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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How can a block be considered more difficult to solve/hash than another one?

In this answer: http://bitcoin.stackexchange.com/a/760/28219 It is said: Because of all this work, when a Bitcoin client signs on to the network it can trust the block chain that was most ...
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5 views

When does a miner decide to stop collecting transaction and start calculating hashes to try to win?

I am confused about whether a miner chooses to wait for more transactions (more fees) or starts as soon as it receives the first transaction from the network. Once a miner has started calculating the ...
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1answer
26 views

What is the protection against a malicious node with a bad block chain?

How does a bitcoin node protects against connecting to a node with a forged block chain? How does it say: "Ok, I just got this block chain and it is a valid/legit one" ?
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Validate chain from `valid-headers` to `valid-fork`

The getchaintips JSON-RPC returns multiple branches of the blockchain. Chain tips can be in various statuses. The active and valid-fork are already validated chains. There is a valid-header ...
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58 views

i have good pc can i mine on it, if i don't have to pay for electricity?

i have gtx 970 g1 gpu and intel i7 4790k cpu. i dont have to pay for my electricity costs. i used to play games but now i don't play them any-more. i was hopping someone will tell me if i can make a ...
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2answers
53 views

How to store data on the blockchain?

I am wondering if it is possible to give someone a bitcoin transaction ID and with that he can read some hidden data, like the blockchain.info notes on transactions, but for real, stored in the ...
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31 views

Get as many blocks as possible (stale, invalid, orphans)

I would like to download (and access) as much blocks as possible - including stale (extinct) blocks, orphans blocks and invalid blocks. I have 0.11 official client. My node is already synchronized but ...
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2answers
80 views

Fastest filesystem for blockchain?

I am running Linux with a harddisk. Currently the blockchain is on an NTFS partition, which probably isn't the fastest. Which filesystem should I choose? As I understand it, a Bitcoin node will only ...
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1answer
87 views

Is it possible for computing power to increase quick enough to break mining retargeting?

So from what I understand, mining bitcoins basically becomes more difficult as more bitcoins are mined. This is done so computing power doesn't get so strong that bitcoin mining becomes trivial to ...
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3answers
27 views

Wanted to back up blockchain to save space, now I cannot open bitcoin QT?

I wanted to back up the blockchain on my hard drive as it took around 50 GB on my laptop. I did so and deleted all the blk000.dat and the rev000.dat from (~/Library/Application Support/Bitcoin/) which ...
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26 views

Best method for getting bulk address information (total sent, received, and final balance)

I need to go through a large list (about 100 000) of bitcoin addresses, and, if they have a final balance, find that as well as the total sent and recieved. I am working in python, and I have looked ...
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52 views

Is 250mb/month enough bandwidth to support the internet needs of 4 mining rigs?

So this question was posed in 2011; I figure by now there may be slightly different factors at work, but mainly I ask if i can use a prepaid hotspot plan for 250mb to connect 4 sp20 mining rigs each ...
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76 views

Why hasn't my bitcoin transaction gone through?

So about 3hrs from now I made a transaction to a different wallet of mine and the money didnt come through in 20mins I checked the blockchain and the number of confirmations kept rising and its up to ...
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1answer
47 views

How to handle POST data sent from Blockcypher WebHook API

I've been trying to get this to work for the past 3 days and I've all but given up on it. Basically, I've used requestb.in to monitor if any POST requests are going through; requestb.in always ...
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41 views

Please help! How do I transfer my wallet from bitcoin core to MultibitHD?

I (should by now) have bitcoins in my wallet,I sent them to my wallet whilst i was using bitcoin core but after taking days to sync (and it still hasn't synced) i have given up and installed ...
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18 views

Is there a service that can track how a coin flows from one wallet to another visually?

I sent some coins to an address and would like to track how these coins are flowing into other wallets. Is there a service that shows this visually? My main point is that I want to know if these coins ...
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1answer
27 views

Can a client leave its mark on the blockchain?

