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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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,...
6
votes
2answers
5k views

How can I copy the blockchain from my working client for use with a live CD savings wallet?

I have the Bitcoin client installed on my Windows PC, but I want to set up a savings wallet with better security that I access with an Ubuntu live CD. I don't want to have to download the entire ...
5
votes
1answer
982 views

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 ...
13
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2answers
6k views

How can I import a private key into the Bitcoin client? [duplicate]

I have a private key and I want to add it to the keys in the Bitcoin client. Is there an easy way to do this?
8
votes
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 ...
11
votes
3answers
6k views

Bitcoin client won't connect to the network

I installed Bitcoin QT yesterday and it was very slow to connect to the network. It didn't actually get there for over an hour. Today I opened it again and it won't connect to the network at all. Any ...
6
votes
1answer
216 views

Is there still a shortage of available inbound connection slots?

David Schwartz's answer to this question states the following: "For some reason that isn't well-understood, the Bitcoin peer-to-peer network is consistently short of available inbound connection ...
9
votes
1answer
1k views

Does the main Bitcoin client blacklist addresses?

Does the main Bitcoin client blacklist any addresses that send too many erroneous messages? If so, how can one whitelist a particular address? I am developing an app that will be communicating with ...
5
votes
1answer
874 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 ...
18
votes
4answers
5k views

Why does the Bitcoin protocol use the little-endian notation?

Why does the Bitcoin use the litte-endian notation? It is less common than big-endian notation, thus when programming low-level applications working with Bitcoin protocol, one quite often has to ...
4
votes
3answers
458 views

Running two bitcoind instances for different nets

Is it possible to run two separate bitcoind instances on one system at the same time, one for mainnet, other for testnet?
1
vote
2answers
170 views

Bitcoin client incentives to share peers and blockchain

Question a bit related to Microsoft's research on incentives of sharing transactions. What is the incentive for a custom-tailored Bitcoin client to share information regarding known clients and the ...
7
votes
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 ...
5
votes
3answers
3k views

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?
10
votes
3answers
1k views

Why does the mainline client limit the number of outbound connections to 8?

The mainline Bitcoin client limits number of outbound connections to 8 however allows up to 125 total connections. To achieve greater than 8 connections (due to outbound limitation) requires either ...
5
votes
2answers
5k views

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?
8
votes
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 ...
18
votes
2answers
3k views

Why was the MIT license chosen for Bitcoin?

Given that an open, transparent, distributed p2p network is a central element of Bitcoin project it seems unusual that it is licensed under the MIT license which allows proprietary closed source ...
5
votes
2answers
1k views

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 ...
5
votes
1answer
431 views

Bitcoin initial communication diagram

I'm trying to understand how exactly does the Bitcoin client communicate initially with another client, as I'm making my own client and learning new things about TCP protocol. As I understand, the ...
9
votes
2answers
5k views

Does the Bitcoin client generate bitcoins automatically?

I mean, you just need to install the software, and with the time, you will get lots of bitcoins?
3
votes
1answer
80 views

Bitcoin client communication time constraints

How long does the standard Bitcoin client wait between sending a message to another client and deciding that the client is not responding? That is, if someone makes a client that takes a couple ...
5
votes
2answers
4k views

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, ...
14
votes
5answers
652 views

Why does the standard Bitcoin client not display the balance per address?

Any Bitcoin wallet holds several bitcoin addresses. Such addresses are either generated manually from the GUI addressbook or automatically collecting the "change" of a "Send" transaction. The total ...
17
votes
2answers
6k views

How does the Bitcoin client encrypt the wallet.dat file?

What is the algorithm used for encrypting the wallet.dat file?
4
votes
1answer
521 views

When will the official client support partial blockchain downloads?

Are there concrete plans for the official client to be able to download just a portion of the blockchain? By concrete I mean what's the issue tracking this on github, is there a planned version for ...
3
votes
3answers
848 views

Bitcoin communication with non-standard ports

I'm writing a Bitcoin web app that is to be deployed on an external server over which I have no control. I probably won't have access to standard Bitcoin port (8333). Will this cause a problem when ...
26
votes
2answers
24k views

How exactly does -rescan work?

-rescan is a command line argument that is passed to the bitcoin client after restoring wallet.dat from backup. Which files get recalculated? Which files does the rescan command read? Why is it a ...
14
votes
1answer
12k views

How do I upgrade my Bitcoin client?

I am working with an older version of Bitcoin and want to upgrade to version .4. Is there a specific way to do this? I want to try to upgrade, but am paranoid that I could lose my wallet if I do ...
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 ...
5
votes
1answer
165 views

What OSes don't yet have Bitcoin clients?

Bitcoin has clients created for many OSes already, but which (semi-)significant operating systems don't yet have a Bitcoin client created for them? Is there some opensource code I can use as a ...
32
votes
1answer
51k views

How can I restore my wallet?

I just purchased a new laptop and I want to decommission my old one. I have a back-up of my wallet.dat file copied to my new PC. What do I need to do to restore it to my Bitcoin (Windows) client? ...