CCA-secure Anonymous Multi-receiver ID-based Encryption

Recently, Fan et al. proposed the first anonymous multi-receiver identity (ID)-based encryption (AMIBE) scheme to encrypt a message for multiple selected receivers while achieving anonymity. They claimed that nobody, except the sender, knows who the selected receivers are. However, their scheme has been shown that any selected receiver can extract the identities of the other selected receivers because their security model cannot capture the full requirement of receiver anonymity. In this article, we first re-define the security model of AMIBE. We then propose a new AMIBE scheme to achieve complete receiver anonymity. We prove that the proposed AMIBE scheme is semantically secure against adaptive chosen cipher text attacks (CCA). Comparisons are given to demonstrate the proposed AMIBE scheme´s advantages.