Suppose that a particular security protocol is well designed and secure. However, there is a fairly common situation where insufficient information is available to complete the security protocol. In such cases, the protocol fails and, ideally, a transaction between the participants, say, Alice and Bob, should not be allowed to occur. However, in the real world, protocol designers must decide how to handle cases where protocols fail. As a practical matter, both security and convenience must be considered. Comment on the relative merits of each of the following solutions to protocol failure. Be sure to consider both the relative security and user-friendliness of each.
a. When the protocol fails, a brief warning is given to Alice and Bob, but the transaction continues as if the protocol had succeeded, without any intervention required from either Alice or Bob.
b. When the protocol fails, a warning is given to Alice and she decides (by clicking a checkbox) whether the transaction should continue or not.
c. When the protocol fails, a notification is given to Alice and Bob and the transaction terminates.
d. When the protocol fails, the transaction terminates with no explanation given to Alice or Bob.