. R1. What are the differences between message confidentiality and message integrity? Can you have confidentiality without integrity? Can you have integrity without confidentiality? Justify your answer.

. R3. From a service perspective, what is an important difference between a symmetric-key system and a public-key system?

. R12. What does it mean for a signed document to be verifiable and non-forgeable?

. R14. Suppose certifier.com creates a certificate for foo.com. Typically, the entire certificate would be encrypted with certifier.coms public key. True or False?

. R23. Suppose Bob initiates a TCP connection to Trudy who is pretending to be Alice. During the handshake, Trudy sends Bob Alices certificate. In what step of the SSL handshake algorithm will Bob discover that he is not commu- nicating with Alice?