Revocable hierarchical identity-based encryption via history-free approach

Further, we propose two RHIBE schemes with shorter secret keys and constant size ciphertexts that implement the aforementioned history-free updates approach and security model. For revocation, our constructions use the Complete Subtree (CS) method and the Subset Difference (SD) method. Both schemes are selectively secure in the standard model under the q-weak Bilinear Diffie-Hellman Inversion assumption.