Efficient Hierarchical Identity Based Encryption Scheme in the Standard Model

Constructing identity based schemes is one of the hot topics of current cryptography. Hierarchical identity based cryptography is a generalization of identity based encryption that mirrors an organizational hierarchy. It allows a root public key generator to distribute the workload by delegating public key generation and identity authentication to lower-level public key generators. Currently, there is no hierarchical identity based encryption scheme that is fully secure in the standard model, with short public parameters and a tight reduction. In this paper, we propose an anonymous hierarchical identity based encryption scheme based on the q-ABDHE problem that is fully secure in the standard model. The ciphertext size is independent of the level of the hierarchy. Moreover, our scheme has short parameters, high efficiency and a tight reduction.