Secure and flexible keyword search over encrypted data with outsourced decryption in Internet of things

The development of Internet of things (IoT) makes data exchange more frequently, and the cloud computing can provide stable storage and efficient computation for data users. To ensure the security and functionality of data, the efficiency of decryption and keyword search should be taken into consideration in resource-constrained IoT scenarios. In order to solve the above problems, a flexible keyword search scheme in IoT is proposed over encrypted data with outsourced decryption. First, the attribute-based encryption technology is applied, by which only users whose attributes meet the access control structure can access the sharing data. Second, the reciprocal mapping of Lagrange polynomials technology is employed to implement keyword search in a large number of ciphertext data. Third, the decryption of ciphertext is outsourced to improve the efficiency of decryption on the client side. The security and performance analysis indicates that the proposed scheme is secure and efficient.