Attribute Based Encryption Method with Revocable Dynamic and Static Attributes for VANETs

The data secure sharing in vehicular ad hoc network (VANET) usually uses group encryption mode. However it is difficult to construct group and to manage group key for vehicular terminal with high mobility. Ciphertext-policy attribute-based encryption (CP-ABE) is a kind of new solution for VANETs' communication security. In the traditional CP-ABE strategy, it has several shortcomings, such as high decryption computation complex, and attributes revoking requires the re-encrypting of the whole cipher-text and the inflexible construction of access policy tree. These shortcomings lead to the limited application of CP-ABE in VANETs. In order to solve these problems, an ABE with revocable dynamic and static attributes (ABE-RDS) is proposed for the data secure sharing of cloud storage in VANETs. In the ABE-RDS, dynamic attribute and static attribute are managed separately, and combination policy tree is constructed, and main decryption part with high computation cost is delegated to servers using decryption proxy. In addition, the vehicular terminal can revoke attributes and refresh dynamic attributes through global and local trusted authority. The proposed ABE-RDS is secure, and it has superiority over traditional CP-ABE in space and time complexity. The performance of ABE-RDS in vehicular terminal decryption, attribute revocation, and system concurrent is evaluated with experiments.