Exchanging Simetric Keys question.

[Steven Colley]

Hi folks, I have a question ..:

Which on the following statements about symmetric cryptography is false? (D).

A - The key must be secure shared between the sender and recipient. TRUE
B - The algorithm that uses the key to transform data is not considered part of the security system. - TRUE.
C - It's undemanding on system resources to encrypt and decrypt information. TRUE
D - It's often used to exchange symmetric keys so that faster symmetric encryption can be used. FALSE.


Folks could you please talk more about options C and D.

Tks in advance!!

[Piotr Swiecicki]

Cite from http://en.wikipedia.org/wiki/Symmetric-key_algorithm:

Symmetric-key algorithms are generally much less computationally intensive than asymmetric key algorithms. In practice, asymmetric key algorithm are typically hundreds to thousands times slower than a symmetric key algorithm.

This explains why C is true.
And D is false because actually the asymmetric encryption is used during SSL handshake to exchange symmetric keys. The second part of the sentence D is true - symmetric keys are later used as such an encryption method is faster