CISA Certified Information Systems Auditor – Question1599 - CISA Certified Information Systems Auditor

A company has decided to implement an electronic signature scheme based on public key infrastructure. The user's private key will be stored on the computer's hard drive and protected by a password. The MOST significant risk of this approach is:

A. use of the user's electronic signature by another person if the password is compromised.
B. forgery by using another user's private key to sign a message with an electronic signature.
C. impersonation of a user by substitution of the user's public key with another person's public key.
D. forgery by substitution of another person's private key on the computer.

Correct Answer: A

Explanation:

Explanation:
The user’s digital signature is only protected by a password. Compromise of the password would enable access to the signature. This is the most significant risk. Choice B would require subversion of the public key infrastructure mechanism, which is very difficult and least likely.
Choice C would require that the message appear to have come from a different person and therefore the true user’s credentials would not be forged. Choice D has the same consequence as choice C.