Plaintext Checkable Encryption with Check Delegation: New Models and Simple Constructions

摘要

Plaintext-checkable encryption (PCE) provides an add-on check interface in addition to traditional public key encryption. It allows that given a target plaintext, a ciphertext and a public key, the check algorithm can check whether the ciphertext encrypts the target plaintext with the public key. With the functionality of checkability, PCE cannot achieve the CPA-security inherently. To make CPA security possible, we can change the system framework and then restrict that only the specific and authenticated checker can perform such the check algorithm. In addition, the sender who encrypts a message does not need to have any information or identity of any checker. In this paper, we achieve these goals by formally providing two new definitions, PCEAC and PCEDC. Accordingly, we propose two simple constructions.