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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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2answers
562 views

How can importprivkey compromise wallet security when importing a publicly known private key?

A question was asked on reddit over here which I gave a reply: https://www.reddit.com/r/Bitcoin/comments/3khrvm/how_do_i_use_private_keys_to_receive_bitcoin/ However, luke-jr replies with: Don't ...
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1answer
548 views

Who made Gavin project leader?

I mean no disrespect to Gavin Andresen whatsoever. I think someone needs to be at the head of the project and Satoshi has stepped down / disappeared / gone back to the NSA / returned to his home ...
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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,...
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2answers
5k views

Is there a light (SPV) version of bitcoin core (bitcoind)?

I'm trying to develop an SPV Bitcoin client which makes use of a library requiring bitcoin core (a running bitcoind service). However, from what I understand, Bitcoin Core is full node, meaning that ...
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1answer
12k views

How do you apply “-zapwallettxes” on Windows?

On May 27 I tried to sell some Bitcoins(for the first time). Since that day the transaction is in the status "unconfirmed". The amount is booked from my wallet, but isn't booked to my bank account. ...
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2answers
10k views

How to access Bitcoin's transaction database?

I want to process the Bitcoin network's transactions. As I understand it, the Bitcoin-Qt client downloads and stores all that information locally. Since version 0.8 LevelDB has been used to access ...
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1answer
1k views

At what point does a hard fork occur?

with the whole debate and concern over a looming Bitcoin hard fork I would like to ask at what point has the hard fork occurred? Is there a specific moment when developers decide to implement BTC/BTU ...
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1answer
909 views

UXTO DB structure

After update Bitcoin Core to version 0.15, chainstate database changed format of data. Old prefix of key has been 0x63, now 0x43, and key/value are different Where is the new format described, or ...
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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 ...
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1answer
9k views

Extract private keys from Bitcoin Wallet

I have encrypted my bitcoin wallet. I know the passphrase, that's not the issue. I want to transfer my bitcoins to blockchain.info but it's asking me for the private key. I cannot find it nor can I ...
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3answers
12k views

Bitcoin Core cannot obtain lock

I downloaded Bitcoin Core (64 bit) and I am still waiting for it to synchronize. But just now, when I open the software, it loads from 1% to 100% and then a message appears with the inscription ...
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3answers
9k views

Why does it take 15 minutes for my Bitcoin client to start?

I use Ubuntu 11.10 and have recently installed the standard Bitcoin client 0.40. But the GUI only appear around 15 minutes after started. My machine is an AMD64 Athlon 4600x2 with 6GB RAM. Is this ...
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2answers
8k 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 ...
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2answers
4k views

Can wallets be shared by different machines?

I have a bitcoin client installed on machine one. Let's say it has 5 coins in there. I then have another machine, with another client on it. Can both machines see the same wallet? Do I have to have a ...
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2answers
307 views

Transaction fees after 0.9 protocol update

As the changelog of bitcoind 0.9 tells, transaction fees should be greatly reduced. What are the implications of this? How were transaction fees determined before the change and after the change? How ...
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1answer
141 views

Does Bitcoin prefer broadcasting transactions crediting it?

I'm currently doing some double-spend testing, and it appears that the standard client prefers broadcasting transactions that credit its wallet. That is to say, a client that receives such a ...
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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 ...
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2answers
931 views

How to get notification on bitcoin receive with bitcoin core

How can I get Bitcoin receive notifications with Bitcoin Core. I have tried the walletnotify and blocknotify options. walletnotify is fired two times when I send or receive bitcoins. And with ...
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3answers
914 views

(Why) is it difficult to merge and split wallet.dat?

It is a common question, how to sync a wallet across different devices. As far as I understand, a wallet is just a collection of private keys. Each private key can be uniquely identified using the ...
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2answers
9k views

To run bitcoin core testnet on Ubuntu 16.04

How can I run Bitcoin core testnet version on ubuntu 16.04 platform ? I am getting so many reference about how to run bitcoin core mainnet but it will take around 20 days to synchronize with the ...
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2answers
4k views

What does qt in bitcoin-qt stand for?

just a simple question: what does qt in bitcoin-qt stand for?
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1answer
8k views

What exactly did `Bitcoin-Qt -rescan -reindex` do?

I spent a ton of time today trying to get Bitcoin-Qt to sync using the bootstrap.dat file and could not get it to work. I found an answer on this forum saying to use: /Applications/Bitcoin-Qt.app/...
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1answer
2k views

Why Bitcoin core creates time locked transactions by default?

I've noticed recently that Bitcoin Core is producing transactions with non-zero lock-time and sequence numbers of inputs being 0xFFFFFFFE, even though I didn't instruct it to do so. The lock-time ...
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2answers
6k views

What does “Activating Best Chain” mean?

What does "Activating Best Chain" mean? My Bitcoin Core doesn't freeze, it just takes a while. I'm curious as to what it's doing.
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3answers
3k views

Why does bitcoin core need to download the blockchain

I understand that the blockchain is what keeps track of who has what coins and makes sure that everything is correct and secure, but why do I have to download it? Isn't that where the miners come in? ...
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2answers
24k views

How do I get my public address in Bitcoin Core?

