CISA Certified Information Systems Auditor – Question2245 - CISA Certified Information Systems Auditor

To affix a digital signature to a message, the sender must first create a message digest by applying a cryptographic hashing algorithm against:

A. the entire message and thereafter enciphering the message digest using the sender's private key.
B. any arbitrary part of the message and thereafter enciphering the message digest using the sender's private key.
C. the entire message and thereafter enciphering the message using the sender's private key.
D. the entire message and thereafter enciphering the message along with the message digest using the sender's private key.

Correct Answer: A

Explanation:

Explanation:
A digital signature is a cryptographic method that ensures data integrity, authentication of the message, and non-repudiation. To ensure these, the sender first creates a message digest by applying a cryptographic hashing algorithm against the entire message and thereafter enciphers the message digest using the sender’s private key. A message digest is created by applying a cryptographic hashing algorithm against the entire message not on any arbitrary part of the message. After creating the message digest, only the message digest is enciphered using the sender’s private key, not the message.