The private key, on the other hand, is kept secret and used only by the owner to decrypt messages encrypted by end-to-end encryption. With end-to-end encryption, the public key encrypts the data and the private key decrypts it.When sending a message through Messenger, the sender generates a SHA3-512 symmetric key, which is used to encrypt the message with a public key, which is stored on the Public Server or Business Account Server. The message's recipient decrypts the symmetric key with the private key, which is decrypted with the password. Dober generates a unique symmetric key for each message.