texts: Unconfirmed bitcoin transaction (Need help)

texts:
I have sent bitcoin since 25th May 2017 till now the transaction haven't confirmed yet.
https://blockchain.info/tx/ac0635c98af0703927f1b364d2d8c19f4b2812c97169c729cb341111adcea866
How can i do? Please kindly help me to get my bitcoin back
Thank you in advance
Tickbit


texts: How can Bitcoin solve societal problems caused by capitalism?

texts:
While trying to explain Bitcoin to a friend, her response was:

  To me this sounds like just an other monetary system which can be
  speculated on while making some people rich and keeping others poor. How
  does it attempt to solve deep rooted problems in our society caused by
  globalisation and capitalism?

She was of course referring to geographic and social inequalities, exploitation of workers, political oppression, depletion of natural resources, etc.

What are some of the ways decentralised proof-of-work currencies (and their underlying protocols) can work to improve these aspects of our society?


texts: It is possible to reinstall Bitcoin Core Offline? I copied all the files to my external HDD. I use Ubuntu. Thanks


texts: Which coins can butterfly-labs miners mine

texts: Can I use a butterfly-labs miner to mine any crypto-currency?


texts: Can I use coldcard wallet to multisig between it and another wallet?

texts:
I want to use coldcard wallet + another device, possibly a smartphone, for multisignature. Ideally I'd like to use Coldcard + Bitpay.
I've found tutorials on coldcard multisig: https://www.youtube.com/watch?v=OMpZ5heLsRg but it involves multisig between coldcards only.
I think BitPay is very user friendly so it wouldn't let you use multisig from importing the pubkey of the coldcard.
What are my options?


texts: Created genesis block and set up node. How to mine?

texts:
Everything seems to be going well creating my altcoin for fun. I forked the BlackCoin source on Ubuntu, successfully mined a genesis block, recompiled. I bought a droplet over on digitalocean running Ubuntu 12.04, compiled my *coind from source, and ran it.

I know that worked because my *coin-qt on my local computer had 0 connections before, now it has 1, and my *coind getconnectioncount on my droplet reports 1 connection.

Here is my problem, my client *coin-qt says there are 80000 blocks remaining. Of course, it is stuck on block 0.

How can I fix this and start mining?


texts:
I started a new Bitcoin Core(testnet) and the download of blocks worked perfectly till 15% and then i don't know what happened, but i got the following error:
unknown new rules activated (versionbit 1)
What should i do?


texts: How to get transaction info by hash using bitcoinj?

texts:
I have a transaction hash (transaction does not belong to my wallet). How can I get information about this transaction through bitcoinj API?
I need information like:

number of confirmations
sender & receiver addresses


texts: my transaction is pending 3 days old ... what to do ? please help

texts:
I have sent 0.278 bitcoins to someone from my blockchain website and my transaction is in pending now is 3 days passed ...I didn't know I have to pay any fees ....it is first time when I use blockchain website ,what's happens they steal my money ?
this is the transaction https://blockchain.info/address/1C5Crpv7UufcqR2mhHjVE2V2tXr2gfBSky

please someone can help me what to do to cancel the transaction and pay the fees ?or what to do ?


texts: How to get started with a Bitcoin wallet

texts: Where should I go to start a wallet? I have downloaded the TOR browser and got online at WEUSECOINS.COM.  Is there another site, perhaps one with more information for beginners, that I should be using?


texts: Installed MacOSX over HDD containing wallet

texts:
I formatted and re installed MacOSX on the HDD that contained my wallet.dat. I have no backup of it.

Any ideas how I could possibly recover this file and my Bitcoins?


texts: What are some compelling reasons to use Electrum?

texts:
I currently use Bitcoin-qt on OSX and I'm considering switching to Electrum.

What are the advantages and disadvantages to using Electrum over another Bitcoin client?

My two major concerns are security and ease of use. Is Electrum safe / trustworthy as a client?


texts: How do I reduce the size of the block chain data on my machine?

texts: The block chain file is getting rather large, ~500MB.  Is there a way to trim it or clean up, or maybe configure it to be limited in the future?  I am using the stock Bitcoin client on Ubuntu.


texts: Unconfirmed transaction emptied my electrum wallet. How can I unstuck it?

texts:
I was using an old Electrum wallet. I sweeped the wallet in a single transaction for which I had not turned on "dynamic wallet" (RBF) yet. The transaction is still unconfirmed after one week. I cannot create another transaction as the wallet is now empty and as I said, RBF had not been activated for the transaction.

I need help recovering my bitcoins, and I'm not finding instructions on how to unstuck the transaction. Could you please provide detailed instructions on how to retrieve my balance?

TXID: 6d75a7d55eee0b1974f5c89cafcd1b983f99e04e48059d84b3c03dd109e7de81

Note, that this is not a duplicate of the canonical question.


texts: Can someone explain to me how do you read the blockchain.info transaction data?

texts:
Ok so i've been using bitcoin for some time now, but i never figured out how to read the blockchain.info transaction data. Here's a sample of what I mean:

http://prntscr.com/2dj7tr --- https://blockchain.info/address/1KnfCxy8XkNQu9pYpqEU1fxAELqRsYDbZK

Here are a few questions that i have:

Are those bitcoin wallet addresses on the left and right column?
What is the top address representing that starts with a 7 and every other address starts with a 1? Whats the difference?
Can someone explain exactly whats going on here? I see 5 addresses that are pointing to the many other addresses on the right column.
On the bottom it seems like it's a total of $1453, but if you add up all those addresses it clearly doesn't equal that.


texts: How to monitor 2of3 Coinbase Vault wallet using xpub

texts: I created a 2of3 wallet on Coinbase. I have 3 different xpub. I tried all 3 xpub on goochain.net but in all appear 0 balance. But I have 2 btc. How to monitor the 2of3 of Coinbase using xpub?


texts:
Me and my friends want to make public pool like rublik.com (site have english vesrion).
So, how can we make a similar pool? Maybe there are some open source solutions like p2pool? We want to make a similar pool, maybe someone knows what solutions rublik.com use? We just want to copy their pool.


texts: What are the safety guidelines for using the Sign Message feature?

texts:
bitcoin-qt's dialog box states, "Be careful not to sign anything vague, as phishing attacks may try to trick you into signing your identity over to them. Only sign fully-detailed statements you agree to."

What would this kind of attack look like?  What are some examples of statements that would be safe to sign agreement to?


texts:
I have several bitcoin addresses (together with corresponding public keys) from Electrum wallet I've used previously. I moved to another CentOS server and now I need to import this addresses back.
But when I do:

electrum sweep [public key] [btc address] -w [path to wallet]

I get:

Traceback (most recent call last):
File "/usr/local/bin/electrum", line 384, in <module>
result = server.run_cmdline(config_options)
File "/usr/local/lib/python3.7/site-packages/jsonrpclib/jsonrpc.py", line 748, in __call__
return self.__send(self.__name, args)
File "/usr/local/lib/python3.7/site-packages/jsonrpclib/jsonrpc.py", line 630, in _request
check_for_errors(response)
File "/usr/local/lib/python3.7/site-packages/jsonrpclib/jsonrpc.py", line 1321, in check_for_errors
raise ProtocolError((code, message))
jsonrpclib.jsonrpc.ProtocolError: (-32603, 'Server error: File "/usr/local/lib/python3.7/site-packages/electrum/bitcoin.py", line 475, in deserialize_privkey | electrum.util.BitcoinException: cannot deserialize privkey 024..c0\n')

What am I doing wrong?


texts: How to change directory for MultiBit HD wallet file away from C:\?

texts:
I know the seed is all I need to recover coins, and all I need to recover coins is the 12 words passphrase, etc. etc.

But, what I really want, for various reasons, is to be able to move my wallet for MultiBit HD (I think it’s the one called multibit.wallet) from now:

C:\Users\<your name>\Appdata\Roaming\Bitcoin
to a new place which could be a USB drive, an encrypted drive etc.

I can easily do so using Bitcoin Core client and also on MultiBit Classic this was and is easy. But how to I move the MultiBit HD wallet from C:\ where I really don´t like to have it?

I even installed MultiBit HD on another disk E:\ - but still the software installs the wallet at C:\Users\<your name>\Appdata\Roaming\Bitcoin
I´ve been searching around here and there but not really found an answer.

Could somebody help me here?


texts:
I'm new to crypto trading and id like to know if bitcoin transactions have ever taken more than 7 days to confirm?
kind regards
rob


texts: I had money sent to my wallet and couldn’t remember my encrypt password.  I had my 12 word recovery phrase written down but it’s abbreviated. I deleted my wallet which I shouldn’t have done because I’m sure I would have figured out the encrypt password by now and I’m going crazy with this recovery phrase. The way I store is 6 rows 2 words per row. 1st problem is I don’t know the order, it could go: left right left right... left right right left.... right left right...right left left right.  6 of the words I’m 100%.  4 words have 3 possible options. 1 has 2 options and the last could be a number of things.  I have the address that I had the money sent to (probably doesn’t help).  I know the name of the wallet (sure that doesn’t mean shit)     At this point I’m sure if I just knew the first and last word(the order) I’d figure it out.  I’d pay someone if I wasn’t certain they would take it plus how would they figure it out.  I’ve seen people that charge 10% but why wouldn’t they take it all? What can I do?   Is there a way to know which of my first two words are first


texts:
I followed the tutorial https://medium.com/@meeDamian/c-lightning-node-on-rbp3-b950660fb835 without error.
When I type:
 sudo systemctl start lightningd
I get
 Failed to start lightningd.service: Unit bitcoind.service not found.

Note: Blockchain syncronization is not finished

Any idea?
thank you


texts: Help decrypting Encrypted Privated Keys (AES)

texts:
I am manually inputting my encrypted private keys and secret key (password) on https://www.browserling.com/tools/aes-decrypt

Is there a way I can input more than 1 encrypted private key at a time? I have hundreds of encrypted private keys I want to check for any btc balance.


texts: Why are miners allowed to change a tx id?

texts:
BIP 62 proposed to make transaction malleability impossible.

Why was this retracted and why are miners allowed to change a transaction id?

Also, what does it mean when someone says signatures cannot sign themselves?  Is this implying we not only need a signature for the transaction, we need another signature for the transaction + signature?


texts:
I would like to seek for your help since I would like to have confident answers on the following questions:
(please include links for official websites)

Is it legal to buy & hold currencies (such as ripple, bitcoin,etc..) as a kind of investment in the USA?
When do you have to tax after it?
Do you have to report is on your tax form even before you sell it or only after you sold the currencies?

So far this is what I found:
https://www.irs.gov/pub/irs-drop/n-14-21.pdf


texts: Is it possible to splice a new participant into a LN channel factory?

texts:
I am reading paper named "Scalable Funding of Bitcoin Micropayment Channel Networks".

If Alice, Bob, and Charlie created a channel factory, I thought that only these three people can make a payment channel within themselves. However, the paper says "Users will be able to enter the system with one blockchain transaction and then open many channels without further blockchain contact." (page 3).

In the above case (i.e., Alice, Bob and Charlie created a channel factory), Hook transaction becomes 3-of-3 multisig. If Diana wants to join the channel factory, Hook transaction consisted of three peoples already. so I think Diana can’t join in their channel factory.

There is no example in this case in the paper(above picture). Is the way I understand correct ? or not ?

