Suppose that Sally (a server) needs access to a symmetric key for user Alice and another symmetric key for Bob and another symmetric key for Charlie. Then Sally could generate symmetric keys KA,KB, and KC and store these in a database. An alternative is key diversi?cation, where Sally generates and stores a single key KS . Then Sally generates the key KA when required as KA = h(Alice,KS ),with keys KB and KC generated in a similar manner. Describe one advantage and one disadvantage of key diversi?cation.