Which of the following cryptography options would increase overhead/cost?

A.
The encryption is symmetric rather than asymmetric.

B.
A long asymmetric encryption key is used.

C.
The hash is encrypted rather than the message.

D.
A secret key is used.

Explanation:

Computer processing time is increased for longer asymmetric encryption keys, and the increase
may be disproportionate. For example, one benchmark showed that doubling the length of an RSA
key from 512 bits to 1,024 bits caused the decrypt time to increase nearly six-fold. An asymmetric
algorithm requires more processing time than symmetric algorithms. A hash is shorter than the
original message; therefore, a smaller overhead is required if the hash is encrypted rather than the
message. Use of asecret key, as a symmetric encryption key, is generally small and used for the
purpose of encrypting user data.