And I wonder how to refund without closing and re-opening ? As you can read in this paper, When a party enters a channel factory, the deposit that the party input is already set at that moment. or.. the meaning of refund in here is moving funds to different channels ?


texts: Does FIPS 140-2 crypto certification matter for Bitcoin?

texts:
I'm implementing part of the Bitcoin client in C# and noticed that I have the choice between FIPS 140-2 and non certified versions of SHA256.  Supposedly both versions give the same hash.

Does the choice of SHA-2 library matter for Bitcoin?  Does the FIPS-2 library exist in Mono and mobile devices?


texts: How is a doublespend prevented in the Lightning Network?

texts:
How Lightning Network handles double-spend? What will happen when the other person is not available online to enforce the integrity of the transactions?

PFB my understanding of the Lightning Network.

  Lightning Network builds an additional layer on top of the Bitcoin network that enables instant off-chain transfer of the ownership of the Bitcoin. Lightning Network utilises bi-directional payments channels that consist of multi-signature addresses.  Meaning Bitcoin will be held in a multi-signature address where transactions will use a multi-signature address as their input and point at two different addresses as their output. The transactions inside the lighting network are not broadcasted to the bitcoin network as long the channel is open (in order to reduce the load on the blockchain).

In this example how is Alice prevented from double spending?

Alice and Bob both send 0.05 BTC into a shared 2-of-2 multisig address. This requires a transaction on the Bitcoin blockchain.
Alice wants to pay 0.1 BTC to Bob.
      a. Alice creates a new transaction B2 and changes the balance to 0.4 BTC to Alice and 0.6BTC to Bob.
      b. Alice signs B2 and sends to Bob
      c. Now Bob creates a new transaction A2 and changes the balance to 0.4 BTC to Alice and 0.6BTC to Bob.
      d. Bob signs A2 and sends to Alice.
After step 2a (before Bob verifies the transaction), can Alice close the channel and double spend the money?


texts: How can I tell when `rescanblockchain` is finished?

texts:
Rescanning the blockchain can take some time. How can I tell (via RPC) when the rescanblockchain command has finished? Will it block until it's done, and only then return? Or is there another RPC I can use to see its progress?

Does the same answer apply to other RPC calls that might trigger a rescan, such as importmulti and loadwallet?

I'm worried about (if it blocks) the user experience of sitting there for possibly minutes with no progress indication; or (if it doesn't block) future RPC calls (such as getbalance) getting stale info before the rescan has completed.


texts: i have lost 83$ worth bitcoin from my blockchain wallet can any one help me to recover it?

texts: on 2018 oct 19 there was a transaction which I haven't done from my wallet of 83$ bitcoin please help me to get it back


texts: How can I physically give someone bitcoins for easy redeeming?

texts:
I want to be capable of giving someone a small amount of bitcoin, in the form of a box (such that can be transfered through the mail or whatever). How can I do it, and make it as easy as possible for them to take ownership and start messing with it?

I've seen paper wallet where you just write a thing down, but I don't want to force them to type in a long key.


texts: What is the purpose of the "Message" field when sending a Bitcoin Core transaction?

texts:
I always set the "Label", but what is the "Message" for? I always leave the "Message" empty.
I know that neither is sent over the network; they are just for your own reference. But why both "label" and "message"?


texts:
I was wondering if somebody could point me to or give me a worked out example of how OP_CHECKMULTISIG works behind the curtains?

I expect that CHECKMULTISIG will call the CHECKSIG function and manipulate the stack to run CHECKSIG in a loop until it terminates and either has its M-out-of-N valid sigs or not?

But how exactly does it work? E.g. for 2-of-3 multisig. If we have OP_0 (sig1) (sig2) in the scriptSig, then the stack will look like:

(sig2)
(sig1)
0

Now from the general way of writing CHECKMULTISIG in the scriptPubKey: 2 (pubKey1) (pubKey2) (pubKey3) 3 OP_CHECKMULTISIG, when pushing all the data onto the stack, the stack for the scriptPubKey will look like:

3
(pubKey3)
(pubKey2)
(pubKey1)
2

What exactly will the first step be of CHECKMULTISIG?

Will it pop the "3" from the stack and then maybe check if there are three pubKeys on the stack?

Or will it just pop the "3" and then immediately run CHECKSIG on (sig2) and (pubKey3), which will not be valid, hence CHECKSIG will push a "0" on the stack?

Will then CHECKMULTISIG remove the "0" that CHECKSIG introduced on the stack and try again with (sig2) and (pubKey2)? Since this is valid CHECKSIG will push a "1" on the stack, but where does CHECKMULTISIG store this "1"?

And will CHECKMULTISIG at the end count how many "1"'s CHECKSIG made and this number must correspond to the last value on the stack, in this case "2", but in general "M"?

I would really like to find a low-level description of CHECKMULTISIG, similarly to the one I could find for CHECKSIG:
https://en.bitcoin.it/wiki/OP_CHECKSIG

Any help would be very appreciated!


texts: What is the "confirmation" field in a block?

texts:
What is the importance of the "confirmation" field in a block?

How many confirmations are required to accept a block in a blockchain?


texts: I'm looking for an exchange to trade my altcoins against each other to take advantage of the volatility. Any suggestions for altcoin exchanges?


texts: Is it possible to determine the total amount of timelocked Bitcoin?

texts: Now that is possible to lock funds until a certain date (https://coinb.in/#newTimeLocked). How to calculate how many of all bitcoin in existence is locked until a certain date? Any service that does this?


texts: Full list of RPCs - including hidden RPCs

texts: Where can I find a full list of RPCs that are not listed in the output of the help command? (such as invalidateblock etc.)


texts: What is the ECC key length for OpenCoin's implementation of Ripple?

texts: http://www.reddit.com/r/Bitcoin/comments/1lubl1/wired_oped_worries_that_elliptic_curve/cc2vhos suggests that key lengths < 500 bits are no longer considered secure from the NSA.  What key length is Ripple using?


texts: Transfer different currencies between wallets

texts:
I had SCOTCOIN in a counterwallet.io address and I transferred it to a Coinbase BTC wallet. I wouldn't have thought the transaction would have worked but it did. The amount of BTC in the Coinbase wallet in no way reflects the going exchange rate.

What's gone wrong and can it be fixed?


texts: Is it possible to spend an output that hasn't yet been confirmed?

texts:
From something I noticed in this thread: Unconfirmed BTC

MtGox will send a transaction to spend one of the outputs of a transaction that hasn't yet been confirmed.

Is it possible for both of the unconfirmed transactions to be in the same block (in the right order)?


texts: replicating in python what the electrum wallet does during (deterministic) wallet creation

texts:
I am trying to replicate in python what the Electrum wallet does during (deterministic) wallet creation. IMHO the docs are a bit sparse on this one bit maybe because its only performed once for most users, all the tutorials etc. seem to focus on the GUI, and I was unable to work out the python code from the spesmilo github for electrum.

From what I can see, Electrum generates a random Wallet Generation Seed

a 13-word mnemonic(or 12 words plus checksum?)
which is unencrypted This is also the Master Private Key?
Then the user enters a password/passphrase(or not) that encrypts the seed so it can be saved as a wallet(file)
The wallet file can only be decrypted with the password/passphrase
Then a Master Public Key is generated from the wallet [Anybody have more detail on this?].
Then the 25-byte binary Bitcoin Address =
{[MPK>sha256>RIPEMD160]+[MPK>sha256>RIPEMD160>versionByteadd>sha256>sha256>first4bytes]}
which in turn is Base58Check encoded to the Bitcoin Address format

Can someone please check if my assumptions (1 to 7) are okay/correct me?
Also, below is how far I got with python(probably grossly incorrect!):

from electrum import mnemonic
import ecdsa
import hashlib
import base58
import getpass

mnemonicInstance = mnemonic.Mnemonic(lang='en')
randseed = mnemonicInstance.make_seed()
print "this is my 13 word wallet gen seed" + randseed
private_key = mnemonicInstance.mnemonic_to_seed(randseed , getpass.getpass()).encode('hex')
print "this is my private key: " + private_key
#the line of code below failed!:
sk = ecdsa.SigningKey.from_string(private_key.decode("hex"), curve = ecdsa.SECP256k1)
vk = sk.verifying_key
public_key = ('\04' + vk.to_string()).encode("hex")
print "this is my public key: " + public_key
ripemd160 = hashlib.new('ripemd160')
ripemd160.update(hashlib.sha256(public_key.decode('hex')).digest())
middle_man = '\00' + ripemd160.digest()
checksum = hashlib.sha256(hashlib.sha256(middle_man).digest()).digest()[:4]
binary_addr = middle_man + checksum
addr = base58.b58encode(binary_addr)
print "this is my BTC address: " + addr

(some of the above lifted from Shultzi's github) I also consulted Andreas' Mastering Bitcoin but not had much joy with this bit.


texts: Code example for Ardor bundler code snippet to filter transactions of a certain criteria to pay ZERO 0 ignis Fees?

texts:
I'm looking to write a custom Ardor bundler to only bundle transactions that have the following properties:

Bundle transactions that are being sent to a specific account only.
Bundle transactions where the sender holds a specific type of asset or monetary system coin.
Bundle transactions only if that user hasn't sent more than 10 transactions in the past hour.

I couldn't find any code snippets of how to go about setting these custom Ardor bundlers.


texts: What is the point of Bitcoins if every transaction has a fee?

texts:
You can't use them without it costing you money! I am asking because I want to give some of my bitcoins to a friend. It is a gift not a transaction.
I don't think it can be useful as a currency if it costs so much to use.
Please can someone explain this simple point. I am not familiar with any of the intricacies or concepts of Bitcoin and am just looking at its possibility of use as an actual useful currency.


texts: Is it safe to encrypt bitcoind wallet if it holds funded addresses?


texts: My mate received and then sent a Bitcoin transaction before his wallet was synchronised and it worked perfectly

texts:
His Bitcoin wallet was only 1% synchronized with the network and yet he was able to receive and send bitcoins without any problems?!

What are the implications / ramifications of this?

What does this mean?


texts: What is the Bitcoin spot price and how is it calculated?

texts: I was offered to buy Bitcoin for today's spot price (MtGox to be specific). So, I am wondering, what is the spot price and how is it calculated? Is there a standard tool to look it up?


texts: Lightning network channel capacities and gambling site jackpot payouts

texts:
Let's say I want to make some kind of gambling app:

The user creates a channel with the business. (local_amt = 1000, remote_amt = 0, capacity = 1000)
User bets a few times and wins a jackpot of 5000 satoshis which is more than the capacity of existing channel.

How do I transfer the 5000 sats over lightning when the channel capacity is 1000? The only way I can see getting the jackpot money to the user is by me opening a new channel with extra capacity, but obviously that would take an undesirable amount of time.

In other words, I'm curious how a site like https://www.lightningspin.com/ accomplishes instant withdrawals.


texts: How to claim BTG from an Electrum wallet?

texts:
Claiming BTG after the Fork did not work

I have tried :
using Coinomi wallet,this way.

