Modern collaborative and group-oriented applications typically involve communications over open networks. Given the openness of today’s networks, communications among group members must be secure and, at the same time, efficient. Group key agreement (GKA) is widely employed for secure group communications in modern collaborative and group-oriented applications. This paper studies the problem of GKA in identity-based cryptosystems with an emphasis on round-efficient, sender-unrestricted, member-dynamic, and provably secure key escrow freeness. The problem is resolved by proposing a one-round dynamic asymmetric GKA protocol which allows a group of members to dynamically establish a public group encryption key, while each member has a different secret decryption key in an identity-based cryptosystem. Knowing the group encryption key, any entity can encrypt to the group members so that only the members can decrypt. We construct this protocol with a strongly unforgeable stateful identity-based batch multisignature scheme. The proposed protocol is shown to be secure under the $k$ -bilinear Diffie–Hellman exponent assumption.

Round-Efficient and Sender-Unrestricted Dynamic Group Key Agreement Protocol for Secure Group Communications

Telemedicine offers medical services remotely via telecommunications systems and physiological monitoring devices. Group-oriented communication is an important application for telemedicine. However, transmission of information over an insecure channel such as Internet or private data storing generates a security problem. Therefore, authentication, confidentiality, and privacy are important challenges in telemedicine. Therefore, developing suitable encryption communication protocol for group communication is quite important for modern medicine. Group key agreement is one way to ensure the security of group-oriented communication for telemedicine. In this paper, we propose a dynamic and cross-domain authenticated asymmetric group key agreement. The protocol adopts cross-domain authentication mechanism to avoid the security risks of key escrow and the complexity of certificate management. It supports the dynamic group key update of nodes for forward secrecy and backward security of group key, and also achieving the key self-certified, the member participated group key agreement can self-certify whether the calculated group keys are correct. The protocol is proven secure under the inverse computational Diffie-Hellman problem assumption, and the performance analysis shows that the proposed scheme is highly efficient. The proposed scheme is more suitable for security group communication in telemedicine.

A Dynamic and Cross-Domain Authentication Asymmetric Group Key Agreement in Telemedicine Application

An authenticated asymmetric group key agreement based on attribute encryption

A hierarchical group key agreement protocol using orientable attributes for cloud computing

Group key agreement is a good way to ensure secure communication within a group. However, the identity authentication, privacy protection, and information sharing access control (different access rights may exist for different sensitivity of information) are key issues to be solved in group key agreement. Aiming at these problems, this paper proposes a group key agreement protocol based on privacy protection and attribute authentication (GKA-PPAA). The protocol proposes identity authentication for hidden attributes; it not only preserves the advantages of traditional identity-based key agreement protocol, but also provides hiding the identity information and privacy protection of the individual, and also proposes information sharing access control, which different secret information is shared among a set of members who have different levels of authority. It increases the flexibility of group key management. In addition, the group key factors are also calculated before the group key agreement, which eliminates most of the computation overhead due to the group key agreement. This protocol is proven secure under the discrete logarithm problem (DLP) and decisional bilinear Diffie-Hellman (DBDH) problem assumptions. The performance analysis shows that the proposed scheme is much more efficient than the existing ones.

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Group Key Agreement Protocol Based on Privacy Protection and Attribute Authentication

Group key agreement (GKA) is a cryptographic primitive allowing two or more users to negotiate a shared session key over public networks. Wu et al. recently introduced the concept of asymmetric GKA that allows a group of users to negotiate a common public key, while each user only needs to hold his/her respective private key. However, Wu et al.’s protocol can not resist active attacks, such as fabrication. To solve this problem, Zhang et al. proposed an authenticated asymmetric GKA protocol, where each user is authenticated during the negotiation process, so it can resist active attacks. Whereas, Zhang et al.’s protocol needs a partially trusted certificate authority to issue certificates, which brings a heavy certificate management burden. To eliminate such cost, Zhang et al. constructed another protocol in identity-based setting. Unfortunately, it suffers from the so-called key escrow problem. In this paper, we propose the certificateless authenticated asymmetric group key agreement protocol which does not have certificate management burden and key escrow problem. Besides, our protocol achieves known-key security, unknown key-share security, key-compromise impersonation security, and key control security. Our simulation based on the pairing-based cryptography (PBC) library shows that this protocol is efficient and practical.

Xianbo Yang

Papers

Efficient Certificateless Authenticated Asymmetric Group Key Agreement Protocol