In 2010, Fan et al. presented an anonymous multi-receiver identity-based encryption scheme where they adopt Lagrange interpolating polynomial mechanism. They showed that their scheme makes it impossible for an attacker or any other message receiver to derive the identity of a message receiver such that the privacy of every receiver can be guaranteed. They also formally showed that every receiver in the proposed scheme is anonymous to any other receiver. In this work, the authors study the security of Fan et al.'s anonymous multi-receiver identity-based encryption scheme. It is regretful that they found their scheme is insecure. Every receiver in Fan et al.'s scheme is not anonymous to any other receiver. The authors showed that simple protocol changes can fix these weaknesses and render Fan et al.'s scheme. The improved scheme is proved to satisfy the confidentiality and receiver anonymity in the random oracle.
In 2010, Fan et al. presented an anonymous multi-receiver identity-based encryption scheme where they adopt Lagrange interpolating polynomial mechanism. They showed that their scheme makes it impossible for an attacker or any other message receiver to derive the identity of a message receiver such that the privacy of every receiver can be guaranteed. They also formally showed that every receiver in the proposed scheme is anonymous to any other receiver. In this work, the authors study the security of Fan et al.'s anonymous multi-receiver identity-based encryption scheme. It is regretful that they found their scheme is insecure. Every receiver in Fan et al.'s scheme is not anonymous to any other receiver. The authors showed that simple protocol changes can fix these weaknesses and render Fan et al.'s scheme. The improved scheme is proved to satisfy the confidentiality and receiver anonymity in the random oracle.
Anonymous multi-receiver identity-based encryption can protect the receiver identity privacy and message confidentiality. Thus, it can be used in many fields, such as Voice over Internet Protocol and pay-TV systems. In 2012, Chien improved an anonymous multi-receiver identity-based encryption scheme. This paper points out that Chien's scheme does not satisfy the indistinguishability of encryptions under selective multi-identity, chosen ciphertext attacks. The analysis is important for understanding the security risks.
In a multi-receiver encryption system, a sender chooses a set of authorized receivers and sends them a message securely and efficiently, as the message is well encrypted and only one ciphertext corresponding to the message is generated no matter how many receivers the sender has chosen. It can be applied to video conferencing systems, pay-per-view channels, remote education, and so forth. Due to privacy considerations, an authorized receiver may not expect that his identity is revealed. In 2010, anonymous multi-receiver identity-based (ID-based) encryption was first discussed, and furthermore, many works on the topic have been presented so far. Unfortunately, we find that all of those schemes fail to prove the chosen ciphertext attacks (CCA) security in either confidentiality or anonymity. In this manuscript, we propose the first anonymous multi-receiver ID-based authenticated encryption scheme with CCA security in both confidentiality and anonymity. In the proposed scheme, the identity of the sender of a ciphertext can be authenticated by the receivers after a successful decryption. In addition, the proposed scheme also is the first CCA-secure one against insider attacks. Moreover, only one pairing computation is required in decryption.
Anonymous multi-receiver encryption (AME) achieves the security properties of confidentiality and anonymity. Thus, it can be used in VoIP (Voice over Internet Protocol), pay-TV systems, et al. In 2012, Zhang et al. proposed an efficient anonymous multi-receiver encryption protocol. They claimed that their protocol can protect the receiver identity privacy and keep message confidential. In this paper, we point out the weaknesses of Zhang et al.'s protocol. Their protocol cannot satisfy the anonymity against the inner attackers. On the other hand, their AME protocol cannot satisfy the indistinguishability of encryptions under selective multi-identity, chosen ciphertext attacks (IND-AME-CCA). Thus, Zhang et al.'s protocol is insecure. The analysis is important for the engineer to mitigate the security risks.
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.
In 2010, Fan et al. first introduced the concept of anonymous multi-receiver identity-based encryption (AMRIBE). They used the concept of Fujisaki–Okamoto transformation (F.O. transformation) to support their proof in random oracle models. Recently, many works on this topic have been proposed. Most of them adopted Fujisaki–Okamoto transformation to achieve the indistinguishability of encryptions under multi-ID, chosen-ciphertext attacks (IND-MID-CCA) security. However, we find out that these schemes do not gain anonymity against insider attacks. In this manuscript, we use a sequence of games to prove that any AMRIBE scheme will fail to gain anonymity under chosen-ciphertext attacks and chosen-plaintext attacks if the IND-MID-CCA security is proven using Fujisaki–Okamoto transformation.