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