Cryptography
The branch of computer science that studies secure communication methods that allow only the sender and recipient of a message to see its contents. The cryptography used to protect cryptocurrencies is called public key cryptography or asymmetric cryptography.
While the public key allows the sender to encrypt the data, the private key allows the recipient to decrypt it. Each asymmetric key pair is unique, which ensures that only the person who has the private key corresponding to the public key can read the encrypted data.