I could not locate the address holding eligible for BTG value.
All addresses i tried was contained no fund.
In the history tab i could not spot the addresses details.


texts: There was a paper somewhere proposing a scheme for filtering email spam with the use of Bitcoin micropayments. I can't remember where I saw it and can't find it now. Anybody knows about it?


texts: My balance says 100. mBTC. How many bitcoins is this, and what is the value in British pounds?

texts:
Cant find an easy answer anywhere? I would like to know what this means and the value etc

Is it 0.100 bitcoin or 0.0100 bitcoin?


texts:
This is a general question, but what's the best way to search the blockchain? Blockchain.info lets you search by address, but it seems to be a side feature instead of its central purpose.

Are there other sites for searching Bitcoin transactions? I want to see all the transactions associated with a single address or to do other arbitrary types of searches?


texts: What is the number of transactions in a block?

texts: What determines the number of transactions that can be validated in a block?


texts: I ran 6 or 7 bitcoinds with version 0.93 on CentOs. I used the default configuration on all of them. Sometimes I found one or two fell behind the others. And I need restart them, then they would work. I don't where is wrong, or there is some problem on the 0.93 version. Do I need update to the 0.10 version? When will the official 0.10 release. Thank you very much.


texts: What aspects of Money Order laws will apply to merchants who use Bitcoin?

texts:
There are several money order laws that apply to merchants who accept them.   Bitcoin seems to have properties of a money order, but also some aspects of value that are driven by demand.

I'm looking for a clear and reasonable explanation of:

How do Bitcoins compare to (and differ from) Money Orders?
What aspects of laws that apply to Money Orders are likely to also apply to Bitcoin?

I'm most interested in US,  UK, and Australia, but any links would be beneficial.


texts: Full node or Full node third-party services pros and cons

texts:
I'm setting up P2P Bitcoin website similar to LocalBitcoin for school project.
Before I go deep into this journey I'm doing some plannings.

I have lot's of questions in my head and have been studying bitcoin technology.
I would like know if its better to run full node on my server and execute RPC commands or should I just look for companies that offer such services to save me some time?

What are the  pros and cons of running full node
I will also appreciate recommendations for third-party services for Bitcoin P2P market


texts: BitCoin Miner - Remote Miners with SSH Access only

texts:
I've graciously been given a big opportunity with a server infrastructure to work with, and I'd like to start it off by starting some Bitcoin mining, however there's a catch. These servers I have access to have all internet access blocked other then the SSH connection that I make in to the machines.

Is there any bit of software that for example, can receive the piece of a block to solve on my main machine at home, and send it off to these servers through SSH to solve, then send it back?


texts: How can I get the raw tx hex from bitcoind with the txid?

texts: Is there any way to get the raw tx hex when I know the txid using bitcoind not third party. Currently I'm using a thirdparty (blockcypher) but now I want to switch to bitcoind.


texts: What / Who is the Bitcoin mining-power useful to?

texts:
I searched the internet to find out who (or what) was taking advantage of the result of mining but I couldn't find a clear and complete answer (and sources).

I know Bitcoin miners decrypt hashes, but what is that useful for? I guess there is something behind that, otherwise why should we need to decrypt hashes, why should we need a huge power 24/7? Is that really ethical to mine Bitcoins ?

I'm not very familiar with virtual money, I may have missed something!


texts: How can I enable more GPUs in Ubuntu for poclbm?

texts:
I have an Ubuntu set up (11.10) and 2 ATI Radeon HD 6870 cards. It detects one, but not the other for some reason when I try to run poclbm.

When I run lspci, it finds both cards.

Any help?


texts: Failing to build bitcoin-core v0.13.1 on debian stretch

texts:
I have recently set up a new machine on debian stretch:

$ uname -a
Linux front 4.8.0-1-amd64 #1 SMP Debian 4.8.7-1 (2016-11-13) x86_64 GNU/Linux

I am now attempting to install bitcoind. I have already set up a directory db4 in my build directory for the Berkeley database version 4.8.30. I have installed all the dependencies as per doc/build-unix, including boost from the distribution:

$ sudo apt-get install libboost-all-dev
$ apt-cache show libboost-all-dev
Package: libboost-all-dev
Source: boost-defaults
Version: 1.62.0.1
...

$ ./autogen.sh
...

$ ./configure LDFLAGS="-L..bitcoin/db4/lib/" CPPFLAGS="-I..bitcoin/db4/include/"
...

$ make
...
CXX      wallet/test/test_test_bitcoin-wallet_tests.o
CXX      wallet/test/test_test_bitcoin-crypto_tests.o
wallet/test/crypto_tests.cpp: In function ‘bool wallet_crypto::OldEncrypt(
const CKeyingMaterial&, std::vector<unsigned char>&, const unsigned
char*, const unsigned char*)’:
wallet/test/crypto_tests.cpp:45:20: error: aggregate ‘EVP_CIPHER_CTX ctx’
has incomplete type and cannot be defined
EVP_CIPHER_CTX ctx;
                ^~~
wallet/test/crypto_tests.cpp: In function ‘bool wallet_crypto::OldDecrypt(
const std::vector<unsigned char>&, CKeyingMaterial&, const unsigned
char*, const unsigned char*)’:
wallet/test/crypto_tests.cpp:69:20: error: aggregate ‘EVP_CIPHER_CTX ctx’
has incomplete type and cannot be defined
EVP_CIPHER_CTX ctx;
                ^~~
Makefile:8232: recipe for target 'wallet/test/test_test_bitcoin
crypto_tests.o' failed
make[2]: *** [wallet/test/test_test_bitcoin-crypto_tests.o] Error 1
make[2]: Leaving directory '/home/john/Libs/bitcoin/src'
Makefile:8370: recipe for target 'all-recursive' failed
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory '/home/john/Libs/bitcoin/src'
Makefile:680: recipe for target 'all-recursive' failed
make: *** [all-recursive] Error 1

Any suggestion is gratefully appreciated.

EDIT: adding the option --disable-wallet to configure leads to a successful build.

EDIT2: however, even with the --disable-wallet , the command make check fails with:

make[4]: Entering directory '/home/john/Libs/bitcoin/src/secp256k1'
  CC       src/tests-tests.o
src/tests.c: In function ‘test_ecdsa_der_parse’:
src/tests.c:3561:52: error: dereferencing pointer to incomplete type
‘ECDSA_SIG {aka struct ECDSA_SIG_st}’
valid_openssl = !BN_is_negative(sig_openssl->r) &&
!BN_is_negative(sig_openssl->s) && BN_num_bits(sig_openssl->r) > 0 &&
BN_num_bits(sig_openssl->r) <= 256 && BN_num_bits(sig_openssl->s) > 0 &&
BN_num_bits(sig_openssl->s) <= 256;

This error relating to the C library secp256k1 on debian stretch has already been reported on this post and it seems to be related to some openssl API change (a work around put forward by Andrew Poelstra is to configure secp256k1 with the option --enable-openssl-tests=no. However, this is not an option available for bitcoind configuration)


texts: Import wallet.dat into a new Bitcoin-Qt client

texts: I had Bitcoin-Qt on my computer with several bitcoins in my wallet, using Vista. Then my computer crashed.  Finally I was able to get my computer fixed and download a new version of Bitcoin-Qt.  Now I would like to import my original wallet.dat from the old client which was encrypted into an new version of Bitcoin-Qt.  How do I do that?


texts: Is there a list of "hardforks that will never happen in Bitcoin"?

texts:
The Hardfork Wishlist lists some fork-causing changes that might actually get introduced (e.g. adding more decimal digits to allow units smaller than a satoshi).

Is there a similar list of forks that will definitelylikely never happen? (might happens in alts, but not in Bitcoin)

One such change is obviously changing the target limit of coin creation from 21,000,000 to something else. Another change might be changing the reward splitting to be continous - such a change is probably too complex without much concrete benefit to be ever implemented in core Bitcoin.


texts: Buying Bitcoins without identity checks?

texts: Are there any exchanges that offer Bitcoins without identity checks? I would like to remain anonymous while buying the currency.


texts: How to activate the mining process in the standard bitcoin client?

texts:
I have done the whole synchronization and now it should be mining bitcoins from what I understand but I don't see anything showing that it is actually mining for bitcoins nor any activity from my cpu… Is this normal ?

Do I need to enter a command to start the mining process or is the process done automatically without having to do anything ?


texts: How to convert a keyPair to JSON and back?

texts:
Using bitcoinjs you can generate a keyPair with the following code:

var keyPair = bitcoin.ECPair.makeRandom();

How can I stringify this object to JSON and then parse it back to an object? JSON doesn't play well with circular objects and I'm struggling to understand how one can work around this.

Thanks,

Connor


texts:
I installed bitcoinjs-lib with command: meteor npm install bitcoinjs-lib.
The installation command "flow-typed install -f 0.27 bitcoinjs-lib@2.2.0" didn't work. No idea what flow-typed is and the influence it has.

This is the code I am running:

  import bip39 from 'bip39';
  import bip32 from 'bip32';
  import crypto from 'crypto';
  import bitcoin from 'bitcoinjs-lib';
  let randomBytes = crypto.randomBytes(32);
  this.mnemonic = "praise you muffin lion enable neck grocery crumble super myself license ghost"; //bip39.entropyToMnemonic(randomBytes.toString('hex'))
  this.seed = bip39.mnemonicToSeed(this.mnemonic);
  console.log("seed:", bip39.mnemonicToSeed(this.mnemonic));

  let bitcoinNetwork = bitcoin.networks.bitcoin;
  var hdMaster = bip32.fromSeed(this.seed, bitcoinNetwork);

  const path = "m/0'/0/0";
  const child1 = hdMaster.derivePath(path);
  const { address } = bitcoin.payments.p2sh({
    redeem: bitcoin.payments.p2wpkh({ pubkey: child.publicKey, network: bitcoinNetwork }),
    network: bitcoinNetwork
  })
  console.log("address: ", address);

Unfortunately bitcoin.payments is undefined.
bitcoin.networks.bitcoin works ok.

