The blockchain is a list of all transactions that have occurred using the Bitcoin currency. DON'T USE THIS FOR THE SERVICE NAMED 'blockchain.info'!

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Bitcoin Forwarding Services?

Anyone can tell me some bitcoin forwarding services? apart of blockcypher blockchain and block.io? Thanks!
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+50

Can Bitcoin-Qt be configured to trim the blockchain?

I run Bitcoin-Qt and Bitcoin Armory on a laptop. I don't have the space to store the whole 20 GB (or however big it is now) blockchain. I understand the need to run through the entire thing for ...
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Problems with Blockchain API

Im having problems because when a user pay to a forwarding address, the forward address receives bitcoins instantly, but takes nearly 1 hour to send those bitcoins to the destination address, the real ...
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Multiple transactions from a single wallet in one block [duplicate]

I am trying to understand how it would be (and if it is) possible for a single wallet address to have more than one transaction in a single block? Does a previous transaction of a wallet address need ...
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Is there a (potential) “Blockchain size problem”, and what solutions are available?

As more and more Bitcoin transactions are produced, the growth of the Blockchain may well, one day, become a problem for systems which want (need?) to store the whole blockchain. Storage usage ...
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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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New to Bitcoin and Blockchain - Want to meet? [closed]

I'm absolutely new to blockchain technology and bitcoin (I know this statement creates emotional bias like "another rookie have found stack exchange" or "eternal september biases", and I appreciate ...
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2answers
102 views

Sending funds on same block of received funds. Confirm sending not received?

My question in quite conceptual: For creating a raw transaction, I just need the txid from the older transaction and the address to send it. Put the funds, the change, what's left is the fee. Sign it ...
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4answers
969 views

Is a private blockchain better in any sense than a database?

Since the banks appear to be currently looking into the idea of "blockchains" but don't want to be dealing with "Bitcoin", it seems that there is a lot of hype for private blockchains out there like ...
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21 views

How to apply blockchaining to data?

I would like to apply blockchaining on unstructured data (any kind of data). I have seen BlockSign use similar concept to sign a document by storing a hash of the document in OP_RETURN block of ...
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1answer
22 views

Blockchain API whitelist all IP addresses

I am currently trying to implement the blockchain API in my application. I have done this successfully however, I am having trouble whitelisting IPs. Each time a user accesses the app with a different ...
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Can coin wallets create their own network/blockchain?

In other words, I want a coin with NO premine and NO mining. Can the wallet, alone, generate the coin(s) and the blockchain, based solely on inter-wallet communication (establishing a wallet ...
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Erroneous blockchain transactions…more coins than I specified! [duplicate]

This isn't directly related to Bitcoin; rather this is related to Infinitecoin, however the technologies are virtually the same. The other day I sent 2,000 IFC from my wallet (Infinitecoin-QT for ...
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Why does bitcoin core need to download the blockchain

I understand that the blockchain is what keeps track of who has what coins and makes sure that everything is correct and secure, but why do I have to download it? Isn't that where the miners come in? ...
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Why does Bitcoin-QT not seem to be catching up on my Mac?

I've had Bitcoin-QT running for about six total hours, and the rate at which it's catching up is glacial at best. It takes about an hour to advance a week, which would make the process take about 4 ...
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39 views

How to monitor the blockchain for new blocks

I want to scan new transactions as they are added to the block chain. Does anyone have a suggestion on how to do this. Are there any APIs that allow for this? Or is there a way to directly tap into ...
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68 views

Bitcoin-QT: which external memory (connected via USB2.0 + TrueCrypt) would work?

Background I have Bitcoin-QT 0.9.3 (zip version). bitcoin-qt.exe sits on the internal HDD of my laptop. All of the other stuff (blockchain, wallet,...) on a 128GB USB drive, fully encrypted with ...
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2answers
307 views

Blockchain - How can I cancel my blockchain transaction, unconfirmed after +1 day

I am using blockchain.info. I have made a bitcoin transaction of 4.79 BTC to the address 1DWaEfPbcKQvjMi9D9eNMrVRQzWiSLVvaS. (exchanger) You can see the transaction at ...
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How to get receiving transaction information from bitcoind (bitcoin server)

I installed bitcoind on a vps and generated an address I sent some bitcoins to from Blockchain.info wallet. One day later, I still don't see any info about it in bitcoind while there are now 75 ...
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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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How does the bitcoin network recover in case of a hash collision in the block hash?

A Bitcoin client has to download the whole blockchain from the P2P network in order to become a full node. A full node is able to determine, if a transaction in the network is valid or not. To ...
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2answers
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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: ...
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How many OP_RETURN transactions in the Blockchain would be too many?

I realize this question may not have an answer and therefore might not be suitable for SE, but I'm very curious about OP_RETURN transactions. OP_RETURN transactions appear to be the accepted ...
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1answer
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Selfish Mining: stale or orphan?

In terms of a selfish attack many sources speak of orphaned blocks, i.e. blocks that are not on the main chain and thus not paying any coinbase transaction to its miner. Still I'm not sure and ...
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2k views

Where do I find the *actual* blockchain size?

