Constant Size Ciphertext and Private Key HIBE without Random Oracles
Xiaoming Hu, Jian Wang, Huajie Xu, Yinchun Yang · 2014
Almost all existing hierarchical identity-based encryption (HIBE) schemes fully se-cure in the standard model at present have a drawback that at least one ciphertext size or private key size must rely on the hierarchy depth of identity. This drawback increases the computation and communication cost. In order to solve the problem, a new HIBE scheme with high efficiency is proposed, which has constant size ciphertext and private key, i.e. both ciphertext size and private key size are independent of the level of the hierarchy. What’s more, the proposed scheme is fully secure in the standard model with a tight re-duction. To the best of our knowledge, it is the first scheme that both ciphertext and pri-vate key achieve O(1) size with full security in the standard model.