κρυπτογράφηση δημόσιου κλειδιού(A method of encryption that uses a pair of mathematically related keys: a public key and a corresponding private key. Either key can be used to encrypt data, but the corresponding key must be used to decrypt it)
κρυπτογράφηση μυστικού κλειδιού(An encryption algorithm that requires the same secret key to be used for both encryption and decryption. Because of its speed, symmetric encryption is typically used when a message sender needs to encrypt large amounts of data)