Questions tagged [bitcoin-core]

This tag should be used for questions pertaining to Bitcoin Core. Bitcoin Core is an MIT-licensed Qt 5 GUI application for the original Bitcoin codebase. Additional/previous names include "Bitcoin-Qt", "Satoshi-Client", and "Standard Client". This tag should be used when referring to the Bitcoin Core software.

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Why is it harder to compute nonce for a hash with a certain number zero prefixes than it is for any other hash?

Based on my rudimentary understanding of Bitcoins and altcoins, network difficulty is adjusted by asking the network to target a hash smaller than a specific number, which translates to calculating ...
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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 ...
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How is bitcoin infinitely divisible? [duplicate]

I've read that bitcoins are infinitely divisible: Bitcoins can be divided up and trade into as small of pieces as one wants How is this possible programmatically? The only thing that comes to ...
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What does the `gen` option in bitcoin.conf do?

The gen option isnt copiously described in the sample bitcoin.conf file ... does that mean that the daemon started up will attempt to mine for coins?
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opening an old wallet.dat

I had about $8 USD worth of bitcoin in a wallet, and I backed up the wallet.dat to my dropbox. According to the modified date of the file this was in April 2013, so it was probaby from bitcoin qt ...
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How to set the language/localization in the standard client?

Version 0.6 introduced automatic client localizations. Personally, I hate using programs in Hebrew, and prefer English, but the client didn't ask for my preferences on this matter and just switched to ...
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1answer
297 views

Stop bitcoin-qt from retrying transaction

I sent some bitcoins, forgot to uncheck "no-fee" checkbox. The transaction started, but never got confirmed. In the blockchain after some time it was "purged". I expected my bitcoins back, however, ...
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Is it possible to make a paper wallet out of a bitcoin-qt wallet?

I have a single bitcoin address with all my savings on it. I want to make a paper backup for precaution (as if my hard drive somehow exploded) with that specific address. Is that possible? Keep in ...
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Bitcoin-qt -how does it choose the address to take money from when sending btcs

I don't have any bitcoins yet, but I have the the wallet program called bitcoin-qt. I am wondering about the send feature. It does not seem to let me choose which address to deduct the coins from. How ...
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1answer
713 views

Faking blockchain data in bitcoin-core

Let's say I found a tarball with blockchain data files which I load to my datadir and start my Bitcoin Core client, what sort of attacks am I vulnerable to? Could the files contain fake balances? If ...
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Question on interpreter.cpp in Bitcoin core - set_success method

https://github.com/bitcoin/bitcoin/blob/master/src/script/interpreter.cpp Line 22 => Where is declare "ScriptError" ? What does the "*" mean ? "inline bool set_success(ScriptError* ret)"...
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How do you spend a P2SH transaction?

I've been running into a lot of trouble getting a transaction to spend coins in a multisig address. I create the raw transaction When I go to sign, I get "Operation not valid with the correct stack ...
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Script - OP_PUSHDATAs

When using OP_PUSHDATAs in different Scripts, how are the next bytes denoting the amount of bytes to be pushed encoded? Are they to be treated as unsigned integer, or signed (like the data that is ...
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Does my client accept inbound connections?

How can I verify that the Bitcoin client is well connected to the network and is able to receive incoming connections?
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Bitcoin client two-way communication

When client A opens a connection to client B, it opens its TCP connection to second client's port 8333. Is this connection solely used for A's queries and B's answers to A's query, or can B also query ...
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Internet speed required to run the Bitcoin client

What is the rough estimate of internet speed needed to run the standard client? Does a faster Internet connection increase the client performance (by that I mean how fast it updates its blockchain, ...
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1answer
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Can the transaction log history size scale?

Four Reasons You Shouldn't Buy Bitcoins, Forbes.com: Scaling. The Bitcoin protocol requires that every node in the network download a copy of every Bitcoin transaction that has ever occurred. ...
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Would it be possible to provide a downloadable blockchain that is updated and verified by a mass of people?

As of November 2012, the blockchain is nearly 3 GB in size with a near-linear growth of about 500 MB/month (cut from exponential growth by the hard-coded block size limit, I guess). I want to install ...
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HTLC (Hash Time Lock Contract) using bitcoin-qt

Is it possible to manually create a HTLC using the bitcoin-qt command line? I know how to manually creating createrawtransaction/sendrawtransaction using the bitcoin-qt clients command line, and ...
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How are eth transaction faster than btc? [closed]

If I'm not wrong miners are trying to find nonce that satisfies a rule. Then why is btc so slow? I want a technical answer. Can btc ever match eth speed, given no politics?
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bitcoin.rpc python library problem

I am working through Master Bitcoin. I got the bitcoin client up and running. I am now trying to access the client from python. In the example, there is a line that says from bitcoin.rpc import ...
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Which inputs will be spent?

Say someone holds 100,000 btc. Over time, this address has been spammed with dust by numerous parties. Now, the oldest funds come from the previous large transaction. If the dust is, say 0....
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1answer
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How can I convert a bitcoin public key to a bitcoin address?

How can I convert a bitcoin public key to a bitcoin address? Note: I am using PHP. Is there an existing bitcoin API or PHP-API to do that converting ?
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1answer
391 views

What can a person do with special private keys?

The Alert message in the Standard Client will only be displayed if it is signed with a correct ECDSA private key. Should anyone get that private key, they would be able to propagate any alert through ...
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1answer
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How does Bitcoin decide which Alert messages to forward?

The Bitcoin protocol lists an Alert message that in the Standard Client is displayed to all users. How does the Standard Client decide which messages to forward and display, and which to ignore? Does ...
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1answer
475 views

From where does the 2 hours limitation on bitcoin time stamp come?

