Searchable Encryption Scheme Supporting Policy Hiding and Constant Ciphertext Length

The Attribute-Based Encryption (ABE) mechanism is one of the key technologies for implementing flexible access control of data in cloud storage. However, the existing ABE schemes have some problems, such as too much ciphertext storage overhead and user privacy leakage, and unsupported public auditing of cloud data. To solve these problems, a new searchable ABE scheme is proposed, and its security can be reduced to the difficulty of q-BDHE (q -decisional Bilinear Diffie-Hellman Exponent) problem and CDH (Computational Diffie-Hellman) problem. The proposed scheme achieves a constant ciphertext length on the basis of supporting keyword search. By introducing strategies to hide ideas, it prevents attackers from obtaining sensitive information and ensures the privacy of users. And the integrity of the data in cloud storage is verified through data public audit mechanism. Compared with the existing similar schemes, this scheme greatly reduces the data encryption overhead, keyword search overhead, ciphertext storage cost and decryption cost, which has a good application prospect to the cloud storage environment.