically) take up nearly 4 GB of disk space. Can the blk0001.dat and blk0002.dat files be safely deleted to free ...
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1answer
109 views

Problem with receiving bitcoins on my VPS

I installed bitcoind v.0.8 on my VPS (with Debian 6 (Squeeze)). Then I generated a wallet for it: 12VWVmNEM1q6N9zMjX9aH3wSfRUbjVkZ21. Here is my transaction to this wallet, but when I'm looking for ...