New constructions of hierarchical identity-based encryption in the standard model

In this paper, a new hierarchical identity-based encryption scheme(HIBE) is proposed at first. The proposed scheme is constructed in the generalized selective-ID model without using the random oracles. Under the decision bilinear Diffie-Hellman inversion (decision BDHI) assumption, the scheme is provably secure against chosen plaintext attacks(CPA). Furthermore, we convert it to a constant size ciphertext scheme and reduce its security to the l-DBDHI problem.