text:
When will I receive bitcoins
Today I sent bitcoin to my bitcoin core wallet.  I used an address under recieve bitcoins.  The transaction has been cleared on the blockchain for several hours but is not showing up in my wallet.    The wallet itself is still downloading the block and is 3 years and 29 months behind.
Does this mean I must wait until this finishes before it shows up?

3 years and 29 months behind??? Why not 5 years and 5 months? As a non-bitcoin person arriving here via HNQ this post further validates my abstinence from cryptocurrencies. I don't know what it means to be 5 years behind but if that's how long you wait to receive your funds then woof.

@MonkeyZeus it only takes a few hours for a brand new node to sync the 10 year Blockchain history. Up to a few days on a slower machine. The progress indicator may report "5 years behind" but that's not how much time you need to wait until your node is synced :-)

The wallet itself is still downloading the block and is 3 years and 29 months behind. Does this mean I must wait until this finishes before it shows up?

Yes, in order to understand the current state of the network (which includes the transaction that you received funds in), your node will need to work through the blockchain history. Otherwise, your node will be unable to determine whether or not a transaction you receive is in fact valid.
Once synced with the network, your balance should display correctly.

can i rescan to pick up the transaction. if so how do i do it?

No, in order for your wallet to understand that the transaction is valid, it needs to first sync to the network.

@wizzwizz4 ‘rescanblockchain’ is a specific rpc call that can be used after the sync is complete

The transaction has been cleared on the blockchain

How did you know that? Did you query the corresponding transaction on an online blockchain explorer?
If you are happy to trust third party services (like the online blockchain explorer you had used), then generally speaking, (you believed that) you have already received these bitcoins.
You just have not validated the transaction with your own full node yet.

can i rescan to pick up the transaction. if so how do i do it?

Rescanning requires full blockchain data, the thing which you have not finished downloading and validating yet.
(In future versions of Bitcoin Core, this might be improved. With BIP158 blockfilterindex, even pruned full nodes can do rescanning as well)
Rescanning would be required only if you had just imported something, or you were not quite sure whether the available balances/transaction history showed by the wallet were correct.

can i import this wallet into another wallet?  i need this money asap.

@burchbit Of course you can. You can execute the "dumpprivkey YOUR_RECEIVING_ADDRESS" in the debug console of Bitcoin Core to get the WIF private key, then you may import it into lightweight wallets like Electrum. However, manual operations on private keys are generally not adviced, since human errors may lead to tragic outcomes, eg. the classical "screw-up-by-change-address", or leaking the private key to trojan horses/malicious QR code generators, ... etc.

thank you.... i got this error........Please enter the wallet passphrase with walletpassphrase first. (code -13)

@burchbit You need to unlock the wallet first, use the "walletpassphrase" command. It will unlock the wallet for a while. If the wallet is successfully unlocked, this command shows nothing as output.

@burchbit If you want to import the WIF private key into Electrum, you will need to create a new wallet with it firstly, then you should choose "Import bitcoin addresses or private keys", after pasting the WIF private key, you need to add a "p2wpkh-p2sh:" prefix to the private key in order to generate 3-starting compatible segwit address, or "p2wpkh:" prefix to generate bc1-starting bech32 native segwit address.

i added the key and it imported another address.  the address i wanted to add cannot be verified by signing message because no key associated

Oh, you must be talking about segwit. A compressed (starting with K/L) private key can derive three types of address: 1-starting P2PKH "legacy" address, 3-starting P2SH-wrapped "compatible SegWit" address, bc1-starting bech32 "native SegWit" address. Unfortunately, there is still no unanimously adopted standard of message signing/verifying of SegWit addresses, that's probably why you received "no key associated" error message (shoud be shown by bitcoin core?)

AFAIK, both Electrum and Trezor had implemented this message sign/verify feature of SegWit addresses, however, they are not compatible with each other.

it is a base58 p2sh

You are still using Bitcoin Core, aren't you? If so, don't worry about the "no associated key" error message when you attempt to sign a message with a P2SH SegWit address.

so how to sign and unlock these funds? or generate a private key.

The "no key associated" error message is incorrect and misleading. There's definitely a public/private key pair associated to a SegWit address. If you want to send the coins out, just send them as usual, there won't be any problem (if you have finished syncing). It's just detailed implementation of the message signing feature that has not been determined by the developers of Bitcoin Core.

If you want to export them to wallets other than Bitcoin Core, you can use the dumpprivkey command in the debug console. If you want to import the private key to Electrum, you need to choose the "New/Recover" option in the "File" menu first, then the "import Bitcoin private keys or addresses" should be chosen, after that, you need to add a "p2wpkh-p2sh:" prefix to the private key.


text:
HELP ME WITH BITCOIN TIME STAMPS
OK, so I had several backed up .dat files on google which I put in opentimestamps
I could see that these files had time stamp data...   so I uploaded and *****below is what the results were.
What does all this mean?
I just want the bitcoins that I know I have.  I had a wallet.dat from a gui miner I downloded on my pc in 2012.  This has been a nightmare.  I am willing to offer a % of the BTC to anyone who can actually help me.  And no python...  That just has frustrated me beyond my limits.  I have over 50k private keys even more addresses.  My Bitcoin Core Wallet was on my pc since 2012.  I have not run a full node and have since lost access to that pc as it crashed.  I have all the backups...  anyhow..  my question (sense the frustration yet?)
****** What do I do with this? Please use as much lamen terms as possible.  Talk to me as if I am in intro to bitcoin in the 5th grade...
Timestamp of d800xxxxxxx7
Document digest (SHA256): d80XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx6
Download this timestamp
Return to upload page
d800XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXxb6 SHA256(Document)
d800aXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXxef
Append(a4a414...)
92bXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXxa
SHA256()
Fork into 3 paths
Fork
1 92bXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx9
Append(dbf1cf...)
1 f2d4XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx
SHA256()
1 5f030XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx
Prepend(5f0304...)
1 5f03XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx4a
Append(1360d4...)
1 Pending attestation: server https://alice.btc.calendar.opentimestamps.org
Attestation
2 92XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx355
Append(e229a8...)
2 9f8XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
SHA256()
2 6XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXcecdXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX62
Prepend(625692...)
2 c00XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX44
SHA256()
2 5f0XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX44
Prepend(5f0304...)
2 5fXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX32
Append(9dd925...)
2 Pending attestation: server https://bob.btc.calendar.opentimestamps.org
Attestation
3 92bXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Append(270839...)
3 2XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXf
SHA256()
3 3XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX6e34aXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX68f
Prepend(3016ec...)
3 1ebeXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
SHA256()
3 5f0XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXxc41
Prepend(5f0304...)
3 5f03XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx16
Append(326fc5...)
3 Pending attestation: server https://finney.calendar.eternitywall.com
Attestation

When you say "I have over 50k private keys even more addresses", Where do you have these private keys? You can import the private key in many wallets and then you have your Bitcoins.

OK, so I had several backed up .dat files on google which I put in opentimestamps

Bitcoin core stores wallet data ina file named wallet.dat so that was one of your .dat files.
Opentimestamps is just a service that provides proof that a document existed on a specific date. It doesn't store the contents of the documents.
You therefore have proof that your wallet.dat existed but that is of no use to you.

I just want the bitcoins that I know I have. I had a wallet.dat

You need to find either

that wallet.dat and any password you used to protect it
or a written copy of the "private key" that the wallet contained.

Otherwise all the money that was in that wallet is forever lost and unusable.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
How to ask a miner for help?
after reading on, and checking my transaction, it think i;ve paid far too little for my transaction - This was not intentional - honest mistake as it was my first time of doing this...
how can i get this pushed through, i don;t mind giving the miner more transaction money to help.
thanks - tim

Here you go https://en.bitcoin.it/wiki/Transaction_accelerator

confirmtx.com, I'd suggest

thanks guys - just used that confirmtx.com - lets see- thanks :)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Transaction unconfirmed - day 12!
I've got a transaction from 2017-12-06 that's still unconfirmed - i really need this money now as ive moved house - how can i get this sorted - I am will to pay for help at this point.
Can anyone please help?? Tim.
https://blockchain.info/tx/44c784d8f82d962103ffdf5d463a1460150a21cc67a0750d4a3f6a35a0d18d9a

I'm in the same situation. If this info is correct your coins should return in two days:  #9312 a72f76c Increase mempool expiry time to 2 weeks (morcos) https://github.com/bitcoin/bitcoin/blob/master/doc/release-notes/release-notes-0.14.0.md

thanks .... once returned, should i then ry with a higher fee? whats a good fee to make this happen quickly?

2 weeks have past, still nothing, can anybody advise? tried the zap wallet thing, and its just removed the transactions, so theres nothing in my wallet on my mac. the only thing i have to go on is the bitcoin link
can anybody help me, am desperate now to get this money - need it for a house move.

Now that you've done the zap wallet thing do bitcoind -rescan and the coins should show in your wallet.

@hermancain  you are the mother f&^king man - sorted it with that command! killed the old transaction and made a new one with a better fee, now i understand all that bit! thank you soo much dude!!!

This question is another duplicate and already answered here by dooode:
Why is my transaction not getting confirmed and what can I do about it?
You have to stop/reverse the old Bitcoin transaction you created without confirmations:
Make a backup of your wallet.dat
Run bitcoind or bitcoin-qt with -zapwallettxes=1 option.

This makes the wallet "forget" any unconfirmed transactions, thus enabling you to reuse their inputs.
Create a new transaction to make your payment and add an appropriate fee this time.
You can now send the bitcoins where ever you want or you can send them all back to yourself.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Help! Transaction unconfirmed after 1 day!
I made a bitcoin transfer yesterday and it is still pending with 0 confirmation. The fee is around 0.003BTC and the miner preference is high though. Can anyone please help me get it confirmed? I'd greatly appreciate it.
Here is the link:
https://live.blockcypher.com/btc/tx/b79bffaec87a0e789be3465faecc394f692ef2c501ef2787dcbc3f56e16c7076/

At this point, AFAIK, no one can help you speed things up. There has been a record number of transactions over the last few days and the queue is really backed up.


text:
Litecoin /Bitcoin addresses
I have just bought some Litecoin and Bitcoin. There are many addresses that seem to be created as I press Send and Receive.
Do I need to allocate one of those generate addresses to my purchased Coin or can I just press Send and put the Recipient address. What happens when I put my email address ?
I'm so bad at this.
Thanks
Chris

Litecoin and Bitcoin addresses are in no way shared.
No need for your email address, this is just a label.
Which wallet software are you using?

