Which is NOT a disadvantage of the symmetric encryption method?

A.
The same key is used for decrypt and encrypt, therefore if someone steals the key they can
decode traffic in both directions.

B.
The keys must be delivered in a secure manner, by telephone of face to face.

C.
It is less efficient.

D.
It is not scalable for large numbers of keys.

Explanation:

: Since we are using only one key to encrypt and decrypt the data (Convert from clear-text to
cipher-text), this method of encryption is like a thousand times more efficient than Asymmetric
encryption that uses 2 keys, one for encrypting and the other for decrypting. However symmetric
encryption its not very scalable for the number of different keys you need to manage, there is also
a security weakness because you can use the same key to encrypt and decrypt the
communications.