Consider the following format for Alice sending signed, encrypted email to Bob:

Alice invents a secret key S and sends {S}_Bob, the message encrypted with S, and the message digest of the message signed by Alice. Is this secure? Your response needs to include a justification with citations. (Hint: Alice only signs the message digest. You may want to breakdown the information the question provides into the syntax of the textbook and compare the results with known methods.)

this is network security question please dont copy other answers thanks