Scott,I will get Trezor very soon but only purchased a VERY small number of Litecoins until I get my head around it. You guys are so generous with your time. Appreciated, Chris

If you're considering pasting your email as a public address to withdraw funds to, then I would recommend you search out some 'intro to bitcoin' or 'how to use bitcoin' videos on Youtube. I think watching a few of those will be quite helpful, at the very least they should provide you with enough knowledge to ask better questions. I'm not trying to be rude, but you're asking vague and wide questions about some very basic functions. Its OK to be 'bad at this', everyone starts there! With a bit of work, the system will seem less foreign to you very soon.
To take a stab at answering your Q more directly: Your wallet software can generate a million addresses, or more. Doing so doesn't really matter or accomplish anything, an address only 'becomes important' once you send bitcoin to it.
The coins you bought are probably sitting on an exchange service right now (I'm assuming you used something like Coinbase), so you probably want to withdraw them to a wallet you actually control. To do so, you'll install some wallet software, and it will generate some receiving addresses for you. Open up your exchange account, and paste one of the receiving addresses into the 'withdraw' field (it doesn't matter which address you paste in, just pick one from your wallet). Next you'll press submit/confirm, and after some time the exchange service should submit a transaction to the network to withdraw your coins.
Litecoin is a separate network, so you'll have to do the same thing again, but using litecoin software that will generate a litecoin receiving address for you.
If you try to withdraw to your email address (or anything else that isn't a valid bitcoin address), the wallet software will give you an error message, you will not be able to submit a transaction like that. The code is built to guard against errors.

@ "Litecoin is a separate network, so you'll have to do the same thing again, but using litecoin software that will generate a litecoin receiving address for you." I propose using the Trezor software to generate a litecoin receiving address.

@ChrisBorrett Glad I could help! A Trezor hardware wallet can handle both btc and ltc software, so that will work just fine. Bitcoin and Litecoin addresses look different, so it should be easy to tell which is which (and like I mentioned, if you mix them up, the software will give you an error and the coins will not send). Using a hardware wallet is a good decision, just make sure to store your seed phrase very securely! (do not store it digitally!)

Thanks again chytrik ...........have a great break.............Chris


text:
Why Bitcoin address are 25-34 bytes long when RIPEMD 160 & SHA-256 are only 20 bytes and 32 bytes long respectively?
(I'm new to Bitcoin & it's technology so correct me wherever u can) .Recently I was reading about Bitcoin and it's underlying technologies. I came to know that for generating addresses Bitcoin uses RIPEMD-160(SHA-256). But most of the Bitcoin Addresses are 25 to 34 Bytes(characters) long & starts with 1 or 3. How is this possible? Is there any underlying Encryption algorithm is there along with Hashing functions like RIPEMD & SHA?

Bitcoin address is generated as follows :
First 256 bits of Private key(k) is generated using underlying operating system's pseudo random number generating function (in wallet).
Then Public key (K) = G * k. , where G is constant on the elliptic curve. i.e. equivalent to k times addition of G and the resulting point K is on the curve which is 65 Bytes.
The address is calculated by performing SHA256 followed by RIPEMD160 on public key (K). so that would be of 160 bits = 20 Bytes of address.
Now, Add version prefix 00(in hex). Perform SHA256 twice on it. Take first 4 Bytes of result and append it to (prefix || address).
Resultant would be final address.

Here you can find a step-by-step description of how bitcoin address is generated: https://en.bitcoin.it/wiki/Technical_background_of_version_1_Bitcoin_addresses
Short answer:
Bitcoin address consists of
<version_byte><20 bytes of RIPEMD-160(SHA-256(PublicKey))><4 bytes checksum> = 25 bytes in total
Checksum is just first 4 bytes of SHA(SHA()) of previous data


text:
My Blockchain Payment Has Been Unconfirmed For 3 Days Now Please Help
https://blockchain.info/tx/342ca53d9a5dea2f63e81be6c4e39b4b3c61d6dae8b69e7e71f8c802f61da415
That’s the link it has been unconfirmed for a long time now can anyone help me please.

How did you send it?  Which client?

Blockchain Regular

I can't find this client.  Do you see a "replace by fee" option in this client?  Can you share a link to download this client?

You can use replace by fee to encourage miners to pick up your transaction.  This should be your next step.  See here for more info:
What is replace-by-fee?
Also, here is a how to:
https://freedomnode.com/blog/75/how-to-fix-slow-bitcoin-transactions-with-replace-by-fee
This site can help recommend what you should use for your fee so that you can set your expectations of when a transaction will be confirmed:
https://bitcoinfees.earn.com/
Basically, the more you pay with a fee, the faster it will be confirmed.  The less you pay, the slower it will be confirmed.

You skimped on the mining fee (only 96 sat/byte). The miners will pickup other higher paying transactions in preference to yours. As mentioned above it is possible to send another transaction through with a higher fee. This is called double spend.
The Core developers have engineered this problem by restricting the blocksize thereby throttling the number of transactions per second that bitcoin can process.


text:
What are some Bitcoin / blockchain projects that are actually doing something?
There are hundreds of blockchain startups out there across a range of industries -- from finance to media to property management. They have identified significant problems and ways that blockchain can solve them. On paper, it all sounds awesome.
But how many blockchain companies or projects have created working solutions? It seems to me that most companies just have ideas, and are still working on their code. In the best cases their platforms are still in the alpha stages and they might have a few users or partners (who are usually willing to pay or be paid in cryptocurrency, which makes them different from the public at large), but have not yet really made a big impact.
Can anyone think of examples of blockchain companies or projects that have a real, fully functioning platform that is actually being used by a critical mass of users who are not themselves all blockchain fanatics?
I'm not asking to be critical. I am really excited by the potential of blockchain. But when people who are not blockchain geeks ask me for examples of how blockchain is actually being used in a meaningful way today, rather than how it could theoretically be used in the future to solve all sorts of problems, I don't have good answers.
I know this question is about blockchain as a whole, not just Bitcoin, but there is no blockchain Stack Exchange, so here we are.

huuh, we can't give you the arguments, that you need to convince "nay sayers" - if there is a crypto ccy market approaching 1 trillion, then there must be something fundamental behind, besides some geeks getting wet dreams on crypto currency. And whatever argument you make, it might turn into "Bitcoin is only a bubble". Really think twice, if you have any value to fight arguments with people, who don't see a value in the world, that you yourself find fascinating...

When observing the market, I think there are several areas: there is for sure transfer of value over the internet (this is all the bitcoin and co stuff). And for sure all the ICOs using Ethereum as platform. Then there is a gaining market for smart contracts (also Ethereum, but others as well), which try to eliminate the middlemen, so that banks/assurances and lawyers (all very expensive parts in transactions) can be eliminated. Another area is some kind of proof, e.g with factum. There you can document, that at a certain time you published s.th, and everyone can verify it. These are some "public" examples.
Then there is the large area of private blockchains, where companies try to improve their workflows. The logistics industry is playing heavily with it (e.g. a container sends a message to the blockchain, that he arrived, and payments can be initiated), the financial industry is looking for better settlement processes, and the charging of electric cars was last recently a hot topic.
I personally like the idea of smart grids, where you produce power with e.g. solar panels, and sell it via crypto currency to the grid/consumer.
And then there are for sure 100s of crypto currencies, which are used as a testing platform for new technologies.
Welcome to the exciting world of crypto currencies!
and next to my comment above, I wanted to add this picture, I cut&pasted from somewhere...

My favorites,
Ether Delta(https://etherdelta.com),  Decentralized exchages controlled by zero entities.
Augur(http://augur.net) Decentralized prediction market/betting company.
So many more, at https://www.stateofthedapps.com


text:
Addresses found in wallet.dat that start 00 14
I found a list of addresses in my dumped wallet.dat file that all start 00 14...    They are script=1.
What are these encoded with and how to decode?

More than likely these are native segwit address scripts. Native segwit scriptPubKey start with 0014 followed by a 20-byte public key hash. There is an online tool available for encoding the public key hash into its native segwit address representation. Note that although the risk of using such tools is minimal in terms of security, there is a possible risk toward privacy. I have not personally verified/reviewed the code for this online tool and you should proceed with caution.
Remove the 00 14 section and paste the remaining 40-character string (20 bytes) into the "Data" field. The associated bitcoin address will be displayed on the right-hand side under "Encoded data".

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
How do i have a 2011 bch transaction?

I was under the impression that BCH did not fork untill 2017.  How was i making transactions in 2011?

Altcoins like BCH copy both code and blockchain of bitcoin. The "blockchain" is the entire history that is copied to the alternative chain hence this transaction from 2011 is also copied and exists in original chain and the copy of it.

The BCH chain shares all of the BTC history up until the point of the fork. If you're using the same address for BCH that you did for BTC in the past, any pre-fork BTC transactions will also appear as BCH transactions.

Thank you.  Im trying to claim those forked coins, but my coinbase wont give the private keys and im still running through my 4000 bitcoin core addresses; which so far are coming up 0.


text:
Bitcoins gone missing in Blockchain Wallet
My wallet password was not compromised but my bitcoins have gone missing from my wallet with a transaction that says - replace by fee.
I have send two messages to support at Blockchain to find out what has happened but keep getting the message back saying they have updated my ticket number but I have not received any emails from them with an update.
I tried to call them but the person on the end of the phone barely speaks English. I am at a loss of what to do. Can anyone help me?
Do you know what replace by fee means?
Can I find out where my bitcoins went with the wallet number?
Can I speak to a person atBlockchain to discuss my problem?
How can I recover my bitcoins?

There’s no phone support for blockchain.info. Anybody claiming to be support for that company with a phone number is a scam.