Bitcoin wiki says that: A timestamp is accepted as valid if it is greater than the median timestamp of previous 11 blocks, and less than the network-adjusted time + 2 hours My question is why 2 ...
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1answer
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Segwit address creation

I'm unable to create a segwit address in Bitcoin Core 15.0.1 64-bit Windows I have tried multiple times but keep getting the same error. The following is the output from the console $ getnewaddress ...
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Bitcoin-Qt source code walkthrough

Has there been content published which provides an overview of how the Bitcoin-Qt software is architected? I would like to dive into the source code, but going from scratch is somewhat taxing. Can ...
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What does Litecoin offer over Bitcoin?

Litecoin is different from Bitcoin in the following ways, however none of them are particularly useful and on the contrary are only less worthy. 84 million vs 21 millions: since Bitcoin is divisible ...
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1answer
361 views

Does the .bitcoin directory shrink in bitcoin-qt 0.7.2 and later?

The bitcointalk.org thread "Ultraprune merged in mainline" implies that a more efficient way of storing block information was introduced. Will this make the .bitcoin directory smaller after an upgrade ...
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turn OFF coin generation

I just recently upgraded from Bitcoin client 0.3.? to 0.6.1-beta for Mac. In the old version I had the option of generating coins; I don't see that option here. Activity Monitor shows Bitcoin-Qt ...
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1answer
879 views

Version field in transactions, blocks, etc

A field labelled "version" appears in many contexts regarding the Bitcoin protocol. Sometimes one uses the current version of the Bitcoin client (version message), sometimes 1 is used (block, tx), why ...
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Is blockchain protected from history spaming?

As I understand, full nodes accept block even if it is not mined on top of most recent block and store it as alternative chain as long as it fullfills protocol rules. What would happen If one start ...
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What versioning scheme does Bitcoin Core follow?

I saw a discussion recently about whether Bitcoin Core was following the Semantic Versioning scheme. I could not find information in the GitHub ReadMe.md or Contributing.md. Luke-Jr stated that ...
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1answer
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How to enable replace-by-fee via command-line in bitcoin-core?

Alright, so I'm convinced replace-by-fee is a good thing. I've read it's opt-in, so how can I enable it in my bitcoin-core wallet? I don't find any flag to pass it when launching it. I want all my ...
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678 views

What is an “insecure transaction type”, as mentioned by Bitcoin Wallet for Android?

I am running Bitcoin Core v0.11.0.0-gd26f951 (64-bit) at home on Ubuntu, and have installed the Bitcoin Wallet for Android on my phone. I sent two transactions from home to my phone: First, Second. ...
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1answer
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Transaction refund address

In the what’s new in Bitcoin Core 0.9.0 notes there is a reference to a refund address. I tried to look it up in the forums and the wikis but I came up with nothing. How can I set a refund address ...
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How can I tell if my Bitcoin-Qt wallet is protected with encryption?

I am a new adopter of Bitcoins, forgive the ignorance. (note these are test transactions) I am using the Bitcoin qt client and I am very confused and think I have done something wrong. I have two ...
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1answer
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What to do about a “stuck” transaction?

I started the standard client with --rescan instead of -rescan after switching wallets and before synchronizing with the latest blockchain, and made an going transaction. This transaction got "stuck",...
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106k views

Where can I see my Bitcoin address?

I use the original client, but I don't know where can I find my Bitcoin address. Can someone help me?
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1answer
382 views

How often does Bitcoin connect to the fallback nodes?

Does the standard client have a preference for connecting to fallback nodes (for example, by trying to have at least 1 connection to such node at all times), or are they treated like any other nodes?
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What is the current (Feb 2012) “bus factor” of the standard client?

Bus Factor (Youtube) is the total number of key developers who would need to be incapacitated (as by getting hit by a bus) to send the project into such disarray that it would not be able to ...
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Can the blockchain be included in future packages of the standard client?

Is it possible to include actual transaction history to new version of Bitcoin client? I mean, when someone new downloads a fresh version from http://bitcoin.org. It is very hard to get more people ...
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133 views

How long are orphaned or stale blocks kept in bitcoin core nodes memory?

If there was a chain reorg, for example: Blockchain: 0a---1a---2a---3a becomes... 0a---1a---2b---3b How long are blocks 2b and 3b kept in memory on the node? If I query the node for block 2b ...
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Why are some Bitcoind commands comparatively slow?

For example, running bitcoin-cli getbalance <address> on an arbitrary, watch-only address takes around 6-7 seconds for a response. Is there any way to improve the response time? How do API ...
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677 views

How to store full blockchain on server and run Bitcoin Core as client only?

How to store full blockchain on server and run Bitcoin Core as client only? I want to run Core wallets on 2 or 3 or even more computers on my local network. The best way to store the full blockchain ...
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1answer
959 views

How to get BIP34Hash and nMinimumChainWork?

I'm interested in the technical question of how you got BIP34Hash and nMinimumChainWork. The changes were introduced here: nMinimumChainWork: https://github.com/bitcoin/bitcoin/commit/...
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Running full node over Tor

I am attempting to run a full bitcoin-core (v0.13.1) node over the Tor network for the first time. I have set up my /etc/tor/torrc file with the following two lines: HiddenServiceDir /var/lib/tor/...
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Blockchain Application

I am currently doing a project that requires blockchain to be applied to other systems. I was wondering where I can easily download the blockchain database and which is the best way of understanding ...
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How much disk space do I need to run Bitcoin Core with txindex on?

Currently the blockchain is at 36 GB, but with txindex turn on, how big is it? And how much disk space should I get to run a Bitcoin Core node with txindex on for say a year?

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