ABSTRACT
This chapter provides the details of the Waters’ Identity-Based Encryption (IBE) scheme. It provides the preliminaries including the security model and hardness assumptions for the IBE scheme. The chapter gives the dual system encryption followed by the Waters’ IBE. In 2009, Waters proposed a new methodology called dual system encryption that allows us to prove that an IBE scheme is fully (adaptively) secure based on static assumptions without random oracle. The crux of Waters’ strategy is to move to a security game where both the challenge ciphertext and secret keys are semi-functional. At this point, any keys the challenger gives out are not useful in decrypting the ciphertext.
