In most security protocols that support authentication, integrity and confidentiality,

A.
Public key cryptography is used to create digital signatures.

B.
Private key cryptography is used to create digital signatures.

C.
Digital signatures are not implemented.

D.
DES is used to create digital signatures.

Explanation:
The correct answer is “Public key cryptography is used to create digital signatures.”.
Answer “Private key cryptography is used to create digital signatures” is incorrect because private
key cryptography does not create digital signatures.
Answer “DES is used to create digital signatures” is incorrect because DES is a private key
system and, therefore, follows the same logic as in “Private key cryptography is used to create
digital signatures”; and answer “Digital signatures are not implemented” is incorrect because
digital signatures are implemented to obtain authentication and integrity.