Today we are going to learn what double spending is.
Double spending is the manipulation of the blockchain of any cryptocurrency in order to spend the same amount of coin several times, sending this coins to different addresses.
Let’s take an example on the bitcoin blockchain.
If we have only one bitcoin on our wallet, and we send it to Marco, this will be awaiting confirmation in the network mempool.
Immediately after closing the transaction to Marco and before waiting for the confirmations, we will send the same amount to Giorgio, and this transaction will also end up in the unconfirmed transaction pool.
When these transactions are checked by the miners, the second transaction will be rejected as invalid and impossible to carry out.
In case of simultaneous sending of several transactions, we will have to wait for the 6 confirmations to understand which of the two transactions will be rejected and which will not