Would it be possible for a client (eg the core client) to leave its mark in the form of META data on the blockchain or even in the mempool so that we know that this client was used to create or send ...
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1answer
36 views

POS Receipt payment identification

Lets have a scenario where POS software wants to support bitcoin payments with zero risk. Ideal is to store Merchant's Bitcoin address in POS settings. The intention here is to uniquelly bind receipt ...
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1answer
28 views

Service that displays how many inputs/outputs there are in the blockchain?

Ideally, I am looking for a service like http://statoshi.info/, but one that displays the real-time number of inputs and outputs in the blockchain. Note that I am not looking for information on the ...
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1answer
58 views

Can bitcoin and altcoin co-exist in sidechain? If Yes, strategy

I have private block chain - tweaked bitcoin blockchain with a private coin by creating a Genesis block. Lets call it "PrivateCoin" I also have a sidechain elements/alpha instance, I effectively ...
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6 views

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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1answer
91 views

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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2answers
108 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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2answers
62 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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4answers
1k 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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33 views

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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1answer
36 views

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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3answers
56 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 ...
2
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1answer
39 views

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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3answers
170 views

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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1answer
101 views

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
54 views

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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97 views

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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1answer
98 views

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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1answer
25 views

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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25 views

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 ...
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79 views

C# parse bitcoin blockchain to get balance of an address

Is there a way to scan the Bitcoin blockchain in C# without using an external API? I am looking for the amount of spendable money of a Bitcoin address. I am using NBitcoin. // create new key pair ...
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1answer
45 views

What is the mechanism of determining the transactions of a new block

I am newbie in the Bitcoin field. I have read about the transactions, blocks, blockchain and other materials. As I know, when a new valid block is found and announced by a user, other users start ...
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1answer
34 views

Bitcoin resistance against forged slow chain

I'm implementing a new protocol with a custom blockchain, and I'm trying to figure out what is the correct way to deal with the "slow chain" problem. In the Bitcoin protocol, nodes constantly gossip ...
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27 views

Source for blockchain dump in machine readable format

Where to get blockchain dump in machine readable format. Text files of JSON will be perfect . I found PSQL database at http://dumps.webbtc.com/bitcoin/ . Any other source?
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1answer
59 views

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 ...
2
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2answers
101 views

What security threats does blockchain technology solve or present?

I am interested in security, identity and authenticity in electronic networks. What sort of security concerns could blockchain technology help with and what sort does it pose? Are there entry and ...
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0answers
80 views

What are the best criticisms of blockchain technology?

What are the best criticisms of blockchain technology? Specifically, what are the top flaws of the blockchain as it's currently implemented by Bitcoin?
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1answer
47 views

Amount of block locator hashes in “getblocks” message

How many block locator hashes are sent in a getblocks message? And how distant are these locator hashes from one another?
2
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1answer
58 views

What are some causes for long chains?

Blockchain.info shows a graph of transactions excluding "long chains" of more than 10: https://blockchain.info/charts/n-transactions-excluding-chains-longer-than-10 This seems to indicate that ~68% ...
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1answer
151 views

How to accept payments with Blockchain in PHP

I am trying to set up sort of a BitPay system where 1) User selects how much money they want to send (price in BTC) 2) PHP Gives user amount of money they need to pay and the address they need to ...
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1answer
86 views

Are there any blockchain inspection tools/libraries?

I am going to write software that gets information from the blockchain directly. Are there any tools or libraries to speed up that process? I am looking for things like decoding and encoding ...
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1answer
77 views

Raw Block data in Hexadecimals

Is there any Web API available for us to query Blockchain data in hex format? The format should follow the standard (https://en.bitcoin.it/wiki/Block#Block_structure) structure rather than JSON.
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40 views

Is this pattern a tracking method or just a Bitcoin wallet making change to itself?

While following a particular transaction from a donation received in 2011 I noticed a pattern in the block chain. The entity donating would send .001 to an address and the remainder of the wallet ...
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2answers
87 views

What can a dishonest node do (or try to do)?

Except this kind of attacks: https://en.bitcoin.it/wiki/Double-spending For example can he simply create a new block that includes some invented transactions that steal money from real address? ...