All data on the Internet is easily copied. As we know, Bitcoin is just one application of Blockchain technology, meaning that each Bitcoin transaction is just one file.

Normally, when dealing online, we will need a third party that we trust (eg, intermediary, shipping company, bank ...) with a database set to verify the transaction to prevent fraud when the crooks use this file repeatedly.

Blockchain technology solves this problem without the need for a reliable third party.

Blockchain is a ledger that records all transactions

The data in the ledger is constantly being updated and maintained by computer networks in the world.

Transactions where A sends X bitcoin to B are recorded across the system, all computers in the network will verify and record that transaction in the general ledger and then distribute this data to other computers.

Blockchain is a standalone dispersed database; computers are constantly performing independent audits by verifying incoming data and comparing it with the signature of the transaction.