Research Of Searchable Encryption Scheme For Internet Of Things Cloud Storage Environment

With the continuous development of Internet of things(IOT) cloud storage, the leaks of user data are occurring frequently. These events cause great losses to individual and enterprise. More and more researchers begin to pay attention to the security and privacy protection of IOT cloud storage. In order to protect the privacy of user data, researchers put the encryption technology into their researches. However, the data in the IOT cloud storage environment has the characters of huge, heterogeneous and redundancy. And there are multiple user accesses in the IOT cloud storage environment. Even if storing the encrypted data in the IOT cloud server, existing searchable encryption scheme unable to search the encrypted data efficiently when the decrypting party is not sure.Thesis designs a public encryption of keys search based on the attribution encryption for the special application scenario-IOT cloud storage environment. This scheme not only can efficiently search the encrypted information in the cloud storage server under the environment of not trusted, but also doesn't leak any information related to plaintext to the cloud storage. This ensures the data security and user's privacy. It is also great to search information among different users fine-grain. The scheme has good flexibility and applicability in the condition of not having fixed decrypting party. The main work of thesis includes the following three aspects:1) Adding access control tree structure to improve the attribute based encryption algorithm. Constructing the algorithms of file encryption and file decryption based on the improved the attribute-based encryption algorithm. Through the attribute partition, the scheme can meet the needs of different user access to search in the IOT cloud storage environment. It can also control the contents when different users search it. The scheme has realized the data security of IOT cloud server and fine-grained access to search;2) Using symmetric encryption idea in the phase of the key encryption and the trapdoor generation. Designing an improved key encryption and trapdoor generation algorithm. And then analyzing the security of the algorithm. The traditional algorithm uses bilinear pairings to encrypt the key and generates the trapdoor using hash function. This results in the low efficiency of key encryption and trapdoor generation. The improved algorithm can effectively solve this problem;3) Applying the distributed technology to the design of server search algorithm, and establishing the index table of “keywords-files” in the side of sever. At last, putting forward the server search algorithm to adapt to the IOT cloud storage environment. Using the XOR(Exclusive OR) operation in the traditional server search algorithm to replace the bilinear pairing operation, in order to improving the efficiency of search server.The function test verifies the feasibility of public encryption of keys search based on the attribution encryption that is put forward in thesis. Then it shows the efficiency comparison diagram of the improved algorithm. Meanwhile, the scheme verifies the efficiency of the improved algorithm in thesis.