Fast query over encrypted data based on B+ tree

There are a lot of important and sensitive data in databases, which need to be protected from attacks. To secure the data, Cryptography support is an effective mechanism. However, a tradeoff must be made between the performance and the security because encryption and decryption greatly degrade the query performance. In this paper, a framework is proposed that can quickly implement query over encrypted data based on B⁺ tree. When data are stored in the form of cipher, it not only stores the encrypted data themselves, but also creates a B⁺ tree index for the data before encrypting them. When querying the encrypted data, firstly, it locates the encrypted records related to the querying predicate based on the B⁺ tree index; secondly, it decrypts the encrypted records to accomplish the results. Meanwhile, it must encrypt the B⁺ tree itself to protect it from leaking confidential information. According to the structure of the B⁺ tree, it encrypts each node of the B⁺ tree separately. The results of experiments show that the query performance over the encrypted data decreases about 20 percent compared with the plaintext query performance, and validate the functionality and usability of our approach.