Consider a scheme that allows a recipient to reply to a message from a chain of Cypherpunk remailers. Assume that encipherment is used throughout the chain.

a. Bob selects a chain of remailers for the return path. He creates a set of keys and enciphers them so that only the key for the current remailer is visible to that remailer. Design a technique by which he could accomplish this. Describe how he would include this data in his message.

b. How should Alice mailer handle the processing of the return address information?

c. When Bob receives the reply, what does it contain? How can he obtain the cleartext reply?