This is the fifth part of a series on searching on encrypted data. 1, 2, 3, 4. In the previous post we covered the most secure way to search on encrypted data: oblivious RAMs (ORAM). I always recommend ORAM-based solutions for encrypted search whenever possible; namely, for small- to moderate-size data 1. Of course, the main limitation of ORAM is efficiency so this motivates us to keep looking for additional approaches.