A Key Insulated Ciphertext Policy Attribute Based Sign Cryption for Mobile Networks

ABE (attribute based encryption) and ABS (attribute based signature) are significant cryptographic primitives which can guarantee secure data sharing between users. However, the traditional sign-then-encrypt mechanism not only consumes much more computation cost on wireless terminal devices, but also brings about high transmission load to mobile communication systems when key updating happens. In this paper, we first combine the advantages of ciphertext policy attribute based encryption (CP-ABE) with ABS and construct a ciphertext policy attribute based signcryption scheme based on LSSS structure. Secondly, we introduce the key-insulation mechanism into our scheme, which helps provide flexible and high efficient key updating as well as guarantees both forward and backward security. Finally, by security analysis and performance comparison, we prove our scheme meets the security demands of confidentiality, unforgeability as well as lower computation cost. The high efficiency with better performance shows that our KI-CP-ABSC (key-insulated ciphertext policy attribute based signcryption) scheme is more appropriate for the data security protection in mobile communication systems.