Why is payments undefined?
Thanks.


texts: We were initially scammed for 1000.00 through blockchain. So then we did some research online about fraud recovery experts. We came across a site called stallionedge.tech and their clients had rave reviews about how long it took to get their money in a matter of days, so we were able to get in touch with them. We called the phone number listed on their website and it was disconnected. They said that they can only contact us, that is why it is disconnected when somebody tries to call them. So we thought okay. They communicated with us back and forth via email. So when it came time to pay them to help, I was told to download whatsapp and that a withdrawal specialist would contact me. The withdrawal specialist, Christopher, contacted me. We initially had to pay 250.00 for services rendered. Well, then he said that we needed to deposit 460.00 to show activity on our blockchain account, so we reluctantly did. It disappeared in a matter of minutes. They said that there was a glitch and that they would help figure it out. That we were his top priority and that they deal with clients like us on a daily basis. Well, a couple of days later, we were asked to deposit 460.00 more and they would help us get the previous 460.00 back along with over 2000.00 that was taken from our blockchain account. It supposedly accrued up to over 2000.00. We received a screenshot of the transaction that they claimed was waiting to be sent to us. It looked legitimate. Well, it wound up disappearing in a matter of minutes, too. The thing is, is that he is still communicating with us via the whatsapp. I have all the texts, emails and screenshots as proof if you need those. Please help. I don't know if there is a way to recover the money that we paid, but their website needs shut down and the people need punished that have taken advantage of us. I am assuming this is a scam, but if it is a legitimate company, they are taking advantage of me. He says that you can contact him. We have his contact info if you need it.


texts: How to convert HD wallet master key to extended key and child keys in javascript?

texts:
I'm trying to learn how HD wallets work internally by writing javascript code that can derive child keys from parent keys. So far, the only thing I've been able to do is convert a BIP39-generated seed to a master key and chain code. I can do that successfully.
Now I would like to convert the master key to an extended key, the long string that starts with xprv. I'd also like to know how to derive child keys from these, and obtain the private key for signing with any of the accounts.
I've been using this confusing BIP32 document as a guide so far, but I'm getting nowhere with it. As far as I can tell, before you derive any keys, you have to serialize the ones you already have.
The serialization process is described like this:

Extended public and private keys are serialized as follows:

4 byte: version bytes (mainnet: 0x0488B21E public, 0x0488ADE4 private;
testnet: 0x043587CF public, 0x04358394 private)
1 byte: depth: 0x00 for master nodes, 0x01 for level-1 derived keys, ....
4 bytes: the fingerprint of the parent's key (0x00000000 if master key)
4 bytes: child number. This is ser32(i) for i in xi = xpar/i, with xi the key
being serialized. (0x00000000 if master key)
32 bytes: the chain code
33 bytes: the public key or private key data (serP(K) for public keys,
0x00 || ser256(k) for private keys)

This 78 byte structure can be
encoded like other Bitcoin data in Base58, by first adding 32 checksum
bits (derived from the double SHA-256 checksum), and then converting
to the Base58 representation. This results in a Base58-encoded string
of up to 112 characters. Because of the choice of the version bytes,
the Base58 representation will start with "xprv" or "xpub" on mainnet,
"tprv" or "tpub" on testnet.

Here is the javascript code I wrote in attempting to follow these instructions.
const crypto = require ('crypto');
const base58 = require ('base58');

const master_key_hex = '5a02ee5cb622f15a4e7ab3dfe7faa9861738da2ae7bb936c685af4dd7b1fbdee';
const chain_code_hex = 'abfbc73691eaad7ca4eb5e25bc51c5804af221cc27a23460634498497f92c92c';

// the 78 bytes of data
var data = '0488ade4';
data += '00';
data += '00000000';
data += '00000000';
data += chain_code_hex;
data += '00' + master_key_hex;

// add the checksum
const hash_1 = crypto.createHash ('sha256');
var sha_256_1 = hash_1.update (data, 'hex').digest ('hex');
const hash_2 = crypto.createHash ('sha256');
var sha_256_2 = hash_2.update (sha_256_1, 'hex').digest ('hex');

var data_with_checksum = data + sha_256_2;

//data = Buffer.from (data_with_checksum, 'hex');
var result = base58.encode (data_with_checksum);
console.log (result);

I tried it with a string and with a Buffer and it gave me the same error message both times. The error message is:
Error: Value passed is not a non-negative safe integer.

I have a feeling I am not even close to doing this right. Does anyone know how it should be coded to derive child keys from a master key?


texts: Source code: Where is address encoding performed?

texts:
I would like to experiment with having fewer characters (trimming a few characters at the end, and fewer checksum) for an address while still retaining enough for adequate security.

I've looked into base56.h but it doesn't seem to actually check addresses?


texts: can i use one Mnemonic Code to create both(TestNet and MainNet) wallets

texts: currently i am using bitcoinj library to create wallet for both Main-net and Test-net using Mnemonic code(Mnemonic Code is different for both), my question is can i create both Wallets(Test-net and Main-net) using one Mnemonic Code, if yes, then how?


texts: Is the difficulty target always truncated for practical purposes?

texts:
The current value of bits in the block header is: 18034379. In target form, this is equal to:

0x0000000000000000034379000000000000000000000000000000000000000000

However, if you calculate the target using the difficulty:

target = maxtarget / difficulty
target = 0x00000000ffff0000000000000000000000000000000000000000000000000000 / 336899932795.8077
target = 0x0000000000000000034379000000004000000000000000000000000000000000

As you can just about see, this calculated value is more accurate than the  truncated target you get using bits.

My question is:

When mining, is the truncated target used (the one you get from bits), as opposed to the more accurate target you get by dividing the maxtarget by the difficulty?
Therefore, for all practical purposes, you should truncate the target you get when you divide the maxtarget by the difficulty?


texts: Why does bitcoin have so many digits if I cannot move anything freely under 10000 satoshi?

texts:
So I have a wallet which has a balance of BTC 0.00005493.

Even when trying to send these last bitcoin with a custom tx fee (1000 satoshi vs. the recommended 10000) Blockchain.info gives an error saying it is not possible to do so.

I know I can use a script called Dust-B-Gone to destroy these "small" amounts of bitcoin but I don't see the point. Why make bitcoins so divisible if anything under 10000 satoshi cannot even be moved around freely?

10000 satoshi is the current equivalent of a USD/EUR 5 cents coin! Are they not worth anything in cyberspace?


texts: Can I use current Bitcoin protocol and Bitcoin client to create my own controlled currency?

texts:
Since Bitcoin network and Bitcoin currency are not so reliable and can't be controlled.
Also, they are open source. How difficult it is to use the current client and protocol to create a new, independent currency controlled by me?

I will use such currency as a medium for money transfer. Much like a website money or credit.
If I used the current Bitcoin as it is, I would be responsible for all Bitcoins in the world. I want to be responsible for the Bitcoins created by me only. So even if the project will end or the value of Bitcoins goes down, I can then compensate my clients for their loss.

What experience and knowledge needed to accomplish this?(Hardware and Software).


texts: Which exchanges support U2F authentication?

texts:
I got myself a nice security key (Yubico Fido) today, which utilises the U2F protocol. But to my surprise not a single Bitcoin exchange seems to support this yet, only Google itself.

So which Bitcoin exchanges (plan to) support U2F?


texts: Can two signed transactions be merged into one?

texts: I'm in a situation where I have a presigned transaction, which, due to a bug in software that generated it, has a fee lower than minimal relay fee. I have that transaction's hex, but it can't be broadcast in a way that'd get it mined, so that's no use. Thus, the question: is it possible to merge it with another transaction which I could arbitary create and sign with my wallet, so that that transaction would unlock enough bitcoin to cover the fee for the resulting transaction? If so, how could I do this?


texts: How does the network apply credit for created blocks?

texts:
First post.  I must say in advance thanks to everyone for all the great conversation and help and software so far.  It's really helped me get familiar with bitcoins and bitcoin mining.

I have a question about functionality of the Bitcoin network and how mining credits are applied to the correct person.

Assume a person is solo mining.  That is, one computer is doing the mining.  IT may be running a pool, but that's not relevant for this question.  So, lets assume a solo miner generates a few blocks and they get accepted.

When the network approves a block that has been created, how is the credit for the block creation (50 bit coins, soon to be 25) applied to the miner's wallet?

Let's say that a GPU miner, like DiabloMiner is running, and getting its work from Bitcoin-QT.  How does Bitcoin-QT, detect the mining credit of 50/25 bitcoins and send it to the correct miner's address?

Thanks.


texts: Pictures and non-transaction data in block chain

texts: It is well known that non transaction related information has found its way into the block chain. This raises multiple questions: (1) How was it done, and is it still possible (2) If someone where to introduce contraband into the block chain, this would be propagated to all copies of the ledger. Could make it illegal real quick. I know my questions are from a devils advocate - not because I don't like BitCoin, to the contrary, but I want to fully understand its risks as well. Thanks


texts: What does "Nonstandard output" mean on Tradeblock transaction page?

texts:
I tried to send bitcoin but the recipient hasn't received it.

The trade block page shows "Nonstandard output" under outputs as shown in the link below:

Tradeblock page for transaction

I used an Electrum wallet and the transaction seemed to confirm as the usual green tick appeared next to it in the transaction history. However my balance was 0BTC and the text "not enough funds" appeared in the bottom left corner.

What's going on? How do I either get my money to the recipient or back to me?


texts: Getting balance/downloading blockhain with bitcoinj

texts:
I am playing around with bitoinj and I can't seem to even get the most basic functionality running.

What I want to do: I have one wallet with one address. I want to dowload blockchain and from that, get the wallet balance.

What I did is following code (in scala, but it is more or less the same thing as Java), the wallet is in address.walet, I want the blockain to be saved at saved.blockchain:

val params = NetworkParameters.prodNet
val walletFile = new java.io.File("address.wallet");
val wallet = Wallet.loadFromFile(walletFile)

val key = wallet.keychain.get(0)
val address:String = key.toAddress(params).toString
println("ADDRESS IS : "+address)

val blockStore = new BoundedOverheadBlockStore(params, new java.io.File("saved.blockchain"))
val chain = new BlockChain(params, wallet, blockStore)
val peerGroup = new PeerGroup(params, chain)
peerGroup.setUserAgent("BitToy", "0.1")

peerGroup.addPeerDiscovery(new DnsDiscovery(params))
peerGroup.addWallet(wallet)
println("START DOWNLOADING BLOCKCHAIN")

peerGroup.start()
peerGroup.downloadBlockChain()
peerGroup.stop()
println("DONE; BALANCE IS :")
println(wallet.getBalance)

I do have balance on the address in the wallet.

Now, when I run it for the first time, the blockchain (or, rather, the headers) gets downloaded and I see the correct balance. However, when I run it for second time, I just see:

ADDRESS IS : [correct address here]
Aug 19, 2012 8:06:00 AM com.google.bitcoin.store.BoundedOverheadBlockStore load
INFO: Reading block store from saved.blockchain
Aug 19, 2012 8:06:00 AM com.google.bitcoin.store.BoundedOverheadBlockStore load
INFO: Read chain head from disk: 00000000000001b10c347b5ec05f9a1910d541905c5cd8827784a5c3e0695c95
Aug 19, 2012 8:06:00 AM com.google.bitcoin.core.BlockChain <init>
INFO: chain head is at height 194575:
v1 block:
   previous block: 00000000000005ac50dc06021362cd4c284fafd4a1bdb7bad2849c978a875bb1
   merkle root: 158aedd0bc3386c7686f85ab933fd9e3ecb38e348b121ed0e61e2e776eda04a1
   time: [1345356028] Sun Aug 19 08:00:28 CEST 2012
   difficulty target (nBits): 436709470
   nonce: 4238997601

START DOWNLOADING BLOCKCHAIN
Aug 19, 2012 8:06:31 AM com.google.bitcoin.discovery.DnsDiscovery getPeers
INFO: DNS lookup for dnsseed.bitcoin.dashjr.org failed.
Aug 19, 2012 8:06:36 AM com.google.bitcoin.core.TCPNetworkConnection$NetworkHandler channelConnected
INFO: Announcing ourselves as: /BitCoinJ:0.6-SNAPSHOT/BitMessage:0.1/
Aug 19, 2012 8:06:41 AM com.google.bitcoin.core.Peer$PeerHandler exceptionCaught
INFO: com.google.bitcoin.core.Peer$PeerHandler@193f6e2 - No route to host
Aug 19, 2012 8:06:46 AM com.google.bitcoin.core.Peer$PeerHandler exceptionCaught
INFO: com.google.bitcoin.core.Peer$PeerHandler@61736e - No route to host
Aug 19, 2012 8:06:52 AM com.google.bitcoin.core.TCPNetworkConnection$NetworkHandler channelConnected
INFO: Announcing ourselves as: /BitCoinJ:0.6-SNAPSHOT/BitMessage:0.1/
Aug 19, 2012 8:06:52 AM com.google.bitcoin.core.PeerGroup handleNewPeer
INFO: Peer(seed.bitcoin.sipa.be/50.130.4.89:8333): New peer
Aug 19, 2012 8:06:52 AM com.google.bitcoin.core.PeerGroup handleNewPeer
INFO:   starting block chain download
Aug 19, 2012 8:06:52 AM com.google.bitcoin.core.PeerGroup setDownloadPeer
INFO: Setting download peer: Peer(seed.bitcoin.sipa.be/50.130.4.89:8333)
Downloading block chain of size 0.
Done downloading block chain
Aug 19, 2012 8:06:52 AM com.google.bitcoin.core.Peer blockChainDownload
INFO: Peer(seed.bitcoin.sipa.be/50.130.4.89:8333): blockChainDownload(0000000000000000000000000000000000000000000000000000000000000000) current head = 00000000000001b10c347b5ec05f9a1910d541905c5cd8827784a5c3e0695c95
DONE; BALANCE IS :
0
Aug 19, 2012 8:06:52 AM com.google.bitcoin.core.PeerGroup$PeerGroupThread run
INFO: shutdown start

and the balance is zero. If I delete the saved blockchain and let it re-download again, it works again, but only for one time.