My wallet password was not compromised but my bitcoins have gone missing from my wallet

It is very difficult to know this with absolute certainty. And even if it is true, there are other ways to have your wallet compromised. Blockchain.com offers some rather insecure backup options: by email, cloud storage, etc. If a backup is compromised, it doesn't matter how strong your password is, the attacker won't need it.

Do you know what replace by fee means?

Replace-by-fee (RBF) is an optional flag that can be added to a transaction, to signal that until confirmed, it can be replaced by a new transaction that spends the same inputs, with a larger fee. See this question for more info.

Can I find out where my bitcoins went with the wallet number?

You can view the transaction that used your bitcoins as input, to see what addresses they were paid to. This is all public information stored in the blockchain, but addresses are pseudonymous by design, there will be no info about who took your bitcoin, or where they reside.
A wallet is software that controls a collection of addresses, but as with addresses, there is no public info available that will tell you with certainty which addresses belong to which wallets, or which wallets belong to which users.

Can I speak to a person atBlockchain to discuss my problem?

If they have a customer service department, then perhaps you can. But keep in mind they are just a business that works with Bitcoin, so they have no special position of control or power over what happens on the blockchain.

How can I recover my bitcoins?

You likely cannot. I would suggest contacting blockchain's customer service, but there is likely not much they can do. If you lost a substantial amount of money, you could contact your local law enforcement to report the crime, but again, there is likely little they can do to recover the funds.

How you secure your funds is a big question for Bitcoin users. Some methods are more secure, while others are less secure but easier to use. I would advise not using blockchain.com's wallet if you are looking for a secure storage method.


text:
Signing transaction for later use
If I have a segwit UTXO  with for example 10 BTC , can I make some raw transactions ready to get broadcasted?

What is the question?

@Pseudonymous can I make some raw transactions ready to get broadcasted? for example if I don't want to reveal my private key ,  can I sign some raw transactions and broadcast them in the future?

Yes. There is no restriction on broadcasting a transaction hours, days or even years after they are signed. You can add a lock time to prevent them from being valid until a certain time if you choose.

@Pseudonymous What if I don't use a segwit UTXO?

Really has nothing to do with segwit either way.

@Pseudonymus If the utxo and receiver are same is the transaction hash the same?

I mean the signed transaction not the transaction hash


text:
How bitcoin finds a few transactions earlier account balance from outputs?
I am reading and watching about transactions and they say a transaction's input is previous transaction's output. They all show diagrams in which these transactions are consecutive.
How an account's balance is found if the latest input and previous output are away from each other away more than 1 transaction.
Also how an account's balance is found if there are some outputs to that account with small values in different transactions and another output which is account's balance? How they are gathered?
With which algorithm wallets traverse blockchain?
I am making my own node and wallet to grasp bitcoin better and couldn't understand these things about transactions.

How an account's balance is found if the latest input and previous output are away from each other away more than 1 transaction.

They never are. They are the same. Someone's input becomes someone else's output, until he decides to spent said output as an input in a new transaction.
Or, am i not understanding the question? Are you asking why a wallet understands why an output ...(that he received more than X blocks away) still belongs to him? See =>

Also how an account's balance is found if there are some outputs to that account with small values in different transactions and another output which is account's balance? How they are gathered?

I don't really understand what you're asking here, but your node keeps track of every transaction, and then creates a UTXO set- Unspent Transaction Output.
In this set are all the unspent outputs of the entire network. The wallet then checks if any of these outputs belong to an adress you own (Note: the wallet doesn't actually directly use the adress to scan for UTXO's, but rather the output script, but for practicality you can just see it as an adress, i  guess.) (have the private key of), and if so - will show it as belonging to you - and thus your (account) balance.

Isn't storing an entire UTXOs set ineffective? I mean, there are millions of bitcoin accounts

@mehmet bitcoin does not operate on account based model but UTXO based models. You need to consume an entire boutput of previous transaction as an input to the next transaction that you create.  If you did not maintain an UTXO model you would have to scan each past block to look if the transaction mentioned is a double spend transaction. Caching the UTXO set in the RAM allows for much faster verification of transactions.

In the backend of the bitcoin network's operation, there is no concept of 'account balance'. Rather, the network keeps track of coin ownership via a UTXO model.
So when a node validates the history of the network during the initial sync, it will construct a UTXO set and update it accordingly as it works through history. So a node will store the blockchain history (or a pruned version of it), along with a 'UTXO set', that represents all coins on the network. Once caught up to the chain tip, the wallet software can present the user with their balance, by simply summing up the value of all UTXOs that the wallet knows it can sign for (ie, the UTXOs it owns).


text:
Bitcoind not publishing blocks via ZMQ after reorganization
On the testnet, I am running a bitcoin core deamon (bitcoind) and am using ZMQ to receive updates about transactions and blocks (subscribed to both 'rawblock' and 'rawtx').
I was curious as to how the ZMQ would handle chain-reorganizations, so I left it running overnight, logging the hash of every block I am notified about.
The next morning, using the getchaintips RPC, I can see that a fork did occur, as seen below:
[
  {
    "height": 1664502,
    "hash": "00000000000000315e8e11c0babc400475f3a9bfc21678f32ca8f0f878f7e807",
    "branchlen": 0,
    "status": "active"
  },
  {
    "height": 1664491,
    "hash": "00000000002d324cbfe1261d506f85e9baf61d30e762e342f4f44429d4d6e1fb",
    "branchlen": 1,
    "status": "valid-fork"
  }
]

According to my own logs however, I only received one block at height 1664491, which was the (now stale) block "...d4d6e1fb", as seen below:
Received block 000000000001a2a613d4c66e78233f4d9fbfcf8e08502507c39c95460120cbda at height 1664490
Received block 00000000002d324cbfe1261d506f85e9baf61d30e762e342f4f44429d4d6e1fb at height 1664491
Received block 000000000000001b8f4e6ba531411eae489a6dc5e9c9c07ef9e2288f3f623014 at height 1664492
Received block 00000000000000436dfb1f1bb687bca8b905a994bcaece65ede27170fd453462 at height 1664493
Received block 00000000002753e7d21158cb6bcb8093779c7a3e7868762161edf7bedf50ce3c at height 1664494
Received block 00000000000000f18a226b32ae8399a3faf3a4c4155e153e7067f02e31c02385 at height 1664495
Received block 00000000000000ff309ae5442d7e5a271fb22cd7cac97d95d8a47a3d9d135c18 at height 1664496
Received block 000000000000606889000756962c02619a11158559d6f060daf68cef25cd0726 at height 1664497
Received block 000000000016c716d24a9dbd115807be235bf74e4fd4dec33d2e84a55a3c3a8a at height 1664498
Received block 000000000000012f5a3553526f751cb385a630cad7c285ba84a5468e8085213a at height 1664499
Received block 0000000000000119e1f42b0d345c59eb9bbf7dc9ed7591b3716ebbc26a9930b9 at height 1664500
Received block 00000000000000022b963361b5b33dcc733f1b9a20adff75336ce48d29be2227 at height 1664501

Curious, I looked up the hash of the now-correct block at height 1664491, which is actually 000000000001d39f8f818382632fd4c4929a34da542103d37ebfba85980d6496.
Using the RPC command getblock, I can get the information about this block from my bitcoind daemon, which means that it knows about it. However, I was never notified about this block through ZMQ, which is somewhat concerning.
Is this expected behaviour? During a chain-reorganization, can I only expect ZMQ to publish the tip of the new chain, leaving me to figure out that a reorganization has occurred and then having to manually retrieve the new blocks?
Is this behaviour documented somewhere? I am not entirely confident in relying on my own experimentation, to figure out how to handle this.

Is this expected behaviour? During a chain-reorganization, can I only expect ZMQ to publish the tip of the new chain

Yes, a ZMQ notification is emitted any time the active tip of the chain changes.
If you have a chain B1-B2-B3, and there is a 1-deep reorg that rewrites B3, you end up with B1-B2-B3'-B4. The tip changes here from B3 to B4; it does not go back to B2 in between.

leaving me to figure out that a reorganization has occurred and then having to manually retrieve the new blocks?

You have to do that anyway. ZMQ is not a reliable protocol, so you must be able to recover from missing messages (and in general, with a node going down temporarily). Dealing with this means discovering that the latest tip is a reorganization compared to what you had before.
This is true in general for ZMQ, you can use it as a notification mechanism to perform an update right when it happens, but you need infrastructure for fetching to recover too.
For more information, see the ZMQ documentation for Bitcoin Core at https://github.com/bitcoin/bitcoin/blob/master/doc/zmq.md.

It's worth noting that ZMQ's behavior will not be as described in the docs for proper reorgs if you simply invalidate a block and then generate over it (github.com/bitcoin/bitcoin/blob/master/doc/zmq.md). Say you have chain A -> B -> C, then invalidate C, then generate two new blocks, yielding A -> B -> C' -> D. ZMQ will notify A, B, C, C', and D, whereas the docs imply that in proper reorgs ZMQ would only notify A, B, C, and D.


text:
In the basic Wallet based in QT, How can i get by RPC the stored addresses and labels?
this question is for you to ask about the QT wallet, in the section to send coins, there is an address window, and it has the list of the stored addresses we save along the time. So using RPC, do you know if there is a way to obtain this data from inside? i am not refering myself on creating a new address or getaddresses by account command, i mean all the addresses we save, independently if they are ours or not.

The closest I know of is
listreceivedbyaddress 0 true

https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_calls_list says:

Listing the bitcoin addresses in your wallet is easily done via listreceivedbyaddress. It normally lists only addresses which already have received transactions, however you can list all the addresses by setting the first argument to 0, and the second one to true.

