Certified Information Systems Auditor (CISA) — Question 409

To create a digital signature in a message using asymmetric encryption, it is necessary to:

Answer options

• A. encrypt the authentication sequence using a public key.
• B. first use a symmetric algorithm for the authentication sequence.
• C. transmit the actual digital signature in unencrypted clear text.
• D. encrypt the authentication sequence using a private key.

Correct answer: D

Explanation

The correct answer is D because a digital signature is created by encrypting the hash of the message (the authentication sequence) with the sender's private key, ensuring that only the sender could have created it. Option A is incorrect since the public key is used for verification, not creation. Option B is irrelevant because symmetric algorithms are not used in the creation of digital signatures. Option C is wrong because transmitting the digital signature in clear text would compromise its integrity.