What is the biggest drawback to symmetric encryption?   It requires a key to be securely shared.   It is too easily broken.   It is available only on UNIX.   It is too slow to be easily used on mobile devices.

Symmetric Encryption is a type of encryption where the same key is used for both the encryption and decryption of data. In other words, the encryption and decryption processes are performed using a single, shared secret key. This contrasts with asymmetric encryption, where two different keys (a public key and a private key) are used for encryption and decryption.