Similar questions (different answers)

How to get all addresses - including the "change" addresses - from bitcoind?


text:
crypto currencies mining
For now i can't afford a great GPU for mining.
But what i am thinking is...
To mine a very low difficulty coin as much as i can with my old cpu and gpu and wait untill the currency price grow up.
But i am searching and I can't get what i want...
What i am searching about and please i need your help for it.
I want a list of currencies with the lowest difficulty and CAN BE MINED.
I found many with low difficulty but not minable.
So please i need a list of minable currencies with lthe lowest difficulty.
Thanks..


text:
rawtx & rawblock ZMQ at the same time?
I need your opinion, do you mind ? :)
I'm bulding a javascript layer on top of bitcoind.
I have bitcoind running on my server with rpc & zmq enabled.
daemon=1
rpcallowip=0.0.0.0/0
rpcuser=xxxxxxxx
rpcpassword=xxxxxxxxx
server=1
rest=1
zmqpubhashblock=tcp://*:28332
zmqpubhashtx=tcp://*:28332
zmqpubrawblock=tcp://*:28332
zmqpubrawtx=tcp://*:28332
rpcworkqueue=100

My program goal is to listen for rawblock and rawtx ZMQ channels. This is my zmq client:
const socket = ZMQ.socket('sub')
socket.connect('tcp://myserverip:28332')

socket.on('message', (channel, data) => {
  console.log(channel.toString())
})

So here is what happens :
subscribing to rawtx alone works, I receive the tx flow (approx 2.5tx per second)
socket.subscribe('rawtx')

subscribing to rawblock alone also works, I receive blocks (approx 1block per 10minutes)
socket.subscribe('rawblock')

But here is my problem, when subscribing to both, i do receive rawtx but no rawblock !
socket.subscribe('rawblock')
socket.subscribe('rawtx')

I'm assuming the ZMQ socket is flooded with rawtx, which result in missing rawblock event.
My question is: how would you debug this ? Have you guys faced this situation already ?
I know I could use the blocknotify option in bitcoind to forward the blockhash back to my client, and then load the rawblock via an rpc call back to bitcoind, but then I would use 2 different mechanisms (one for rawtx and blocknotify for rawblock) for something that was supposed to work in the first place :)
Thanks for your feedback !!

Are you sure that socket.subscribe allows you to subscript to multiple things in the way that you have done it? It seems like it could only be subscribing to the latest thing that subscribe was called on, and that would be rawtx. What happens if you reverse the order?

order does not matter I've checked. and if I sub to rawtx & hashtx i receive both. I just don't receive rawblock when used with rawtx at the same time

Try to subscribe by using prefix raw as topic . After this you will get both message on the one listener.
socket.subscribe('raw');

socket.on('message', (topicRaw: Buffer, bodyRaw: Buffer, ...tailRaw: Buffer[]) => {

    const sequenceRaw = tailRaw[tailRaw.length - 1];
    const sequence = sequenceRaw.readInt32LE(0);
    const topic = topicRaw.toString();

    if (topic == 'rawtx') {
        const rawTX = bodyRaw.toString('hex');
        console.log(topic, sequence, rawTX);

    } else if (topic == 'rawblock') {

        const rawBlock = bodyRaw.toString('hex', 0, 80);
        console.log(topic, sequence, rawBlock);
    }
});


text:
Dynamic Transaction Hash Confirmation
I am working on a donation based community website (using PHP) where participants register for an account to participate. Each account carries the participant's bitcoin address. A participant makes a commitment to donate say $10 and is paired with another participant (recipient). The donor confirms payment by pasting his/her Transaction hash id on his dashboard to confirm payments. I currently use Blockchain.info API to read the transaction details and check the inputs and outputs of the transaction to ensure that they contain both donor and recipient BTC addresses and the expected amount.
My problem is that most wallet providers generate new BTC address after each transaction making it difficult for my code to confirm transaction as the address will not match if new ones are generated.
How do I confirm transactions for dynamic BTC addresses using PHP OR how would you handle this use case?
Thanks

Submitting transaction ID is not a safe way to verify payments. As you know bitcoin transactions are public and anyone can get see all TXIds. Same reason why even the donor bitcoin address is not a good method to verify. Someone else can see that address on blockexplorer and claim himself to be donor.
I can suggest few options:

Ask the donor to sign a message proving ownership of the source address in TX. Most wallet have this functionality
Ask the participant to submit his xpub (extended public key) instead of address. When donor wants to donate, generate a unique address from this xpub for each attempt. This way you are sure, this donor paid to that address


text:
I have a private key and wallet passphrase
I have a private key and wallet passphrase generated some time ago, how do I now access my funds?

private key is use to spend Bitcoin while  wallet passphrase is use to recover your wallet as well as generate the private key to the wallet, in order for you to use access your fund you can import the private key in to another wallet such as blockchain wallet
watch this YouTube video for clarification
https://m.youtube.com/watch?v=03RbWB4ONFY

Hi Dprincebh, please edit existing answers instead of adding new ones, except you are providing different answers.

kindly import the private key into another wallet such as blockchain you can access your Bitcoin there

Welcome to Bitcoin.SE! To make this answer better, it would be helpful if you expanded a bit on what the private keys are for or how to import them into another wallet (for example by providing a link to some instructions for common wallets or another SE question on importing keys) :)


text:
Bitcoin Country of origin analysis
I would like to analyze bitcoin transactions based on the origin by country.
Is there a API or program (maybe like Datasploit, only the other way around) to cross reverence location and transactions. I prefer python to analyze but of course all input is welcome on tools used and reliability of the analytics.

Location is not a detail recorded in transactions.  Specific Exchanges might record the IP address or location where their clients are located at the time they make a transaction, however that is clearly only going to be a small portion of the overall chain of transactions.

and against the idea of privacy in bitcoin :-)


text:
Search for bitcoin with ipv4 address
I am working on a way to monitor bitcoin transactions and found that on blockchain info it's possible to find info about a bitcoin by ipv4 address. Is there an API supporting this on a larger scale? Or is bitcoin info using it's own database to connect ip with transaction?

All bitcoin transaction are not linked to user ip address, unless some wallets which links your transactions to your ip address.
I don't know what blockchain.info doing but what i know it's not possible to track any bitcoin transaction through ip address.


text:
Where is seed in Bitcoin Core in comparison to Bread Wallet
Im new to Bitcoin. I know the main software of bitcoin is Bitcoin Core. Recently i started using an iOS wallet called Bread. Its very simple! It gives me a 12 word key and says your master private key can extract from this and no need to backup your wallet as a file.
My question is: i readed that Bitcoin Core in the new versions is an HD Wallet. But it never gives me a seed like bread. Im confused.
I have an assumption but i dont know its right or not:
My master private key stored in a file unlike bread. I have to encrypt my walled from bitcoin core settings menu and the from file menu choose Backup Wallet and save it. In fact, in the future, i have to import that file and enter encryption passphrase that i created in the encryption step and the software fetches my private key from that file and load my entire wallet from blockchain. In bread i enter that 12 word and bread creates my private key and so on... in bitcoin core i need backup just one time. In Bread i have to write down my seed and in Bitcon Core i have to backup both passphrase and wallet file.
is this true? bitcoin works like this?
As i know i cant import wallet i created in Bread to bitcoin core. Each software has its own seed to private key mechanism. Is this true? I want to use bread and Bitcoin Core both in my pc and mobile.

In Bread i have to write down my seed and in Bitcon Core i have to backup both passphrase and wallet file. is this true?

Yes.

Each software has its own seed to private key mechanism. Is this true?

No. What you call the "seed" is actually called the mnemonic. Most wallets that give you a mnemonic use BIP 39. BIP 39 specifies how the mnemonic should be created and how to convert the mnemonic to an actual seed value.  Most HD wallets then use BIP 32 to convert that seed into your private keys
Bitcoin Core implements BIP 32, but not BIP 39.

Thanks for your clear answer. I accepted it. I dont want to any private software and put my money in it. I need to freedom to convert etc. i need to follow standards. My questions is because of this.


text:
Is 10K full nodes enough to bitcoin to avoid 51% attack?
As I know bitcoin has about 10K full nodes. And the question is in my mind is that: This number is not huge! If someone has 6K servers, Can control the bitcoin via 51% attack?
I was thinking if bitcoin had millions of nodes everything was ok but 10K is enough? What is the magic here that people trust bitcoin with 10K nodes?

Note that it's not about the number of full nodes but the computing power that can influence such an attack

I know, But that full nodes are not special powerful computers. I know it costs too much but I'm thinking if someone want to destroy bitcoin, It seems it's possible. Just need a few thousands PC's with good GPU. I mean "someone" like Russia, China or... they have that money and power

@Fcoder you are confusing 'network full nodes' with 'miners'. Running 10k full nodes has nothing to do with a 51% attack. GPUs are useless when mining bitcoin, specialized ASIC hardware is required.

A few thousand PCs with GPUs will not even make a dent in the total hashrate. 10000 GPUs, assuming the best available hardware, can hash at around 10 Thash/s. The global hashrate is approximately a million times more than that.


text:
Storing private key in apps and softwares that are local
Im new to butcoin. I installed an app in my phone called Bread. And another in my computer called Electrum.
Both of them generated a seed(12 words) for me and it seems that seeed is my private key in the bitcoin network.
My question is: these softwares has my private key and i dont know if they stored it in remote servers. This means someone other has my private key and can access my money? This is a safe way in bitcoin culture? They are really local?
I want to use safest way to work with bitcoin and i dont want store my info in any website or app that can access my account, delete my account or any other intervention.
For safest way should i have my own copy of public ledger in a personal server? What is the safest way?

BreadWallet & Seed: the seed is not your private key, it is used to generate the private key, and it is stored locally on your phone. However, the level of trust in me (or anyone else) is not sufficient, when saying this. You might want to do a source code review by yourself to be 100% sure. In general I use Bread as well, for daily usage, not for big amounts. It is a fairly well working wallet, and the value in it is comparable to the wallet with FIAT money. There are privacy issues with such wallets like BREAD (they are called SPV wallet), and the risk with these SPV wallets is, you trust someone else that they verify the bitcoin blockchain correctly. E.g. there was the risk to fall victim of the segwit2x fork, and then you would think you are on the original bitcoin, but in fact the provider (and all SPV wallets) would be on a new blockchain, which has changed parameters. So with SPV wallets, only use small amounts of money.
Electrum: this is similiar, the seed is used to generate the privkeys. Electrum is also an SPV type of wallet, and you trust the provider's blockchain. I am not sure about the possibility of code review though.
Wanting to be 100% secure and safe, you need to run a full node (aka bitcoin core client or similiar), and get used to the idea of cold storage. There is lots of links to cold storage here in the forum.

