Computer Security

Q1: Public Key Certificates (8 pts) Suppose that Alice and Bob are in domains X and Z respectively. The certificate authority CAx is responsible for the domain X, and CAZ is responsible for the domain Z. Assume that both CAx and CAZ are under a root authority CAY (i.e., CAY issues the public key certificates for both CAX and (Az). Assume Alice wants to use Bob's public key to encrypt a message and then sends the encrypted message to Bob. To ensure the validity of Bob's public key, what public key certificates does Alice need to collect and how does Alice verify these certificates