Which of the following best describes a digital signature?

A.
A method of transferring a handwritten signature to an electronic document

B.
A method to encrypt confidential information

C.
A method to provide an electronic signature and encryption

D.
A method to let the receiver of the message prove the source and integrity of a message

Explanation:
A digital signature provides authentication (knowing who really sent
the message), integrity (because a hashing algorithm is involved), and
nonrepudiation (sender cannot deny sending the message).