Efficient Revocable Identity-Based Encryption with Equality Test

Identity-based encryption with equality test (IBEET) provides an attractive method to test whether two ciphertexts are encryptions of the same plaintext without certificate managements. However, none of the existing IBEET constructions can provide a way to revoke the user in the scenario where the user's private key is compromised or identity gets expired, which is undesirable for identity-based setting. Furthermore, the user cannot revoke the tester when it no longer wants the tester to test its ciphertexts. How to achieve both user and tester revocation in IBEET remains a challenging task. In this paper, we propose a new primitive called revocable identity-based encryption with equality test (R-IBEET), which can solve the aforementioned two problems simultaneously, and formalise the security models of R-IBEET against three types of adversaries. Then we propose a concrete construction of R-IBEET. Our scheme is pairing-free, thus is more efficient compared with the related work.