In a world of pain at the moment. I downloaded Bitcoin Core, and before I realised I'd need the complete downloaded Blockchain, my friend transferred some coins to my address. I did some research ...
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2answers
1k views

Transaction confirmed by network but never showed up in bitcoin-qt

I've sent a large amount of coins to 1K7SzBTPGyyEtWsudwHpjg31LjrPf17qr4 but my bitcoin-qt client (V. 4.7.4) doesn't show any balance. 1) Under the "Receive coins" tab it shows the same address 2) The ...
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2answers
4k views

What is the minimum transaction fee used for?

I have the bitcoin-qt client running on Ubuntu 12.10 and I see a transaction fee box in the preferences, but I am unsure of what it actually means - the wiki is overly complex, and I am unable to find ...
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1answer
1k views

Does Bitcoin still use the IRC channel?

I recently read an article on Bitcoin Media, that claimed: Jeff Garzik pointed out that Bitcoin-Qt no longer operates using the IRC bootstrap, and on inspection he’s right. This mainly applies to ...
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1answer
6k views

How can I benefit by running a full Bitcoin node?

I noticed that I can run a node with Bitcoin Core. If I open my computer always and make the full node run on my device, what benefits can I get? Is there any reward for serving this?
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2answers
6k views

How to create a sending address with Bitcoin Core?

I downloaded Bitcoin Core and I'm just having a look around and I can't for the life of me figure out how to create a sending address. I'm using a site to buy stuff and to register I need to "Setup ...
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1answer
8k views

How do I use Multisig transactions to handle escrow needs?

I want to do a private escrow between me and someone else for a Bitcoin miner, and it will take weeks or months for that miner to arrive. I think multisig is an easy trust-free way to accommodate ...
7
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1answer
404 views

Could Neutrino technically as side-effect, incentivize centralization of the bitcoin network?

TWO questions on Neutrino:: 1) Could Neutrino technically as side-effect, incentivize centralization of the bitcoin network? Or other formulation: ...hinder higher degree of decentralization? Why ...
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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 ...
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1answer
2k views

Can I retrieve my bitcoins from years ago that I never received?

How can I get hold of my bitcoins that never made it to my wallet years ago? I purchased some bitcoins years ago (have got my receipt and all emails from who I purchased). I downloaded Bitcoin-Qt 7, ...
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1answer
1k views

Why does Github say that the Bitcoin project is 74% TypeScript?

For the Bitcoin project on Github clicking "Show language statistics" shows that the source code is almost 74% TypeScript. Why is this so when ostensibly Bitcoin is written almost entirely in C++. ...
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2answers
630 views

What alternatives are there to hardcoding checkpoints into the Bitcoin client?

Checkpoints seem like a crucial part of the security & validation apparatus in Bitcoin. Is there a written policy in place, among the developers defining the maximum interval between checkpoints? ...
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1answer
2k views

Port forwarding plus Bitcoin

Bitcoin has only 8 active connections, and I read somewhere that it helps to forward ports. I know how to forward a port, but which port should I forward, and how should I tell Bitcoin-qt to use the ...
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2answers
2k views

No menu in Ubuntu bitcoin-qt

When I run bitcoin-qt on Ubuntu 12.04, I see this: As you can see, there is no menu on the top menu bar. There is the "beginning" of a menu with the word "Bitcoin" but there are no "File", "Settings"...
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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?
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1answer
3k views

Running Bitcoin on command-line-only system

I want to run a Bitcoin client on a command-line-only system (Amazon EC2). Is there some specific command-line parameters I should use in order to run the main client without the GUI, or will it run ...
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3answers
2k views

Using the bitcoin wallet PKI for message encryption

Is it possible for a message sender to encrypt a message string with a receiver's public wallet address, email this ciphertext to the receiver and then have the receiver decrypt the message using ...
7
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1answer
2k views

The use of Bloom filter in SPV nodes

I know what Bloom Filter (BF) is, and I'm aware of this post and this paper. But I don't understand how it's used in bitcoin. I can imagine that an SPV node encodes the transaction(s) it's ...
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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
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1answer
180 views

What level of mathematical understanding do I need in order to contribute or to understand the crypto behind bitcoin?

My mathematical knowledge is up to CALC II (college level.) Is this enough mathematical maturity in order to understand the crypto in bitcoin or do I need more knowledge? If I do indeed need more ...
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1answer
2k views

How is locktime enforced in the standard client?

I am trying to study the locktime feature of transactions ( https://en.bitcoin.it/wiki/Protocol_specification#tx ). I have created some raw transactions in the testnet with different locktimes, but, ...
7
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1answer
207 views

Why are 0.13.1 Core nodes connecting only to Witness (e.g. 0.13.1) nodes?

I have my Core 0.13.1 node configured to connect to 16 nodes, and invariably I see it connected only to other 0.13.1 nodes, even though, according to bitnodes leaderboard, these nodes form a minority. ...
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2answers
1k views

Ubuntu bitcoin PPA

Since bitcoin is a software package that involves "real" money (inasmuch as any currency is "real"), I know there are major incentives for unscrupulous people to build backdoors into software related ...
7
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1answer
315 views

What was the vulnerability in v0.3.4 that allowed an attacker to steal coins?

Reference: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2010-5141 What was the specific exploit in the Tx script evaluation process?
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5answers
251 views

What is the transaction rate bottle neck?

I recently read (Scalability link) that bitcoin can do 3.3 to 7 transactions per second... I am curious, what is the bottle neck for the transaction rate? Is it verifying the signatures? or maybe it'...