Thanks for your complete and perfect answer. I have another question. If i install bitcoin core on a safe server, there is a way to communicate with my server from my phone? Something like a mobile client that just send and receive messages to my own server. Apps like bread or electrum can connect my own server and its safe? I want everything in my own control in any scenario. I can protect my own server but its not possible to carry a laptop everywhere.

we are going beyond the crypto ccy here, but it somehow relates. And your questions are perfect. What do you want to communicate with your server from mobile? At the end, security is always a trade off. Use case specific. And a windows free zone :-) I have it setup in a way, where "my" server is behind a firewall (OpenBSD, what else!), and the firewall rules are modified in a way, that let me go through from extern with SSH only. On my iPhone or iPad I have installed "reflection". This allows me enough to to "my" things. One could even think of tunneling X... As I said, just my setup.

Thank you. I think i have setup a bitcoin core with accessing via ssh from pc or mobile. And a mobile client like bread for small and daily transactions. Whe i need bitcoin, send it from main account to another in my phone and use it.

And one last question. In Apps like bread, how can i backup my wallet? I dont see anything related to this. Bread says to me that we can recover tour account if your phone stolen with your seed. But how? Where my bitcon stored? Its in bread’s servers? Im confused. I did not any bitcoin transaction ever and im new to bitcoin. Everytime i get money, i get a code? And i have to protect it? Or my money stored in blockchain and i need only my private key to access it? Whe people says “backup”, what that means? Backing up what?

Your bitcoins are on the blockchain as Unspent Transaction Outputs (UTXO). You need to use your private key un order to create a transaction and spend your bitcoins. When people say "backup", they mean backup those private keys. As mentioned earlier, your seed is used to genarate your private keys.


text:
Get Seed from wallet on regtest mode
I am doing some tests for an application that signs Bitcoin transactions. I already downloaded the binary files bitcoin-cli,bitcoind and bitcoin-wallet from bitcoin.org. I need to know that the seed of the wallet created by regtest. It is available when the bitcoin-wallet -regtest info command returns:
Wallet info                                                                             │
===========                                                                             │
Encrypted: no                                                                           │
HD (hd seed available): yes                                                             │
Keypool Size: 1999                                                                      │
Transactions: 103                                                                       │
Address Book: 2

I need that seed for run recovery on my app and check if it sign correctly a Bitcoin transaction.
Thanks in advance

You are looking for the dumpwallet command.
While in regtest open the console a/k/a debug window, and type:
dumpwallet "C:\myfolder\dump.txt"
This will create a text file with all your keys. At the top you will see your extended master private key. And if you are looking for your HD seed, do a control+f for hdseed, you should find a key with the label hdseed=1.
https://bitcoincore.org/en/doc/0.18.0/rpc/wallet/sethdseed/


text:
Wrong Address when Transfering BTC to Paper Wallet
I think I fucked up when transfering my BTC from exchange to paper wallet.
I used the private Bitcoin address you get when u make a paper wallet instead of receive address generated in blockchain.info. The transaction was confirmed but the BTC never received.
Where did the BTC go?

Can you link a txid? If the transaction confirmed, then it paid to whatever address you specified. If you somehow paid to a private key (I don't think this is possible?), then the BTC are lost, since you don't have a private key that will be able to sign a transaction spending those coins.

If that address is the address for your paper wallet, then yes, you should be able to recover those funds from the paper wallet, by importing the private key to a wallet you control. Note that it is important you understand how change addresses work, so that you do not accidentally lose coins. Paper wallets can be dangerous if not used correctly.


text:
lightning network bitcoin howto install
Hello fellow bitcoiners,
I would like to install lightning over Bitcoin core - I already have a full node. But every guide I follow ends up with a broken build or some issue preventing to finish the install of lightning. Did you have success with a good howto by any chance? I would preciate if someone could post a proven working install howto.
Thank you very much, /cr!?ptal

Which operating system do you use?

linux ubuntu based

You can do
sudo apt-get install -y software-properties-common
sudo add-apt-repository -u ppa:bitcoin/bitcoin
sudo add-apt-repository -u ppa:lightningnetwork/ppa
sudo apt-get install bitcoind lightningd

If you don't want to add external repositories you can flollow the clightning docs from https://github.com/ElementsProject/lightning/blob/master/doc/INSTALL.md they worked perfectly last time I checked and are copied here for your convenience.
Library Requirements
You will need several development libraries:

libsqlite3: for database support.
libgmp: for secp256k1
zlib: for compression routines.

For actually doing development and running the tests, you will also need:

pip3: to install python-bitcoinlib
valgrind: for extra debugging checks

You will also need a version of bitcoind with segregated witness and estimatesmartfee economical node, such as the 0.16 or above.
To Build on Ubuntu
OS version: Ubuntu 15.10 or above
Get dependencies:
sudo apt-get update
sudo apt-get install -y \
  autoconf automake build-essential git libtool libgmp-dev \
  libsqlite3-dev python python3 python3-mako net-tools zlib1g-dev libsodium-dev \
  git gettext

Clone lightning:
git clone https://github.com/ElementsProject/lightning.git
cd lightning

For development or running tests, get additional dependencies:
sudo apt-get install -y valgrind python3-pip libpq-dev
sudo pip3 install -r tests/requirements.txt -r doc/requirements.txt

Build lightning:
./configure
make
sudo make install

Running lightning:
bitcoind --datadir=<path_to_blockchain> && ./lightningd/lightningd && ./cli/lightning-cli help

Note: You may need to include testnet=1 in bitcoin.conf

thak you @Rene Pickhardt. I have an issue early on: $ sudo add-apt-repository -u ppa:bitcoin/bitcoin
Usage: add-apt-repository [options] repository
add-apt-repository: error: no such option: -u

I removed "-u" option. Now I have another issue: sudo apt-get install bitcoind lightningd > "unable to locate package lightningd".

What happens if u do without adding external repositories to the package manager and step by step?

it just works :-) with a few corrections, I edit your response if I may

Sure! That is what the site is about. We work collaboratively to bring the best information / education together


text:
Block.io set smaller fees?
Is it possible to set a custom transaction fee with block.io? We are using their API and their "Low" fee is still far too high (currently $3)

I really don't suggest to use block.io since they will limit your number of your bitcoin addresses.
Any way they don't support custom fee.
As on block.io site

Estimate network fee will be paid on withdrawal of given amounts

What alternative do you suggest? I don't really like blockchain.info - Ideally we would have our own BItcoin node but that maybe too difficult.

i'm afraid that there's no other alternatives.

But please consider that if the fee is too high it might be of your transactions.
Because transaction fee on most bitcoin wallet depends on your previous inputs(transactions)

Please check out my answer in here: https://bitcoin.stackexchange.com/questions/63607/why-is-the-mining-fee-so-high/63617#63617

Thanks but it's coming from one and their fee/kb is far too high. I guess ill have to go with blockchain.info - Do they allow custom fees and unlimited wallets? Also do they charge like block.io because I can't find any pricing. Also who would I use for LTC?

Blockchain is free  but they have many issues, Like you may miss callbacks.
And create wallet is unlimited but you can't create more than 20 empty address, because the blockchain will not scan these addresses as defined on bip44.

From blockchain:
wallet software will not scan past 20 unused addresses. Given enough requests from this API that don't have a matching payment, you could generate addresses past this horizon, which would make spending funds paid to those addresses quite difficult. For this reason, this API will return an error and refuse to generate new addresses if it detects it would create a gap of over 20 unused addresses. If you encounter this error, you will either need to switch to a new xPub (within the same wallet is fine), or receive a payment to one of the previous 20 created addresses

Also you can't use it for LTC

Ok thanks for clearing that up. I think my only choice now is to get our own nodes wallet integrated. We may have hundreds possibly thousands of signups and each account must have their own wallet. 50% of which maybe empty. Do you see any problems we may face with Bitcoin/LTC nodes?

Own address not wallet.


text:
Bitcoin RPC - settxfee specific amount rather than based off transaction size?
How am I able to use the "sendfrom" command with a specific amount of 0.0005 BTC as fees no matter how small or big the transaction is in bytes?
settxfee is based off fees per bytes.


text:
Why can you mine so much more of other cryptocurrencies with a lower hash rate?
I have been researching bitcoin mining and one thing has stumped me. Why is it that you can you mine so much more of other cryptocurrencies with a lower hash rate? I've looked on cryptocurrency calculators and it says that 1 TH/s for Ethereum makes a profit of about $2M per month, but only $53 per month with bitcoin. If your hardware is capable of producing a high hashrate, why not mine a smaller cryptocurrency and exchange it right away?

Comparing hashes per second for Bitcoin and Ethereum mining is comparing apples and oranges. You can only compare hashes per second, if coins in question use the same hash functions for proof-or-work. Bitcoin uses double SHA256, which is a general purpose hash function and can be massively parallelized and optimized in hardware (ASICs). Ethereum uses Ethash, which is more memory-hard and mostly mined on GPUs. Zcash uses Equihash, Litecoin uses scrypt, and so on.
Miners who have SHA256-specific equipment can only choose between SHA256 coins (Bitcoin, Bitcoin Cash, Namecoin (?)). Miners with GPUs have more options, as many memory-hard hash functions are more or less GPU mineable.

Hash operations are not fungible.
Hardware that can produce 1 TH/s for Bitcoin's proof of work cannot do any hashes for Ethereum's proof of work.

Does that mean that I would have to buy specific hardware to mine Ethereum?

Yes, the best hardware depends on the type of PoW.


text:
How can I see if my bitcoin core money is in my wallet?
I had funds deposited in my bitcoin core account about a year and have still not seen them appear in my wallet. Is there a way I can make sure the transaction went through, and how I can have access to the funds? I have the receiving address where the funds were sent to. Thank you

First, make sure that you downloaded the blockchain.
If it's the case and If you are really the receiver and you have the private key, you can reindex the chain by access to the console in the software.
You must convert your private key in WIF (Wallet Import Format) and enter the command importprivkey("PRIVATE KEY").
How to convert a private key to the WIF ?
The private key is 32 bytes in hexadecimal format.

