An efficient IBE scheme with tight security reduction in the random oracle model

We present a new practical identity-based encryption (IBE) system that can be another candidate for standard IBE techniques. Our construction is based on a new framework for realizing an IBE trapdoor from pairing-based groups, which is motivated from the ‘two equation’ revocation technique suggested by Lewko et al. (IEEE Symposium on Security and Privacy, 2010). The new framework enables our IBE system to achieve a tight security reduction to the Decisional Bilinear Diffie–Hellman assumption in the random oracle model. Due to its the tightness, our system can take as input the shorter size of security parameters than the previous practical BF, SK, and (Formula presented.) systems, which provides better efficiency to our system in terms of computational cost.