What am I doing wrong?


texts: Is there a PoW system that shows cumulative work without an ever-increasing proof size?

texts:
Let's say I have an output in the blockchain at height 100,000. At height 200,000, I want to prove that my output has the work of 100k blocks built onto it, securing it. In Bitcoin, proving that the output has X number of hashes securing it requires providing the full chain of headers, or 80 bytes * 100,000.

Is there an alternative proof of work where these 'work-proofs' do not grow in size indefinitely?

EDIT:

Now that I have found some resources, the terminology for I was looking for is "compact SPV proofs".


texts: Why did the Mempool suddenly drop to zero

texts:
What caused the huge drop of the mempool from 60 MB to Less then 1 MB?

These transaction didn't get processed there was no 60 MB block mined at the time.

This occurred at 10:38 pm 29th August 2017 NZ time


texts: Can a transfer be done over postal mail?

texts:
Suppose I'm stuck in the middle of nowhere with no internet access and I want to make a payment to a certain Bitcoin address.

Is it possible to do a transfer via postal mail, and if so what information would I need to send?

Assume the following:

I have both the recipient's Bitcoin address and my (the sender's) own private key(s) memorized or written down on a piece of paper.
The person who receives the mail (my agent) has access to the Bitcoin network and will act on my behalf.
The mail is delivered securely (i.e. no chance of theft)

What information would I need to send in the mail?

Consider the following possibilities:

A)  Trust

I trust my agent to do the transfer to the given address (e.g. the agent is the recipient), but I can't trust my agent with my private key(s)
I trust my agent with all my information (private keys and all)
I do not trust my agent at all

B)  Access to a computer

I have access to a computer, so I can run any program/scripts that may be required for generating any signatures
I don't have access to a computer (and I'm not Rain Man)


texts: Is there any way to prevent intra wallet transaction fees?

texts:
I heard about it somewhere, but no where found a complete step by step solution.

I've heard that for addresses in the same wallet, the transaction fees can be avoided. Is it a rumor ?

If no, then please help on how to attain it.

By wallet, I mean to say the wallet that is being used by bitcoind/litecoind or bitcoin-qt/litecoin-qt on a machine. (they usually use the wallet.dat)


texts: What does 889271 represent in the blockchain index leveldb databases?

texts:
I am opening up the blockchain index databases with leveldb, and I am seeing a repeating number, 889271, at the start of every value entry...

I am attempting to decipher the following key value pair

'b'e2bf047e7e5a191aa4ef34d314979dc9986e0f19251edaba5940fd1fe365a712 = 889271000b010008010000000000000000000000000000000000000000000000000000000000000000000000d9ced4ed1130f7b7faad9be25323ffafa33232a17c3edf6cfd97bee6bafbdd97b9aa8e4ef0ff0f1ecd513f7c

Using

https://bitcoin.org/en/developer-reference#block-headers
https://en.bitcoin.it/wiki/Bitcoin_Core_0.11_(ch_2):_Data_Storage

I believe i have everything deciphered properly, except for 889271

Any chance someone can confirm what 889271 represents?


texts: When using bitcoin-cli I get an error regarding fallback fees when trying to send regtest Bitcoin. How do I resolve this?

texts:
I have been doing an assignment on Bitcoin Core 0.20. Now every time I try to do a transaction:
Apples-iMac:bitcoin apple$ bitcoin-cli -regtest sendtoaddress bcrt1qd3jck0lv87yuk25tk3xy5rqq67apwasee874xk 25
error code: -4
error message:
Fee estimation failed. Fallbackfee is disabled. Wait a few blocks or enable -fallbackfee.

Can some one help me - what should I change? Please give a step by step guide as I am a complete newcomer.


texts: How do cryptocurrency exchanges handle users' accounts?

texts:
I recently became aware of the fact that exchanges have trading engines that execute all trades within the exchange itself, and not on the blockchains. That is to say, if User A sells to User B, there is no corresponding blockchain transaction transferring those coins. Instead, both users have accounts on the exchange which are debited and credited. A blockchain transfer only takes place during deposits and withdrawals.

Please explain the same case for currency like Bitcoin as it manages its assets using UTXO Model which is a record of unspent outputs. And for other currency like Ethereum using the account-balance model as the transactions aren't included in the blockchain. So, how they will reflect changes in the account of a user?


texts: Is there a blockexplorer with a websocket API that includes relay IP address?

texts:
I have a visualization that shows realtime bitcoin transactions plotted on earth: https://blocks.wizb.it.

I relies on blockchain.info's websocket API, which used to include the relay IP per transaction but unfortunately it is now always including 0.0.0.0 instead of a public IP. I've tweeted them about it, but I am looking for an alternative. Does anyone know one?

I am running a full node already, however it is not well connected enough to do this myself and actually get more than 10 different peers.


texts: Does a long time storage wallet need to be online?

texts:
I have a offline computer that has never been connected to a network. I use this computer for long time storage of sensitive data, all data transfer to and from this computer is done by USB memory. I want to move most of my bitcoins to this computer, so will it work this way:

Install bitcoin wallet on the offline computer and generate public address.
Send bitcoin from my online wallet to the address of the offline wallet.
Download bitcoin blockchain on a online computer and move it to the offline computer by USB memory?


texts:
I'm checking out the test net and a friendly person gave me access to his private key so that I didn't need to generate coins, so I importprivkey the key, sent me some coins and...

Well, I understand that now my wallet contains those 2 addresses, how can I remove his address, if possible?

Why do I want to do this? Because I'm testing stuff out and I don't want his transactions / tests cloud mine.

Thanks


texts:
is there an example of how using BitcoinJ send BTC with an attachment? Lets say I want to write to blockchain "Vaclav Bilek Born 1991".
If I understand it correctly, its just about sending minimum bitcoins possible with current minimum fee?
Is here a way how to do this in BitcoinJ ?
Usual syntax of sending BTC allow me only to send BTC like this:

kit.wallet().sendCoins(kit.peerGroup(), to, value);

How to achieve adding attachment? And how long can the attachment be? What if I want to send longer attachment, is here standardised way how to do that? Or I just make two TX and tell the people who I wants to see it, that one half is in TX1321... and other hald in TX3214... ?
Thank you


texts: confusion about open/close values on 1800 seconds periods

texts:
I'm pulling tickers from Poloniex using this python API wrapper, with intervals of 1800 seconds.

I get back dictionaries that look like this (here I show two consecutive ones for 'BTC_XRP'):

{'close': '4.402e-5',
'date': 1491163200,
'high': '4.89e-5',
'low': '4.333e-5',
'open': '4.849e-5',
'quoteVolume': '51355222.751243',
'volume': '2370.18161649',
'weightedAverage': '4.615e-5'}

{'close': '4.38e-5',
'date': 1491165000,
'high': '4.6e-5',
'low': '3.888e-5',
'open': '4.492e-5',
'quoteVolume': '92451720.795809',
'volume': '3902.07294323',
'weightedAverage': '4.22e-5'}

Why is the opening price of the second one not equal to the closing price of the first one? Isn't a period ending when the next one begins?


texts: Are there any ways to sync mempool from another nodes faster?

texts: I still use bitcoin 0.13.2 for some reasons. Recent mempool size is very high so syncing mempool takes for a long time, over two days. Are there any ways to sync mempool faster? I have some bitcoind nodes. Some of them have already finished to sync full mempool. I hope I can copy mempool from my another nodes.


texts:
I'm writing a thesis on Bitcoin system and as a part of my assignment i have to explore Bitcoin-core source code.

I 've downloaded the code, compiled it and manage to run it.
However, I wanted to make a trivial change to the code and add some simple custom command as part of blockchain.cpp.
Problem is that my changes are not visible after i run make and when I run bitcoin-cli -testnet .

I always get:
error code: -32601
error message:
Method not found

Also, i tried commenting out one already functional method and tried to run bitcoin-cli and calling that function and it runs successfully.
NOTE: command "make" runs smoothly and it does detect errors if there are any.

Can someone explain me what is a proper way to make change to bitcoin-core? I am not planning to push any of those changes to master branch, I'm just interested in experimenting with code.

Thanks in advance :)


texts: Create multisignature wallet from xpub keys in bitcoin core

texts:
I can create Multisignature wallet electrum with 2 xpub keys.

How can I create bitcoin core to do that?

Standart use;
Add a multisig address from 2 addresses

  bitcoin-cli addmultisigaddress 2 "[\"16sSauSf5pF2UkUwvKGq4qjNRzBZYqgEL5\",\"171sgjn4YtPu27adkKGrdDwzRTxnRkBfKV\"]"

Is there way to do like;

  bitcoin-cli addmultisigaddress 2 "[\"tpubDAenfwNu5GyCJWv8oqRAckdKMSUoZjgVF5p8WvQwHQeXjDhAHmGrPa4a4y2Fn7HF2nfCLefJanHV3ny1UY25MRVogizB2zRUdAo7Tr9XAjm\",\"tprv8erNzbjXdtYpKbKF4HeZpBCQj2W64MS2SAJCcWxgqLueSZ9KLTPZGoDTu8NugecLLqeS2RYan2f6qcexUTjp3m2HGxmpAiP48BaUz7XHxzQ\"]"


texts: Wondering about the viability of a Hardware Wallet

texts:
I want to roll my own hardware wallet using a USB stick. I have some concerns:

Do I need to download the entire blockchain in order to create a new wallet?
Do I need to download and store the entire blockchain on the USB in order to send and receive funds?
Do I need to plug in the USB wallet in order to send funds?
Do I need to plug in the USB wallet in order to receive funds?

.

I'm hoping that the answer to the first question is "no", as I really am not keen on downloading and maintaining a local copy of the entire blockchain. It's such a waste of space.
I'm hoping that the answer to the second question is "no". Because again, I really don't want to spend time and bandwidth downloading the entire blockchain, and also I don't want to have to store it. Those are gigabytes that could be spent on something else.
I'm hoping that the answer to question three is "no" for security reasons.  I don't want random cυnts on the other side of the world transfering my money without my consent.
I'm hoping that the answer to question four is "yes" for convenience reasons. I don't want to have to plug in the wallet every time someone sends me money.

