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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705 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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1answer
75 views

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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1answer
1k views

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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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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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 ...
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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, ...
5
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1answer
918 views

Is there a reason to why Bitcoin Core does not implement BIP39?

Is there a specific reason to why BIP39 isn't added to Bitcoin Core? Seems very trivial to add and am confused to why it isn't there.
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1answer
2k views

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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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 ...
5
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1answer
975 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 ...
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2answers
1k views

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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2answers
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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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2answers
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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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2answers
5k views

16: mandatory-script-verify-flag-failed (Non-canonical DER signature) (code -26)

I try to send transaction via sendrawtransaction in console of bitcoind. Sig is: ...
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2answers
340 views

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
389 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
209 views

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 ...
5
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1answer
442 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
2k views

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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1answer
1k views

File format — rev*.dat

Can anyone help me to find out the format of rev*.dat file? There is an array with [F9BEB4D9 + 32byte number + variable raw data] for each element. What is that 32b number? And may be how to ...
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3answers
2k views

Does Bitcoin Core support HD wallet?

Does Bitcoin Core (bitcoind or bitcoin-cli) support HD wallet? Can Bitcoin Core ... Q1. create HD wallets? Q2. import HD wallets from other wallet software? Q3. watch HD wallet? (watch transaction ...
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1answer
2k views

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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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 ...
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1answer
357 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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2answers
1k views

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
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 ...
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2answers
102 views

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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1answer
116 views

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
2k views

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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1answer
610 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
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 ...
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2answers
5k views

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
2k views

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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2answers
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
377 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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3answers
308 views

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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2answers
156 views

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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2answers
742 views

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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1answer
920 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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1answer
2k views

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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1answer
193 views

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 ...
5
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1answer
816 views

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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2answers
842 views

How to receive payments online to single address per user in scalable way?

Suppose we are building online casino/market and want to receive payments. To be scalable, safe and have good user experience, we: cannot generate new address for every single payment. Having single ...
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2answers
399 views

Are desktop wallets transferable?

I know you can make a transaction across the blockchain to move your Bitcoins from say Bitcoin-QT to Multibit, but is it possible to import my wallet.dat file from Bitcoin-QT to another desktop wallet ...
5
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1answer
439 views

How to turn off “change” address in bitcoind?

I would like to keep backup of my wallet on paper, but that's impossible or at least impractical when the bitcoind keeps creating new addresses for "change". I know it is possible in theory to do it ...
5
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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 ...
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2answers
318 views

RPC call to bitcoin node on local machine respond back with code: 401

I am trying RPC request to bitcoind node,using Kotlin. My code looks like import khttp.delete as httpDelete val node_url = "http://rpcusr:rpcpass@127.0.0.1:18443" val json_resp = khttp.post(url = ...
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1answer
379 views

Does full node store all valid forks and “alternative” blocks from blockchain history?

Forks are possible when mining the blockchain and happen "all the time" during mining. This means the nodes monitoring the blockchain have recorded many forks during blockchain's lifetime, with some ...
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2answers
2k views

64: too-long-mempool-chain

I am using bitcoind json rpc api to send bitcoin to multiple bitcoin addresses. I am using sendrawtransaction. When i have 24 unconfirmed payments sent from my account, i can't send anymore because i ...
5
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3answers
768 views

Keeping old blocks on an external hard drive and latest blocks on an SSD

I would like to keep the latest 512 MB of blocks on my SSD (using pruning?) and the rest of the blockchain on an external non-SSD hard-drive. Is there a way to do this already, or do I need to write a ...