user behavior – Log in before confirming a transaction

My team and I are building a self-service web portal that allows users to make the transaction as they would in person at a bank…first, when the users visit the web portal they process the transaction but before they make a payment they are made to log in before taken to a checkout page. I was wondering if it was a good user experience logging in before confirming the transaction.

bitcoin core – How to create a double spend to prioritize a new transaction over a previous unconfirmed transaction?

I’d like to generate a double spend transaction and increase the gas fees over the previous, unconfirmed transaction that has been stuck for a week. I know there’s other answers regarding double spend but I’m looking for more of a technical answer specific to my thought process and sample code.

I understand the general premise is to recreate the originating transaction in its entirety. I’ve started by utilizing bitcore-lib to perform a getRawTransaction of my currently stuck transaction. From here, I’m iterating over the vin and performing a getRawTransaction of the vin’s txid to retrieve the parent. I’m then parsing the parent, iterating over each vout and looking for vout.n to match the previous vin.vout. Once I find a match, I’m generating a utxo which effectively looks like this:

const utxo = {
    address: output.scriptPubKey.addresses(0),
    txId: vin.txid,
    outputIndex: vin.vout,
    script: output.scriptPubKey,
    satoshis: output.value
};

I then use these utxos to generate and sign the transaction as follows (sorry for lack of full class, but the actual process of signing transactions is fully functional):

const transaction = new Bitcore.Transaction();

transaction.fee(this.fee());
transaction.from(utxos);
targets.forEach((target) => {
    transaction.to(target.address, this.amountToSatoshis(target.amount));
});
transaction.change(address);
transaction.sign(this.privateKey(privateKey));

So my questions are…

  1. Is my thought process correct in how I could go about regenerating the original transaction for submission by bitcore?
  2. Is there an easier way to regenerate the transaction and increase the fees than how I’m trying to do it?
  3. When attempting to replicate/duplicate the previous utxos, would I want to also provide the sequence number in the utxo?
  4. Will this even work or will I even be able to submit this transaction to my same core node?
  5. If it won’t work, would it work if I ran -zapwallettxes on the core node first?

attack – Transaction Denial of Service

attack – Transaction Denial of Service – Bitcoin Stack Exchange

How do I double spend using electrum for fix unconfirmed transaction

I have two Blockchain.com wallets.(Both of them are mine)
Some days ago i did a big mistake.
I sent 1100$ From wallet #1 to wallet #2. (10.0 sat/vB > As you see this is very very low) (TX LINK)
And i sent that 1100$ to my friend from wallet #2 after the transaction upper immediately. (99.3 sat/vB) (TX LINK)
Because of low fee in first transaction, both transactions have n’t confirmed yet.
I asked people to fix these unconfirmed transactions.
They told me use another wallet like Electrum wallet and double spend those unconfirmed transactions.
So i installed Electrum in my windows 7 os.
For double spend using electrum i found this link :
https://steemit.com/bitcoin/@profitgenerator/tutorial-how-to-fix-unconfirmed-transactions
But it seems it has deprecated.
I could n’t understand one part of this tutorial :

Re-create the transaction, but this time put a higher fee.
Sign your transaction, and save it to a file, it should end with .txn extension

My questions :

  1. As you know Blockchain.Com has no RBF option. So those two transactions have n’t RBF flag.
    In this situation can i use double spend with electrum?
  2. How can i create a transaction in offline mode and sign and save it?
    I tried it.But after setting fee and click send button electrum tried to broadcast.And i could n’t find an option for sign or save transaction with .txn ex.
    Would you please share a complete step by step tut about this.
  3. If i double spend first transaction what happen to second unconfirmed one? (I am a bit confused about this)
  4. Should i double spend two unconfirmed transactions with two temp wallets in electrum or double send of first one is enough?

Prepare transaction with multiple recipient

Do you think it is possible programmaticall prepare a Bitcoin transaction that has multiple recipient to send the amount to?

Do you think I can show this trasaction in QR code, so payer can scan it with any of the available wallet app?

Hey can someone mine a transaction for me, I really need this transaction to go through

Here’s the transaction ID
08d34b593c13c0f505d2cf525cac6abeefedeaf4c2d1bfb349f04939f4681e80
I should’ve put the fee higher my bad. Please and thank you to whoever can mine the transaction. Not sure if it works like that though.

transaction fees – How to handle accounts balances

My goal is to manage a huge group of people investments.

enter image description here

let say each month each one puts in a different amount of dollars (it may even be 1 $) and I need to send to his wallet that amount in bitcoin.

If I’ll send to each person his own share of bitcoin, I’ll lose a lot of money because of fees, there are a lot of micro transactions.

is there any suggestions how I can manage this the best way?

When you come to think about it, any chance it’s similar to how stock exchanges dealing with managing accounts balances? no way they are paying the bitcoin transfer fee on each transaction inside the exchange. it’s not sustainable.

1) I thought about maybe purchasing the bitcoin in bulk, and save it, and to write each account balance in my own ledger, that way each user doesn’t really have a wallet.

pros: no transactions fees.

cons: user doesn’t really have a wallet, I’m fully in charge of his money in case his getting hacked.
How does the exchanges handle keeping all that crypto assets??

  1. I thought about creating each user a wallet, but it means I can’t support small investments.

I’d love some help here.

Does the miner machine get any other type of reward except confirmation of transaction in bitcoin?

Does the miner machine get any other type of reward except confirmation of transaction in bitcoin?(The answer precedes ​another question)

BlockChain.Com Wallet – Why transaction FEE Is very HIGH

I have two wallets in BlockChain.Com web site.
When i want to transfer bitcoin from one of them situation is like this :

Money for transfer : $1000
Transaction Fee = Priority = $26

In another wallet situation is like this :

Money for transfer : $1000
Transaction Fee = Priority = $210

I am so confused!!!!!!!!!!!!!
Why does BlockChain.Com act like this?
How can i reduce second wallet’s fee?

dogecoin – Why is more debited from my wallet than just the transaction fee and the value of my order?

This is not quite a bitcoin specific question but more a general question, I think.
I tried transferring 1 doge. I know there was 1 doge of transfer fee. Yet I suddenly see this “11,37” doge appearing in my transaction at the bottom:

enter image description here

https://dogechain.info/tx/aa0735452429dcc3837369e4d2ca1af38cd20d21bbda805861f803608c0f92df

Why is there suddenly 11,37 being debited from my wallet? Are these 11,37 doge lost?

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