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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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 ...
1
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1answer
33 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 ...
0
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1answer
19 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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6answers
901 views

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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0answers
6 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 ...
0
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1answer
31 views

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 ...
14
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6answers
5k 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 ...
2
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3answers
320 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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0answers
44 views

Its been hours and still unconfirmed! [on hold]

http://puu.sh/iIjyz/e992fbe540.png What the hell is wrong? I sent almost 600 euros of bitcoins to blockchain and still can't use any of them! Example one of my transactions has 18 confirmations, BUT ...
3
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1answer
446 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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1answer
50 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
20 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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2answers
72 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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0answers
18 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 ...
1
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2answers
81 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? ...
0
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1answer
53 views

Erroneous blockchain transactions…more coins than I specified!

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 ...
1
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1answer
36 views

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 ...
4
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3answers
377 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 ...
3
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2answers
317 views

Can I get an overdraft?

Hypothetically... A uses a desktop bitcoin client, who would like an overdraft facility. B has lots of bitcoins and would like to offer that overdraft and charge interest on the overdrawn amount. ...
8
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4answers
11k 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?
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0answers
38 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 ...
0
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1answer
32 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 ...
1
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1answer
28 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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1answer
27 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 ...
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0answers
13 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?
2
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2answers
54 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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4answers
3k views

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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2answers
50 views

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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1answer
76 views

Call function for block n on blockchain

I've been going through main.cpp in order to roughly find out which function calls the best block and I found out depending on situation there are several similar-sounding function names and code ...
0
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1answer
89 views

How can I run bitcoind in pruning mode?

I read this comment: You could consider running a pruning node, which is practically the same as a full node (including security), except it throws away some of the old history. Version 0.11 ...
0
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1answer
38 views

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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1answer
62 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 ...
0
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1answer
39 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?
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0answers
48 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?
2
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1answer
36 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
51 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 ...
0
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1answer
123 views

Blockchain Receive Payments API Not Working

I want to accept payments with the Blockchain Receive Payments API (https://blockchain.info/api/api_receive) but I can't seem to figure out how to work it. I cannot test it too much because there is a ...
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1answer
46 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 ...
0
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1answer
33 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.
7
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2answers
629 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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0answers
22 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 ...
1
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1answer
74 views

Bought a bitcoin, sender said it was sent, not showing in blockchain or wallet. Where is it?

So I bought a full btc off of localbitcoin with amazon giftcard code. I sent the code and clicked that payment was completed. It's been about 2 hours. About 1 hour since he said that he sent the ...
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2answers
129 views

Alternatives to OP_RETURN to store data in Bitcoin blockchain

I am working on iOS camera app and would like to store hash of photos inside blockchain for the "proof of existence". AFAIK transaction with OP_RETURN in output has some disadvantages ...
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1answer
42 views

Why the same confirmed transaction in the Testnet has different block hash and other fields?

Chain.com http://explorer.chain.com/transactions/a4bfb8e21ae3d6232183dfb8ef5fcee8c9b8f223c2d25738e24765a75abd009b Chain.so ...
0
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1answer
75 views

How fast is the NXT blockchain growing in 2014?

Is there a place that where I can find out how fast the NXT blockchian is growing? I'm curious because its this year (2014) where a bunch of nxt features came into the scene and was wondering how one ...
19
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6answers
2k views

What encourages Bitcoin miners to relay blocks?

Lets say I'm mining bitcoins, and I've just received a new block that someone else has mined. What encourages me to send that block to anyone else. I can understand how the original miner wants to ...
3
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2answers
75 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 ...
2
votes
1answer
101 views

Blockchain over 36GB and causing disk space issues

I want to install the bitcoind daemon on a computer with relatively little free space (about 35GB available). I thought that the blockchain was some 20 GB in size and figured that would be no problem, ...
4
votes
1answer
428 views

What exactly is checked at various -checklevel's?

The standard bitcoin-qt/bitcoind client has an option -checklevel which purports to perform various checks on the block data stored on disk. Is there current documentation (other than the source) ...
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1answer
43 views

“Array& params”: How to understand “&” after “Array” - type modifer?

I'm trying to understand how "invalidateblock"-function works, literally line by line. Since I'm at basic level in C++, I couldn't explain to myself what's the "&" after "Array" there to achieve ...