SOLVING THE DOUBLE SPENDING PROBLEM

The attack: successful use of the same fund twice
A transaction is generated with BTC 10 to both Bob and Carol at the same time
The solution:
The transactions are irreversible (computationally impractical to modify)
Every transaction can be validated against the existing blockchain

so this proof of work also solves a problem in any digital cryptocurrency which means– known as a double-spending problem or this double-spending can also work as an attack

sometime so the double-spending means the successful use of the same fund twice so the attacker is trying to transfer the same Bitcoin to two different people almost at the same instance of time so the attacker can launch a transaction A to B with certain Bitcoin with certain say Bitcoin xx and then the attacker launches another transaction to see with the same Bitcoin 20 and here the attacker say has only 20 Bitcoin with him or her so that way this kind of attack is known as the double-spending attack in the digital currency literature so Bitcoin by utilizing this proof-of-work mechanism

it also solves the double pending spending problem because the transactions that we are putting in the block are irreversible or at least they are computationally impractical to

modify we are not saying that it is impossible to modify but as I have

mentioned that the attacker has to do a significant amount of work or rather

they have to do the work more than the collective work of the blockchain and

that way it is computationally impractical and that is why the attacker will not be encouraged to launch this kind of attack so that way whatever transactions which have been already

submitted in the blocks they are kind of permanent transactions so they are

kind of permanent transactions means you can think of them as the permanent

ledger and whenever some new transaction comes you can also always validate that whether the new transaction confirms with the existing transactions which are there in Blockchain read more