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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1answer
70 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 ...
6
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2answers
407 views

What is a soft fork?

When people talk about possible changes to how Bitcoin works they sometimes say a particular change can be implemented as a soft fork. What does that mean? How does this compare to a hard fork?
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2answers
39 views

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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3answers
186 views
+50

Using Bitcoin or another Altcoin for Decentralized Database Storage

I was wondering has there been any attempts on using the blockchain as a decentralized database storage system? Would it be feasible to use it on Bitcoin or another Altcoin and if so which altcoin ...
2
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1answer
63 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 ...
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0answers
22 views

How to check Bitcoind block chain download progress level without blockchain explorer?

so my problem isn't with bitcoin particularly but with a dying altcoin, I have the same problem as here. But can't use a blockchain explorer site, since there doesn't exist one. Is there any way to ...
0
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0answers
12 views

When all bitcoins have been mined, how can the Block Chain's interaction be supported? [duplicate]

I've understood for a while that bitcoin mining was a process that required computers to solve increasingly difficult problems in order to mine a block. It wasn't until now that I realized those ...
1
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1answer
63 views

Blockchain parser for transaction level details

I'm looking for transaction level data for both inputs and outputs. The znort block parser returns the type of data I'm looking for, however it doesn't seem to detect multisig transactions. Has anyone ...
2
votes
1answer
408 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 ...
4
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2answers
122 views

How can services that use the bitcoin blockchain help secure it?

There are many projects being worked on that involve using the bitcoin blockchain for its public verifiability and immutability. A few examples would be Counterparty, Medici, Factom, etc. But each use ...
0
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3answers
292 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
28 views

Bitcoin database needs to rebuild every time after defrag or reboot

I'm running Windows 10 technical preview 10049 and I'm running bitcoin-qt from my data hard drive with 1.17TB available disk space. It is a striped volume and due to much data writing and deleting it ...
3
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2answers
4k views

How do I lookup Blockchain sizes for crypto-currencies like Litecoin and Dogecoin?

I am new to mining cryptocurrencies. I am planning to set up a wallet for both Litecoin and Dogecoin. I am just curious on asking what are the current total blockchain sizes of both coins? This is to ...
5
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2answers
978 views

Is it possible to view others' transactions in bitcoin client?

This seems like a really basic question, but I'm having trouble searching for answers on it. My understanding is that my bitcoin client (Bitcoin v0.7.1-beta) has basically theoretically downloaded the ...
2
votes
1answer
111 views

Why do some outputs have a zero value and no address?

What does it mean when an output has a value of zero and no address? I'm looking at some fairly recent transactions, and I don't understand what this means. Here's an example: ...
2
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2answers
78 views

How does “headers first” effect BLKxxxx.dat structure?

Assuming a full node running Bitcoincore v0.10 (with txindex=1), how exactly does the new "headers first" functionality affect the structure of the blockchain data? (Specifically, the blkxxxx.dat ...
0
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0answers
18 views

What happens when the Block Reward of a Currency is Changed to a Greater Value? [duplicate]

What Happens if the Reward for block solving is changed to a very great extent and if most / all of the users update to that version with the edit.. For example if block reward is 12 x and it is ...
4
votes
2answers
75 views

Is there a special name for the block currently at the head of the chain?

Just as we have the genesis block which is block 0, is there a special name for the block currently at the head of the chain? Obviously such a block would be observer dependent and never absolute but ...
2
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1answer
45 views

Bitcoin transactions over Ripple Network

I am interested in using the ripple network in conjunction with bitcoin transactions, but am curious as to interplay between the ripple ledger verification and the bitcoin blockchain verification. I ...
12
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1answer
2k views

How is the whitepaper decoded from the blockchain (Tx with ~1000x m of n multisig outputs)

The whitepaper is apparently encoded at 54e48e5f5c656b26c3bca14a8c95aa583d07ebe84dde3b7dd4a78f4e4186e713, which is an m of n multisig Tx with 947 outputs (just under the scriptsig limit of 20kB!). ...
2
votes
2answers
106 views

Non standard Tx with obscure OP codes: examples

I've been writing Python code to fetch various transactions and came across this: 77822fd6663c665104119cb7635352756dfc50da76a92d417ec1a12c518fad69. The script field is as follows: scriptPubKey: ...
5
votes
1answer
576 views

Can any Bitcoin client do local peer discovery and blockchain synchronization?

Usually, when a full Bitcoin client such as bitcoind, Bitcoin-QT, or Multibit start on a fresh installation, they connect "to the network" to download the blockchain. If someone has multiple computers ...
0
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2answers
67 views

Create alternative blockchain with proof-of-work

For learning purposes, I want to create an alternative special-purpose blockchain. It would use a proof-of-work function that is different than the one in Bitcoin. Short of forking bitcoin and going ...
6
votes
2answers
201 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 ...
2
votes
2answers
6k views

Is there a block chain bootstrap for Litecoin?