Take the private key
Prepend version number which is a byte in the mainnet equals to 0x80.
Append compression flag which is by default a byte equals to 0x01 but can be 0x00.
Append checksum. Checksum is the first 4 bytes of double sha256 hash of whatever is being checkedsum'ed (80 + privKey + 01/00).
Base58 encoded data is easier to read and manage. This is reversible. It's available on https://appdevtools.com/base58-encoder-decoder.

Best regards.

If you haven't seen them appear you may be seeing one of two problems:

Your Bitcoin Core application is not synchronizing with the network properly
You deposited your Bitcoin to a wrong address

I would find out where the Bitcoin is on the blockchain to be sure; only if you remember the sender of the Bitcoin. You can read up on the technicality of Bitcoin here.

Go to https://blockchain.info and enter the receiving address into the search at the top right of the screen.  This will show you the details about what transactions have occurred against the address.
This is what the search box looks like:


text:
How do I get Bitcoin sale proceeds into my Bank account?
I have received confirmation from Bitcoin Account Services that my trade has been processed and that the sale price was $6,842AUD. How do I get these funds into my Australian Commonwealth Bank account?

Who are "Bitcoin Account Services"? Do you have a web site address?

Unsure about web sit address, but email address is info@track.consumer-club8.com

If you were to receive a certain amount of Bitcoin into a "wallet" software of your choice, you could move that bitcoin into a cryptocurrency exchange such as coinbase or gemini. From there you can add a bank account to your account and sell your Bitcoin by placing a sell order.
As an aside, I have never heard of "Bitcoin Account Services" and a google search does not yield any results. Bitcoin does not belong to any company and transactions within Bitcoin are not controlled by any entity. The Bitcoin network is fully autonomous and can only be interacted with by running certain software that can only ask certain questions.


text:
Unconfimed transaction
I have sent BTC to cryptopay wallet. It is still showing pending. It has been 8 hours up to now. Can you please tell me what could be the error or the problem and how I can solve the issue
Thank you

The fee specified by your send transaction could be too small for any miner to include it in a block of transactions.
Some -- possibly too much -- information about fees is here: https://en.bitcoin.it/wiki/Transaction_fees

First check a block explorer like blockchain.info to see if the transaction was even broadcast.  If it was not, then look into resetting your wallet.
If you see the tx on a public block explorer, then you probably underpaid fees - See this answer.  Here are some options:

If BTC was sent from Electrum (or another wallet that supports RBF), then add a larger fee.
If you own the destination wallet, you can try using Child-Pays-For-Parent -- just send the unconfirmed amount to yourself with a very high fee.
If neither of the above are true and you didn't use Bitcoin Core, you may have to just wait or find some other way to double spend your tx...

More info on ways to modify fees after tx is sent: Replace-by-Fee vs Child-pays-for-Parent?


text:
Total Market Cap Data Set
I want to get the data for the total market cap similar to what I see when I view this page in the total market capitalization graph.
https://coinmarketcap.com/charts/
I already have the bitcoin market cap data but are there any publicly available datasets or is there anyway to get it directly from coinmarketcap? I'd like to be able to get as much data as I can.

https://www.coingecko.com/en also has some dataset you can collect
Like example for a coin https://www.coingecko.com/en/coins/bitcoin
you can use the export as excel or csv to get some data
good luck!

Have you tried CMC's REST API? https://coinmarketcap.com/api/


text:
Bitcoin sent but not received.
This is the log
0 confirmed/ in memory pool
1NJBNxv5c7oB6risrN7Zrh4J5bomjrsrNM
Debit: -0.56748446 BTC
Transaction fee: -0.00098910 BTC
Net amount: -0.56847356 BTC
Transaction ID: bc28bfac6984ddeaab814cc73a71fd9f8fb49780997beb39d0f9a8bce519f242
Transaction total size: 98570
Any ideas on what is keeping it from arriving.
I have sent to this address before with no problems.
Thank you
Frank

This thread might help you... https://bitcoin.stackexchange.com/questions/9046/why-is-my-transaction-not-getting-confirmed-and-what-can-i-do-about-it

In did not set the fee.  In fact I noticed it was smaller than others I sent and was not sure why.  I would gladly pay more, how do I fix this?  Thank you for the help!

This transaction hasn't confirmed yet because it has a low satoshi/weight unit transactoin fee (0.251 sat/wu, or 1.003 sat/byte).
The transaction you linked is very large, you can check all the inputs using this link. Transaction fees are calculated according to the amount of data transmitted (tx weight/size), not the amount being transacted, or the receiving address.
The mempool appears to be fairly empty right now, but with a fee this low, I'm still not sure your tx will confirm anytime soon.

This transaction tries to gather a massive number of microscopic outputs. That's very expensive and such a low fee just won't do it. Whatever is sending you all these tiny payments, figure out some way to get it to stop because you are wasting money.

I am fairly new to this, mined a Bitcoin and was just sending to a couple of other wallets than Bitcoin core.

What mining pool / software are you using? You could perhaps set your withdrawal limit higher, so that you end up with less txs of higher value.

If it does not get any confirmations, will it come back to my wallet so I can fix the fee?


text:
Wallet Balance does not match Transaction Total
Obviously, I am a newbie.....I have made several "buys" on Coinbase and the Wallet balance does not match the transaction totals - they are off a considerable percentage amount. Am I looking at it wrong or what?

Without some level of detail, it's impossible to tell if there is a problem or you are just "looking at it wrong".  Add the details to your question via the [edit] link.


text:
Step by step to make a SPV bitcoin node
As I know, there is a light node version called SPV.
for now I have started a full node and it has downloaded 82222 blocks, but I don't want to have a full node with full blockchain, my purpose is to have a node that provide me:

check balance or unspent amount for an address
sign and broadcast a transaction

is this possible?

bcoin is a nodejs Bitcoin library with both full and SPV node applications: https://GitHub.com/bcoin-org/bcoin

@pinhead thank you, only can I ask a question? I have downloaded bitcoin source from here https://github.com/bitcoin/bitcoin and after all steps I can run bitcoin-cli. now it downloaded blocks 8222, but I don't want to download 300GB of blocks and only I want to download headers. this has any line config in bitcoin.conf or
Is something completely separate from bitcoin core?

Bitcoin Core does not have an SPV mode. It can serve SPV clients but by design it is only a full node. If disk space is your only issue you can run it with pruning on. A pruned node deletes old blocks from disk but still maintains a complete UTXO set which is sufficient for full validation.

@pinhead The bcoin re write bitcoin in node application with SPV mode? or inside of Node app connect to P2p network with SPV mode? or like me install bitcoin core and only different config? Thank you about "pruning", disk space and bandwidth.

Bcoin is an alternative implementation of the bitcoin protocol. It was written from scratch in nodejs and shares very little code in common with Bitcoin Core which is written in C++. Some open source libraries like the crypto library libsecp256k1 are included with license. But otherwise it is a complete rewrite including networking, wallet, and block validation.

@pinhead Great, Thank you very much. So there is no need to install bitcoin core when we want to have a SPV node, I was looking a way to change a config that change type of message from block to Header. you said there is not this config and bitcoin core doesn't support SPV node.Am I right? Do you know like this in php please?

Yeah sounds like you get the concept. Please learn more about the trade offs involved with SPV before using it. I'm not aware of any useful PHP bitcoin library.

@pinhead I asked another question, answer it please if you like and get points:
https://bitcoin.stackexchange.com/questions/95676/how-to-getheaders-from-blockchain

By design, Bitcoin Core is a fully validating Bitcoin node and does not have an SPV client mode.
If disk space is your primary concern, you can run Bitcoin Core with pruning active. This will delete old blocks from disk but maintain a full UTXO set which is sufficient for full blockchain validation.
Bitcoin Core can serve SPV clients, although there has been discussion to deprecate this service or at least switch the service off by default. Before using an SPV wallet yourself, you should understand the tradeoffs for both security and privacy.
There are other software libraries capable of running a bitcoin wallet with Simple Payment Verification. One such library is bcoin which is written in nodejs:
https://GitHub.com/bcoin-org/bcoin


text:
generate wallets in exchanges like binance?
I'm a Laravel developer and I have a project in exchanges field. I need to know how can I generate deposit address for per coin belongs to per user.
I want to do this in secure way and I need to best suggestions.
Is HD wallets best choice for this situation? Do all coins have HD wallets?

According to https://bitcoin.org/en/glossary/hd-protocol
Definition
The Hierarchical Deterministic (HD) key creation and transfer protocol (BIP32), which allows creating child keys from parent keys in a hierarchy. Wallets using the HD protocol are called HD wallets
So this allows you to create lots of addresses just from a Master Key
Are they secure?
As far as you don't leak your mnemonic, all your addresses are safe
Do all coins have HD wallets?
HD wallets provides you a way of managing the addresses more efficiently and easily. So coins don't have wallets, addresses managed by those wallet can hold coins
Hope this was helpful!

Thank you for your response.As you said: "So coins don't have wallets" I confused about addresses for alt coins or Eth coin or ripple and others. Do I need to generate address to get coins and alt coins, right? or you mean bitcoin address can hold and receive all coins? I mean assume a person wants to send me ETH or others, and I have to give my ETH address,right?

Yes, different types of coins have different addresses and those addresses can only hold the supported coins. So ETH address can only hold ETH and related alt coin while BTC address can only hold BTC and related alt coins and so on...

Great. So I think all coins don't have HD wallets and this concept is only for BTC. Am I right?

This line is not true 'So I think all coins don't have HD wallets'. HD wallets just provide you the addresses which are related to certain blockchain and that addresses can store the coins of only that blockchain only. So for example a typical BTC address looks like : 3PbJsixkjmjzsjCpi4xAYxxaL5NnxrbF9B. It can hold any coins which use btc technology. LIkewise a typical ETH address looks like : 0xb46a3Cc3A5a247A831484e1D6aC6d8Fd25B804eE. It can hold any coins using ETH technology. So HD wallets can be used to create addresses of any blockchain and are not limited to just BTC

Thank you. Do you have any useful links for these concepts and any tutorials to develop HD wallets?

