ABSTRACT
This chapter explains predicate encryption (PE) and functional encryption (FE). The first part of the chapter defines PE and provides the comparison of PE followed by the definition of FE. The next part of the chapter provides preliminaries required starting from the discussion of bilinear map and hardness assumptions. The first hardness assumption is the asymmetric decisional bilinear Diffie-Hellman. Analyzing the surrounding situations from encrypted communications and the ensuing operation may allow an attacker to obtain hints about the future troop movements and encrypted communications. In the medical field, people can also see the importance of ensuring privacy in data transmissions. Although medical data usually require a high degree of privacy, they are referenced by many entities such as the patient himself/herself or staff from various departments or belonging to different medical institutions. Even partial exposure of those attributes could hurt the patient’s privacy.
