Symmetric encryption algorithms are known to be fast but present great challenges on the key
management side. Asymmetric encryption algorithms are slow but allow communication with a
remote host without having to transfer a key out of band or in person. If we combine the strength
of both crypto systems where we use the symmetric algorithm to encrypt the bulk of the data and
then use the asymmetric encryption system to encrypt the symmetric key, what would this type of
usage be known as?
A.
Symmetric system
B.
Combined system
C.
Hybrid system
D.
Asymmetric system
Explanation:
Because of the complexity of the underlying problems,most public-key algorithms
involve operations such as modular multiplication and exponentiation,which are much more
computationally expensive than the techniques used in most block ciphers,especially with typical
key sizes. As a result,public-key cryptosystems are commonly “hybrid” systems,in which a fast
symmetric-key encryption algorithm is used for the message itself,while the relevant symmetric
key is sent with the message,but encrypted using a public-key algorithm. Similarly,hybrid signature
schemes are often used,in which a cryptographic hash function is computed,and only the resulting
hash is digitally signed.
C