Authorized Equality Test of Encrypted Data for Secure Cloud Databases
Sha Ma · 2018
Equality test is popular in the implementation of database operators, e.g., the keyword search or the natural join. For the privacy concern, public key encryption with equality test (PKEET) as a useful tool to query on the encrypted data has been introduced for the cloud computing in the recent years. In this paper, we propose a variant of PKEET to capture a new feature that only the specified users' ciphertexts could be compared by the cloud server under the users' authorization for the secure cloud database applications. The proposed scheme supports both the user-level authorization and the ciphertext-level authorization for the specified users. Our scheme has a noticeable property that the user is allowed to authorize a third party (e.g., a cloud server) to perform the three types of testing (all-to-all test, one-to-all test and one-to-one test) as well as to make the internal test by the specified users themselves. We prove that our scheme can achieve the IND-CCA security against the outside attack and the PRIV-P-CCA security against the inside attack under the random oracle model, where the latter case is stronger than OW-CCA in most related work.