And I have a question about BIP. according this link https://github.com/bitcoin/bips we have many BIP. For know there are many many Bips and the latest is bip-0342, these are updated version of HD wallets or per BIP is totally different and belongs to others improvements and issues?

(https://iancoleman.io/bip39/), (https://ethereum.stackexchange.com/questions/70017/can-someone-explain-the-meaning-of-derivation-path-in-wallet-in-plain-english-s), The first link will cover everything in terms of concepts and all but hd wallet creation depends on programming language as well. So its hard to provide a link for the same reason.

BIP is Bitcoin Improvement Proposal, so it provides with different proposals to improve bitcoin. BIP32 shows how to implement HD wallets and so that is important for your work and BIP44 as well. So BIP is overall improvements of Bitcoin and HD wallets are part of those


text:
How to change checking processes - bitcore-node
We are trying to set up bitcore-node to work with other cryptocurrency core. Lets say that everything in core is pretty much the same like in bitcoin core so everything should work.
After resolving some problems we stuck on starting and exiting node process. It looks like this:

[2017-11-09T12:20:29.239Z] info: Using config: /Users/gitsad/GIT/bitcore-node/ourcoinNode/bitcore-node.json
[2017-11-09T12:20:29.241Z] info: Using network: testnet
[2017-11-09T12:20:29.242Z] info: Starting bitcoind
[2017-11-09T12:20:29.244Z] info: Using bitcoin config file: /Users/gitsad/GIT/bitcore-node/ourcoinNode/data/dash.conf
[2017-11-09T12:20:29.249Z] info: Starting dash process
OurCoin Core server starting
[2017-11-09T12:20:29.294Z] warn: Dash process unexpectedly exited with code: 0
[2017-11-09T12:20:29.295Z] warn: Restarting dash child process in 5000ms
[2017-11-09T12:20:29.315Z] info: Dash Height: 0 Percentage: 0.01
[2017-11-09T12:20:29.324Z] info: Dash Daemon Ready
[2017-11-09T12:20:29.325Z] info: Starting web
[2017-11-09T12:20:29.369Z] info: Bitcore Node ready
[2017-11-09T12:20:29.802Z] warn: ZMQ connection delay: tcp://127.0.0.1:28332
[2017-11-09T12:20:29.802Z] info: ZMQ connected to: tcp://127.0.0.1:28332

Process exits and starts again:

[2017-11-09T12:20:34.301Z] info: Using bitcoin config file: /Users/gitsad/GIT/bitcore-node/ourcoinNode/data/dash.conf
.
.
.
the same stuff

We found in lib code in bitcore-node/lib/services/bitcoind.js

self.spawn.process.once('exit', function(code) {
      if (!self.node.stopping) {
        log.warn('Bitcoin process unexpectedly exited with code:', code);
        log.warn('Restarting bitcoin child process in ' + self.spawnRestartTime + 'ms');
        setTimeout(function() {
          self._spawnChildProcess(function(err) {
            if (err) {
              return self.emit('error', err);
            }
            log.warn('Bitcoin process restarted');
          });
        }, self.spawnRestartTime);
      }
    });

We changed it by adding return; at the end of line:

self.spawn.process.once('exit', function(code) { return;

And this resolved our problem with the restarting process.
The question is:
Where can we find the conditions on which this function checks the process and how we can change it?
Every help will be appreciated. Thanks!


text:
When generate WIF private key , base58check('80'.decode('hex')) not prefix as '5'
i try to generate WIF private key with python.
import base58
import hashlib

def b58(hex):
    return base58.b58encode(hex)

def sha256(hex):
    return hashlib.sha256(hex).digest()

def main():
    k = sha256('private_key')
    extend = '80' + k.encode('hex')
    sha1 = sha256(extend.decode('hex'))
    sha2 = sha256(sha1)
    print b58(extend.decode('hex') + sha2[:8])

if __name__ == '__main__':
    main()

the result's prefix is not '5' but 'V'
i try to just base58encode 0x80 and the result is 3D ???
where is mistake in this code?

By comparing all variables with this tool, I've found that the mistake is in this line:
print b58(extend.decode('hex') + sha2[:8])

Remember that sha2 is a byte array and not a hex string. You can replace the 8 with a 4 to make your code work.
You can also simplify the code even further to:
def b58(hex):
    return base58.b58encode_check(hex)

def sha256(hex):
    return hashlib.sha256(hex).digest()

def main():
    k = sha256('private_key')
    extend = '80'.decode('hex') + k
    print b58(extend)

For today's Python 3 I found working this code:
#!/usr/bin/env python3
import base58
import hashlib
import sys

def b58(hex):
    return base58.b58encode_check(hex)

def sha256(hex):
    return hashlib.sha256(hex).digest()

def main():
    k = sha256(str(sys.argv[1]).encode('utf-8'))
    extend = '80' + k.hex()
    print(b58(bytes.fromhex(extend)).decode('utf-8'))

if __name__ == '__main__':
    main()


text:
Processed withdrawal not reflecting in my blockchain wallet
Given below are the transaction details for the transaction which is not reflecting in my blockchain wallet,
Transaction batch :f28888630e090d083ce2be5658f526b148d3e8259a33bbcfa58063cc13e8a4c0
wallet address : 1NUf8TSGw5nuDpUre42n927dKhpDmeMdTo
Please note that i have some bitcoins before from 1HG43hWnE7ZZAcbhA3umYxB7JgPU99kATJ using the same wallet. So for the above transaction i just took the above wallet address and forward it to the one who was supposed to send me other bitcoins.
The transaction is showing on the blockchain explorer but it hasnot reflected in my blockchain wallet.
Please kindly assist, how can i recover the bitcoins if possible.
Kushie

The transaction shows for me. If it doesn't show for you, perhaps your wallet is out of sync or on the wrong chain. Easy thing to try is to restart the wallet.


text:
How long would it take for all the Bitcoin Key pairs to be calculated?
Is this even something one should be worried about?

This is more fun to calculate for yourself than to ask for the answer.  Why not try it and ask if you get stuck?

I guess I should take the time it takes to calculate a single key pair and multiply it with the total number of private keys, not the total number of possible addresses (to account for expected(?) collisions). So, totalTime = singleKeyPairTime * 2^256. Right?

Sure.  Of course, they could be computed in parallel, so if you want the real time required to calculate all keys, you should divide by the number of machines being used.

The closest I have come to answering how long a single ECDSA key generation takes is "some milliseconds". I ran the numbers and even if you run thousands of computers in parallel + assume one computer can calculate tens of thousands of keyGenerations/s, the infinitesimally small percentage of public keys you will find in your lifetime, is simply not worth it.

Does this answer your question? How long would it take a large computer to crack a private key?

related: Is Each Bitcoin Address Unique?

No, you shouldn't worry about it.
3Blue1Brown has made a great video explaining how large 256 bit is, check it out


text:
can i run a full node on a laptop without a 3rd party router?
i am  using verizon fios and have attemped to connect to full node. verizon said that i can n0t do it on their router and would need to purchase a 3rd party router and daisy chain to theirs. Any suggestions would be appreciated. thanks.

Do you want to connect from the laptop to a (other person's) full node or do you want to run your own full node on the laptop?

In any case what did they say why it won't work? You might try out, probably the hotline employees aren't the Bitcoin experts. If you want to run your own node I'd only recommend if the laptop has good RAM and has an SSD (for speed reasons) - however the SSD won't live as long as usally I heard because the Bitcoin node is doing so many write operations...

What is the actual issue with using their router? Does it not allow you to customize the port forwarding rules?

You seem confused. You can run a full node on your laptop just fine, regardless of what router you have. You may be unable to let other nodes connect to you, but that is just charity to the network, and not doing doesn't make your node any less full or any less useful.

To run a full node you don't need to have opened incoming port. It will function correctly being just a "fetching" node.
When you are behind NAT which one you do not manage you still can achieve your node visibility in various ways:
1) Using third party "middleman" services.
as Randy mentioned, there is a dyn.com, where you install their client and then you have a domain, which will be routed to your WAN ip, even it changes all the time. I thought this service solves only dynamic WAN IP change - in this case this won't help you if your provider still is blocking incoming connections (need port forward). but probably they offer also so-called "port tunneling" with their client.
there's also great service by https://ngrok.com/ , you can configure it to access your bitcoind REST api even you are behind filtered NAT.
Be aware that in this case all the data you exchange probably can be read by those service providers (still very unlikely)
2) [RECOMMENDED, most self-controlled and private option] You can use Tor hidden service. The complete guide is available here: https://2019.www.torproject.org/docs/tor-onion-service.html.en . In short: you spin up a tor daemon, and then create so called "tor hidden service", which basically means that you need to set in config some "tor port forwarding".
HiddenServiceDir /var/db/tor/your/local/path/for/particular/onion
HiddenServicePort 8333 127.0.0.1:8333 #exposing to TOR network bitcoind communication port
HiddenServicePort 8332 127.0.0.1:8332 #exposing to TOR network bitcoind RPC port

In a /var/db/tor/your/local/path/for/particular/onion directory you can find hostname file which will be smth like 32j46jh46r4hy45hy435j7h47h4e6yhreu.onion. Then any bitcoin node which is operating via TOR proxy will be able to connect to your node. The advantage of such approach is that you can also use remotely RPC commands in encrypted way (all data transmission is encrypted in TOR)
3) i'll take this question as opportinity to shill my own service https://bitclouds.sh - you can spin up full bitcoin node which will be pre-synced and available on regular internet. Reliable and 24/7 connected, because located in high-grade datacenters. You have full control of such node, it has TORed outgoing connections out-of-box, you are able to RPC remotely (but be aware of risks when allowing remote RPC, its not reccomended and remote calls are not enabled by default on bitclouds - you need to change line in bitcoin.conf). Here's more info: https://github.com/bitcoin-software/bitbsd-clouds/tree/master/bitcoind (non-custodial, keys and configs under your control). Thanks to underlying filesystem (ZFS) i am using i am able to offer such bitcoind "containers" just for 66 sats per hour, so it is even cheaper to run on old PC at home.


text:
How to implement 2/2 multi-signature transactions with bitcoinj
I am using bitcoinj to implement a 2/2 multi-signature transaction. Now I  want to use bitcoinj to generate a 2/2 multi-signature address and its corresponding Redeem Script through the public keys of the two parties, and  to perform sequential signatures between the two parties. I didn't find a similar example in the description document of bitcoinj. Can you give me a specific implementation?

