CompTIA Security+ Question E-5

Company A submitted a bid on a contract to do work for Company B via email. Company B was insistent that the bid did not come from Company A. Which of the following would have assured that the bid was submitted by Company A?

A. Steganography
B. Hashing
C. Encryption
D. Digital Signatures

Answer: D

A digital signature is similar in function to a standard signature on a document. It validates the integrity of the message and the sender. The message is encrypted using the encryption system, and a second piece of information, the digital signature, is added to the message.