Double spending is a flaw in digital currency systems where a single digital coin can be spent more than once. In a traditional physical transaction, when you give someone a dollar bill, you no longer have that bill. The act of handing it over transfers ownership to the other person. However, with digital money, things work differently.
When you make a transaction with digital cash, you’re essentially sending a message to a network of computers (called ‘nodes’) that confirms and records the transaction. These nodes are responsible for ensuring that the transaction is valid and that the same coin isn’t spent twice.
However, this confirmation process takes time. During this period, there’s a risk that someone might try to copy the transaction and send it out again before the network has fully confirmed the original transaction. This could result in the same digital coin being used more than once, which is known as double spending.