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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107 views

What percentage of Bitcoins stored in a multi sign address?

I am looking for a statistic of the usage of multi-sig addresses over time. More concrete: what is the percentage of Bitcoins stored in a multi-sig address over time.
0
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1answer
131 views

What is current size of various databases in Bitcoin Core as of July 2014?

This question is related to question: What is the database for? What is size in MB of: blockchain itsef - blocks/blk*.dat blocks/index/* chainstate/* blocks/rev*.dat Is the size of chainstate and ...
3
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2answers
104 views

Are NXT messages stored on the blockchain and are they encrypted or publicly viewable?

Are nxt messages stored on the blockchain? What is the character limit on these messages? And are the messages encrypted or publically viewable? If they are public, is there a site to just view all ...
0
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1answer
101 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 ...
9
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2answers
385 views

What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?

I am wondering if I can use node.js and levelup to access a copy of the blockchain database directly. But from what I can see, I need to know the name of the key(s) before I can get any data, as this ...
0
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1answer
238 views

How big is the NXT blockchain in disk usage compared to the Bitcoin Blockchain as of June 2014? And rate of increase?

Currently I'm looking for the disk usage size of the NXT and Bitcoin blockchain size as of June 2014 and the current rate of of increase every day/week/year?
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1answer
54 views

What determines how many transactions end up in a given block?

What determines how many transactions end up in a given block? Blocks can have various numbers of transactions, so what decides how many are in a certain block?
2
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0answers
45 views

How do I prevent Bitcoin-qt from having to keep reindexing the blockchain?

Is it likely that anti-malware or anti-virus software is causing this issue? (I have told such programs to exclude the Bitcoin folders from scans)
2
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1answer
78 views

What is the best way to implement withdrawal in online service?

Suppose we have a service, which holds user balance in Bitcoin. How to implement withdrawal from bitcoin perspective? Which RPC call to use? How to archive transaction to have a proof of sending ...
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1answer
44 views

blockchain - strange problem

I have Windows 7 and i’m using the bitcoin-qt client v0.8.6-beta. Last night i tried to open up the client – but there was a message that said i had some issues with the blockchain. Which is weird, i ...
2
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0answers
278 views

Custom altcoin won't sync with node and neither will accept a miner connection

I forked the BlackCoin source, changed the ports, generated the genesis block, merkle, blah blah blah. I set up a node on a DigitalOcean server and compiled my coin daemon there as well as on my local ...
2
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1answer
158 views

Created genesis block and set up node. How to mine?

Everything seems to be going well creating my altcoin for fun. I forked the BlackCoin source on Ubuntu, successfully mined a genesis block, recompiled. I bought a droplet over on digitalocean running ...
4
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1answer
95 views

Why is my new altcoin trying to connect to peers and sees almost 200k blocks remaining?

I downloaded and forked the Blackcoin source code. I changed all of the references to BlackCoin, changed the pszTimestamp string along with the current Unix timestamp. Then, I successfully mined the ...
0
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1answer
54 views

Miners produced/ing duplicated hash values

This transaction is contained in two MainChain-Blocks: https://blockchain.info/tx/e3bf3d07d4b0375638d5f1db5255fe07ba2c4cb067cd81b84ee974b6585fb468 On Blockexplorer there is a note of this anomaly: ...
0
votes
1answer
316 views

what is Create wallet using blockchain api (PHP)

Im wondering to know, what is use of Create wallet programitically Block chain API Block Chain api here What it will provide? Where can i get the api code? Any tutorials ? Can i provide my ...
0
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1answer
53 views

How to find a block containing a transaction using transaction hash only?

Well, the title says it all. I have a transaction hash and I want to find this transaction in the blockchain. I am working with bitcoinj. I am probably missing something very obvious here, but I ...
1
vote
1answer
53 views

Purpose of a BlockChain in local wallet application

I have installed the BitCoin wallet application on my PC, so that I can cold store my BitCoin. It's "Synchronizing with the network" and has 272 weeks of BC left to download (painfully slow!!) What I ...
1
vote
1answer
673 views

How many coins does Satoshi have? [duplicate]

There are rumors that the creator of Bitcoin, Satoshi Nakamoto, currently possess as much as 1.5m bitcoins. What are the steps involved to determine / guess how many coins Satoshi has?
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1answer
48 views

How to choose address in BlockChain Android Application?