Okay, my hard drive is a bit cramped, and the Blockchain for my Bitcoin client is completely sucking up my free space. I want to know how much room I need to be prepared to lose. This isn't a ...
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BitCoin Api, Result Keys,BitCoin Protocol documentation

I am developing android application using https ://blockchain.info/api. i am having problem to understand the Keywords used in result for https: //blockchain.info/address/$bitcoin_address?format=json. ...
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1answer
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What if block N were based not on N-1 but on both N-2 and N-3?

If the bitcoin protocol were changed so that the merkle root from block N-1 were replaced in block N by the two roots of blocks N-2 and N-3, then it would become possible to mine 2 blocks at a time in ...
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Alt currencys blockchain viewer

I know we have blockchain.info for bitcoin I am trying to track a missing FTC transaction going to btc-e (seems a very common thing money going missing with these jokers) Are there any similar ...
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1answer
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Where can I direct download the NXT blockchain data instead of from the client?

When installing the nxt nrs client from scratch I need to redownload the nxt_db database blockchain. Is there a place where I can just download it from directly on a fast connection? It seems that it ...
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How many Bitcoin addresses are/have been carrying a balance?

Bitcoin addresses can be generated at will, and the theoretical limit to their number is high. Addresses are constantly being generated to receive funds or balance transactions, but they are also ...
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1answer
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BlockChain API playground OR SandBox?

I am android developer. I have used https://blockchain.info/api/blockchain_wallet_api API for my application But the problem is now how can I test my application (transactions) with out having ...
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3answers
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How to make a new blockchain from scratch

In the same vein as setting up a private DNS root server and using whatever domain names you want, how do you generate your own blockchain and mine your own coins? P.S. I don't want any answers ...
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478 views

How to find a specific bitcoin address from all the addresses?

Recently, I found a site that show all the addresses in a huge list, divided in 904625697166532776746648320380374280100293470930272690489102837043110636675 pages. The site's link is ...
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156 views

How to generate a private key to create wallet through api in Block chain

I need to pass private key while creating a wallet in blockchain.info through api call which is defined here https://blockchain.info/api/create_wallet I'm using php for creating wallets. Please ...
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5k views

Is it possible to transfer BitCoins from BlockChain to CoinBase?

I have BitCoins in BlockChain - is it possible to transfer these into my CoinBase account?
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What's the best practice for creating and maintaining an address index?

I am working on a Blockchain.info-like block explorer, and I have some questions regarding best practice for data retrieval. Bitcoin Core stores and serves all blocks and, if txindex is set to 1, all ...
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Valid fork in regtest - Change blockchain via RPC?

I've created a regtest network consisting of 2 nodes - node0 & node1. I'd like to have a fork on the common blockchain and seemingly achieved it by doing so: nodes start node0 adds node1 via ...
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Ubuntu. (blockchain of version 0.9.3 compatible with 0.10.1?)

I have version 0.9.3 of bitcoind on my Ubuntu server and I want to upgrade to 0.10.1, I have nothing in my wallet. Does the blockchain 0.9.3 compatible with 0.10.1? Do I have anything to keep from ...
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blockchain.info transaction timestamps set into the future

There seem to be some irregularities with Blockchain.info's transaction timestamp (aka Received Time) for a set of blocks. The transaction times are recorded with unix timestamps well into the future ...
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Getting bitcoin globe data

I just saw this bitcoin globe https://blockchain.info/nodes-globe?series=topBlockRelay It has two modes,"Online Now" and "Miners". I wanted to ask if anyone knows what the bars and colors stand for ...
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What is the Merkle root?

The Bitcoin wiki Vocabulary article explains why the Merkle root exists: Every transaction has a hash associated with it. In a block, all of the transaction hashes in the block are themselves ...
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Block Chain Library

I was wondering if there are any open source blockchain libs that I could use to build a project with? Thanks
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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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bc.info transactions with no timestamp

The last transaction in blocks 219882, 219888, and 219892 don't have a timestamp. And by last transaction I mean the last transaction shown in the json file. 219882 219888 219892 I find this to ...
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How to check if the block chain is up to date using bitcoind or json-rpc?

I read the full api method list and did not seem to find one. I suppose there is no command specifically for that purpose, so what is the general way of doing this? I would consider checking the ...
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3answers
400 views

How do I compose a transaction with OP_RETURN in Python?

Currently trying to figure out how to use Python to construct a transaction with OP_RETURN. I tried to encode the message myself, and had no luck. I found a function, OPReturn(), on the internet, but ...
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459 views

How to store 30kb file using Decentralized Blockchain Data Storage on NXT (nxtcoin) by attach messages?

I'm curious to how would one store a 30kb file on the NXT blockchain since the NXT protocol can attach a 1000byte message. My test scenario is storing a 30kb midi file on the nxt blockchain and then ...
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Stress test? Whats it for?

How long does the stress test usually last on the blockchain? Also what is it for? I'm fairly new to bitcoin and was having trouble processing transactions in a fair amount of time earlier.
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How to access peer's tip of chain?

In case I'm a selfish miner and have successfully forked the blockchain, I'd like to know the state of progress of my honest nodes at any given time - how can I achieve this? Do peers on separate ...
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How to access locally stored inventory data?

I'm looking for objects in the source code of Bitcoin Core that record all block inventories distinguished by their miners - Is there a container that keeps track of blocks on chainActive and stores ...