Which of the following is the MOST likely cause of users being unable to verify a single user’s
email signature and that user being unable to decrypt sent messages?

A.
Unmatched key pairs

B.
Corrupt key escrow

C.
Weak public key

D.
Weak private key

Explanation:
In a PKI the sender encrypts the data using the receiver’s public key. The receiver decrypts the
data using his own private key. The sender and receiver must have a matching key in order for the
receiver to decrypt the data.