If I want to receive funds using the Blockchain Android application I click on the arrow on the top of the screen which brings up the Request Bitcoin screen, showing the QR-code for easy scanning. ...
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0answers
133 views

How to find utxo?

I might be over thinking this, but I'm trying to figure out the best way to build an unspent output pool. Should I just naively parse every block? Every input gets removed from the hash set, and every ...
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2answers
262 views

Is there database of orphaned blocks?

Is there database of orphaned blocks? https://blockchain.info/orphaned-blocks does not work right now Does anybody keep them? Also I am looking for those transactions which were not included in ...
1
vote
1answer
93 views

How can “undo” bitcoin transactions be “private”?

BitUndo private transactions: If you choose to make your undo transaction private, nobody will be able to see that you tried to undo a transaction, unless it succeed. You have to know that a ...
1
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1answer
52 views

Wallet programming, search transactions by address

This may be a silly question, but I keep running in circles. Using either bitcoind or JSON-RPC is there a way to search all transactions involving a address hash? I understand every wallet and most ...
3
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2answers
91 views

How do we check the time when a transaction hits x confirmations?

Consider the transaction 948a427.. which has 3341 confirmations as of now: We can see that the time the relay is received at 8:36:30 and it has one confirmation at 08:50:04 (after 14 minutes). How ...
2
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1answer
136 views

A clarification about Wallet and Addresses (In Armory)

I've just a dumb (Probably) question about bitcoin wallet and addresses (in Armory): If I've understood correctly (Correct me If I'm wrong), a wallet works as a "container" where you can store ...
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1answer
30 views

Optimising the inputs for a transaction

I have a list of unspent outputs. Let's say: 0.4 BTC, 0.6 BTC and 1.0 BTC. Now I want to create a new transaction for a 0.5 BTC. How I understand it, it would be best to take the 0.6 BTC output as ...
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1answer
63 views

How does a Bitcoin client know its transaction has been accepted by the whole network?

Say Belly, Alice and Teddy are Bitcoin clients. Belly makes a transaction to send 1 btc to Alice. He broadcasts this transaction to the P2P network. Teddy calculates a valid hashcode and add Belly's ...
2
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1answer
219 views

How can Blockchain.info wallet send unconfirmed bitcoins?

So i just opened a Blockchain.info wallet after years of using Bitcoin-qt. My Blockchain.info wallet had an empty wallet, i sent some bitcoins to it and right after that without waiting for ...
3
votes
1answer
47 views

How will the new Internet Neutrality Act affect Bitcoin?

How do you think the neutrality act that is being talked about as I write this post will affect the Bitcoin community. Not only in transactions, but mining, how will it affect Bitcoin economically ...
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1answer
83 views

Why doesn't the Bitcoin blockchain truncate past data? [duplicate]

AFAIK, verification of transactions on the blockchain doesn't require the full chain data and six to ten verification will be enough (which makes uses of a Merkle tree). Thus, why cannot it abridge ...
2
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2answers
82 views

SHA256 * 2 on header - what am I doing wrong?

I've been experimenting with the php code here: https://en.bitcoin.it/wiki/Block_hashing_algorithm (after correcting the small bug of $x=; to $x=""; ) With these blocks 0 and 125552 (for example) it ...
0
votes
2answers
50 views

How Is Block Assembled?

I think I understand mining well enough, but what I don't get is how the blocks of transactions are assembled. According to this post - What exactly is Mining? - the miners assemble the blocks and ...
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1answer
42 views

Transaction verification up to coinbase?

Do full nodes verify the entire transaction chain up to coinbase when verifiying a single transaction to be included on the block which they are working on ?
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0answers
117 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: ...
2
votes
1answer
66 views

Mini-Blockchain proposal: How is the proof-chain secured against injections?

