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2. Alice sends an email to Bob that she wants to be reasonably certain other people do not see. Discuss security methods, if any, one might use in the cases below. Indicate why these methods are needed for the specific scenario; in particular, discuss your solution in terms of the desired security goals. • Alice and Bob are at the same company location on a protected network • Alice emails Bob, who is at a public hotspot • Alice emails Bob; they are at separate company locations each on a protected network Feel free to define what “protected network” means if it matters. 3. Suppose Alice and Bob share a long-term master key, and that is all they share. • Show how Alice can send a message to Bob that satisfies confidentiality and integrity. Describe the steps explicitly. Mention which algorithms you are using. [If you appeal to an existing protocol, you must indicate why it is appropriate and still answer the questions.] • Indicate the steps that Bob needs to do when he receives the message. • Why was this method not considered when we discussed email security? What aspects of email makes this method difficult to realize in practice?

          2. Alice sends an email to Bob that she wants to be reasonably certain other people do not see. Discuss security methods, if any, one might use in the cases below. Indicate why these methods are needed for the specific scenario; in particular, discuss your solution in terms of the desired security goals.
• Alice and Bob are at the same company location on a protected network
• Alice emails Bob, who is at a public hotspot
• Alice emails Bob; they are at separate company locations each on a protected network
Feel free to define what “protected network” means if it matters. 

3. Suppose Alice and Bob share a long-term master key, and that is all they share.
• Show how Alice can send a message to Bob that satisfies confidentiality and integrity. Describe the steps explicitly. Mention which algorithms you are using. [If you appeal to an existing protocol, you must indicate why it is appropriate and still answer the questions.]
• Indicate the steps that Bob needs to do when he receives the message.
• Why was this method not considered when we discussed email security? What aspects of email makes this method difficult to realize in practice?

Added by Aaron Z.

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