For Bitcoin, various people distribute a bootstrap.dat file which contains a snapshot of the blockchain. A new Bitcoin user can download this file and verify it with their client, which is often more ...
2
votes
1answer
255 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: ...
0
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1answer
225 views

Bitcoind stuck loading blockchain after -reindex -rescan

I am running bitcoind on EC2. I did portforward 8333 and tried -reindex -rescan. My debug.log shows 2015-02-08 20:02:19 ProcessBlock: ACCEPTED 2015-02-08 20:02:19 ProcessBlock: ACCEPTED 2015-02-08 ...
3
votes
1answer
63 views

Live Blockchain Backup

What is a good strategy for backing up bitcoind's blockchain files (not its wallet file) without having to take (e.g.) a bitcoind that is powering a counterparty-server instance offline? Copying the ...
2
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0answers
26 views

What is the minimal block time practically possible? [duplicate]

There have been so many altcoins that experimented with parameters like block-time, and I was wondering what turned out to be the minimal feasible time? If its 10 seconds for example, there will be ...
7
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3answers
2k views

Creating my own bootstrap.dat?

Since I have been tearing down and setting up bitcoin clients a lot for some experiments lately, I was wondering whether there is a simple way to speed up the synchronization with the network. One ...
1
vote
4answers
149 views

If bitcoin fails as a currency, how will blockchain tech still be secure for other applications?

We often hear proponents, like Andreas Antonopoulos, say things along the lines of Bitcoin being an application of the Blockchain technology and that Bitcoin as a currency can fail, but blockchain ...
7
votes
1answer
99 views

How does merged mining work on a technical level?

In bitcoin, miners hash header twice with the SHA256 function. This header is consist of the below fields, as described by this question. version previousHashBlock merkleRoot time difficulty nonce ...
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2answers
152 views

What is the estimated size of complete blockchain when all bitcoins are mined. i.e around 2140?

By size, I mean how many GBs or TBs of data storage I would need to save entire blockchain starting from Genesis block when all bitcoins are mined?
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0answers
82 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 ...
0
votes
1answer
88 views

How to store blockchain data

If I wanted to imprint the blockchain data on a database, with the purpose of performing complex or just different than the RPC-based queries, how would I do it? Would I have to go for a relational ...
3
votes
1answer
60 views

blockchain.info and blockexplorer.com show different balance for the same address

Does blockexplorer.com have a bug or some other reason? https://blockexplorer.com/q/getreceivedbyaddress/1KWd23GZ4BmTMo9zcsUZXpWP4M8hmxZwRU 1.95331249 ...
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0answers
34 views

Blockchain (lack of backwards) compatibility in Bitcoincore 0.10.x

From Bitcoincore release notes: Because release 0.10.0 makes use of headers-first synchronization and parallel block download (see further), the block files and databases are not ...
0
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0answers
44 views

Blockchain.info RPC API and deposit/withdraw problem

I'm using blockchain.info RPC to detect deposits using Node.JS as server, using listTransactions method. Because blockchain.info doesn't has walletnotify api. When processing deposits, there is no ...
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0answers
18 views

What do people mean by solving bitcoin transactions? [duplicate]

I have been looking at a lot of posts about how bitcoins are generated. They keep talking about how miners do computations of other "transactions". Do they mean bitcoin transactions or other forms of ...
3
votes
2answers
437 views

blockchain.info JSON API problem

I'm trying to get the time series for a specific period from Blockchain but the JSON seems to not be there anymore. Does anyone know if the JSON API is not available anymore or it is a temporary ...
1
vote
2answers
59 views

How to generate a Litecoin Private key and correspondent Public Address in C#

I found this C# tool to generate addresses for Bitcoin (compressed and uncompressed): https://en.bitcoin.it/wiki/Bitcoin_Address_Utility https://github.com/casascius/Bitcoin-Address-Utility It ...
6
votes
4answers
631 views

Is there a way to use the block chain as entropy in random number generator? [closed]

I want to create a transparent gambling/lotto site and use the block chain as entropy for lotto numbers, dice rolls, that kind of thing. Would the transaction hash of the latest transaction be the ...
0
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1answer
34 views

How is UTXO tracked?

What is the best way to compute UTXO of any address? Do I have to traverse whole block chain each time? Is there a efficient way to compute it?
3
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2answers
524 views

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

Every time a new block is added on top of block chain, the miners have to restart their work because the next block has to have a proper reference to previous block. Let's suppose that there is some ...
2
votes
1answer
66 views

Verifying Bitcoin ownership

Suppose Alice has 30 bitcoins from David. Now Alice wants to transfer amount 20 bitcoins to Bob. Now, Alice creates a transaction with Bob's bitcoin address. To prove authenticity and integrity, ...
1
vote
1answer
172 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 ...
41
votes
7answers
25k 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
1answer
40 views

blockchain webgame - use api or actual blockchain to build database?

I am currently designing a blockchain based web game, and part of the game is to display data from the blockchain in table format on the site. The data will be updated peroidically, or in short ...
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0answers
56 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? ...
0
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5answers
494 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 ...