Certified Information Systems Auditor (CISA) — Question 1437

Which of the following will MOST likely compromise the control provided by a digital signature created using RSA encryption?

Answer options

• A. Altering the plaintext message
• B. Deciphering the receiver's public key
• C. Obtaining the sender's private key
• D. Reversing the hash function using the digest

Correct answer: C

Explanation

The correct answer is C, as obtaining the sender's private key would allow an attacker to create fraudulent signatures. The other options, while potentially harmful, do not directly compromise the digital signature's control like gaining access to the private key would.