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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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3
votes
1answer
3k views

Since which version the mining functionality removed from wallet?

As I'm starting to learn to create a new altcoin, I found there is a remarkable difference between old and new Bitcoin/Litecoin Core wallet is that old versions (0.6.9 of Litecoin) have mining ...
3
votes
3answers
1k views

Can I sell my BTC and still claim my BCH?

I held a small amount of BTC back in August (had them since 2014) but now wish to sell them. Do I need to claim my BCH before selling my BTC or am I correct in thinking that the two completely ...
19
votes
1answer
8k views

When should I use -reindex-chainstate and when -reindex

What is the difference between the options -reindex and -reindex-chainstate? Is one of the options faster? When should each option be used?
16
votes
2answers
11k views

ECDSA r, s encoding as a signature

An ECDSA algorithm when signing a given messages produces a pair of outputs, r and s. How, given a sigStr from a Tx can one extract r and s? Are they just concatenated byte arrays of a specific length,...
24
votes
2answers
12k views

Bitcoin-Qt command line control on Mac

I'm trying to communicate with the new Bitcoin-Qt -server via a command line on Mac. I run ./Bitcoin-Qt -server, the application starts, but my terminal window is stuck on an empty line (no matter ...
18
votes
5answers
18k views

How to decode private key from Android Bitcoin Wallet?

I want to import my private key from the android's Bitcoin Wallet (the one created by Andreas Schildbach) but it can export it only in an encrypted way. How do I decrypt the file so I can import the ...
15
votes
1answer
11k views

How to generate SegWit address

How do I generate a SegWit address using Bitcoin Core CLI? Also will I be able to redeem those outputs and send them to a "legacy" address? If so, will this second transaction be accepted by older, ...
13
votes
1answer
9k views

How to get a bitcoin address's balance?

I know blockchain.info has an API: https://blockchain.info/q/addressbalance/134dV6U7gQ6wCFbfHUz2CMh6Dth72oGpgH gets the bitcoin address's balance,but it's not open source and must connect to the ...
10
votes
4answers
6k views

Is there a way to not pay the transaction fees when using the standard Bitcoin client?

I tried sending one satoshi (0.00000001 BTC) to one of my friend and the client always showed a dialog prompting me to pay 0.0005 BTC in fee, with the only options being OK (pay the fee) or cancel (...
12
votes
1answer
2k views

How many addresses does my wallet.dat contain? Do I need to make a new backup every time I make a transaction?

I'm having little problem here, trying to figure out the safest way to backup my wallet.dat to make sure that no BTC may be lost in case of recovery. I'm not sure how the process of adding new ...
5
votes
1answer
5k views

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 ...
4
votes
2answers
2k views

Why would Bitcoin-QT attempt to charge a processing fee, when I have my transaction fees set to zero? [duplicate]

I'm attempting a test transaction of an amount less than 0.0015 BTC with my transaction fee set to 0 BTC, yet I'm getting this message: The total exceeds your balance when the 0.0015 BTC ...
3
votes
3answers
19k views

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 ...
16
votes
3answers
479 views

What happens if the developers make a controversial change to the “standard” client?

One criticism I commonly hear of Bitcoin is that it merely transfers trust from some sort of central bank or government entity to the developers of the main project. Can anyone provide a clean ...
15
votes
3answers
6k views

How can I limit bandwidth usage in Bitcoin-qt client?

I've just finished the intial blockchain download/verify in my BitcoinQt client (17 hours..) and I now see that BitcoinQt is happily eating all of my upstream bandwidth. (About 110kByte/sec on my ADSL ...
11
votes
1answer
795 views

What BIPs are supported by the standard client Bitcoin Core?

There is different BIP, each has a status. I read somewhere that BIPs are not considered part of the Bitcoin protocol until "active". Nevertheless, Bitcoin Core seems to support a number of BIPs that ...
9
votes
1answer
6k views

What does Bitcoin Core's “Coin Control Features” do and how do I use it?

What is Bitcoin Core's "Coin Control Features"? How do I use it, and what can I do with it?
8
votes
2answers
8k views

Backing up my bitcoin wallet - is wallet.dat all I care about?

I know that there are many duplicates of this but I'm hoping that the way in which I word this explains and helps not just me, but others as well. In any of the coin wallet bitcoin and the alt coins,...
8
votes
2answers
15k views

Can you mine bitcoins with an intermittent Internet connection?

I've got a very precise question and this is not a dupe of: Does Bitcoin rely on the internet? My question boils down to: when you mine bitcoins, how "often" does the computer/hardware doing the ...
8
votes
2answers
916 views

How does the standard client prioritize transactions?

I've heard that the standard client prioritizes which transaction to relay based on the Bitcoin Days Destroyed and the fee paid on the transaction, but what is the exact formula used to determine ...
7
votes
1answer
559 views

Expected use model for PSBT

I want to use Bitcoin Core to create a PSBT for offline signing (cold storage) of a multisig p2wsh-in-p2sh address, such as that created by Glacier. Based on the PSBT doc I assume I want the online ...
6
votes
1answer
1k views

How secure are the DNS servers for Bitcoin?

With the version 0.6, Bitcoin introduced the DNS servers that populate the initial peers for new clients. How secure are those servers in terms of being immune to takedown attacks, or injection of ...
5
votes
1answer
921 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/...
5
votes
2answers
3k views

How do you sweep a paper wallet with Bitcoin-Qt?

Sweeping involves importing a private key, then sending it's entire balance to a new address in your wallet via a new transaction. This would protect your paper wallet's bitcoins from being stolen if ...
4
votes
3answers
8k views

Can I remove the passphrase from my Bitcoin Wallet?

