Bitcoin and its many derivatives are known as cryptocurrencies. The system uses cryptography—extremely advanced cryptography called a blockchain—to generate new “coins” and verify the ones that are transferred from one user to another. The cryptographic sequences serve several purposes: making the transactions virtually impossible to fake, making “banks” or “wallets” of coins easily transferable as data, and authenticating the transfer of Bitcoin value from one person to another.
https://www.howtogeek.com/141374/htg-explains-what-is-bitcoin-and-how-does-it-work/