I have just finished reading the paper Purely P2P Crypto-Currency With Finite Mini-Blockchain by J.D. Bruce. While I got the impression, that the rolling blockchain as an idea might work, I was left ...
4
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1answer
187 views

Is a full blockchain fork possible?

Let's say someone creates a blockchain fork starting from the genesis block, when the difficulty was absurdly low compared to today; then he starts mining new blocks from there up to the current block ...
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vote
1answer
57 views

Do receiving addresses expire on Multibit?

Okay so I have tried Resetting Blockchain and Transactions plenty of times. The only thing is I used an old receiving address that I used about 2 months ago. Do these addresses expire? Can they only ...
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0answers
83 views

What Prevents the number of Bitcoins from being increased? After 21 Million? [duplicate]

Can the bitcoin MAX_MONEY attribute simply be changed from 21 Million to a higher number? If not what prevents this from being done? What would happen to existing addresses and accounts if MAX_MONEY ...
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0answers
35 views

Reclaiming Disk Space [duplicate]

According to section 7 of the original bitcoin spec. by Satoshi: Once the latest transaction in a coin is buried under enough blocks, the spent transactions before it can be discarded to save ...
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0answers
28 views

How many addresses are in blockchain? [duplicate]

I understand that client like bitcoin-qt can generate addresses indefinitely, but only true or active addresses are in blockchain. How many addresses are in blockchain? Is somewhere statistics data ...
2
votes
1answer
154 views

Running Bitcoin Core for first time

I was using the official Bitcoin client some time ago. It was version 0.5 I think. Then my computer crashed and didn't use Bitcoin for a long time. I was lucky because I had a backup of the wallet. ...
9
votes
2answers
488 views

How to minimize risk when accepting zero confirmation payments?

I'm trying to setup a way of accepting Bitcoin payments in real life situations, where waiting for confirmations is typically not an option. I understand this is never 100% risk free (especially with ...
6
votes
1answer
480 views

How does BitCoin prevent fraud during confirmation period?

I'm trying my best to understand how bitcoin works and while I've grasped the basics, there's a lingering question: What's to stop me from spending my bitcoin multiple times during a confirmation ...
0
votes
1answer
155 views

How to establish connection for mining testnet blocks?

I am new here. I really want to know how scryptcoins work so i wanted to create and altcoin to learn on something. I learned c++ years ago so i know i have some basic knowledge but sometimes i get ...
-1
votes
1answer
57 views

I am a newbie in bitcoin and want to mine bitcoins [duplicate]

Hello greetings to everyone, I am Ravindra Barthwal from India and now i want to mine bitcoins but i don't know where to start even i search many times on google and everything goes away from my mind. ...
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0answers
138 views

Just installed bitcoin, but it won't connect

Total newbie at bitcoin; long time Linux user. kubuntu precise 64: My first attempt was just to download it (a slightly older version than the one from the ppa below), untar it and run the ...
1
vote
1answer
84 views

Can I run bitcoind without downloading new blocks? [duplicate]

I want to run bitcoind to interact with the daemon, but having bitcoin download new blocks and verify them is taking a toll on my CPU. I do not want the latest data - I just want the daemon to be ...
0
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1answer
65 views

Tracing Bitcoins to their original blocks

Can I find (always, without fault) the specific set of blocks from which the Bitcoins that I hold originated? If yes, would such a trace-back be computationally costly?
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2answers
1k views

How is a side-chain merging back to Bitcoin chain protected against double-spend? Where are the side-chain mining fees?

I am struggling to understand the concept of "side-chains" that's discussed a lot lately, but never trully explained. How I understand "side-chain": it's an altcoin, with a separate blockchain, with ...
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1answer
111 views

Using blockchain to publish downloadable software verification codes

What is the point of comparing sha256 of downloaded file with published on the same website code? Why can't developers of currencies publish file version and sha256 hash on blockchain as alias or ...