Blockchain technology is based on a decentralized database, exact copies of which simultaneously exist on many different computers. In contrast to a bank, there is no centralized server that manages every transaction. Whenever a blockchain transaction is carried out, an entry to the database is created and recorded as a new block. If someone pays for a car, for example, many computers all over the world register the transaction – anonymously of course. Since every action is permanently and irreversibly recorded in every copy of this mirrored database and must be authenticated by all the computers in the network, transactions via blockchain are virtually impossible to manipulate. Bitcoin is one popular system based on blockchain technology.