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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How to check on speed of the syncronizing progress? [duplicate]

I've got the feeling my network syncronization sometimes stops. I'd like to keep an eye on incoming information. Preferably something that shows XXX Kb/s or that simply shows me the data that is ...
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Does a new block necessarily include all transactions that occurred before its generation? What about network latency?

I read What exactly is Mining? and What are bitcoin miners really solving?, but was left wondering: What happens if a new transaction comes in, whilst mining? To answer that, I found Do transactions ...
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Why aren't bitcoin transactions processed and verified by normal bitcoin clients?

My understanding is that the blockchain is exclusively built by miners. My question is, why isn't that verification done by every bitcoin client - kinda like p2p file sharing programs allowed people ...
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How does one programmatically “walk-back” on the block chain?

I'm thinking (probably erroneously) along the lines of a linked list and C pointers, but how would one follow the block chain from some block all the way back to the genesis block? The previous ...
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1answer
141 views

Help understanding the blockchain [duplicate]

I am trying to better understand the fundamentals of the BLOCKCHAIN. I am not technical and am hoping someone can offer up an explanation in LAY TERMS. Thanks in advance.
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Transactions show up on blockchain but not in multibit? [duplicate]

1JPEobzLgKo5EKEfDVN8aJ61Pdryse6ccf This address shows transactions I was not aware of for unknown reasons, and does not show up in multibit(version 0.5.16). Which one is accurate, and how can I sync ...
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162 views

Running two bitcoin instances on a linux server, can't get peers on second instance

I am running two bitcoin instances using the method described in this previous thread: http://bitcoin.stackexchange.com/a/13584/6024 I have set the new datadir and each instance has a different ...
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348 views

LiteCoin Wallet balance does not match block-explorer.com

My Litecoin wallet version v0.8.6.2-beta is showing a balance of 26.579 ltc When I query http://block-explorer.com/address/LejrG23b2HcjqPRbZU8UWFxZhdJTUc75pS it is showing 0 balance. I just sent 2 ...
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How do I find the transaction ID of what I just transacted?

If I send or receive something (with Bitcoin-QT), how can I get the transaction ID of that transaction? context: I'm playing satoshi bones and they have verification code I can run to make sure ...
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74 views

Checks to Verify money sent to any address in a transaction

I'm using wallet-less bitcoin daemon (it just syncs blockchain) ā€“ the purpose is to read blocks and transactions in them, and do some useful things. This particular question is focused on determining ...
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119 views

Bitcoind doesn't find transactions / synchronize / update until last block from Testnet

I set up bitcoind as server. It downloads the testnet blockchain but it is inconsistent with public data: http://blockexplorer.com/testnet/q/getblockcount 182951 (As of 18/02/14) And bitcoind ...
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Do I need to wait for blockchain to complete to use private key elsewhere?

As the title says: My blockchain sync still needs to sync 56 weeks, but I want to export my private keys from the bitcoin qt wallet to blockchain.info. Is it possible to do that without waiting for ...
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265 views

What is the NTX ID that Mt. Gox refer to in their Feb 17th Statement?

Mt. Gox have released a statement concerning their recent withdrawal problems. In order to launch the new system, we are going through the following steps: Re-indexing the entire ...
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How will Bitcoin deal with the year 2106 problem? [duplicate]

The Bitcoin protocol currently uses uint32_t to record timestamps. While the year 2106 is still a long way off, I'm wondering why not just go with int64_t and be done with it?
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Will the performance of calculating the balance for an address degrade over time?

If balances are calculated on the fly by offsetting all the transactions flowing in and out of a public address, will this degrade the performance of calculating such balances in years to come, i.e. ...
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1answer
136 views

What trust am I placing where when I use Electrum?

I have read that Electrum never is given your private keys (which makes sense), but I'm still unsure what sacrifices it makes in order to not require you to not store the entire ~14GB blockchain. So ...
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127 views

Transaction fees when a block chain is discarded

I'm a bit new to the bitcoin system, so I apologize if this is a "noob" question. A user attempts to take all the unverified transactions it knows about and aggregate them in a chain block. The same ...
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1answer
141 views

Should there be a minimum transaction limit to prevent dust spam?

With all these reports of people receiving spam through dust transactions (e.g. Enjoy Sotchi, Bitwars etc) what would be the implications of setting a minimum transaction amount on the network? Why ...
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Transaction Malleability in the blockchain

How does a transaction malleability look like in the blockchain? Are there any examples?
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329 views

How much space does the blockchain take up per day and per hour when running bitcoinQT on my computer?

the blockchain is about 20GB today, but i was wondering how much space does it take up each day if i were to leave bitcoinqt on regularly? also by hour? reason why im asking is im thinking about just ...
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83 views

Clean blockchain? [duplicate]

Wouldn't it be theoretically possible, to just cut everything older than say 4 weeks from the blockchain? What use does transaction data from 3 years ago have anyway? Isn't it also safer in terms of ...
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1answer
125 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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329 views

Can you help with Bitcoin block hashing algorithm ( PHP, C, Python, Javascript)? [closed]

can you help with Bitcoin block hashing algorithm ( PHP, C, Python, Javascript) ? I was working really hard to write block hashing algorithm in plain Javascript. Unfortunately the developed ...
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1answer
149 views

What is the difference between a wallet and paired keys? [duplicate]

So I've read that a wallet is basically a public address key paired with a private key. But is it more than that? Does the physical wallet file contain transaction and balance information as well ...
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Where are the blocks in the blockchain stored?

