With symmetric cryptography, the complete secrecy of the key must be assured. Whereas asymmetric cryptography requires only half of the secrecy, namely that of the private key (sk).
Secondly, symmetric cryptography utilizes the same secret key for the encryption and decryption of the ciphertext, but in asymmetric cryptography two different keys (namely the public and the private keys) are used for the encryption and the decryption of the ciphertext.