My understanding is that there is the public key for receiving, and the private key for sending. Am I correct in thinking that the only thing you fundamentally have to keep secure is the private key? If that's the case, surely I don't have to download the entire blockchain?


texts: How do bitcoin exchanges commit the limit/market orders?

texts:
I'm trying to understand the topic of blockchain and bitcoins as well. So, the only one question I want to get answer for: how do exchanges commit orders?
I mean, how the transaction could be started by exchange? As I understand, only the owner of wallet (with the pair of pub/private key) can start transaction for transferring some amount of btc. So, I can't find the information about "remote control" of wallet. Maybe I am wrong, please correct me.
And excuse me for my English. It's not my native language.


texts: How to check Bitcoind block chain download progress level

texts:
I have installed bitcoind on ubuntu server, and when I run screen -x for btc it says error -10 blockchain is downloading.

How do I know the progress level? currently 125600 blocks are downloaded, but how many blocks yet to go? where do i check the blockchain download progress level? does it has capability to resume if the server is powered off?


texts: Are mining pools evenly distributed across the planet?

texts: Are mining pool managers evenly distributed across the planet? where are the biggest ones located? Like where are the servers physically located? Recently the backbone ISP for all of the Universities in Michigan went down and everyone on each campus was offline1. Could something larger of this nature potentially take out some pool managers and therefore some pools, thereby increasing the hash share of the online pools and risking a 51% attack?


texts:
I read different sourcing claiming the size of the blockchain for bitcoin.

Some says it's 8GB, some a 100GB and some 800GB.

Now I'm wondering do all the miners computers (nodes) have to store it all ? In case it's a TB it seems like a lot. Even though it's not it's still growing everyday, so is the blockchain really entierely stored on each nodes ?

Note : I used to mine a few years back I don't remember having my storage taken up by the blockchain.


texts: During a IBD : Initial Block Download by a full node, from where is the blockchain downloaded?

texts:
I understand that a full node requires to do an IBD before being able to verify transactions. So, it downloads the ledger upto now, which is known as Initial Block Download.
But what I don't understand/know is, from where is the blockchain information being downloaded? Are other full nodes contributing in this activity, or is this information stored somewhere, and is retrieved from there?
Any help appreciated!


texts: Is Z-man's PTLC construction implementable using libsecp256k1-zkp?

texts:
In a mailing list post Z-man details a PTLC construction which he claims is "is almost entirely a MuSig ritual". My question is whether this MusigTweak is what is called the adaptor (last argument of secp256k1_musig_session_combine_nonces) in secp256k1-zkp? And has in fact been implemented?

How is MusigTweak computed? Is it the per-hop tweaked payment point, which means it will be the payment point for the hop connecting to the payer?

In a way, that wouldn't make sense since MusigTweak takes three arguments, and the payment point is the same for both channel partners. But on the other hand, maybe Z-man is describing how the tweaking works internally in libsecp256k1-zkp, and I can safely just use the tweaked payment point for both peers for the adaptor argument because the implementation will treat the adaptor differently depending in the index of the signer?


texts: How can I recover an Exodus Wallet with lost password?

texts: Four years ago, I bought Bitcoin for my son. I bought this via Coinbase which I then transferred to an Exodus Wallet. I lost my Exodus password. I saved a string with 34 characters containing a mixture of numbers, upper case and lower case letters. I can't remember what this was for. Is there anything I can do to recover my 12 word phrase?


texts: Get the price of a currency at specific time in the past using binance historical data api

texts:
I want to query the binance api for historical data but i want to indicate the specific time i want. For instance i want to know the price of etherum at 1103 hours Friday 31 August 2018.

Is this kind of thing possible on binance api?.


texts: How to set a specific fee in satoshis per transaction?

texts:
I'm currently working on a personal project which is a small bitcoin exchange website, I've figured out how to create a raw transaction and broadcast it (createrawtransaction -> fundrawtransaction -> signrawtransactionwithwallet -> sendrawtransaction).
There's a option in fundrawtransaction which lets you set the fee but it's in BTC/kB. Are there any options on how to send the transaction specifying the final fee in satoshis? Or how do I know the final size of the transaction to calculate the fee? I want users to choose the fee in satoshis and not in BTC/kB.
I don't know if this has something to do but I'm using bech32 addresses. Thanks for your help!


texts: Do P2Pool nodes always accept real blocks over share blocks?

texts:
The standard rule in bitcoin is that if you see two blocks on a chain that has the same work, you accept the one that you saw first as the correct one.

If this extended to P2Pool chains, some nodes could see share blocks before a real block. Would the P2Pool members not then accept their own pool members real solved block? I would hope not!


texts: Is it still possible to recover Multibit Classic wallet from multibit.key file?

texts:
I have the file mulibit.key (long string starting with U2FsdGVkX19E+pw) and password.
Cannot find the Multibit Classic wallet to import the key and export to Electrum...
Tried to decrypt the key with
openssl enc -d -p -aes-256-cbc -a -in multibit.key -out key.txt -pass pass:Mypassword
but got only such response:
*** WARNING : deprecated key derivation used.
Using -iter or -pbkdf2 would be better.
salt=44FA9C205936F29D
key=8E260D08EE31BB97AB7544D70BC41535369
iv =B6B2A8A90712B2393DDF8
bad decrypt
140404139345280:error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt:crypto/evp/evp_enc.c:588

EDIT WITH FULL ANSWER:
The problem was different version of open ssl... After adding flag -md md5 my multibit.key get encrypted! So I could enter the private key into Electrum wallet
openssl enc -d -p -aes-256-cbc -md md5 -a -in multibit.key  -out key.txt  -pass 'pass:myPassword'


texts:
version is newest 0.5.12, 0 . I'v send to my multibit some BTC, then I waited for a very long time and it still shows unconfirmed, on blockchain.info shows transaction was finished, so I pressed the button "reset blockchain and transaction", then balance became zero, I waited 6 houres and it's still zero, how long will the sync take?!
in the message said"Synchronised with network." , means sync finished? but balance is still zero?!


texts: Will the block data saved or discarded after synchronization? Does it get removed when uninstalling?

texts: When I first installed the program I noticed that it was synchronising with the network, and whilst it was doing so it was downloading blocks. I wanted to know if these blocks will be saved on my hard drive or will be be deleted after the synchronising is complete. If the files are stored on my hard drive I wanted to know if when I uninstall the program will the files also be deleted?


texts: generate wallet addresses from extended public key

texts:
i am trying to generate addresses from Extended Public Key using bitcoinj but can't figure out, how can i possibly do this.

  i need those addresses for watch-only wallet, those addresses were
  unsigned, right?

further i can sign those addresses for sending transaction.


texts:
I searched for tutorial to run Vanitygen 24/7 on VPS. However, I'm not able to find any that work. I have a VPS running on Debian 7. I want to use this VPS to search for Bitcoin private key 24/7.

How do I run vanitygen 24/7 on a Debian 7 VPS?


texts: How may bitcoins hash algorithm be secured in the future from quantum computing brute forcing?

texts:
Other threads already answer very clearly that quantum comps could easily "break" /attack bitcoins chain.

Now: Are there any ideas among the bitcoin devs circulating out there, how to save bitcoin from future quantum attacks? its only a couple years away right?

What could be viable options to change and make btc quantum proof, changing hashing algorithm to which new algorithm?

Thanks!

__


texts: Are there any revenue sharing blog websites that pay out in Bitcoin?

texts:
There are plenty of revenue-sharing blog websites out there (ie they share advertising revenue with the bloggers) but it would make a lot of sense for payments to be made out in Bitcoin, as transaction fees would be very low and the minimum payment amount could be kept small. It would also easily allow participants of any nationality.

Are there any blog hosting sites that share revenue and payout in Bitcoin?


texts: Bitcoin fork resolution - Fork losers download previous blocks 'til common block?

texts:
When resolving a naturally occurring fork in Bitcoin, do the miners who were working on the orphaned fork download previous blocks from the miner who won the block reward that resolved the fork until they find a common block?

My understanding is that miners accept a new block as long as it is valid. As long as it's one block, they can just add it to their local version and start on the next block. However, if they receive a new block that is the head of a different fork that split off from their fork 10 blocks previously, how do the miners of the orphaned fork get the blocks from the other fork? How do they know to?


texts: Setting wallet directory independent to data directory

texts: Obviously with datadir=C:... I can chance the directory bitcoin uses. I would like to store my wallet on a different hard drive than the blockchain. Is there a command for that?


texts: What is the price of an ask order bought if a bid order is placed at a higher price? For example, if there exist two ask orders at $50 and $49, and I place a bid order at $50 of an amount larger than amount of the two ask orders, will I buy the $49 ask order at $49? Or will I pay $50 for both orders, losing $1 on the lower one?


texts: Transaction unconfirmed long time help me please

texts:
I made a payment at 2:13 PM but this payment is still not accepted. It's about the following link >>> https://blockchain.info/en/address/359cnHYeEJoRQDVU2BnKfXp6o9uCSX89tR

SEND
June 13 @ 02:13 PM
To:
359cnHYeEJoRQDVU2BnKfXp6o9uCSX89tR
From:
My Bitcoin wallet

Is there anybody who can help me to make this payment confirmed?

I apologize for the many types of mistakes.

Thanks in advance,

Sincerely

Michel


texts: How to retrieve extended private key from extended public key + master seed / root private master key

texts:
I have a master seed (I use a hardware wallet).
I know how to transform it into a (root) private key.
I have also several public keys, which all was obtained by derived a private/public keys of the root private key.
Questions:

How can I get all the private keys corresponding to the public keys mentioned above?
What is the best tool to do this thing ?

In otherm term, I want to retrive derivated private key like that:
derivated private key = function(derivated public key, master root key)

My ultimate goals is then to import all these private keys in a Electrum wallet for instance.


texts: What transactions will be included in the next block?

texts:
The miners decide whether a transaction will be included in the block.

What information do miners have about unconfirmed transactions?

How can I know, in detail, what transactions are going to be included in the block?


texts:
So I decided to take a look at this bitcoin stuff. I would like to test Ufasoft for CPU mining. Don't really care about performance.

There is this nice guide: https://50btc.com/en/articles/view/68

And I follow the steps:

Download http://ufasoft.com/open/bitcoin/
Install it
Run "%ProgramFiles%\Ufasoft\Coin\coin-miner.exe"-u you@email.com -o http://pool.50btc.com:8332

After running that, well, the command line stays there, with no feedback whatsoever. I can't type anything on it so I guess it is indeed doing something.

Anyway, out of curiosity I check out the activity monitor, and the CPU usage is almost always at 1% or 2%. Sometimes it may suddenly pick to 5%.

I was under the impression that CPU mining would cause some sort of greater spike, so I'm not sure if the miner is actually doing something.

It then ocurred to me to, of course, check out the 50BTC dashboard.

I have a worker, whose name is the same as my account name (which is the email address I used to startup the miner), so I guess this worker is the one that should be showing some sort of feedback. However, it says it is "offline", so it seems like, after all, the miner is indeed doing nothing.

Normally I'd just go on and try another miner, but I'd like to solve this anyway.

What have I done wrong?

