A Key-Insulated Ciphertext Policy Attribute Based Signcryption for Mobile Networks

Attribute based signcryption (ABSC) combines the merits of ABE and ABS, which can provide both confidentiality and authentication in a single step. In this paper, we present a key insulated ciphertext policy attribute based signcryption scheme (KI-CP-ABSC) for data protection in wireless networks. In our scheme, a target access structure is embedded into ciphertexts, while user's private key corresponds an attribute set. Only the two are matched can a receiver decrypt the ciphertexts and verify whether it is from valid data signer. We introduce key insulation mechanism into our scheme by dividing the system lifetime into several time periods. When key exposure happens, the system will evolve into the next time period to preserve the forward security. We eliminate bilinear parings in our KI-CP-ABSC thus the computation burden on the terminal devices are reduced sharply. The high efficiency and proved security make our KI-CP-ABSC a promising tool for secure data sharing in wireless environments.