Any special reason why you want to use bitcoinj? Eletrum might be easier for multisig...


text:
How to sign a 2-of-2 multisig address?
I want to implement 2-of-2 multisig in bitcoinj, and I implement the methods which are used to sign the first time and the second time. But there is a bug that using the same key for the first signing and second signing can also pass the transaction verification and can be broadcast. Where the mistake is？
sign_first_time(Transaction spendTx, String firstkey,String redeemScript_String){
        ECKey key1 = HexToECKey(firstkey);
        Script redeemScript = new Script(hexStringToByteArray(redeemScript_String));
        Sha256Hash sighash = spendTx.hashForSignature(0, redeemScript, Transaction.SigHash.ALL, false);
        ECKey.ECDSASignature ecdsaSignature = key1.sign(sighash);
        TransactionSignature transactionSignarture = new TransactionSignature(ecdsaSignature, Transaction.SigHash.ALL, false);
        Script inputScript = ScriptBuilder.createP2SHMultiSigInputScript(Arrays.asList(transactionSignarture), redeemScript);
        TransactionInput input = spendTx.getInput(0);
        input.setScriptSig(inputScript);
       }

sign_second_time(String transactionString,String secondkey){
        Transaction spendTx = new Transaction(params, hexStringToByteArray(transactionString));
        Script inputScript = spendTx.getInput(0).getScriptSig();
        List<ScriptChunk> scriptChunks = inputScript.getChunks();
        List<TransactionSignature> signatureList = new ArrayList<TransactionSignature>();
        Iterator<ScriptChunk> iterator = scriptChunks.iterator();
        Script redeemScript = null;

        while (iterator.hasNext())
        {
            ScriptChunk chunk = iterator.next();

            if (iterator.hasNext() && chunk.opcode != 0)
            {
                TransactionSignature transactionSignarture = TransactionSignature.decodeFromBitcoin(chunk.data, false,false);
                signatureList.add(transactionSignarture);
            } else
            {
                redeemScript = new Script(chunk.data);
            }
        }
        Sha256Hash sighash = spendTx.hashForSignature(0, redeemScript, Transaction.SigHash.ALL, false);
        ECKey.ECDSASignature secondSignature;
        ECKey key2 = HexToECKey(secondkey);
        secondSignature = key2.sign(sighash);
        TransactionSignature transactionSignarture = new TransactionSignature(secondSignature, Transaction.SigHash.ALL, false);
        signatureList.add(transactionSignarture);
        inputScript = ScriptBuilder.createP2SHMultiSigInputScript(signatureList, redeemScript);
        spendTx.getInput(0).setScriptSig(inputScript);
        return spendTx;
    }


text:
Sent BTC from Coinbase, blockchain explorer says Confirmed. Is recipient lying or could something else be the issue?
Sent BTC (approx $500) from Coinbase,  Blockchain explorer says Confirmed. Is recipient lying they have not received or could something else be the issue such as his wallet?
Recipient says it could be because his 'hard' wallet is set up in a way so it activates/acknowledges/receives with $1000 transaction minimum?
He is meant to send back a larger payment to my wallet ( from which i sent the payment) as part of some investment returns. Don't want to think i'm being scammed so giving the benefit of the doubt and seeing what the community answers with.
https://www.blockchain.com/btc/tx/8fc6a9b6a4678efa77d07c959652e2cd7a5c2a7a00b948766d6bcd551bcffec4

Most certainly a scam, sorry. Cut your losses and move on, not much else can be done here.

This is 100% definitely a scam. Investments simply don't work the way you're describing.

Is recipient lying they have not received or could something else be the issue such as his wallet?

Seems likely in this case.

Recipient says it could be because his 'hard' wallet is set up in a way so it activates/acknowledges/receives with $1000 transaction minimum?

This is not a thing, you're almost certainly being scammed. Wallets don't require activation or acknowledgement to receive coins. If you sent coins, and the tx is confirmed, the wallet has received it.

He is meant to send back a larger payment to my wallet ( from which i sent the payment) as part of some investment returns.

This is 100% a scam - Do not send this person any more money and cut your losses now.

Thanks for the feedback Raghav.

Tell receiver to send tx id, check on block explorer, if confirmed, then there are two reasons ;

It is either you sent to another public address or
The receiver is not honest.

I think the number 2 :)


text:
When exactly do the transactions get validated?
I have some gaps in my understanding to the life cycle of the transaction that I want someone to help me fill them specially with the validation.
What I understand about the life cycle with my questions:
1) Transaction is signed off by the user through the wallet app and broadcasted to the blockchain network.
The question at this step is: does the wallet app perform any kind of transaction validation that requires to check the whole history of the blockchain at this level ?

2) The broadcasted transaction is now sent to many nodes on the network, and these nodes forward/ "propagate" the transactions to other nodes till all the nodes have this transaction in their "pool of unconfirmed transactions" ?
Tell me if I'm getting any part wrong or not in it's right order

3) Each miner will pick some transactions and start the mining (doing the proof of work till finding a correct hash)
At this level when the miner picks the transactions, does he perform a validation of each transaction that requires full scan of the history of the blockchain ?

4) When the miner solves the block, he will broadcast that block along with the hashed value he produced to the blockchain network in the same way the transaction was broadcasted to some nodes and propagated to the rest. Then the nodes will hash the block header to verify whether or not it produces the same hash so they can accept that block.
The question here is: do the nodes perform another validation at all the transactions sent with the block header to verify they are real transactions not fake ones created by the miner who solved the block ?
Does the validations on these transactions require a check against all the history of the blockchain ?
I know how merkle trees hash multiple transactions and that any modification to a transaction's hash will change the merkle root's value, but my question here is how is that helpful ? wouldn't the miner who already faked up any of the transactions have the right merkle root for all the transactions in the block since he is the one who added them in the first place ? My point is how does merkle root help ? what value does it add ? what kind of attack does it prevent ?

The last question is the consensus, from its definition it is that all nodes agree that they are at the same level with the new block. I know the PoW, but how all the nodes check and communicate together to acknowledge that all of them got the same block ?

The question at this step is: does the wallet app perform any kind of transaction validation that requires to check the whole history of the blockchain at this level ?

It depends on the wallet.
In general, a wallet will likely do some validation as a sanity check to ensure that the transaction they create is valid and will be accepted by nodes on the network. They will usually check that the signatures are valid and that the transaction is valid assuming that the previous transactions it spends from are also valid.
Whether those previous transactions are valid are a different story. There are different validation and security models that are employed. But generally, a wallet will only store and recognize a transaction as its when it believes it to be valid. It will then rely on the assumption that it is valid (whether it validated it or has some other means to believe it is valid) so that it does not need to re-validate the transaction later.

2) The broadcasted transaction is now sent to many nodes on the network, and these nodes forward/ "propagate" the transactions to other nodes till all the nodes have this transaction in their "pool of unconfirmed transactions" ?

That is correct. But at this stage, nodes validate the transaction using the full transaction history before they relay the transaction further onto other peers. Note that they don't re-validate previous transactions nor do they linearly search through the blockchain. Rather they have databases and  indexes which make transaction validation extremely fast.
Additionally, not all nodes need to have the transaction or to have seen the transaction. There is also no way to know whether all nodes have seen and validated a particular transaction.

The question here is: do the nodes perform another validation at all the transactions sent with the block header to verify they are real transactions not fake ones created by the miner who solved the block ?

Naively (and previously), yes. A simple implementation would simply re-validate every single transaction received in a block.
A faster implementation (and what Bitcoin Core does now), is to cache whether a particular transaction has been validated before and whether it was valid. So when it goes through a block, instead of re-validating all the transactions that the node has seen before, it just calls up the validation result previously. This can be easily done by restricting the mempool (pool of unconfirmed transactions) to transactions that would be valid if they are included in he next block. So if a transaction that is received in a block is found in the mempool, then it is known to be valid and does not need to be re-validated.

I know how merkle trees hash multiple transactions and that any modification to a transaction's hash will change the merkle root's value, but my question here is how is that helpful ? wouldn't the miner who already faked up any of the transactions have the right merkle root for all the transactions in the block since he is the one who added them in the first place ? My point is how does merkle root help ? what value does it add ? what kind of attack does it prevent ?

The merkle root has nothing to do with transaction validity.
The merkle serves two purposes: to ensure that all transactions are included in the block hash, and to prove that a particular transaction was in a block without needing the block itself.
Since the merkle root is part of the block header, and since it is the hash of all transactions in a block, it serves to commit all of those transactions to the block header and to the Proof of Work. It just ensures that the block hash covers the transactions as well.
The merkle tree used to produce the merkle root also means that anyone with a full block can produce a simple proof that a transaction was included in a particular block. This is useful for SPV wallets. It does not prove that a transaction is valid and has no effect on whether a transaction is valid. A miner could include an invalid transaction and it would be part of the merkle tree. This doesn't make that transaction valid, nor does it make the block valid.

The last question is the consensus, from its definition it is that all nodes agree that they are at the same level with the new block. I know the PoW, but how all the nodes check and communicate together to acknowledge that all of them got the same block ?

They don't; there is no need to. Consensus is reached because nodes are connected to each other and broadcast blocks to each other. Because every node is programmed to follow the blockchain with the most work and to do its best to ensure that its peers learn about what it thinks is the best blockchain, the network naturally achieves consensus without any sort of agreement and acknowledgment. By relying on nodes switching to use the valid blockchain with the most work, nodes will converge onto the same blockchain as eventually, one blockchain will have the most work.