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'.

learn more… | top users | synonyms (1)

0
votes
0answers
5 views

Book question on Bitcoin [duplicate]

I was wondering if you have any books in order to understand more in depth both Blockchain technology and Mining
0
votes
1answer
44 views

How to find Z value of multisig transaction?

for example this transaction: http://2coin.org/txinfo.aspx?txid=6c3dc603da32bba3f56f2b33053aaf0f0f17322386c0c6846786bffe49f6ef22&cur=BTC Script not of right size to be a scriptSig, expecting 2 ...
0
votes
3answers
438 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 ...
1
vote
2answers
165 views

Bitcoin spend before received

When browsing the Blockchain I came across this address. It seemed peculiar to me, that the amount of 0.6 BTCs has allegedly been spend before received. Is it because the "receiving transaction" ...
3
votes
1answer
49 views

Is there a fixed order for all transactions in the block chain?

Every block in the block chain contains a list of transactions. This list has a certain order which is basically set by the miner introducing the block. The merkle root in the block header requires ...
1
vote
1answer
32 views

How do text, scripts, and other information get embedded inside the blockchain?

Someone recently suggested that scripts could get embedded inside the blockchain and executed independently by designated machines. What exactly can get stored inside the blockchain, and what are the ...
1
vote
1answer
62 views

What is a block?

I know bitcoin has a block chain that is from my best representation a list of blocks. I know the block holds many transactions. But i'm still very much lost as to what a block is and how a block can ...
0
votes
0answers
28 views

Bitcoin-QT blockchain: your speed experience with using any HDD connected via USB2.0 with TrueCrypt?

Background (I've never used bitcoin before.) 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 ...
12
votes
1answer
717 views

What happens when a miner does not claim all fees/generated coins?

Suppose that a miner for some reason has the generation transaction of their blocks not take all the possible coins. This can happen for a variety of reasons, almost all of which are bugs: An ...
3
votes
2answers
465 views

How is that concurrent miners do not subvert each other work?

Every time new block is added on top of block chain, the miners have to restart their work because next block has to have proper reference to previous block. Lets suppose that there is some nonce for ...
1
vote
1answer
29 views

Is it necessary for all miner to reset minig when the tip of blockchain has chenged?

Each block in blockchain contains a pointer to previous block (block header). If multiple blocks reference certain block as their parent, only the one that is part of longest chain is accepted. ...
4
votes
3answers
301 views

Why doesn't bitcoin place additional constraints on competing block chain forks, other than length of chain? (e.g., time and confirmation count)

In Bitcoin's proof-of-work system, consensus on which chain of blocks should be considered the "true" block chain is based only(?) on which chain is longer. Accordingly, to quote a nicely written ...
1
vote
1answer
32 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 ...
13
votes
1answer
1k views

Can private keys remain offline for their entire life?

I am new to Bitcoin and this question is based on 3 assumptions that may be incorrect. Assumption 1: If I understand correctly, the Bitcoin address is generated algorithmically independent of the ...
13
votes
5answers
4k views

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 ...
4
votes
2answers
132 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) ...
2
votes
2answers
215 views

Earliest block with spent coinbase

What is the earliest block in the blockchain that has a spent coinbase? I have manually looked at the first dozen or so but they are all unspent.
4
votes
1answer
456 views

Details on Genesis Block

The question asked here displays the genesis block in pretty good detail. I am still trying to get a breakdown of some of the elements seen here (and some others not seen here): The Merkle Root Time ...
2
votes
1answer
45 views

Is it chain of headers rather than a chain of blocks?

We know widely used explanation of the blockchain: "Every block contains a hash of the previous block". The sentence above implies that since every block contains a hash of the previous block, ...
1
vote
1answer
36 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 ...
0
votes
1answer
286 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 ...
2
votes
1answer
63 views

How to download blk.dat files from a specific block number?

I want to download blk.dat of a specific block number, How can I do this ? Note: I'm only interested in specific blocks, I only want to download blocks for example that are numbered between 100 and ...
1
vote
1answer
146 views

What is the probability of generating 6 sequential blocks, less than an hour?

