Multiple review submission/retrieval occurs when
Alice wants to send Bob several rounds of review
information instead of one round. In this case, each
review is encrypted by using the symmetric key for the
submission process. Meanwhile, multiple decryptions are
required during the retrieval process. The performance of
multiple review submission/retrieval is showed in Figure
5. Specifically, we evaluate the performance of 5, 10, 15,
20, and 25 messages' symmetric key encryptions and
decryptions, respectively.