Forward Secure Equality Test for Secure Data Sharing in Healthcare Systems

In healthcare systems, the protection of the sensitive data of patient during sharing across multiple entities is crucial. Encrypting these data before outsourcing to the healthcare server is an effective method to protect data privacy. As a solution to protect data sharing within healthcare systems, identity-based encryption with equality test (IBEET) is an effective strategy that allows testing whether two ciphertexts encrypted from the same plaintext without certificate management. However, current IBEET schemes often lack of control over the trapdoors’ lifetime, i.e., the malicious server could use trapdoor to test whether two ciphertext generated after the trapdoor encrypted by the same plaintext all the time, potentially leaking sensitive data which the user are unwilling to see. To address this problem, we introduce a forward secure IBEET (FS-IBEET) scheme. This new scheme prevents the malicious server from accessing useful information from newly encrypted files. We perform a thorough security analysis using the random oracle model under the q-BDHI assumption. Our experiments demonstrate that the performance of our scheme in comparison to other schemes.