I'm on Windows 7 with 4 cores. GPU mining has worked fine with software such as BitMinter in the past.


texts: In NXT, how long do you have to wait for 1440 blocks to be mined?

texts: I see this referenced in many places with NXT for 1440 blocks. How long is that exactly?


texts:
I'm new to this field.It seems that mining Bitcoins using a normal computer has become tough.I have got a normal laptop with Intel i5 processor and GeForce 930MX graphics card.Which is the easiest coin to mine and get some real money(how less does not matter)

Just wanna try and see how it works.
Out of curiosity.

Thanks


texts: Why do the creators of ASICs not just keep them for themselves?

texts:
If ASICs are able to mine BC so fast, why are the creators of these machines even selling them? If they just created them to mine with them themselves, they could get so many BC and in turn make BC worth so much (as BC for the rest of us would be so few in comparison) that they'd theoretically make a hell of a lot more money that way than by actually selling these machines.

What's the hidden agenda with sharing these machines? Do the creators of ASICs think/know that BC is a bubble/fraud and just want to make as much money as possible before people realize that their machines were BS?


texts:
I updated the bitcoin node to version to 140200 on top of which one of my applications was running. There wasn't any issue with the flow of the application estimatefee RPC I get -1 for no matter what I give as the number of blocks. Also the alternate fee api estimatesmartfee returns negative values.
When I execute the same api on a node with version 140100 it gives me a positive result
How do I resolve this ?


texts:
I have an old block erupter, used to mine BTC with on Slush's pool.
To operate it, I had to download their mining proxy onto another computer on my home network and configure the ASIC so it would point to my computer's IP address.
Is there any way to configure the block erupter to mine XVG with a pool (i.e thecoin.pw)?


texts: Is there any wallet that allows safely storing private keys in an offline computer?

texts:
I have a computer that is 100% disconnected from the internet. I'd like to:

Generate my own private keys by dice rolls;
Import them on the offline computer wallet;
Send coins to their addresses;
Spend those coins by signing the transaction offline and sending to the network from another connected computer, i.e., the online computer never has access to the private keys.

Is there any Bitcoin wallet that allows this use case?


texts: I use electrum as a bit wallet and curious to find out if it's uses static or dynamic fees as I never set the option, and the fees seem to be 0.00001 B


texts:
I'm making a full-service wallet, I already made the UTXOs selection algorithm and now I want to push the transaction hex bytes. It works when I push only a transaction with only 1 input, but if I try to push the hex from a tx I made with 2 inputs from the same account, I get this:

OP_EQUALVERIFY: non-equal data

Here is my decoded hex:

{
   "lock_time":0,
   "size":339,
   "inputs":[
      {
         "prev_out":{
            "index":0,
            "hash":"3a896625fce1f18ce4c3139863359631d5677cff4e4fd8dac25ca6327c0dadd8"
         },
         "script":"473044022070f3b03cca6a75038ffe150be347a97d0e07adc857cc93e245739db55e3a6d36022051eb72b21e35a5e7309e1864f00e1b107a5b5262d80b1128e9fb45fbe7971c7b012102bb05325000709d3a3d8063f9913777859b8fa30b83e4c4f981bb2d9781b7c91a"
      },
      {
         "prev_out":{
            "index":1,
            "hash":"436094120d4412c32b97738f9051a32a237c037abe31cafbdc8a02d16f2a659c"
         },
         "script":"483045022100da7abc59e24d2afea9219ee24d1f3df4e1b9a2efa154d9704ed903210abfdb40022015a8237d38e18f558172872af1aa5c244b38c3ad8f594463c0dcad18dbfcf5f5012102bb05325000709d3a3d8063f9913777859b8fa30b83e4c4f981bb2d9781b7c91a"
      }
   ],
   "version":1,
   "vin_sz":2,
   "hash":"c5991f9f044f9d829fc01eeda76f36a514271270f9f891ea7b584f504ed404ea",
   "vout_sz":1,
   "out":[
      {
         "script_string":"OP_DUP OP_HASH160 7ff85ee854794422531b7b5c3d380c5f50011a4e OP_EQUALVERIFY OP_CHECKSIG",
         "address":"1CfeMTtDP9HNjc8vsuuHGgUfABexvW5Qkf",
         "value":350000,
         "script":"76a9147ff85ee854794422531b7b5c3d380c5f50011a4e88ac"
      }
   ]
}

Links for the transactions being used:

https://blockchain.info/tx/3a896625fce1f18ce4c3139863359631d5677cff4e4fd8dac25ca6327c0dadd8
https://blockchain.info/tx/436094120d4412c32b97738f9051a32a237c037abe31cafbdc8a02d16f2a659c

My address is 1FebYgpxQ1exSNdJENkbmNPmSfsiP3kZiT.

And my code using the BitcoinJS library is the following:

key = bitcoin.ECPair.fromWIF(privatekey);
var tx = new bitcoin.TransactionBuilder()
var sum_outputs = 0;

var input_utxos = defineInputs(utxos, amount);

for(var a = 0; a < input_utxos.length ; a++){
    tx.addInput(input_utxos[a].tx,a)
    sum_outputs+=parseInt(input_utxos[a].amount);
}

tx.addOutput(to, parseInt(amount));
var change_amount = sum_outputs - parseInt(amount);
if(change_amount > 0) {
    tx.addOutput(from, change_amount);
}

for(var a = 0; a < input_utxos.length; a++) {
    tx.sign(a, key);
}

result = tx.build().toHex();

console.log(result);

So my questions are:

Why is this working with 1 input from my address and not for 2 inputs?
How can I correctly sign the second input that I assume is the cause for the error?


texts: What is the difference between secp256k1_ecmult_gen and secp256k1_ecmult?

texts:
libsecp256k1 has two implementations, secp256k1_ecmult in ecmult.h and secp256k1_ecmult_gen in ecmult_gen.h, to multiply the points of an elliptic curve.
secp256k1_ecmult_gen supports simple multiplication such as a*G and secp256k1_ecmult supports multiplication involving addition such as a*P + bG. However, secp256k1_ecmult can be used for simple multiplication by setting b=0, actually, it is used as such in eckey_impl.h#secp256k1_eckey_pubkey_tweak_mul.
How should these two functions be used properly? Is there any difference in the performance?


texts: Running multiple bitcoin instances on same server system

texts:
I wish to run multiple instances of bitcoind on my server to support highly read intensive RPC applications.

Following links:

how to run multiple bitcoind node on one server?

Running Multiple Full Nodes on one Host

Is it possible to run more than one client instance on a machine?

How do I run two instances of bitcoind on the same linux machine with different conf files?

suggests that by using different conf file and data dir we can run multiple instances.

However, my doubt is that since in each case, we are specifying different config file and data dir to same binary bitcoind, e.g.

bitcoind -datadir=./bitcoinNode1/ -conf=./bitcoinNode1/bitcoin.conf
bitcoind -datadir=./bitcoinNode2/ -conf=./bitcoinNode2/bitcoin.conf
bitcoind -datadir=./bitcoinNode3/ -conf=./bitcoinNode3/bitcoin.conf

Does same single binary bitcoind is going to handle request for all instances (bitcoinNode1, bitcoinNode2, bitcoinNode3)? In such case load will be on single binary and I have a doubt for performance gain.

Or is it better to create different binaries bitcoind1, bitcoind2 etc. for each config+data_dir combo?

Thanks.


texts: Transaction still unconfirmed after 2 days

texts:
Last time I tried sending a transaction with the minimum fee it was succesful after 1 day. 2 days ago i tried sending one with a higher fee and double the bitcoin amount but its still unconfirmed.
https://blockchain.info/tx-index/7e3e62569bb24f029ddce8730320bd2dbce10bc6893e4c117f5c49be18c96cf1


texts: How to perform a double spend attack in websites that accept transactions with 0 confirmations?

texts:
To perform a Finney attack or a 51% attack I need to have lots of computational power, but in this case (a website that accepts transactions with 0 confirmations) it seems to me that I only need to issue two transactions almost simultaneously. Depending on what the miner chooses to include in the next block, I might get lucky.

Is it that easy or am I forgetting something?


texts: How is the bitcoin 21 million cap implemented?

texts:
Just to check what would take for that limit to be changed. (not that I want to be changed, quite the opposite). I know the total number of bitcoin reward is halved every 4 years.

So does the verifying nodes check if the number of rewarded bitcoins match the distribution schedule?


texts: DumpMempool() and LoadMempool() in src/validation.cpp

texts:
My understanding is that DumpMempool() saves the memory pool state (unconfirmed txs received from other peers and if any txs broadcasted from this node) to disk and LoadMempool() is used if this state is required. Is this correct or how does this work and what should be my approach if I am testing Dandelion (right now trying to solve conflicts)?
https://github.com/bitcoin/bitcoin/blob/3caee16946575e71e90ead9ac531f5a3a1259307/src/validation.cpp#L5139
This is what I see in mempool.dat file:

What exactly is happening in src/validation.cpp and what is saved in mempool.dat, when is this data required, what happens if there is an issue saving or loading data from the file?


texts: Can I generate an offline Bitcoin wallet using only OpenSSL?

texts:
From what I understand about Bitcoin, a wallet is really just a pair of public/private keys.

So, if someone needs to send me Bitcoins, all I need to do is just generate a pair or public/private keys using OpenSSL or some other tool, and send the public key to that person, without actually downloading a Bitcoin client (which will download a 12 GB block chain), or saving a wallet.dat.

Am I correct?


texts: I am still quite new to Bitcoin, and my question may be a little bit stupid. So I am wondering how can I track the transaction or the newest block on my computer. I know there are tons of websites showing the real-time information, so I guess my question is like is there any way I can type something on my terminal of the PC and shows the data on it? Something like constructed the dataset on my own.


texts: I lost my computer, inside my hive wallet , I do have my adress and password can I recover my bitcoins?

texts: Is it possible to login from other wallet with adress and password to get back my btc?


texts:
I would like to new address generate with this command
bitcoin-cli -testnet getnewaddress "adr1" "p2sh-segwit"  but I get this msg:
error message:
Wallet file not specified (must request wallet RPC through /wallet/<filename> uri-path).
Try adding "-rpcwallet=<filename>" option to bitcoin-cli command line.

then I added the -rpcwallet command like that:
bitcoin-cli -testnet -rpcwallet=/home/bitcoin/.bitcoin/ getnewaddress "adr1" "p2sh-segwit"  but I got an error again like this:
error message:
Requested wallet does not exist or is not loaded````

what should I do?

thank you


texts: Is there a cost to having many different addresses?

texts:
Whenever I want to receive funds to my bitcoin wallet, it gives me a different address and says that it is "your current bitcoin address".
Suppose I collect money from 100 different people, and then want to spend all this money in a single transaction. Will I have to create a transaction with 100 different sources (the 100 different addresses) and a single destination? Will this transaction cost more than a simple one-source one-destination transaction (e.g. because it is larger)?


texts: Setting up a basic test transaction for p2p donation web app - API recommendation

texts:
My question relates to the use case of trying to build a simple payment flow where one user (a donor) can donate directly to another user (a recipient) with Bitcoin.
To begin with, I would like to manually load up and input 2 addresses that respond to a Donate button and ideally get processed from test accounts on the Testnet blockchain.