I'd like to determine the probability of a fairly powerful miner (or pool) generating 6 sequential blocks in an hour. (so they would rebroadcast it later) For example, given Hash/second: X A ...
0
votes
1answer
54 views

What's the impact of net-splits on block generation… over a long period of time?

Part 1 For this question, assume the overall hashrate of the environment is constant. If 25% of the network hashpower were to be isolated (Australia had no Internet for example), what is the effect ...
6
votes
2answers
516 views

What does the term “Longest chain” mean?

What does the term "Longest chain" mean, as there is only one 'right' blockchain exists? How another longer chain would make the 'right' chain invalid?
3
votes
5answers
12k views

My client stopped synchronizing, how can I access my wallet?

My wallet has been stuck synchronizing for 21 days, my transfer is in the block chain but I can't get it to sync with my wallet. I've closed firewalls, uninstalled and reinstalled QT with back up and ...
10
votes
5answers
365 views

How do you create a planet-specific cryptocurrency that will ignore longer block chains from other planets?

I'm sure that cryptocurrencies will play a huge part of the economy across the solar system, when we have colonized many different planets, moons, and asteroids. But there are problems with using a ...
0
votes
2answers
36 views

Why use OP_RETURN for long-term timestamping if they are pruneable?

There are some timestamping services such as proofofxistence.com that use OP_RETURNS transactions to store a document's hash, so in the future a 3rd party can verify the existence of the hash (and the ...
9
votes
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 ...
0
votes
3answers
226 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 ...
1
vote
1answer
117 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 ...
1
vote
1answer
464 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 ...
2
votes
0answers
25 views

What restrictions does merged mining place on the sidechain?

What restrictions are imposed by merged mining on the structure or functionality of a side chain (besides it having to use the same PoW schema)? For example, could the side chain have a higher block ...
6
votes
4answers
9k views

What is the fastest possible way to download the blockchain?

How to download the blockchain with full bandwidth? How to download the blockchain fast?
2
votes
3answers
91 views

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

On Bitcoin-Wiki's page about Blocks, it says that "Bitcoin transactions are broadcast to the network by the sender, and all peers trying to solve blocks collect the transaction records and add them to ...
0
votes
1answer
39 views

Is the block timestamp reliable enough to timestamp the hash of a document?

In using the blockchain to timestamp the hash of a document, so to prove that it existed before a certain time. Is it reliable? Do you think it can stand on court? (IANAL and probably you neither) ...
1
vote
2answers
86 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 ...
3
votes
0answers
44 views

How many transaction and btc have been cancelled?

How many btc have been transferred in orphan blocks, but then never included in any later block? How many btc have been transferred in zero-confirmation transactions that have never been included in ...
9
votes
2answers
390 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 ...
8
votes
7answers
1k views

Can more than 1 block be solved per 10 mins on average (LONG TERM)?

I am wondering whether it is possible for a supercomputer to find the next 1000 blocks in a very short amount of time. Hypothetically, if a government agency concentrated a supercomputer on hashing, ...
2
votes
0answers
34 views

Filter transactions per block 50 BTC or Higher

I'm using the blocktrail python api, to try and display transactions above 50 BTC per block for a visualization project. I think I'm almost there but can anyone help me understand where I'm stuck? ...
6
votes
1answer
147 views

What if some group of people start sending small transactions from wallet to wallet just to make the blockchain bigger?

What if some government start using their computers to move the tiniest amount of Bitcoin possible, from wallet to wallet, just to make the blockchain REALLY big? Is this possible? And also, is it ...
10
votes
0answers
357 views

Peergroup download of the blockchain stalls?

I'm using bitcoinsharp to build my client. I try to download the blockchain in a peergroup network. Download starts, but when progress is 98%, the download is stopped & the client is waiting (2 ...
-1
votes
2answers
81 views

Help me understand Bitcoin analytics [closed]

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? \\ ...
1
vote
3answers
92 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 ...
1
vote
1answer
317 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 ...
38
votes
6answers
23k 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 ...
0
votes
0answers
28 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 ...
5
votes
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 ...
-1
votes
1answer
72 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.