I'm using the standard Mac Bitcoin client and I added a passphrase. I'd like to remove that passphrase. Is that possible?
4
votes
3answers
6k views

get Armory to use an existing blockchain?

I'm trying to set up Armory but it wants to download the whole blockchain. The thing is I already have the blockchain downloaded on the same machine for bitcoin-qt. Is there any way to get Armory to ...
4
votes
2answers
4k views

How to move the blockchain data while still being able to use the wallet?

Using the standard client, Bitcoin-Qt, v0.8.1: (win10x64) I would like to move the blockchain data from its default location to a different location (maybe even an external disk or NAS drive). What ...
2
votes
1answer
2k views

Data directory issue

I have everything set up normally. My only issue is that my data directory is in C:\Users\User Name\AppData\Roaming\Bitcoin. Normaly this is what you would want, but, if you noticed, my username has ...
2
votes
2answers
2k views

How does the Bitcoin Standard Client wallet encryption work?

I encrypted my wallet using Bitcoin QT, then closed the application. When I restarted Bitcoin QT, it did not ask for the passphrase. But I could still access the wallet. How is it possible to access ...
2
votes
2answers
1k views

How do I migrate my Bitcoin Core wallet to an HD wallet?

I created a wallet before Bitcoin Core 0.13.0 was released so my wallet is not a HD wallet. How do I make my wallet a HD wallet?
2
votes
1answer
701 views

interacting with bitcoin over docker

I've created a docker container of an ubuntu machine, loaded it up with all the dependencies specified in the unix build doc and then built bitcoin and run it with the following command: ./src/...
2
votes
2answers
177 views

Why does importmulti not support zpub and ypub?

As far as I can tell importmulti does not work with zpub/ypub. Why not? FWIW I prefer only to deal with xpubs, but I am curious.
0
votes
1answer
145 views

Bitcoin ABC, When Fed Bitcoin Core Chain Syncs to Aug 1 6:23AM 2017, Then Freezes

I've installed Bitcoin ABC, set bitcoin.conf to point at a copy of my directory from Bitcoin Core, and let it sync with the network. All was well until it froze at the fork (Aug 1, 2017, 6:23AM). ...
-1
votes
2answers
345 views

Free bitcoins are real? [closed]

That's confusing the bitcoins used for marketing are real or not.. like some posted a code in facebook or in social media for free bitcoin so those bitcoin are real or a just marketing, hacking ...
14
votes
3answers
7k views

Attacking Bitcoin with a supercomputer

The difficulty in Bitcoin is recalculated every 14 days. What if immediately after this difficulty adjustment someone targets Bitcoin nodes with a supercomputer and start creating new blocks? Such ...
11
votes
3answers
2k views

Why are m-of-n transactions not used today?

BIP 11 supports m-of-n transactions. While BIP 16 and BIP 17 are being debated and voted upon, I have to ask: why haven't there been evidence of BIP 11 used in for m-of-n transactions? All that BIP ...
10
votes
1answer
3k views

Does the Bitcoin Qt client have a minimum transaction fee?

I'm trying to transfer all of my 0.1 BTC located in one wallet to another wallet. I don't care how long it takes to finish, so I'd rather send it without paying any transaction fee. I'm new to this, ...
7
votes
2answers
5k views

What are seednodes?

A follow up from a comment on this answer. What are seednodes, and how do they differ from fallback nodes?
7
votes
1answer
9k views

How do I retrieve my backed up wallet to Bitcoin Core?

I backed up my Bitcoin wallet on a drive for safety. Luck has it that my computer crashed. So now I downloaded Bitcoin Core, but do not how to retrieve my backup. Please help. thanks
6
votes
2answers
1k views

Import multiple watch-only addresses using importaddress?

With the importaddress RPC command it is possible to import one watch-only address. But how can I do that with, let's say, 100?
6
votes
1answer
698 views

How is the transaction malleability issue being fixed?

With the upcoming release of Bitcoin Core 0.9, I am wondering how the transaction malleability issue is being fixed and what are the consequences of the fix? It appears that transaction malleability ...
5
votes
4answers
7k views

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 ...
5
votes
3answers
996 views

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 ...
4
votes
1answer
3k views

How to connect to a remote Bitcoin Core remotely

If I have 24/7 running bitcoind on a headless server, is there a graphical way to connect, maybe only temporarily to the server's Bitcoin Core daemon or its client to see if everything is going ...
4
votes
2answers
2k views

transaction creation failed

I am using bitcoin Qt version v0.7.0-beta and when I tried to send a transaction (1.5 bitcoins) I received a message transaction creation failed what can be the reason? Few minutes ago I sent 0.1 ...
3
votes
3answers
1k views

Stuck duplicate transaction in BitcoinQT

I received two payments with the following transaction: https://blockchain.info/tx/12e487de6fd8d920446cd8663dc11977d185ceaa25b7c6f36921fb76e58875f0 On this transaction ...
2
votes
2answers
1k views

Is it possible to transfer blockchain data from one machine to another?

I want to run a bitcoin full node at home but the initial sync-up is taking days because of my slow internet connection. Can I download the blockchain data from a machine with faster connection and ...
2
votes
1answer
754 views

Can't specify rpcport for testnet

Was there a recent change where it is no longer possible to specify rpcport? I noticed these two warnings: Warning: Config setting for -addnode only applied on test network when in [test] section. ...
2
votes
4answers
1k views

What would happen to the Bitcoin network if all ISP's collectively block port 8333 at once?

Will nodes still be able to find each other using today's official Bitcoin client?
2
votes
0answers
56 views

Bitcoin QT “No block source available”… stuck at “180200 out of 225430” [duplicate]

I have downloaded Bitcoin-qt and have encountered similar problems that others have on here. However, the offered solutions don't apply to me, because I run Mac OS. I get a status message that says "...