Equality test with an anonymous authorization in cloud computing

With the rapid popularity and wide adoption of cloud storage, providing privacy-preserving by protecting sensitive information becomes a matter of grave concern. The most effective and sensible way to address this issue is to encrypt the data before uploading it to the cloud. However, to search over encrypted data with different keys is still an open problem when it comes to the deployment of emerging technologies such as healthcare applications and e-marketplace systems. To address these issues, in this paper, we proposed a secure and efficient public-key encryption with an equality test technique that supports anonymous authorization, abbreviated as (PKEET-AA). Our proposed scheme allows a specific user to identify who can perform the equality test process among various cloud servers without compromising sensitive information. It also provides an anonymous approach to search for some statistical information about specific identical encrypted records in several databases. Moreover, we prove that our proposed PKEET-AA scheme is one-way secure against chosen-ciphertext attack (OW-CCA) and undistinguishable against adaptive chosen ciphertext attack (IND-CCA) in the random oracle model. Thus, to provide authorization/multi-authorization anonymity under the Decisional Diffie–Hellman assumption.