I understand that every transaction of bitcoin is stored in a "block" which is then added to the "blockchain". I realize that this is data of some sort that must have a physical location. Where is ...
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How can this input address have multiple values at the same time?

For the transaction: https://blockchain.info/tx/ee1658bb4d0de80a91d2e0005218d4cfab7c302a352458bd6afb6376b47fbf81 it looks like there are multiple inputs with different values for the same address. I ...
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283 views

safely delete the blockchain from .bitcoin directory

I have bitcoind installed and I'd like to free up space by deleting the blockchain from my .bitcoin directory. What set of files and directories should I delete such that the next time I start ...
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1answer
188 views

Is there a limit on number of transactions included in a block? [duplicate]

As per my understanding, every transaction is included in a block and the difficulty to find a block gets adjusted such that one block is found for every 10 minutes. Is it the case that all ...
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1answer
50 views

Why are the blocks out of order?

When I look at blockchain.info or blockexplorer.com, it shows the latest blocks. The most recent block, #283653, has time 2014-02-01 22:42:08. The previous block, #283652, has time 2014-02-01 ...
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2answers
239 views

Is it possible to know my ip address by simply connecting to the Bitcoin network?

It is saying that in order to stay anonymous, it is usefull to use Tor whenever connecting to the Bitcoin network. How does someone can discover my ip adress if I'm simply connecting to the bitcoin ...
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48 views

Searching through the blockchain

When a miner includes a transaction in a block, according to the integrity rules the miner should search for a previous transaction which output the coins being used in the current transaction. Now, ...
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134 views

Any need for coinbase field in coinbase transaction?

My understanding is that every block in the bitcoin blockchain has a coinbase transaction which contains a coinbase field. It is essentially an orphan field (placeholder) for use in claiming existing ...
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Problem with receiving bitcoins on my vps

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

Will old accepted blocks ever be removed?

Or are they kept forever such that the chain from the Generation Block will always remain verifiable?
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109 views

Merged mining: are there any ways to prevent it?

Supporting merged mining allows a cryptocurrency A to improve the security its blockchain (increase the hash rate) by accepting work done on the blockchain of cryptocurrency B through insertion of a ...
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Location of blockchain locally on different platforms, and structure of blockchain file?

I just downloaded Bitcoin-QT, and torrented a snapshot of the block chain that is a couple weeks old. I put the bootstrap.dat in ~/Library/Application Support/Bitcoin and started up the app. Right now ...
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1answer
89 views

How to get last transactions made to a non-wallet bitcoin address?

I know I can rebuild my block index by setting txindex=1 in my bitcoin.conf file and restart bitcoind with -reindex so that I can view non-wallet transactions using: bitcoind getrawtransaction ...
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1answer
77 views

What parameters are used to calculate the challenge string during bitcoin mining (blockchain creation)?

How is the challenge string computed mathematically? What's preventing some node on the bitcoin network from broadcasting a challenge + proof to other nodes as it's own when it received it from some ...
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152 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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125 views

Does there exist a SPV-client in another language than Java?

The only (active) project I know that implements a full SPV client is BitcoinJ, which is in Java. Does somebody if there are any SPV implementations in other languages (like C) too?
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Bitcoind server strategy. How much disk space?

I need to host a Bitcoind on a VPS. My main issue is the disk space strategy. I don't know the amount of MB the blockchain adds per day or per month. On my disk I have 26GB of disk spent for the ...
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64 views

Download only first few blocks of blockchain

Is there an archive location or a place where I could be able to download only the first few hundred blocks of the block chain?
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42 views

Is access to mining the only obstacle to centralised bitcoin-like currency?

Considering the value of bitcoin beside dollars there seems to be so many applications where a centralised bitcoin-like system may be ideal for internal accountancy and transfers, especially among ...
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What's the formula giving the % of succesfully maliciously messing the blockchain?

With the recent (early 2014) GHash.io concerns about that particular mining pool getting too big, many people have talk about what a powerful miner could do if it wanted to "harm" bitcoin or ...
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415 views

How to make a block explorer (like blockchain.info)? [duplicate]

I've tried JSON-RPC, but it's very slow. What other things can you recommend?
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1answer
416 views

How to make a block explorer?

I need to make a block explorer for some alternative cryptocurrencies. I'm using Litecoin for testing, but JSON-RPC requests through PHP are very slow. Maybe JSON-RPC isn't the right thing for such ...
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2answers
1k views

Can blockchain size become a blocker for bitcoin adoption?

When I run bitcoin-qt, I noticed that it is taking lot of time to download recent blocks. It gives me impression that the more transactions, the bigger the blockchain. Even today the download is ...
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1answer
715 views

bitcoin-qt keeps on quitting with “failed to read block”

I just wanted to install bitcoin-qt on another machine (all others are working fine) but I cannot seem to retrieve the block chain using bitcoin-qt 0.8.6-beta (as downloaded from ...
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92 views

Detecting generation transactions

I'm implementing my own blockchain reader but I'm stuck validating transactions. I can validate a common transaction checking the UTXO and executing both scripts, but... how do I validate generation ...
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299 views

Why can't we make the Bitcoin software start the blockchain from the beginning?

I"m really wondering: you see 13 gigabytes (current blockchain size) is big enough only because there are all of transactions. Can Bitcoin developers create such a piece of code which will shrink the ...