I am new to bitcoin development and want to understand the underlying mechanics rather than immediately implementing a more sophisticated and abstracted plugin (e.g. Stripe).
Additionally, my preferred language is Ruby so I have been favouring APIs with Ruby SDKs.

So far I have a shortlist of the following APIs:

Chain.com (https://chain.com/docs/ruby#bitcoin-transaction-overview)
Blockcypher (http://dev.blockcypher.com/#payments) >> provide direct access to Testnet, not clear how would implement with others
Blockchain.info (can't link with current rep points) >> may force you to use their wallets

Has anyone worked with these and can provide guidance on which is best to implement the above use case? Other suggestions welcome. Appreciate this could be interpreted fairly broadly but I can try and specify further if you have questions.


texts: What value stores can be exchanged for bitcoin purely pseudonymously?

texts: What can I trade with bitcoin without having to give out private details like name and address? (Imagine I don't even have a name or address.) I'm looking for stores of value like gold or stocks. Naturally litecoin and other cryptocurrencies fit, but I'm looking for more than that. And alpaca socks, though they may be durable and resalable, may lose value after a perception of being "used", and therefore are not a good store of value.


texts: What would happen if two miners were mining two blocks with two different set of transactions?

texts:
If two miners picked from the mempool two different sets of transactions, that were not dependent on each other.

Then could both miners, mine both blocks and not create a fork?

So miner 1 finishes the block and miner two sees that the block had nothing to do with his block, so he continues mining and adds that block onto miner 1s block after about a second?

I am assuming that forks only happen when both blocks mined have transactions that exist in both blocks


texts: What would be the Internet Usage For 100 Antminer S7?

texts: I am planing to set up a mini farm with 100 S7 Miners, but am little concerned about the internet usage and speed.  What speed do I need and how much bandwidth it will consume per month?


texts: If block sizes go up, won't sigop limits have to change too?

texts:
Gavin Andresen, one of the core developers, has discussed increasing the block size to 16.7 MB (and doubling that every two years).

The maximum number of signature operations per block is currently set to 20000:

  [...] About the scriptSig being an arbitrary byte array, there is one caveat: the checksig operations in it are counted towards the block sigop limit (20000), so you probably don't want to accidentally trigger this. Making it a list of just push operations (including of the extranonce) avoids that.

A back-of-the-envelope calculation tells me that there will be around 100K signature operations in a 16.7 MB block. Will the maximum number of signature operations per block also need to change?


texts: Getting "Can't run the JVM" when starting Ardor on Windows 10

texts:
When running Ardor 2.2.1 on Windows 10, I'm getting "Can't run the JVM" error. Also tried going to the command line and going to:

C:\Program Files\Ardor

and running run.bat

It just pops open a window and closes.


texts: Unconfirmed transaction for 7days now, please i need help

texts: Transaction to the  address 39j2nuZWr4F2hZ5wYDwQwZWzsTJC4H6ujn from my bitcoin wallet and it unconfirmed, i am new to this, i need help please, help me out


texts: Running out of memory, how can I reduce the size of wallet.dat?

texts:
My wallet.dat is 260MB big. I am using 32bit bitcoind (bitcoin-0.10.2), linux.

Bitcoind is having memory problems:

 ["errors"]=>
  string(89) "EXCEPTION: St9bad_alloc
std::bad_alloc
bitcoin in ProcessMessages()

Current memory allocation:
  2.9 GB virt, 2.3 GB virt.

How can I resolve the memory problem? Can I delete old unused addresses?
I did not find an API call to remove old addresses.
Probably bitcoin-0.11.0 does not resolve the problem either, it has already nearly same values: 2.45 GB Virt, 2.1 GB Res.


texts: I have received 0.00000001 BTC random payment and the status symbol is a pentagram? Am I being used to tumble someone's stolen coin there are a lot of other wallets in the transaction?


texts: A NodeJS implementation on creating addresses from a Bitcoin (zpub, xpub) address

texts:
I'm looking for a lightweight node package which can handle creating btc receiving addresses on the server using an extended public key (segwit).

Like this one: zpub6nYqvTejCbqMTRTGz9rHkJnrJKbLsx36LqLnUJChDdJ6a5NA7hBumEpn9HTSDgWpNTNCponkPCBL5VKeAaScVxbXa1H4RPmA4j19rzgJPRp

I tried using https://www.npmjs.com/package/bitcoin-receive-payments
But I don't want an OpenExchangeRates account to use this.

There is this guide on PHP https://freedomnode.com/blog/58/generate-bitcoin-wallet-addresses-from-extended-public-key-with-php

But I can't find any equivalent for JS.

I would also be very thankful if there is any explaination for non Math people, as I am just looking to generate addresses on a server based off an extended address.

Someone knows?


texts: Where can I find proof of work in the Bitcoin Core source code?

texts: Does anyone knows which part of the Bitcoin Core source code contains the proof of work for mining, creating of block and adding to blockchain? What are the files and functions involved?


texts: Blockchain.info handling gap of 20 unused addresses limit

texts:
I am looking for a way to handle the limitation of Blockchain.info, for which it will stop generating public addresses (or at least watching them) after 20 consecutive of them don't have any transaction.

I thought to initially generate many addresses (over the limit of Blockhain, using the gaps_limit parameter) and then reuse them more times, so that after some time there will not longer be gaps. But I am not sure if Blockchain simply can't watch too long gaps or can only watch 20 addresses at a given time.

Any suggestion? I am also open to other solutions.


texts:
Looking for a way to decrypt a private key that was exported by Multibit WITHOUT using Multibit. I need to move they key elsewhere.

I need to go this route because I can't get the key to import into Multibit properly (even though I have the password).

Thanks!


texts: Double spend attempts examples on testnet?

texts:
Where can I find some double spend attempts examples on testnet? Can anyone refer me some TXIDs with double spends on testnet?

EDIT: I need some example in which an outpoint was intended to be used in two different transactions, like this one:

https://blockchain.info/tx/6900440e3bf9d7177ef69b8ca8bb620cb439d9261ce54b3df564f6778547003c

but on the testnet.


texts:
On Ubuntu 14.04 I have not been able to get the Bitcoin daemon to automatically restart. Rarely the daemon dies and it is important that it starts again without manual intervention. To get it to start automatically with Upstart I have followed the guide linked below. It starts with sudo start bitcoind as expected but the service does not restart if it fails.

Ubuntu Linux — How do I start bitcoind as a service to run automatically?

My conf file in /etc/init/ is as follows.

description "bitcoind"

start on filesystem
stop on runlevel [!2345]
oom score -500
expect fork
respawn
respawn limit 20 90 # 10 times in 60 seconds

script
user=bitcoinuser
home=/home/$user
cmd=/usr/bin/bitcoind
pidfile=$home/.bitcoin/bitcoind.pid
# Don't change anything below here unless you know what you're doing
[[ -e $pidfile && ! -d "/proc/$(cat $pidfile)" ]] && rm $pidfile
[[ -e $pidfile && "$(cat /proc/$(cat $pidfile)/cmdline)" != $cmd* ]] && rm $pidfile
exec start-stop-daemon --start -c $user --chdir $home --pidfile $pidfile --startas $cmd -b --nicelevel 15 -m
end script

If I run ps -aux | grep bitcoind to get the process ID and kill it the daemon does not restart as desired. I have followed the guide and cannot see what is wrong with the set up. As a side note sudo stop bitcoind does not actually stop it from running.

Any help on this would be appreciated.


texts: Double spending from "green addresses" & mitigation

texts:
Suppose a user pays for a service (service1) using a "green address" (0 confirmations required) and service1 needs to immediately respend it using it's own green address

How many blocks should the service wait before respending that money to a normal Bitcoin-QT user?  (assuming the QT client doesn't recognize Green addresses)

Suppose the service sends the funds to another service  (service2) that recognizes it's coming from a green address.  There are still zero confirmations.

What would the block chain look like?  (Specifically can the multiple transactions appear in the same block?)
Can the multiple zero confirmations appear out of order?  (I know the answer is "no", but I'd like to know how & why)


texts:
I have seen many videos about paper wallets and different ways to store BTC. And I have choose to store using a cold wallet (paper wallet). But I am not sure what option I should choose: a normal BIP38 encrypted paper wallet, or a brain wallet printed in paper.

And plz tell me the differens with BIP38 and brain wallet.Thanks for your answer :D

P.S: Which one is securest?


texts: Bitcoin Core Old Wallet.dat Vulnerability

texts:
Own a wallet.dat file from 2010-2011. Yesterday I saw there was a vulnerability which is makes attacking somewhat easier if your wallet is generated by old client and I'm pretty sure my wallet is affected that vulnerability because my last transaction is made 2010.

So my problem is I don't have any idea about wallet passphrase. Maybe the vulnerability helps to open my wallet. It is about AES padded encryption. But i don't have enough cryptographic knowledge to handle it. I'm aware it is brute force task but the vulnerability decreases time of task.

I hope that someone can create a brute force tool for me which is using the vulnerability, so that I can recover my wallet.

Github Report about vulnerability : https://github.com/bitcoin/bitcoin/commit/c682cdf3eda0f55297eb0e72a04508b7b9c2f5df

VulDB report : https://vuldb.com/?id.4883


texts: When making your first bitcoin transaction, at what time do you generate the public and private keys and how do you store your private key on a hardware wallet?


texts: Is it safe to store seed phrases (private keys) in a bank vault?

texts:
If written on a piece of paper, would the recovery seed phrase or questions for accessing a collection of web wallets and hardware wallets be safe to keep in a mini vault drawer at the bank? Do bank employees have access to vault drawers somehow, i.e. in the event of natural disaster, or are there any procedures for opening vault drawers that might compromise the words on the piece of paper?
Given the above, also how safe is it to additionally store a copy of the same paper at another branch location as a back-up?


texts: What would be the process for identifying a person that performed a transaction from a wallet on a personal device?

texts:
I presume the legal process would be something along the lines of

Get IP address from blockchain.
Get ISP to tell you whose that is or was at the time.

So I expect that this would normally require some legal warrant in most countries for ip address to user mapping, which of course can be made difficult.

Are mobiles client easier to trace?

What about an illegal but still pragmatic process?


texts:
Writing a research article on Binance, and I'm trying to work out when their ICO was, and when they opened doors to their trading platform. Does anyone have an authoritative source for this?

I can see on Crunchbase that they raised 10m USD in 2018, and it also lists an ICO in September, although some ICO websites claim their ICO was Dec 31, and others in July. Sites seems to agree the ICO was 15m USD.

Is there an authoritative source for when Binance started, and when and for how long their ICO ran?


texts: Bitcoin API(s) - how to pair (or obtain) BOTH sender and receiver addresses with a transaction ID (hash)

texts:
Various block explorers exist, which offer REST APIs. So far been using blockchain.info and btc.com

Here is what we have:
- List of bitcoin addresses

Here is what can easily be got with that info:
 - Historic list of transactions (hashes, or IDs) for the given addresses
 - I can also discover which input or output was OUR address, and therefore:
 - value, and whether the transaction was being sent or received

Now, here's what we need to obtain:
 - the OTHER (to/from) address!

So:
How can you use a transaction ID to obtain BOTH the sender's and receiver's wallet address - with some kind of REST API preferably?

(...knowing that sometimes transaction IDs are associated with multiple inputs and multiple outputs)

Endpoint references:
https://blockchain.info/q
https://btc.com/api-doc